Title Page
Life The Science of Biology
The Vision of Life: The Science of Biology
Life is ENGAGING
Life is ACTIVE
Life is FOCUSED ON SKILLS
Life in LAUNCHPAD
Life and ASSESSMENT
Life is VISUAL
Life is CURRENT
Acclaim for Life
Authors
Acknowledgments
Reviewers and Contributors
Media and Supplements
Investigating Life: Corals in Hot Water
Key Concept 1.1 Living Organisms Share Similarities and a Common Origin
Life arose from non-life via chemical evolution
Cellular structure evolved in the common ancestor of life
Photosynthesis allows some organisms to capture energy from the sun
Biological information is stored in a genetic code common to all organisms
Populations of all living organisms evolve
Biologists trace the evolutionary tree of life
Cellular differentiation and specialization underlie multicellular life
Organisms extract energy and raw materials from the environment
Living organisms must regulate their internal environment
Living organisms interact
1.1 recap
Key Concept 1.2 Biologists Investigate Life through Experiments That Test Hypotheses
Observing and quantifying are important skills
Scientific methods combine observation, experimentation, and logic
Good experiments have the potential to falsify hypotheses
Statistical methods are essential scientific tools
Discoveries in biology can be generalized
Not all forms of inquiry are scientific
1.2 recap
Key Concept 1.3 Understanding Biology Is Important for Health, Well-Being, and Public-Policy Decisions
Modern agriculture depends on biology
Biology is the basis of medical practice
Biology can inform public policy
Biology is crucial for understanding ecosystems
Biodiversity helps us understand, enjoy, and appreciate our world
1.3 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: Tracking a Dinosaur
Key Concept 2.1 Atomic Structure Explains the Properties of Matter
What are atoms?
An element consists of only one kind of atom
Each element has a unique number of protons
The number of neutrons differs among isotopes
The behavior of electrons determines chemical bonding and geometry
2.1 recap
Key Concept 2.2 Atoms Bond to Form Molecules
Covalent bonds consist of shared pairs of electrons
Ionic attractions form by electrical attraction
Hydrogen bonds may form within or between molecules with polar covalent bonds
Hydrophobic interactions bring together nonpolar molecules
van der Waals forces involve contacts between atoms
2.2 recap
Key Concept 2.3 Atoms Change Partners in Chemical Reactions
2.3 recap
Key Concept 2.4 Water Is Critical for Life
Water has a unique structure and special properties
The reactions of life take place in aqueous solutions
Aqueous solutions may be acidic or basic
2.4 recap
Investigating Life
Chapter Summary
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Investigating Life: Weaving a Web
Key Concept 3.1 Macromolecules Characterize Living Things
Chemical groupings determine the structures of macromolecules
The structures of macromolecules reflect their functions
Most macromolecules are formed by condensation and broken down by hydrolysis
3.1 recap
Key Concept 3.2 The Function of a Protein Depends on Its Three-Dimensional Structure
Monomers of proteins link together to make the macromolecule
Peptide linkages form the backbone of a protein
The primary structure of a protein is its amino acid sequence
The secondary structure of a protein requires hydrogen bonding
The tertiary structure of a protein is formed by bending and folding
The quaternary structure of a protein consists of subunits
Shape and surface chemistry contribute to protein function
Environmental conditions affect protein structure
Protein shapes can change
Molecular chaperones help shape proteins
3.2 recap
Key Concept 3.3 Simple Sugars Are the Basic Structural Unit of Carbohydrates
Monosaccharides are simple sugars
Glycosidic linkages bond monosaccharides
Polysaccharides store energy and provide structural materials
Chemically modified carbohydrates contain additional functional groups
3.3 recap
Key Concept 3.4 Lipids Are Defined by Their Solubility Rather Than by Chemical Structure
Fats and oils are triglycerides
Phospholipids form biological membranes
Some lipids have roles in energy conversion, regulation, and protection
3.4 recap
Investigating Life
Chapter Summary
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Investigating Life: Looking for Life
Key Concept 4.1 Nucleic Acid Structures Reflect Their Functions
Nucleic acids are informational macromolecules
Base pairing occurs in both DNA and RNA
DNA carries information and is expressed through RNA
The DNA base sequence reveals evolutionary relationships
Nucleotides have other important roles
4.1 recap
Key Concept 4.2 The Small Molecules of Life Originated on Primitive Earth
Living organisms do not repeatedly come from inanimate nature
Life began in water
Prebiotic synthesis experiments model early Earth
Life may have come from outside Earth
4.2 recap
Key Concept 4.3 The Large Molecules of Life Originated from Small Molecules
Complex molecules could be formed from simpler ones on primitive Earth
RNA may have been the first biological catalyst
4.3 recap
Key Concept 4.4 Cells Originated from Their Molecular Building Blocks
How did the first cells with membranes come into existence?
Some ancient cells left a fossil imprint
4.4 recap
Investigating Life
Chapter Summary
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Investigating Life: Natural Sunscreen
Key Concept 5.1 Cells Are the Fundamental Units of Life
What is the cell theory?
Cell size is limited by the surface area-to-volume ratio
Microscopes reveal the features of cells
The cell membrane forms an outer boundary of every cell
Cells may be classified as either prokaryotic or eukaryotic
5.1 recap
Key Concept 5.2 Prokaryotic Cells Are the Simplest Cells
What are the features of prokaryotic cells?
Specialized features are found in some prokaryotes
5.2 recap
Key Concept 5.3 Eukaryotic Cells Contain Organelles
Compartmentalization is important to eukaryotic cell function
Organelles can be studied by microscopy or isolated for chemical analysis
Ribosomes are factories for protein synthesis
The nucleus contains most of the genetic information
The endomembrane system is a group of interrelated organelles
Some organelles transform energy
There are several other membrane-enclosed organelles
The cytoskeleton is important in cell structure and movement
Biologists can manipulate living systems to establish cause and effect
5.3 recap
Key Concept 5.4 Extracellular Structures Have Important Roles
What is the plant cell wall?
The extracellular matrix supports tissue functions in animals
5.4 recap
Key Concept 5.5 Eukaryotic Cells Evolved in Several Steps
Internal membranes and the nuclear envelope probably came from the cell membrane
Some organelles arose by endosymbiosis
5.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Sweating and Membranes
Key Concept 6.1 Biological Membranes Are LipidâProtein Bilayers
Lipids form the hydrophobic core of the membrane
Membrane proteins are asymmetrically distributed
Membranes are constantly changing
Cell membrane carbohydrates are recognition sites
6.1 recap
Key Concept 6.2 The Cell Membrane Is Important in Cell Adhesion and Recognition
Cell recognition and adhesion involve proteins and carbohydrates at the cell surface
Three types of cell junctions connect adjacent cells
Cell membranes adhere to the extracellular matrix
6.2 recap
Key Concept 6.3 Substances Can Cross Membranes by Passive Processes
Diffusion is the process of random movement toward a state of equilibrium
Simple diffusion takes place through the phospholipid bilayer
Osmosis is the diffusion of water across membranes
Diffusion may be aided by channel proteins
Carrier proteins aid diffusion by binding substances
6.3 recap
Key Concept 6.4 Active Transport across Membranes Requires Energy
Active transport is directional
Different energy sources distinguish different active transport systems
6.4 recap
Key Concept 6.5 Large Molecules Enter and Leave a Cell through Vesicles
Macromolecules and particles enter the cell by endocytosis
Receptor-mediated endocytosis is highly specific
Exocytosis moves materials out of the cell
6.5 recap
Investigating Life
Chapter Summary
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Investigating Life: A Signal for Bonding
Key Concept 7.1 Signals and Signaling Affect Cell Function
Cells receive several types of signals
A signal transduction pathway involves a signal, a receptor, and responses: Overview
7.1 recap
Key Concept 7.2 Receptors Bind Signals to Initiate a Cellular Response
Receptors that recognize chemical signals have specific binding sites
Receptors can be classified by location and function
Intracellular receptors are located in the cytoplasm or the nucleus
7.2 recap
Key Concept 7.3 The Response to a Signal Spreads through the Cell
The cell amplifies its response to ligand binding
Second messengers can amplify signals between receptors and target molecules
Signal transduction is highly regulated
7.3 recap
Key Concept 7.4 Cells Change in Response to Signals in Several Ways
Ion channels respond to signals by opening or closing
Enzyme activities change in response to signals
Signals can initiate DNA transcription
7.4 recap
Key Concept 7.5 Adjacent Cells in a Multicellular Organism Can Communicate Directly
How do animal cells directly communicate?
Plant cells communicate through plasmodesmata
Modern organisms provide clues about the evolution of cell-cell interactions and multicellularity
7.5 recap
Investigating Life
Chapter Summary
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Investigating Life: How Aspirin Works
Key Concept 8.1 Physical Principles Underlie Biological Energy Transformations
There are two basic types of energy
There are two basic types of metabolism
The first law of thermodynamics: Energy is neither created nor destroyed
The second law of thermodynamics: Disorder tends to increase
Chemical reactions release or consume energy
Chemical equilibrium and free energy are related
8.1 recap
Key Concept 8.2 ATP Plays a Key Role in Biochemical Energetics
ATP hydrolysis releases energy
ATP couples exergonic and endergonic reactions
8.2 recap
Key Concept 8.3 Enzymes Speed Up Biochemical Transformations
To speed up a reaction, an energy barrier must be overcome
Enzymes bind specific reactants at their active sites
Enzymes lower the energy barrier but do not affect equilibrium
8.3 recap
Key Concept 8.4 Enzymes Bring Substrates Together so Reactions Readily Occur
Enzymes can orient substrates
Enzymes can induce strain in the substrate
Enzymes can temporarily add chemical groups to substrates
Molecular structure determines enzyme function
Not all enzymes are proteins
Some enzymes require other molecules in order to function
The substrate concentration affects the reaction rate
8.4 recap
Key Concept 8.5 Enzyme Activities Can Be Regulated
Enzymes can be regulated by inhibitors
Allosteric enzymes are controlled via changes in shape
Allosteric effects regulate many metabolic pathways
Many enzymes are regulated through reversible phosphorylation
Enzymes are affected by their environment
8.5 recap
Investigating Life
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Investigating Life: A Weighty Matter
Key Concept 9.1 Cells Harvest Chemical Energy from Glucose Oxidation
How do cells obtain energy from glucose?
Redox reactions transfer electrons and energy
The coenzyme NAD+ is a key electron carrier in redox reactions
An overview: Harvesting energy from glucose
9.1 recap
Key Concept 9.2 In the Presence of Oxygen, Glucose Is Fully Oxidized
In the glycolysis pathway, glucose is partially oxidized
Pyruvate oxidation links glycolysis and the citric acid cycle
The citric acid cycle completes the oxidation of glucose to CO2
Pyruvate oxidation and the citric acid cycle are regulated by the concentrations of starting materials
9.2 recap
Key Concept 9.3 Oxidative Phosphorylation Forms ATP
What are the steps in oxidative phosphorylation?
The respiratory chain transfers electrons and protons, and releases energy
ATP is made through chemiosmosis
Experiments demonstrate chemiosmosis
Some microorganisms use non-O2 electron acceptors
9.3 recap
Key Concept 9.4 In the Absence of Oxygen, Some Energy Is Harvested from Glucose
Cellular respiration yields much more energy than fermentation
The yield of ATP is reduced by the impermeability of mitochondria to NADH
9.4 recap
Key Concept 9.5 Metabolic Pathways Are Interrelated and Regulated
Catabolism and anabolism are linked
Catabolism and anabolism are integrated
Metabolic pathways are regulated systems
9.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Saving FACE
Key Concept 10.1 Photosynthesis Uses Light to Make Carbohydrates
Photosynthesis involves light and gas exchange
Experiments with isotopes show that O2 comes from H2O in oxygenic photosynthesis
Photosynthesis involves two pathways
10.1 recap
Key Concept 10.2 Photosynthesis Converts Light Energy into Chemical Energy
Light energy is absorbed by pigments in photosynthesis
Light absorption results in photochemical change
Reduction leads to ATP and NADPH formation
Chemiosmosis is the source of the ATP produced in photophosphorylation
10.2 recap
Key Concept 10.3 Chemical Energy Trapped in Photosynthesis Is Used to Synthesize Carbohydrates
How were the steps in carbohydrate synthesis elucidated?
The Calvin cycle is made up of three processes
Light stimulates the Calvin cycle
10.3 recap
Key Concept 10.4 Plants Have Adapted Photosynthesis to Environmental Conditions
How do some plants overcome the limitations of CO2 fixation?
C3 plants undergo photorespiration but C4 plants do not
CAM plants also use PEP carboxylase
10.4 recap
Key Concept 10.5 Photosynthesis Is an Integral Part of Plant Metabolism
Photosynthesis interacts with other metabolic pathways
10.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Immortal Cells
Key Concept 11.1 All Cells Derive from Other Cells
Prokaryotes divide by binary fission
Eukaryotic cells divide by mitosis followed by cytokinesis
11.1 recap
Key Concept 11.2 The Eukaryotic Cell Division Cycle Is Regulated
Specific internal signals trigger events in the cell cycle
Growth factors can stimulate cells to divide
11.2 recap
Key Concept 11.3 Eukaryotic Cells Divide by Mitosis
The centrosomes determine the plane of cell division
The spindle begins to form during prophase
Chromosome separation and movement are highly organized
Cytokinesis divides the cytoplasm
11.3 recap
Key Concept 11.4 Cell Division Plays Important Roles in the Sexual Life Cycle
Sexual life cycles produce haploid and diploid cells
11.4 recap
Key Concept 11.5 Meiosis Leads to the Formation of Gametes
Meiosis reduces the chromosome number
Chromatid exchanges during meiosis I generate genetic diversity
During meiosis homologous chromosomes separate by independent assortment
Meiotic errors lead to abnormal chromosome structures and numbers
The number, shapes, and sizes of the metaphase chromosomes constitute the karyotype
Polyploids have more than two complete sets of chromosomes
11.5 recap
Key Concept 11.6 Cell Death Is Important in Living Organisms
Programmed cell death removes cells that do not benefit the organism
11.6 recap
Key Concept 11.7 Unregulated Cell Division Can Lead to Cancer
Cancer cells differ from normal cells in important ways
Cancer cells lose control over the cell cycle and apoptosis
Cancer treatments target the cell cycle
11.7 recap
Investigating Life
Chapter Summary
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Investigating Life: What Are the Rules of Inheritance?
Key Concept 12.1 Inheritance of Genes Follows Mendelian Laws
Mendel's laws arose from controlled crosses of pea plants
Mendel's first experiments involved monohybrid crosses
Mendel's first law states that the two copies of a gene segregate
Mendel verified his hypotheses by performing test crosses
Mendel's second law states that copies of different genes assort independently
Probability can be used to predict inheritance
Mendel's laws can be observed in human pedigrees
12.1 recap
Key Concept 12.2 Alleles Can Produce Multiple Phenotypes
New alleles arise by mutation
Many genes have multiple alleles
Dominance is not always complete
In codominance, both alleles at a locus are expressed
Some alleles have multiple phenotypic effects
12.2 recap
Key Concept 12.3 Genes Can Interact to Produce a Phenotype
Hybrid vigor results from new gene combinations and interactions
The environment affects gene action
Most complex phenotypes are determined by multiple genes and the environment
12.3 recap
Key Concept 12.4 Genes Are Carried on Chromosomes
Linked genes are inherited together
Genes can be exchanged between chromatids and mapped
Linkage is revealed by studies of the sex chromosomes
12.4 recap
Key Concept 12.5 Some Eukaryotic Genes Are Outside the Nucleus
12.5 recap
Key Concept 12.6 Prokaryotes Can Transmit Genes by Mating
Bacteria exchange genes by conjugation
Bacterial conjugation is controlled by plasmids
12.6 recap
Investigating Life
Chapter Summary
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Investigating Life: Targeting DNA Replication in Cancer Therapy
Key Concept 13.1 Experiments Revealed the Function of DNA as Genetic Material
Circumstantial evidence indicates that the genetic material is DNA
DNA from one type of bacterium genetically transforms another type
Viral infection experiments confirmed that DNA is the genetic material
Eukaryotic cells can also be genetically transformed by DNA
13.1 recap
Key Concept 13.2 DNA Has a Structure That Suits Its Function
How did Watson and Crick deduce the structure of DNA?
Four key features define DNA structure
The double-helical structure of DNA is essential to its function
13.2 recap
Key Concept 13.3 DNA Is Replicated Semiconservatively
An elegant experiment demonstrated that DNA replication is semiconservative
There are two steps in DNA replication
DNA polymerases add nucleotides to the growing chain
Many other proteins assist with DNA polymerization
The two DNA strands grow differently at the replication fork
Telomeres are not fully replicated and are prone to repair
13.3 recap
Key Concept 13.4 Errors in DNA Can Be Repaired
Repair mechanisms preserve DNA
13.4 recap
Key Concept 13.5 The Polymerase Chain Reaction Amplifies DNA
The polymerase chain reaction can make multiple copies of a DNA sequence
13.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Employing the Genetic Code to Combat Superbugs
Key Concept 14.1 Genes Code for Proteins
Observations in humans led to the proposal that genes determine enzymes
Experiments on bread mold established that genes determine enzymes
One gene determines one polypeptide
14.1 recap
Key Concept 14.2 Information Flows from Genes to Proteins
Three types of RNA have roles in the information flow from DNA to protein
In some cases, RNA determines the sequence of DNA
14.2 recap
Key Concept 14.3 DNA Is Transcribed to Produce RNA
RNA polymerases share common features
Transcription occurs in three steps
The genetic code specifies which amino acids will be included in the polypeptide
14.3 recap
Key Concept 14.4 Eukaryotic Pre-mRNA Transcripts Are Processed prior to Translation
Noncoding sequences called introns often appear between genes in eukaryotic chromosomes
Pre-mRNA processing prepares the mRNA transcript for translation
14.4 recap
Key Concept 14.5 The Information in mRNA Is Translated into Proteins
A transfer RNA carries a specific amino acid and binds to a specific mRNA codon
Each tRNA is specifically attached to an amino acid
The ribosome is the workbench for translation
Translation takes place in three steps
Polysome formation increases the rate of protein synthesis
14.5 recap
Key Concept 14.6 Polypeptides Can Be Modified and Transported during or after Translation
How are proteins directed to their cellular destinations?
Mitochondria and chloroplasts make some of their own proteins and import others
Many proteins are modified after translation
14.6 recap
Investigating Life
Chapter Summary
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Investigating Life: The Angelina Jolie Effect
Key Concept 15.1 Mutations Are Heritable Changes in DNA
Mutations have different phenotypic effects
Point mutations are changes in single nucleotides
Chromosomal mutations are extensive changes in the genetic material
Retroviruses and transposons can cause loss-of-function mutations or duplications
Mutations can be spontaneous or induced
Mutagens can be natural or artificial
Some base pairs are more vulnerable than others to mutation
Mutations have both benefits and costs
15.1 recap
Key Concept 15.2 Mutations in Humans Can Lead to Diseases
Disease-causing mutations may make proteins dysfunctional
Disease-causing mutations may involve any number of base pairs
Expanding triplet repeats demonstrate the fragility of some human genes
Cancer often involves somatic mutations
Most diseases are caused by multiple genes and environment
15.2 recap
Key Concept 15.3 Mutations Can Be Detected and Analyzed
Cleavage of DNA by restriction enzymes can be used to rapidly detect mutations
Gel electrophoresis separates DNA fragments
DNA fingerprinting combines PCR with restriction analysis and electrophoresis
DNA analysis can be used to identify mutations that lead to disease
Genetic markers can be used to find disease-causing genes
15.3 recap
Key Concept 15.4 Genetic Screening Is Used to Detect Diseases
Genetic screening can be done by examining the phenotype
DNA testing is the most accurate way to detect abnormal genes
Allele-specific oligonucleotide hybridization can detect mutations
15.4 recap
Key Concept 15.5 Genetic Diseases Can Be Treated
Genetic diseases can be treated by modifying the phenotype
Gene therapy offers the hope of specific treatments
15.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Gene Expression and Behavior
Key Concept 16.1 Prokaryotic Gene Expression Is Regulated in Operons
Regulating gene transcription conserves energy
Operons are units of transcriptional regulation in prokaryotes
Operator-repressor interactions control transcription in the lac and trp operons
Protein synthesis can be controlled by increasing promoter efficiency
RNA polymerases can be directed to particular classes of promoters
16.1 recap
Key Concept 16.2 Eukaryotic Gene Expression Is Regulated by Transcription Factors
General transcription factors act at eukaryotic promoters
Specific proteins can recognize and bind to DNA sequences and regulate transcription
Specific protein-DNA interactions underlie binding
Transcription factors underlie cell differentiation
The expression of sets of genes can be coordinately regulated by transcription factors
16.2 recap
Key Concept 16.3 Viruses Regulate Their Gene Expression during the Reproductive Cycle
Viruses undertake two kinds of reproductive cycles
Eukaryotic viruses can have complex life cycles
HIV gene regulation occurs at the level of transcription elongation
16.3 recap
Key Concept 16.4 Epigenetic Changes Regulate Gene Expression
DNA methylation occurs at the promoter and silences transcription
Histone protein modifications affect transcription
Epigenetic changes can be induced by the environment
Global chromosome changes involve DNA methylation
16.4 recap
Key Concept 16.5 Eukaryotic Gene Expression Can Be Regulated after Transcription
RNA splicing can result in different mRNAs being made from the same gene
Small RNAs are important regulators of gene expression
Translation of mRNA can be regulated by proteins
16.5 recap
Investigating Life
Chapter Summary
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Investigating Life: The Dog Genome Project
Key Concept 17.1 Genomes Can Be Sequenced Rapidly
The base sequence of a short DNA fragment can be determined quickly
Genome sequences yield several kinds of information
17.1 recap
Key Concept 17.2 Prokaryotic Genomes Are Compact
Prokaryotic genomes have distinctive features
The sequencing of prokaryotic and viral genomes has many potential benefits
Metagenomics allows us to describe new organisms and ecosystems
Some sequences of DNA can move about the genome
Will defining the genes required for cellular life lead to artificial life?
17.2 recap
Key Concept 17.3 Eukaryotic Genomes Contain Many Types of Sequences
Genome sequences of model organisms provide important information
Eukaryotes have gene families
Eukaryotic genomes contain repetitive sequences
17.3 recap
Key Concept 17.4 Human Biology Is Revealed through the Genome
Comparative genomics reveals the evolution of the human genome
Human genomics has potential benefits in medicine
17.4 recap
Key Concept 17.5 Proteomics and Metabolomics Can Provide Insights beyond the Genome
The proteome is the complete set of proteins in a cell, tissue, or organism at a given time
Metabolomics is the study of chemical phenotype
17.5 recap
Investigating Life
Chapter Summary
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Investigating Life: DNA Technology Meets Medicine
Key Concept 18.1 DNA from Different Sources Forms Recombinant DNA
18.1 recap
Key Concept 18.2 There Are Several Ways to Insert DNA into Cells
Selectable genetic markers are used to identify host cells containing recombinant DNA
Genes can be inserted into prokaryotic or eukaryotic cells
Inserted DNA is usually integrated into the host chromosome
Reporter genes help select or identify host cells containing recombinant DNA
18.2 recap
Key Concept 18.3 Any Sequence of DNA Can Be Used for Cloning
DNA for cloning can come from a library
cDNA is made from mRNA transcripts
Synthetic DNA can be made by PCR or by organic chemistry
18.3 recap
Key Concept 18.4 Several Tools Are Used to Modify DNA and Study Its Function
Gene expression can be modulated by DNA technology
DNA mutations can be created in the laboratory
Genes can be inactivated and changed by CRISPR technology
Complementary RNA can prevent the expression of specific genes
DNA microarrays reveal RNA expression patterns
18.4 recap
Key Concept 18.5 DNA Can Be Manipulated for Human Benefit
Cells can be turned into factories for a desired protein
Medically useful proteins can be made using biotechnology
DNA manipulation is changing agriculture
Synthetic biology can create living factories for new products
There is public concern about biotechnology
18.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Stem Cell Therapy
Key Concept 19.1 The Four Major Processes of Development Are Determination, Differentiation, Morphogenesis, and Growth
Development involves four distinct but overlapping processes
As development proceeds, cell fates become restricted
Cell differentiation is sometimes reversible
Multipotent stem cells differentiate in response to environmental signals
Pluripotent stem cells can be obtained in two ways
19.1 recap
Key Concept 19.2 Gene Expression Differences Determine Cell Fate and Cell Differentiation
Cytoplasmic segregation can determine cell fate
Inducers passing from one cell to another can determine cell fate
Differential gene transcription is a hallmark of cell differentiation
19.2 recap
Key Concept 19.3 Gene Expression Determines Morphogenesis and Pattern Formation
Morphogen gradients provide positional information
Expression of transcription factor genes determines organ differentiation in plants
A cascade of transcription factors establishes body segmentation in the fruit fly
19.3 recap
Key Concept 19.4 Changes in Gene Expression Underlie the Evolution of Development
What is evo-devo?
Developmental genes in distantly related organisms are similar
Genetic switches govern how the genetic toolkit is used
Modularity allows for differences in the patterns of gene expression
19.4 recap
Key Concept 19.5 Developmental Gene Changes Can Shape Evolution
Mutations in developmental genes can cause major morphological changes
Conserved developmental genes can lead to parallel evolution
19.5 recap
Investigating Life
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Investigating Life: An Evolutionary Arms Race Between Bats and Moths
Key Concept 20.1 Evolution Is Both Factual and the Basis of Broader Theory
Darwin and Wallace introduced the idea of evolution by natural selection
20.1 recap
Key Concept 20.2 Mutation, Selection, Gene Flow, Genetic Drift, and Nonrandom Mating Result in Evolution
Mutation generates genetic variation
Selection acting on genetic variation leads to new phenotypes
Natural selection increases the frequency of beneficial mutations in populations
Gene flow may change allele frequencies
Genetic drift may cause large changes in small populations
Nonrandom mating can change genotype or allele frequencies
20.2 recap
Key Concept 20.3 Evolution Can Be Measured by Changes in Allele Frequencies
Evolution will occur unless certain restrictive conditions exist
Deviations from HardyâWeinberg equilibrium show that evolution is occurring
20.3 recap
Key Concept 20.4 Selection Can Be Stabilizing, Directional, or Disruptive
Stabilizing selection reduces variation in populations
Directional selection favors one extreme
Disruptive selection favors extremes over the mean
20.4 recap
Key Concept 20.5 Multiple Factors Account for the Maintenance of Variation in Populations
Neutral mutations accumulate in populations
Sexual recombination amplifies the number of possible genotypes
Frequency-dependent selection maintains genetic variation within populations
Heterozygote advantage maintains polymorphic loci
Genetic variation within species is maintained in geographically distinct populations
20.5 recap
Key Concept 20.6 Evolution Is Constrained by History and Trade-Offs
Developmental processes constrain evolution
Trade-offs constrain evolution
Short-term and long-term evolutionary outcomes sometimes differ
20.6 recap
Investigating Life
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Investigating Life: Using Phylogeny to Improve a Genetic Tool
Key Concept 21.1 All of Life Is Connected through Its Evolutionary History
Phylogenetic trees are the basis of comparative biology
Derived traits provide evidence of evolutionary relationships
21.1 recap
Key Concept 21.2 Phylogeny Can Be Reconstructed from Traits of Organisms
Parsimony provides the simplest explanation for phylogenetic data
Phylogenies are reconstructed from many sources of data
Mathematical models expand the power of phylogenetic reconstruction
The accuracy of phylogenetic methods can be tested
21.2 recap
Key Concept 21.3 Phylogeny Makes Biology Comparative and Predictive
Phylogenetic trees can be used to reconstruct past events
Phylogenies allow us to compare and contrast living organisms
Phylogenies can reveal convergent evolution
Ancestral states can be reconstructed
Molecular clocks help date evolutionary events
21.3 recap
Key Concept 21.4 Phylogeny Is the Basis of Biological Classification
Evolutionary history is the basis for modern biological classification
Several codes of biological nomenclature govern the use of scientific names
21.4 recap
Investigating Life
Chapter Summary
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Investigating Life: Rapid Speciation in African Lake Cichlids
Key Concept 22.1 Species Are Reproductively Isolated Lineages on the Tree of Life
We can recognize many species by their appearance
Reproductive isolation is key
The lineage approach takes a long-term view
The different species concepts are not mutually exclusive
22.1 recap
Key Concept 22.2 Speciation Is a Natural Consequence of Population Subdivision
Incompatibilities between genes can produce reproductive isolation
Reproductive isolation develops with increasing genetic divergence
22.2 recap
Key Concept 22.3 Speciation May Occur through Geographic Isolation or in Sympatry
Physical barriers give rise to allopatric speciation
Sympatric speciation occurs without physical barriers
22.3 recap
Key Concept 22.4 Reproductive Isolation Is Reinforced When Diverging Species Come into Contact
Prezygotic isolating mechanisms prevent hybridization
Postzygotic isolating mechanisms result in selection against hybridization
Hybrid zones may form if reproductive isolation is incomplete
22.4 recap
Key Concept 22.5 Speciation Rates Are Highly Variable across Life
Several ecological and behavioral factors influence speciation rates
Rapid speciation can lead to adaptive radiation
22.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Evolutionary Theory Helps Us Make Better Flu Vaccines
Key Concept 23.1 DNA Sequences Record the History of Gene Evolution
Evolution of genomes results in biological diversity
Genes and proteins are compared through sequence alignment
Models of sequence evolution are used to calculate evolutionary divergence
Experimental studies examine molecular evolution directly
23.1 recap
Key Concept 23.2 Genomes Reveal Both Neutral and Selective Processes of Evolution
Much of evolution is neutral
Positive and purifying selection can be detected in the genome
Genome size also evolves
23.2 recap
Key Concept 23.3 Lateral Gene Transfer and Gene Duplication Can Produce Major Changes
Lateral gene transfer can result in the gain of new functions
Most new functions arise following gene duplication
Some gene families evolve through concerted evolution
23.3 recap
Key Concept 23.4 Molecular Evolution Has Many Practical Applications
Molecular sequence data are used to determine the evolutionary history of genes
Gene evolution is used to study protein function
In vitro evolution is used to produce new molecules
Molecular evolution is used to study and combat diseases
23.4 recap
Investigating Life
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Investigating Life: When Giant Insects Ruled the Skies
Key Concept 24.1 Events in Earth's History Can Be Dated
Radioisotopes provide a way to date fossils and rocks
Radiometric dating methods have been expanded and refined
Scientists have used several methods to construct a geological time scale
24.1 recap
Key Concept 24.2 Changes in Earth's Physical Environment Have Affected the Evolution of Life
Earth's continents and climates have changed over time
Earth's climate has shifted between hot and cold conditions
Volcanoes have occasionally changed the history of life
Extraterrestrial events have triggered changes on Earth
Oxygen concentrations in Earth's atmosphere have changed over time
Extinction happens continuously, but mass extinctions result from sudden environmental changes
24.2 recap
Key Concept 24.3 Major Events in the Evolution of Life Can Be Read in the Fossil Record
Several processes contribute to the paucity of fossils
Precambrian life was small and aquatic
Life expanded rapidly during the Cambrian period
Many groups of organisms that arose during the Cambrian later diversified
Geographic differentiation increased during the Mesozoic era
Modern biotas evolved during the Cenozoic era
The tree of life is used to reconstruct evolutionary events
24.3 recap
Investigating Life
Chapter Summary
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Investigating Life: Bacteria Light Up the Sea
Key Concept 25.1 Bacteria and Archaea Are the Two Primary Divisions of Life
The two prokaryotic domains differ in significant ways
The small size of prokaryotes has hindered our study of their evolutionary relationships
The nucleotide sequences of prokaryotes reveal their evolutionary relationships
Lateral gene transfer can lead to discordant gene trees
The great majority of prokaryote species have never been studied
25.1 recap
Key Concept 25.2 Prokaryote Diversity Reflects the Ancient Origins of Life
Two early-branching lineages of bacteria live at very high temperatures
Firmicutes include some of the smallest cellular organisms
Actinobacteria include major pathogens as well as valuable sources of antibiotics
Cyanobacteria were the first photosynthesizers
Spirochetes move by means of axial filaments
Chlamydias are extremely small parasites
The proteobacteria are a large and diverse group
Gene sequencing enabled biologists to differentiate Archaea from Bacteria
Prokaryotic archaea live in extremely diverse environments
25.2 recap
Key Concept 25.3 Ecological Communities Depend on Prokaryotes
Many prokaryotes form complex communities
Microbiomes are critical to the health of many eukaryotes
A small minority of bacteria are pathogens
Prokaryotes have amazingly diverse metabolic pathways
Prokaryotes play important roles in element cycling
25.3 recap
Key Concept 25.4 Viruses Have Evolved Many Times
Many RNA viruses probably represent escaped genomic components of cellular life
Some DNA viruses may have evolved from reduced cellular organisms
Viruses can be used to fight bacterial infections
25.4 recap
Investigating Life
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Investigating Life: Predicting Toxic Red Tides
Key Concept 26.1 Eukaryotes Acquired Features from Both Archaea and Bacteria
The modern eukaryotic cell arose in several steps
Chloroplasts have been transferred among eukaryotes several times
26.1 recap
Key Concept 26.2 Major Lineages of Eukaryotes Diversified in the Precambrian
Alveolates have sacs under their cell membranes
Stramenopiles typically have two unequal flagella, one with hairs
Rhizarians typically have long, thin pseudopods
Excavates began to diversify about 1.5 billion years ago
Amoebozoans use lobe-shaped pseudopods for locomotion
26.2 recap
Key Concept 26.3 Protists Reproduce Sexually and Asexually
Some protists reproduce without sex and have sex without reproduction
Some protist life cycles feature alternation of generations
26.3 recap
Key Concept 26.4 Protists Are Critical Components of Many Ecosystems
Phytoplankton are primary producers
Some microbial eukaryotes are deadly
Some microbial eukaryotes are endosymbionts
We rely on the remains of ancient marine protists
26.4 recap
Investigating Life
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Investigating Life: A Toxic Spill of Ancient Fossil Algae
Key Concept 27.1 Primary Endosymbiosis Produced the First Photosynthetic Eukaryotes
Several distinct clades of algae were among the first photosynthetic eukaryotes
Two groups of green algae are the closest relatives of land plants
There are ten major groups of land plants
27.1 recap
Key Concept 27.2 Key Adaptations Permitted Plants to Colonize Land
Adaptations to life on land distinguish land plants from green algae
Life cycles of land plants feature alternation of generations
Nonvascular land plants live where water is readily available
The sporophytes of nonvascular land plants are dependent on the gametophytes
Liverworts are the sister clade of the remaining land plants
Water and sugar transport mechanisms emerged in the mosses
Hornworts have distinctive chloroplasts and stalkless sporophytes
27.2 recap
Key Concept 27.3 Vascular Tissues Led to Rapid Diversification of Land Plants
Vascular tissues transport water and dissolved materials
Vascular plants allowed herbivores to colonize the land
The closest relatives of vascular plants lacked roots
The lycophytes are sister to the other vascular plants
Horsetails and ferns constitute a clade
The vascular plants branched out
Heterospory appeared among the vascular plants
27.3 recap
Investigating Life
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Investigating Life: Brought Back from Extinction by a Seed
Key Concept 28.1 Pollen, Seeds, and Wood Contributed to the Success of Seed Plants
Features of the seed plant life cycle protect gametes and embryos
The seed is a complex, well-protected package
A change in stem anatomy enabled seed plants to grow to great heights
28.1 recap
Key Concept 28.2 Once Dominant Gymnosperms Still Thrive in Some Environments
There are four major groups of living gymnosperms
Conifers have cones and lack swimming sperm
28.2 recap
Key Concept 28.3 Flowers and Fruits Led to Increased Diversification of Angiosperms
Angiosperms have many shared derived traits
The sexual structures of angiosperms are flowers
Flower structure has evolved over time
Angiosperms have coevolved with animals
The angiosperm life cycle produces diploid zygotes nourished by triploid endosperms
Fruits aid angiosperm seed dispersal
Recent analyses have revealed the phylogenetic relationships of angiosperms
28.3 recap
Key Concept 28.4 Plants Play Critical Roles in Terrestrial Ecosystems
Seed plants have been sources of medicine since ancient times
Seed plants are our primary food source
28.4 recap
Investigating Life
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Investigating Life: The Accidental Discovery of Antibiotics
Key Concept 29.1 Fungi Digest Food Outside Their Bodies
Yeasts are unicellular, free-living fungi
Multicellular fungi use hyphae to absorb nutrients
Fungi are in intimate contact with their environment
29.1 recap
Key Concept 29.2 Fungi Are Decomposers, Parasites, Predators, or Mutualists
Saprobic fungi are critical to the planetary carbon cycle
Some fungi engage in parasitic or predatory interactions
Mutualistic fungi engage in relationships that benefit both partners
Endophytic fungi protect some plants from pathogens, herbivores, and stress
29.2 recap
Key Concept 29.3 Sex in Fungi Involves Multiple Mating Types
Fungi reproduce both sexually and asexually
Microsporidia are highly reduced, parasitic fungi
Most chytrids are aquatic
Some fungal life cycles feature separate fusion of cytoplasms and nuclei
Arbuscular mycorrhizal fungi form symbioses with plants
The dikaryotic condition is a synapomorphy of sac fungi and club fungi
The sexual reproductive structure of sac fungi is the ascus
The basidium is the sexual reproductive structure of club fungi
29.3 recap
Key Concept 29.4 Fungi Have Many Practical Uses
Fungi are important in producing food and drink
Fungi provide important weapons against diseases and pests
Lichen diversity and abundance are indicators of air quality
Fungi record and help remediate environmental pollution
Reforestation may depend on mycorrhizal fungi
Fungi are used as model organisms in laboratory studies
29.4 recap
Investigating Life
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Investigating Life: A Mysterious Animal Discovered in an Aquarium
Key Concept 30.1 Some Animal Characteristics Evolved More Than Once
Animal monophyly is supported by gene sequences and morphology
A few basic developmental patterns differentiate major animal groups
30.1 recap
Key Concept 30.2 Animals Diverged with Distinct Body Plans
Most animals are symmetrical
The structure of the body cavity influences movement
Segmentation improves control of movement
Appendages have many uses
Nervous systems coordinate movement and allow sensory processing
30.2 recap
Key Concept 30.3 Animals Use Diverse Forms of Movement to Feed
Filter feeders capture small prey
Herbivores eat plants
Predators and omnivores capture and subdue prey
Parasites live in or on other organisms
Detritivores live on the remains of other organisms
30.3 recap
Key Concept 30.4 Animal Life Cycles Involve Trade-Offs
Many animal life cycles feature specialized life stages
Most animal life cycles have at least one dispersal stage
Parasite life cycles facilitate dispersal and overcome host defenses
Some animals form colonies of genetically identical, physiologically integrated individuals
No life cycle can maximize all benefits
30.4 recap
Key Concept 30.5 The Root of the Animal Tree Provides Clues to Early Animal Diversification
Ctenophores are the sister group of all other animals
Sponges are loosely organized animals
Placozoans are abundant but rarely observed
Cnidarians are specialized predators
Some small groups of parasitic animals may be the closest relatives of bilaterians
30.5 recap
Investigating Life
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Investigating Life: Exploring the Diversity of Life on Earth
Key Concept 31.1 Protostomes Account for More Than Half of All Described Species
Cilia-bearing lophophores and trochophores evolved among the lophotrochozoans
Ecdysozoans must shed their cuticles
Arrow worms retain some ancestral developmental features
31.1 recap
Key Concept 31.2 Many Lophotrochozoans Have Ciliated Feeding Structures or Life Stages
Most bryozoans and entoprocts live in colonies
Flatworms, rotifers, and gastrotrichs are structurally diverse relatives
Ribbon worms have a long, protrusible feeding organ
Brachiopods and phoronids use lophophores to extract food from the water
Annelids have segmented bodies
Mollusks have undergone a dramatic evolutionary radiation
31.2 recap
Key Concept 31.3 Ecdysozoans Grow by Shedding Their Cuticles
Several marine ecdysozoan groups have relatively few species
Nematodes and their relatives are abundant and diverse
31.3 recap
Key Concept 31.4 Arthropods Are the Most Abundant and Diverse Group of Animals
Arthropod relatives have fleshy, unjointed appendages
Jointed appendages appeared in the trilobites
Chelicerates have pointed, nonchewing mouthparts
Mandibles and antennae characterize the remaining arthropod groups
More than half of all described species are insects
31.4 recap
Key Features of Protostome Evolution
Investigating Life
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Investigating Life: Which Came First, the Chicken or the Egg?
Key Concept 32.1 Deuterostomes Include Echinoderms, Hemichordates, and Chordates
Deuterostomes share early developmental patterns
There are three major deuterostome clades
Fossils shed light on deuterostome ancestors
32.1 recap
Key Concept 32.2 Echinoderms and Hemichordates Are Restricted to Marine Environments
Echinoderms have unique structural features
Hemichordates are wormlike marine deuterostomes
32.2 recap
Key Concept 32.3 Chordates Have a Dorsal Nerve Cord and a Notochord
Adults of most lancelets and tunicates are sedentary
A dorsal supporting structure replaces the notochord in vertebrates
The phylogenetic relationships of jawless fishes are uncertain
Jaws and teeth improved feeding efficiency
Fins and swim bladders improved stability and control over locomotion
32.3 recap
Key Concept 32.4 Life on Land Contributed to Vertebrate Diversification
Jointed limbs enhanced support and locomotion on land
Amphibians usually require moist environments
Amniotes colonized dry environments
Reptiles adapted to life in many habitats
Crocodilians and birds share their ancestry with the dinosaurs
Feathers allowed birds to fly
Mammals radiated after the extinction of non-avian dinosaurs
32.4 recap
Key Concept 32.5 Humans Evolved among the Primates
Two major lineages of primates split late in the Cretaceous
Bipedal locomotion evolved in human ancestors
Human brains became larger as jaws became smaller
Humans developed complex language and culture
32.5 recap
Investigating Life
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Investigating Life: Bread of the Tropics
Key Concept 33.1 The Plant Body Is Organized in a Distinctive Way
Most angiosperms are either monocots or eudicots
Plants develop differently than animals
Apical-basal polarity and radial symmetry are characteristics of the plant body
33.1 recap
Key Concept 33.2 Plant Organs Are Made Up of Three Tissue Systems
The dermal tissue system forms the outer covering of a plant
The ground tissue system makes up most of the plant body
The vascular tissue system develops into the plantâs transport system
33.2 recap
Key Concept 33.3 Meristems Build a Continuously Growing Plant
How do plants increase in size?
Meristems generate the plant body
Indeterminate primary growth originates in apical meristems
The root apical meristem gives rise to the root cap and the root primary meristems
The products of the rootâs primary meristems become root tissues
The root system anchors the plant and takes up water and dissolved minerals
The products of the stemâs primary meristems become stem tissues
The stem supports leaves and flowers but can have other roles
Leaves are determinate organs produced by shoot apical meristems
Many stems and roots undergo secondary growth
33.3 recap
Key Concept 33.4 Domestication Has Altered Plant Form
33.4 recap
Investigating Life
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Investigating Life: Thirsty Rice
Key Concept 34.1 Plants Acquire Water and Minerals from the Soil
Water potential differences govern the direction of water movement
Water and ions move across the root cell's cell membrane
Water and ions pass to the xylem by way of the apoplast and symplast
34.1 recap
Key Concept 34.2 Water and Minerals Are Transported in the Xylem
Various hypotheses have proposed how water moves in the xylem
The transpiration-cohesion-tension mechanism accounts for xylem transport
34.2 recap
Key Concept 34.3 Stomata Control the Loss of Water and the Uptake of CO2
Stomata control water loss and gas exchange
The guard cells control the size of the stomatal opening
34.3 recap
Key Concept 34.4 Solutes Are Transported in the Phloem
Sucrose and other solutes are carried in the phloem
The pressure flow model accounts for translocation in the phloem
34.4 recap
Investigating Life
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Investigating Life: Improving Plant Nutrition to Feed the World
Key Concept 35.1 Plants Require Nutrients
Plants require nutrients in different amounts
Deficiency symptoms reveal inadequate nutrition
Hydroponic experiments identified essential elements
35.1 recap
Key Concept 35.2 Plants Acquire Nutrients from the Soil
Plants rely on growth to find nutrients
Nutrient uptake and assimilation are regulated
35.2 recap
Key Concept 35.3 Soil Structure Affects Plant Nutrition
Soil provides anchorage and nutrients for plants
Soils form through the weathering of rock
Soils are the source of plant nutrition
Fertilizers add nutrients to soil
35.3 recap
Key Concept 35.4 Soil Organisms Increase Nutrient Uptake by Plant Roots
Plants send signals to soil organisms
Mycorrhizae expand the root system
Soil bacteria are essential in getting nitrogen from air to plant cells
Nitrogenase catalyzes nitrogen fixation
Biological nitrogen fixation does not always meet agricultural needs
Ammonia formation is the first step in nitrogen assimilation by plants
35.4 recap
Key Concept 35.5 Carnivorous and Parasitic Plants Obtain Nutrients in Unique Ways
Carnivorous plants supplement their mineral nutrition
Parasitic plants take advantage of other plants
The plant-parasite relationship is similar to plant-fungus and plant-bacteria associations
35.5 recap
Investigating Life
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Investigating Life: A Nobel Prize for a Plant Biologist
Key Concept 36.1 Plants Develop in Response to the Environment
Plant growth is regulated
In early development, the seed germinates and forms a growing seedling
Several hormones and photoreceptors help regulate plant growth
Genetic screens have increased our understanding of plant signal transduction
36.1 recap
Key Concept 36.2 Gibberellins and Auxin Have Diverse Effects but a Similar Mechanism of Action
Gibberellins have many effects on plant growth and development
Auxin plays a role in differential plant growth
Auxin affects plant growth in several ways
At the molecular level, auxin and gibberellins act similarly
36.2 recap
Key Concept 36.3 Other Plant Hormones Have Diverse Effects
Cytokinins are active from seed to senescence
Ethylene is a gaseous hormone that hastens leaf senescence and fruit ripening
Brassinosteroids are plant steroid hormones
36.3 recap
Key Concept 36.4 Photoreceptors Initiate Developmental Responses to Light
What are plant photoreceptors?
Phototropins, cryptochromes, and zeaxanthin are blue-light receptors
Phytochromes mediate the effects of red and far-red light
Phytochrome stimulates gene transcription
Circadian rhythms are entrained by light reception
36.4 recap
Investigating Life
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Investigating Life: What Signals Flowering?
Key Concept 37.1 Most Angiosperms Reproduce Sexually
How does the flower function as a structure for sexual reproduction?
Flowering plants have microscopic gametophytes
A pollen tube delivers sperm cells to the embryo sac
Many flowering plants control pollination or pollen tube growth to prevent inbreeding
Angiosperms perform double fertilization
Embryos develop within seeds contained in fruits
Seed development is under hormonal control
37.1 recap
Key Concept 37.2 Hormones and Signaling Determine the Transition from the Vegetative to the Reproductive State
Flowering occurs at specific places and specific times
A cascade of gene expression leads to flowering
Photoperiodic cues can initiate flowering
Plants vary in their responses to photoperiodic cues
Night length is a key photoperiodic cue that determines flowering
The flowering stimulus originates in a leaf
Florigen is a small protein
Flowering can be induced by temperature or gibberellin
Some plants do not require an environmental cue to flower
37.2 recap
Key Concept 37.3 Angiosperms Can Reproduce Asexually
Plants reproduce asexually by several methods
Vegetative reproduction has a disadvantage
Vegetative reproduction is important in agriculture
In apomixis, flowers are used in asexual reproduction
37.3 recap
Investigating Life
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Investigating Life: Can Scientists Breed Disease-Resistant Wheat?
Key Concept 38.1 Plants Respond to Pathogens with Constitutive and Induced Responses
Physical barriers form constitutive defenses
Plants can seal off infected parts to limit damage
General and specific immunity both involve multiple responses
Specific immunity is genetically determined
Specific immunity usually leads to the hypersensitive response
Systemic acquired resistance is a form of long-term immunity
38.1 recap
Key Concept 38.2 Plants Have Mechanical and Chemical Defenses against Herbivores
Plants have mechanical defenses against herbivores
Plants produce constitutive chemical defenses against herbivores
Plants respond to herbivory with induced defenses
Jasmonates trigger a range of responses to wounding and herbivory
Plants don't always win the arms race
38.2 recap
Key Concept 38.3 Plants Can Adapt to Environmental Stresses
Plants can adapt to dry conditions
Some plants grow in saturated soils
Plants can respond to drought stress
Plants can cope with temperature extremes
Plants can adapt to salty soil
Some plants can tolerate heavy metals
38.3 recap
Investigating Life
Chapter Summary
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Investigating Life: Heat Limits Physical Performance
Key Concept 39.1 Animals Are Composed of Organs Built from Four Types of Tissues
How would you build a multicellular animal?
There are advantages and challenges to getting bigger
There are four tissue types
Organs are built from multiple tissues
39.1 recap
Key Concept 39.2 Physiological Systems Maintain Homeostasis of the Internal Environment
The internal environment is the extracellular fluid that serves all the needs of the cells of the body
Physiological systems are regulated to maintain homeostasis
39.2 recap
Key Concept 39.3 Biological Processes Are Temperature-Sensitive
Temperature affects living systems
Q10 is a measure of temperature sensitivity
Animals acclimatize to seasonal temperatures
Small changes in temperature can have large physiological effects
39.3 recap
Key Concept 39.4 Body Temperature Depends on the Balance between Heat In and Heat Out of the Body
Animals can be classified by their thermoregulatory characteristics
Endotherms produce substantial amounts of metabolic heat
Ectotherms and endotherms respond differently to changes in environmental temperature
Energy budgets reflect adaptations for regulating body temperature
Both ectotherms and endotherms control blood flow to the skin
Some fish conserve metabolic heat
Some ectotherms regulate metabolic heat production
39.4 recap
Key Concept 39.5 Body Temperature Is Regulated through Adaptations for Heat Production and Heat Loss
Basal heat production rates of endotherms correlate with body size
Endotherms respond to cold by producing heat and adapt to cold by reducing heat loss
Evaporation of water can dissipate heat, but at a cost
The mammalian thermostat uses feedback information
Some animals conserve energy by turning down the thermostat
39.5 recap
Investigating Life
Chapter Summary
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Investigating Life: The Exercise Hormone
Key Concept 40.1 Hormones Circulate Around the Body and Affect Target Cells
There are multiple chemical communication systems in the body
Endocrine signaling can act locally or at a distance
Hormones are divided into three chemical groups
Hormone action is mediated by receptors on or within their target cells
Hormone action depends on the nature of the target cell and its receptors
Hormone structure is conserved through evolution, but functions change
40.1 recap
Key Concept 40.2 The Endocrine System and Nervous System Work Together
The pituitary is an interface between the nervous and endocrine systems
Hypothalamic neurohormones control the anterior pituitary
Negative feedback loops regulate hormone secretion
Hormones influence the nervous system
40.2 recap
Key Concept 40.3 Hormones Play Important Roles in Development
Insect development consists of either complete or incomplete metamorphosis
Experiments on insect development revealed hormonal signaling systems
Three hormones regulate molting and maturation in arthropods
Sex steroids control sexual development
40.3 recap
Key Concept 40.4 Hormones Regulate Metabolism and the Internal Environment
Thyroxine stimulates many metabolic processes
Three hormones regulate blood calcium concentrations
PTH lowers blood phosphate levels
Insulin and glucagon regulate blood glucose concentrations
The adrenal gland is two glands in one
Many chemicals may act as hormones
The pineal gland has a daily cycle of melatonin release
40.4 recap
Investigating Life
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Investigating Life: Vaccines and Immunity
Key Concept 41.1 Animals Use Innate and Adaptive Mechanisms for Defense
Innate defenses evolved before adaptive defenses
Mammals have both innate and adaptive defenses
Blood and lymph tissues play important roles in defense
White blood cells play many defensive roles
Immune system proteins bind pathogens or signal other cells
41.1 recap
Key Concept 41.2 Innate Defenses Are Nonspecific
Specialized proteins and cells participate in innate immunity
Inflammation is a coordinated innate response to infection or injury
41.2 recap
Key Concept 41.3 Adaptive Defenses Are Specific
What are the key features of adaptive immunity?
Macrophages and dendritic cells play a key role in activating the adaptive immune system
Two types of adaptive immune responses interact
Adaptive immunity develops as a result of clonal selection
Clonal deletion helps the immune system distinguish self from nonself
Immunological memory results in a secondary immune response
Vaccines are an application of immunological memory
41.3 recap
Key Concept 41.4 The Humoral Adaptive Response Involves Antibodies
Antibody protein structure reflects function
There are five classes of immunoglobulins
Immunoglobulin diversity results from DNA rearrangements and other mutations
The constant region is involved in immunoglobulin class switching
41.4 recap
Key Concept 41.5 The Cellular Adaptive Response Involves T Cells and Receptors
MHC proteins present antigen to T cells, causing recognition
T-helper cells and MHC II proteins contribute to the humoral immune response
Cytotoxic T cells and MHC I proteins contribute to the cellular immune response
Regulatory T cells suppress the humoral and cellular immune responses
41.5 recap
Key Concept 41.6 Malfunctions in Immunity Can Be Harmful
The immune system mounts an excessive response in allergic reactions
Autoimmune diseases are caused by reactions against self antigens
AIDS is an immune deficiency disorder
41.6 recap
Investigating Life
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Investigating Life: No Time to Waste
Key Concept 42.1 Asexual Reproduction Is Efficient but Limits Genetic Variability
Asexual reproduction limits genetic diversity
Budding and regeneration produce new individuals by mitosis
Parthenogenesis is the development of unfertilized eggs
42.1 recap
Key Concept 42.2 Sexual Reproduction Involves the Union of Haploid Egg and Sperm
Gametogenesis produces eggs and sperm
Fertilization is the union of sperm and egg
Spawning and mating behaviors get eggs and sperm together
Some individuals can function as both male and female
The evolution of vertebrate reproductive systems parallels the move to land
Animals with internal fertilization are distinguished by where the embryo develops
42.2 recap
Key Concept 42.3 Male Sex Organs Produce and May Deliver Sperm
Semen is the product of the male reproductive system
The penis and the scrotum are the male external genitalia
Male sexual function is controlled by hormones
42.3 recap
Key Concept 42.4 Female Sex Organs Produce Eggs and Nurture Embryos
Ovarian cycles produce mature eggs
The uterine cycle prepares an environment for a fertilized egg
Hormones control and coordinate the ovarian and uterine cycles
FSH receptors determine which follicle ovulates
In pregnancy, hormones from the extraembryonic membranes take over
Breast feeding delays the return of the ovarian cycle
Childbirth is triggered by hormonal and mechanical stimuli
Birth as well as reproduction is timed
42.4 recap
Key Concept 42.5 Fertility Can Be Controlled
Humans use a variety of methods to control fertility
Reproductive technologies help solve problems of infertility
42.5 recap
Investigating Life
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Investigating Life: Go With the Flow
Key Concept 43.1 Fertilization Activates Development
The sperm and the egg make different contributions to the zygote
Fertilization sets the stage for determination
43.1 recap
Key Concept 43.2 Mitosis Divides Up the Early Embryo
Cleavage produces a multicellular embryo
Cleavage in mammals is unique
The fates of blastomeres depend on the cytoplasm they receive during cleavage
Reproductive germ cells are determined early in cleavage
43.2 recap
Key Concept 43.3 Gastrulation Generates Multiple Tissue Layers
Invagination at the vegetal pole initiates gastrulation in the sea urchin
Frog gastrulation begins at the gray crescent
The dorsal lip of the blastopore organizes the formation of the amphibian embryo
Transcription factors and growth factors underlie the organizerâs actions
Properties of organizer cells change as they migrate from the dorsal lip
The amount of yolk influences gastrulation
Gastrulation in mammals is similar to avian gastrulation
How is bilateral symmetry broken?
43.3 recap
Key Concept 43.4 Organs Develop from the Three Germ Layers
The organizer sets the stage for organogenesis
Body segmentation is an early feature of vertebrate development
Hox genes control differentiation along the anteriorâposterior axis
43.4 recap
Key Concept 43.5 Extraembryonic Membranes Nurture Avian and Mammalian Embryos
Birds develop four extraembryonic membranes
The mammalian placenta forms from extraembryonic membranes
Human gestation is divided into trimesters
43.5 recap
Investigating Life
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Investigating Life: Balancing the Brain
Key Concept 44.1 Neurons and Glia Are Unique Cells of Nervous Systems
Vertebrate neurons and macroglia originate in the embryonic neural tube
The structure of neurons reflects their functions
Glia are the “silent partners” of neurons
44.1 recap
Key Concept 44.2 Neurons Generate and Transmit Electric Signals
Simple electrical concepts underlie neuronal function
Activities of neurons are recorded as changes in membrane potential
Ion transporters and channels generate membrane potentials
Ion channels and their properties can be studied directly
Gated ion channels alter membrane potential
Graded changes in membrane potential can integrate information
Sudden changes in Na+ and K+ channels generate action potentials
Action potentials are conducted along axons without loss of signal
Action potentials jump along myelinated axons
44.2 recap
Key Concept 44.3 Neurons Communicate with Other Cells
The neuromuscular junction is a model chemical synapse
The arrival of an action potential causes the release of neurotransmitter
Synaptic functions involve many proteins
The postsynaptic membrane responds to neurotransmitter
Synapses can be excitatory or inhibitory
The postsynaptic neuron sums excitatory and inhibitory input
Electrical synapses are fast but do not integrate information well
The action of a neurotransmitter depends on the receptor to which it binds
To turn off responses, synapses must be cleared of neurotransmitter
The diversity of receptors makes drug specificity possible
44.3 recap
Key Concept 44.4 Neurons and Glia Form Information-Processing Circuits
Nervous systems range in complexity
Reflexes are controlled by simple circuits involving sensory neurons, interneurons, and effectors
The vertebrate brain is the seat of behavioral complexity
44.4 recap
Investigating Life
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Investigating Life: Seeing in the Dark
Key Concept 45.1 Sensory Receptor Cells Convert Stimuli into Action Potentials
Sensory transduction involves changes in membrane potentials
Sensory receptor proteins act on ion channels
Sensation depends on which neurons receive action potentials from sensory cells
Many receptors adapt to repeated stimulation
45.1 recap
Key Concept 45.2 Chemoreceptors Respond to Specific Molecules
Olfaction is the sense of smell
Some chemoreceptors detect pheromones
The vomeronasal organ contains chemoreceptors
Gustation is the sense of taste
45.2 recap
Key Concept 45.3 Mechanoreceptors Respond to Physical Forces
Many different receptor cells respond to touch and pressure
Mechanoreceptors are also found in muscles, tendons, and ligaments
Hair cells are mechanoreceptors of the auditory and vestibular systems
Auditory systems use hair cells to sense sound waves
Flexion of the basilar membrane is perceived as sound
Various types of damage can result in hearing loss
The vestibular system uses hair cells to detect forces of gravity and momentum
45.3 recap
Key Concept 45.4 Photoreceptors Respond to Light
Invertebrates have a variety of visual systems
Image-forming eyes evolved independently in vertebrates and cephalopods
The vertebrate retina receives and processes visual information
Opsins are the universal photoreceptor molecule in animals
Rod and cone cells are the photoreceptors of the vertebrate retina
Information flows through layers of neurons in the retina
45.4 recap
Investigating Life
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Investigating Life: The Brains of Taxi Drivers
Key Concept 46.1 Functions Are Localized in the Nervous System
Functional organization is based on flow and type of information
The anatomical organization of the CNS emerges during development
The spinal cord transmits and processes information
The brainstem carries out many autonomic functions
The core of the forebrain controls physiological drives, instincts, and emotions
The cerebrum is responsible for complex behavior and consciousness
The size of the human brain is off the curve
46.1 recap
Key Concept 46.2 Nervous System Functions Rely on Neural Circuits
Pathways of the autonomic nervous system control involuntary physiological functions
The visual system is an example of information integration by the cerebral cortex
Three-dimensional vision results from cortical cells receiving input from both eyes
46.2 recap
Key Concept 46.3 Higher Brain Functions Involve Integration of Multiple Systems
Sleep and dreaming are reflected in electrical patterns in the cerebral cortex
Language abilities are localized in the left cerebral hemisphere
Some learning and memory can be localized to specific brain areas
We still cannot answer the question “What is consciousness?”
46.3 recap
Investigating Life
Chapter Summary
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Investigating Life: Champion Jumpers
Key Concept 47.1 Interactions of Actin and Myosin Cause Muscles to Contract
Sliding filaments of actin and myosin cause skeletal muscle to contract
Actin-myosin interactions cause filaments to slide
Actin-myosin interactions are controlled by calcium ions
Cardiac muscle is similar to and different from skeletal muscle
Smooth muscle causes slow contractions of many internal organs
47.1 recap
Key Concept 47.2 Many Factors Affect Muscle Performance
The strength of a muscle contraction depends on how many fibers are contracting and at what rate
Muscle fiber types determine endurance and strength
A muscle has an optimal length for generating maximum tension
Exercise increases muscle strength and endurance
Muscle ATP supply limits performance
Insect muscle has the greatest rate of cycling
47.2 recap
Key Concept 47.3 Muscles and Skeletal Systems Work Together
A hydrostatic skeleton consists of fluid in a muscular cavity
Exoskeletons are rigid outer structures
Vertebrate endoskeletons consist of cartilage and bone
Bones develop from connective tissues
Bones that have a common joint can work as a lever
47.3 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: The Breath of Life
Key Concept 48.1 Respiratory Gas Exchange Is Governed by Physical Factors
Diffusion of gases is driven by partial pressure differences
Fick's law applies to all systems of gas exchange
Air is a better respiratory medium than water
High temperatures create respiratory problems for aquatic animals
O2 availability decreases with altitude
CO2 is lost by diffusion
48.1 recap
Key Concept 48.2 Enhancing Diffusion Maximizes Respiratory Gas Exchange
Respiratory organs have large surface areas
Ventilation and perfusion of gas exchange surfaces maximize partial pressure gradients
Insects have airways throughout their bodies
Fish gills use countercurrent flow to maximize gas exchange
Birds use unidirectional ventilation to maximize gas exchange
Tidal ventilation produces dead space that limits gas exchange efficiency
Small residual volume prevents the bends in seals
48.2 recap
Key Concept 48.3 Humans Have Tidal Respiration
Lungs are ventilated through a branching system of airways
Respiratory tract secretions aid ventilation
Lungs are ventilated by pressure changes in the thoracic cavity
48.3 recap
Key Concept 48.4 Respiratory Gases Are Transported by the Blood
Red blood cells are produced in the bone marrow
Hemoglobin combines reversibly with O2
Myoglobin holds an O2 reserve
Hemoglobin's affinity for O2 is variable
Most CO2 is transported as bicarbonate ions in the blood
48.4 recap
Key Concept 48.5 Breathing Is Homeostatically Regulated
Breathing is controlled in the brainstem
Regulating breathing requires feedback
48.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Athletes with Big Hearts
Key Concept 49.1 Circulatory Systems Serve Many Functions
Some animals do not have a circulatory system
Circulatory systems can be open or closed
Open circulatory systems move extracellular fluid
Closed circulatory systems circulate blood through a system of blood vessels
49.1 recap
Key Concept 49.2 Vertebrate Circulatory Systems Evolved from Single to Double Circuits
Circulation in fishes is a single circuit
Lungfishes evolved a gas-breathing organ
Amphibians have partial separation of systemic and pulmonary circulation
Reptiles have exquisite control of pulmonary and systemic circulation
Birds and mammals have fully separated pulmonary and systemic circuits
49.2 recap
Key Concept 49.3 Heart Function Depends on Properties of Cardiac Muscle
Blood flows from right heart to lungs to left heart to body
The heartbeat originates in the cardiac muscle
A conduction system coordinates the contraction of heart muscle
HCM can disrupt conduction
Electrical properties of ventricular muscles sustain heart contraction
The ECG records the electrical activity of the heart
49.3 recap
Key Concept 49.4 Circulatory System Functions Depend on Blood and Blood Vessels
Red blood cells transport respiratory gases
Platelets are essential for blood clotting
Arteries withstand high pressure, arterioles control blood flow
Materials are exchanged in capillary beds by filtration, osmosis, and diffusion
Blood flows back to the heart through veins
Lymphatic vessels return interstitial fluid to the blood
Vascular disease is a killer
49.4 recap
Key Concept 49.5 The Circulation Is Controlled by Hormonal and Neural Signals
Autoregulation matches local blood flow to local need
Arterial pressure is regulated by hormonal and neural mechanisms
49.5 recap
Investigating Life
Chapter Summary
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Investigating Life: Thrifty Phenotypes
Key Concept 50.1 Food Provides Energy As Well As Materials for Biosynthesis
Energy needs and expenditures can be measured
Sources of energy are stored in the body
Food provides carbon skeletons for biosynthesis
Animals need mineral elements for a variety of functions
Animals must obtain vitamins from food
Nutrient deficiencies result in diseases
50.1 recap
Key Concept 50.2 Diverse Adaptations Support Ingestion and Digestion of Food
The food of herbivores is often low in energy and hard to digest
Carnivores must find, capture, and kill prey
Vertebrate species have distinctive teeth
Digestion usually begins in a body cavity
Tubular guts have an opening at each end
Digestive enzymes break down complex food molecules
The gut microbiome contributes to digestion
50.2 recap
Key Concept 50.3 The Vertebrate Gastrointestinal System Is a Disassembly Line
The vertebrate gut consists of concentric tissue layers
Gut motility moves food through the gut and aids digestion
Chemical digestion begins in the mouth and the stomach
The stomach gradually releases its contents to the small intestine
Most chemical digestion occurs in the small intestine
Nutrients are absorbed in the small intestine
Absorbed nutrients go to the liver
Water and ions are absorbed in the large intestine
Herbivores rely on their microbiota to digest cellulose
50.3 recap
Key Concept 50.4 Nutrient Availability Is Controlled and Regulated
Hormones control many digestive functions
The liver stores and releases the molecules that fuel metabolism
The liver produces lipoproteins: the good, the bad, and the ugly
Insulin and glucagon control fuel metabolism
The brain plays a major role in regulating food intake
50.4 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: How Vampire Bats Use Blood as Fast Food
Key Concept 51.1 Excretory Systems Regulate Osmotic and Ionic Concentrations
Osmosis causes water to enter or to leave cells
Excretory systems control extracellular fluid osmolarity and composition
Aquatic invertebrates are either ionic conformers or regulators
Vertebrates are osmoregulators and ionic regulators
51.1 recap
Key Concept 51.2 Animals Excrete Nitrogen as Ammonia, Urea, or Uric Acid
Ammonia is toxic
Urea is highly soluble in water
Uric acid is not very soluble in water
Most species produce more than one nitrogenous waste
51.2 recap
Key Concept 51.3 Invertebrate Excretory Systems Use Filtration, Secretion, and Reabsorption
Protonephridia of flatworms excrete water and conserve salts
Metanephridia of annelids process coelomic fluid
Malpighian tubules of insects use active transport to excrete wastes
51.3 recap
Key Concept 51.4 The Nephron Is the Basic Functional Unit of Vertebrate Excretory Systems
Marine fishes must conserve water
Terrestrial amphibians and reptiles must avoid desiccation
Mammals can produce highly concentrated urine
The nephron is the functional unit of the vertebrate kidney
Blood is filtered into Bowman's capsule
The renal tubules convert glomerular filtrate to urine
51.4 recap
Key Concept 51.5 The Mammalian Kidney Can Produce Concentrated Urine
Kidneys produce urine and the bladder stores it
Nephrons have a regular arrangement in the kidney
Most of the glomerular filtrate is reabsorbed by the proximal convoluted tubule
The loop of Henle creates a concentration gradient in the renal medulla
Water permeability of kidney tubules depends on water channels
The distal convoluted tubule fine-tunes the composition of the urine
Urine is concentrated in the collecting duct
The kidneys help regulate acid-base balance
Kidney failure is treated with dialysis
51.5 recap
Key Concept 51.6 Kidney Function Is Regulated
Glomerular filtration rate is regulated
Regulation of GFR uses feedback information from the distal tubule
Blood osmolarity and blood pressure are regulated by ADH
The heart produces a hormone that helps lower blood pressure
51.6 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: An Instinct to Learn
Key Concept 52.1 Ethology Led to Modern Behavioral Biology
Conditioned reflexes are a simple behavioral mechanism
Ethologists focused on the behavior of animals in their natural environment
Ethologists probed the causes of behavior
52.1 recap
Key Concept 52.2 Behavior Can Be Genetically Determined
Single gene mutations can alter behavioral phenotypes
Knockout experiments reveal the roles of specific genes
Gene cascades can control complex behavioral phenotypes
52.2 recap
Key Concept 52.3 Behavior Can Be Studied Developmentally
Hormones can determine behavioral potential and timing
Some behaviors can be acquired only at certain times
Birdsong learning involves genetics, imprinting, development, and social interactions
The timing and expression of birdsong are under hormonal control
52.3 recap
Key Concept 52.4 Selective Pressures Shape Behavior
Animals are faced with many choices
Behaviors have costs and benefits
Territorial behavior carries significant costs
Foraging behavior has costs and benefits
52.4 recap
Key Concept 52.5 Behavior Can Be Studied Mechanistically
Biological rhythms coordinate behavior with environmental cycles
Animals must find their way around their environment
Animals use multiple modalities to communicate
52.5 recap
Key Concept 52.6 Social Interactions Shape the Evolution of Behavior
Mating systems evolve to maximize fitness
Fitness can include more than your own offspring
Eusociality is the extreme result of kin selection
Group living has benefits and costs
Can the concepts of sociobiology be applied to humans?
52.6 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: The Largest Experiment on Earth
Key Concept 53.1 Ecology Is the Study of the Interrelationships among Organisms and the Environment
Modern ecology has a more “use-inspired” focus
Ecology is studied at many levels of organization
Answering ecological questions requires observations, experiments, and models
53.1 recap
Key Concept 53.2 Global Climate Is a Fundamental Component of the Physical Environment
Solar radiation drives global climate patterns
Earth is a sphere, creating latitudinal variation in global temperature and precipitation
Earth spins on an axis, producing prevailing winds and ocean currents
The tilt of Earth's axis and its orbit result in seasons
53.2 recap
Key Concept 53.3 Topography, Vegetation, and Humans Modify the Physical Environment
Earth's topography affects the local and regional physical environment
Vegetation affects the local and regional physical environment, especially climate
Humans have transformed their physical environment, including urban climate
53.3 recap
Key Concept 53.4 Biogeography Is the Study of How Organisms Are Distributed on Earth
Patterns of biogeography are interconnected across a hierarchy of spatial and temporal scales
Terrestrial biomes reflect global patterns of temperature and precipitation
Biogeographic regions reflect evolutionary isolation
Diversity varies with latitude and longitude
Geographic variation in diversity is explained by multiple factors
53.4 recap
Key Concept 53.5 Geographic Area and Humans Affect Regional Species Diversity
Humans exert a powerful influence on biogeographic patterns
53.5 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: Earth’s Human Carrying Capacity
Key Concept 54.1 Populations Show Dynamic Variation in Size over Space and Time
Population dynamics are controlled by the physical environment, biological interactions, and dispersal
Ecologists use a variety of approaches to estimate population size and extent
54.1 recap
Key Concept 54.2 Population Growth Describes the Change in Population Size over Time
Births increase and deaths decrease population size over time
All populations have the potential for exponential growth
Logistic growth occurs as a population approaches its carrying capacity
Factors limiting population growth can be density-dependent or density-independent
Life tables keep track of demographic events
54.2 recap
Key Concept 54.3 Life History Is the Lifetime Pattern of Growth, Reproduction, and Survival
Life history strategies can vary at species and population levels
Life history strategies arise from constraints on growth, reproduction, and survival
54.3 recap
Key Concept 54.4 Population Biology Can Be Used in Conserving and Managing Populations
Management plans must take life history strategies into account
Management plans must be guided by the principles of population dynamics
Knowledge of metapopulation dynamics helps us conserve species
54.4 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: The Lionfishes King
Key Concept 55.1 Species Interactions Vary in Direction and Strength across a Continuum
Species interactions are not always clear-cut
Some interactions result in evolutionary change in the species involved
55.1 recap
Key Concept 55.2 Predation Is a Trophic Interaction in which Predators Benefit and Prey Are Harmed
Carnivory results in a range of capture and avoidance mechanisms
Herbivory is a widespread but specialized interaction
Most parasites specialize on hosts, and most hosts house many species of parasites
Predator populations can cycle with their prey populations
Predators can have dramatic effects on communities
55.2 recap
Key Concept 55.3 Competition Is a Negative Interaction in which Species Overlap in the Use of Some Limiting Resource
Resource partitioning allows species to coexist despite overlapping use of limiting resources
The physical environment, disturbance, and predation can each alter the outcome of competition
Competition can affect species' distributions
55.3 recap
Key Concept 55.4 Positive Interactions Occur When at Least One Species Benefits and None Are Harmed
Positive interactions are more common in stressful environments
Positive interactions can have dramatic effects on populations and communities
55.4 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: Rising from the Ashes
Key Concept 56.1 Communities Are Groups of Interacting Species Occurring Together in Space and Time
Ecologists often use a subset of species to define communities
Species diversity and composition are important descriptors of community structure
56.1 recap
Key Concept 56.2 Community Membership Depends on Species Supply, Environmental Conditions, and Species Interactions
Community membership depends on species supply
Environmental conditions are critical to community membership
Resident species can restrict or promote community membership
56.2 recap
Key Concept 56.3 Communities Are Complex Networks of Species Interactions That Vary in Strength and Direction
Indirect interactions are important to community structure
Strongly interacting species often regulate community structure
Species with similar effects on one another may coexist by chance
56.3 recap
Key Concept 56.4 Communities Are Always Changing
Change in communities can be caused by abiotic and biotic factors
Succession is a process of change in communities over time
Both facilitation and inhibition influence succession
Alternative successional pathways result in variations in community composition
56.4 recap
Key Concept 56.5 Relationships between Species Diversity and Community Function Are Often Positive
Species diversity is associated with productivity and stability
Diversity, productivity, and stability differ between natural and managed communities
56.5 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: Food Webs in an Acidic and Warming Ocean
Key Concept 57.1 Ecosystem Science Considers How Energy and Nutrients Flow through Biotic and Abiotic Environments
Energy flowing through ecosystems originates with sunlight and inorganic and organic compounds
Nutrients cycling through ecosystems originate in soil, water, and the atmosphere
57.1 recap
Key Concept 57.2 Energy and Nutrients in Ecosystems Are First Captured by Primary Producers
Net primary production is the amount of carbon remaining in plants after respiration
Patterns of primary production vary with latitude and ecosystem type
Rainfall and temperature largely control terrestrial primary production
Light and nutrients combine to control aquatic primary production
57.2 recap
Key Concept 57.3 Food Webs Transfer Energy and Nutrients from Primary Producers to Consumers
The amount of energy transferred within food webs depends on trophic efficiency
Food webs are controlled by bottom-up and top-down forces
The number of trophic levels can control the flow of energy through food webs
57.3 recap
Key Concept 57.4 Nutrient Cycling in Ecosystems Involves Chemical and Biological Transformations
Water cycles rapidly around the globe
The carbon cycle is being altered by human activities, resulting in climate change
The nitrogen cycle is dominated by biotic processes
The global phosphorus cycle is dominated by geochemical processes
The burning of fossil fuels affects the sulfur cycle
57.4 recap
Key Concept 57.5 Ecosystems Provide Important Services and Values to Humans
The value of ecosystem services can be measured
57.5 recap
Investigating Life
Chapter Summary
Apply What You've Learned
Investigating Life: Fatal Fungus Final Fate for Frogs?
Key Concept 58.1 Human Activities Are Changing the Biosphere, Resulting in Biodiversity Loss
Biodiversity has great value to human society
Diversity loss at one scale affects diversity loss at other scales
Species diversity is being lost at unprecedented rates
We can predict the effects of human activities on biodiversity
58.1 recap
Key Concept 58.2 Most Biodiversity Loss Is Caused by Habitat Loss and Degradation
Habitat loss and degradation endanger species
Overharvesting has driven many species to extinction and changed food webs
Invasive predators, competitors, and pathogens threaten many species
Species and ecosystems are already being affected by climate change
58.2 recap
Key Concept 58.3 Protecting Biodiversity Requires Conservation and Management Strategies
Protected areas preserve habitat and curtail biodiversity loss
Degraded ecosystems can be restored
Captive breeding programs can maintain a few species
Ending trade is crucial to saving some species
Species invasions must be controlled or prevented
Biodiversity can be conserved as a consequence of its economic value
58.3 recap
Investigating Life
Chapter Summary
Apply What You've Learned
APPENDIX A - The Tree of Life
APPENDIX B - Making Sense of Data: A Statistics Primer
Why Do We Do Statistics?
How Does Statistics Help Us Understand the Natural World?
Step 1: Choose an Experimental Design
Step 2: Collect Data
Step 3: Organize and Visualize the Data
Step 4: Summarize the Data
Step 5: Make Inferences from the Data
APPENDIX C - Some Measurements Used in Biology
Chapter Introduction
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Chapter 12
Chapter 13
Chapter 14
Chapter 15
Chapter 16
Chapter 17
Chapter 18
Chapter 19
Chapter 20
Chapter 21
Chapter 22
Chapter 23
Chapter 24
Chapter 25
Chapter 26
Chapter 27
Chapter 28
Chapter 29
Chapter 30
Chapter 31
Chapter 32
Chapter 33
Chapter 34
Chapter 35
Chapter 36
Chapter 37
Chapter 38
Chapter 39
Chapter 40
Chapter 41
Chapter 42
Chapter 43
Chapter 44
Chapter 45
Chapter 46
Chapter 47
Chapter 48
Chapter 49
Chapter 50
Chapter 51
Chapter 52
Chapter 53
Chapter 54
Chapter 55
Chapter 56
Chapter 57
Chapter 58
Glossary
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