Principles of Life
The Authors
Brief Table of Contents
Preface
Advisors and Reviewers
Launchpad for Principles of Life, SECOND EDITION
Table of Contents
Principles of Life
1.1: Living Organisms Share Common Aspects of Structure, Function, and Energy Flow
1.2: Life Depends on Organization and Energy
1.3: Genetic Systems Control the Flow, Exchange, Storage, and Use of Information
1.4: Evolution Explains the Diversity as Well as the Unity of Life
1.5: Science Is Based on Quantitative Observations, Experiments, and Reasoning
Cells
The Chemistry and Energy of Life
2.1: Atomic Structure Is the Basis for Life’s Chemistry
2.2: Atoms Interact and Form Molecules
2.3: Carbohydrates Consist of Sugar Molecules
2.4: Lipids Are Hydrophobic Molecules
2.5: Biochemical Changes Involve Energy
Summary
Nucleic Acids, Proteins, and Enzymes
3.1: Nucleic Acids Are Informational Macromolecules
3.2: Proteins Are Polymers with Important Structural and Metabolic Roles
3.3: Some Proteins Act as Enzymes to Speed up Biochemical Reactions
3.4: Regulation of Metabolism Occurs by Regulation of Enzymes
Summary
Cells: The Working Units of Life
4.1: Cells Provide Compartments for Biochemical Reactions
4.2: Prokaryotic Cells Do Not Have a Nucleus
4.3: Eukaryotic Cells Have a Nucleus and Other Membrane-Bound Compartments
4.4: The Cytoskeleton Provides Strength and Movement
4.5: Extracellular Structures Provide Support and Protection for Cells and Tissues
Summary
Cell Membranes and Signaling
5.1: Biological Membranes Have a Common Structure and Are Fluid
5.2: Passive Transport across Membranes Requires No Input of Energy
5.3: Active Transport Moves Solutes against Their Concentration Gradients
5.4: Large Molecules Cross Membranes via Vesicles
5.5: The Membrane Plays a Key Role in a Cell’s Response to Environmental Signals
5.6: Signal Transduction Allows the Cell to Respond to Its Environment
Summary
Pathways that Harvest and Store Chemical Energy
6.1: ATP and Reduced Coenzymes Play Important Roles in Biological Energy Metabolism
6.2: Carbohydrate Catabolism in the Presence of Oxygen Releases a Large Amount of Energy
6.3: Carbohydrate Catabolism in the Absence of Oxygen Releases a Small Amount of Energy
6.4: Catabolic and Anabolic Pathways Are Integrated
6.5: During Photosynthesis, Light Energy Is Converted to Chemical Energy
6.6: Photosynthetic Organisms Use Chemical Energy to Convert CO₂ to Carbohydrates
Summary
Genetics
The Cell Cycle and Cell Division
7.1: Different Life Cycles Use Different Modes of Cell Reproduction
7.2: Both Binary Fission and Mitosis Produce Genetically Identical Cells
7.3: Cell Reproduction Is Under Precise Control
7.4: Meiosis Halves the Nuclear Chromosome Content and Generates Diversity
7.5: Programmed Cell Death Is a Necessary Process in Living Organisms
Summary
Inheritance, Genes, and Chromosomes
8.1: Genes Are Particulate and Are Inherited According to Mendel’s Laws
8.2: Alleles and Genes Interact to Produce Phenotypes
8.3: Genes Are Carried on Chromosomes
8.4: Prokaryotes Can Exchange Genetic Material
Summary
DNA and Its Role in Heredity
9.1: DNA Structure Reflects Its Role as the Genetic Material
9.2: DNA Replicates Semiconservatively
9.3: Mutations Are Heritable Changes in DNA
Summary
From DNA to Protein: Gene Expression
10.1: Genetics Shows That Genes Code for Proteins
10.2: DNA Expression Begins with Its Transcription to RNA
10.3: The Genetic Code in RNA Is Translated into the Amino Acid Sequences of Proteins
10.4: Translation of the Genetic Code Is Mediated by tRNAs and Ribosomes
10.5: Proteins Are Modified after Translation
Summary
Regulation of Gene Expression
11.1: Many Prokaryotic Genes Are Regulated in Operons
11.2: Eukaryotic Genes Are Regulated by Transcription Factors
11.3: Gene Expression Can Be Regulated via Epigenetic Changes to Chromatin
11.4: Eukaryotic Gene Expression Can Be Regulated after Transcription
Summary
Genomes
12.1: There Are Powerful Methods for Sequencing Genomes and Analyzing Gene Products
12.2: Prokaryotic Genomes Are Small, Compact, and Diverse
12.3: Eukaryotic Genomes Are Large and Complex
12.4: The Human Genome Sequence Has Many Applications
Summary
Biotechnology
13.1: Recombinant DNA Can Be Made in the Laboratory
13.2: DNA Can Genetically Transform Cells and Organisms
13.3: Genes Come from Various Sources and Can Be Manipulated
13.4: Biotechnology Has Wide Applications
Summary
Genes, Development, and Evolution
14.1: Development Involves Distinct but Overlapping Processes
14.2: Changes in Gene Expression Underlie Cell Fate Determination and Differentiation
14.3: Spatial Differences in Gene Expression Lead to Morphogenesis
14.4: Changes in Gene Expression Pathways Underlie the Evolution of Development
14.5: Developmental Genes Contribute to Species Evolution but Also Pose Constraints
Summary
Evolution
Processes of Evolution
15.1: Evolution Is Both Factual and the Basis of Broader Theory
15.2: Mutation, Selection, Gene Flow, Genetic Drift, and Nonrandom Mating Result in Evolution
15.3: Evolution Can Be Measured by Changes in Allele Frequencies
15.4: Selection Can Be Stabilizing, Directional, or Disruptive
15.5: Genomes Reveal Both Neutral and Selective Processes of Evolution
15.6: Recombination, Lateral Gene Transfer, and Gene Duplication Can Result in New Features
15.7: Evolutionary Theory Has Practical Applications
Summary
Reconstructing and Using Phylogenies
16.1: All of Life Is Connected through Its Evolutionary History
16.2: Phylogeny Can Be Reconstructed from Traits of Organisms
16.3: Phylogeny Makes Biology Comparative and Predictive
16.4: Phylogeny Is the Basis of Biological Classification
Summary
Speciation
17.1: Species Are Reproductively Isolated Lineages on the Tree of Life
17.2: Speciation Is a Natural Consequence of Population Subdivision
17.3: Speciation May Occur through Geographic Isolation or in Sympatry
17.4: Reproductive Isolation Is Reinforced When Diverging Species Come into Contact
Summary
The History of Life on Earth
18.1: Events in Earth’s History Can Be Dated
18.2: Changes in Earth’s Physical Environment Have Affected the Evolution of Life
18.3: Major Events in the Evolution of Life Can Be Read in the Fossil Record
Summary
Diversity
Bacteria, Archaea, and Viruses
19.1: Life Consists of Three Domains That Share a Common Ancestor
19.2: Prokaryote Diversity Reflects the Ancient Origins of Life
Summary
The Origin and Diversification of Eukaryotes
20.4: Protists Are Critical Components of Many Ecosystems
Summary
The Evolution of Plants
21.1: Primary Endosymbiosis Produced the First Photosynthetic Eukaryotes
21.2: Key Adaptations Permitted Plants to Colonize Land
21.3: Vascular Tissues Led to Rapid Diversification of Land Plants
21.4: Seeds Protect Plant Embryos
21.5: Flowers and Fruits Increase the Reproductive Success of Angiosperms
Summary
The Evolution and Diversity of Fungi
22.1: Fungi Live by Absorptive Heterotrophy
22.2: Fungi Can Be Saprobic, Parasitic, Predatory, or Mutualistic
22.3: Major Groups of Fungi Differ in Their Life Cycles
22.4: Fungi Can Be Sensitive Indicators of Environmental Change
Summary
Animal Origins and Diversity
23.1: Distinct Body Plans Evolved among the Animals
23.2: Some Animal Groups Fall outside the Bilateria
23.3: Protostomes Have an Anterior Brain and a Ventral Nervous System
23.4: Arthropods Are Diverse and Abundant Animals
23.5: Deuterostomes Include Echinoderms, Hemichordates, and Chordates
23.6: Life on Land Contributed to Vertebrate Diversification
23.7: Humans Evolved among the Primates
Summary
Plant Form and Function
The Plant Body
24.1: The Plant Body Is Organized and Constructed in a Distinctive Way
24.2: Apical Meristems Build the Primary Plant Body
24.3: Many Eudicot Stems and Roots Undergo Secondary Growth
24.4: Domestication Has Altered Plant Form
Summary
Plant Nutrition and Transport
25.1: Plants Acquire Mineral Nutrients from the Soil
25.2: Soil Organisms Contribute to Plant Nutrition
25.3: Water and Solutes Are Transported in the Xylem by Transpiration–Cohesion–Tension
25.4: Solutes Are Transported in the Phloem by Pressure Flow
Summary
Plant Growth and Development
26.1: Plants Develop in Response to the Environment
26.2: Gibberellins and Auxin Have Diverse Effects but a Similar Mechanism of Action
26.3: Other Plant Hormones Have Diverse Effects on Plant Development
26.4: Photoreceptors Initiate Developmental Responses to Light
Summary
Reproduction of Flowering Plants
27.1: Most Angiosperms Reproduce Sexually
27.2: Hormones and Signaling Determine the Transition from the Vegetative to the Reproductive State
27.3: Angiosperms Can Reproduce Asexually
Summary
Plants in the Environment
28.1: Plants Have Constitutive and Induced Responses to Pathogens
28.2: Plants Have Mechanical and Chemical Defenses against Herbivores
28.3: Plants Adapt to Environmental Stresses
Summary
Animal Form and Function
Fundamentals of Animal Function
29.1: Animals Eat to Obtain Energy and Chemical Building Blocks
29.2: An Animal’s Energy Needs Depend on Physical Activity and Body Size
29.3: Metabolic Rates Are Affected by Homeostasis and by Regulation and Conformity
29.4: Animals Exhibit Division of Labor, but Each Cell Must Make Its Own ATP
29.5: The Phenotypes of Individual Animals Can Change during Their Lifetimes
29.6: Animal Function Requires Control Mechanisms
Summary
Nutrition, Feeding, and Digestion
30.1: Food Provides Energy and Chemical Building Blocks
30.2: Animals Get Food in Three Major Ways
30.3: The Digestive System Plays a Key Role in Determining the Nutritional Value of Foods
30.4: The Vertebrate Digestive System Is a Tubular Gut with Accessory Glands
30.5: The Processing of Meals Is Regulated
Summary
Breathing
31.1: Respiratory Gas Exchange Depends on Diffusion and Bulk Flow
31.2: Animals Have Evolved Diverse Types of Breathing Organs
31.3: The Mammalian Breathing System Is Anatomically and Functionally Elaborate
Summary
Circulation
32.1: Circulatory Systems Can Be Closed or Open
32.2: The Breathing Organs and Systemic Tissues Are Usually, but Not Always, in Series
32.3: A Beating Heart Propels the Blood
32.4: Many Key Processes Occur in the Vascular System
32.5: The Blood Transports O{sub}2{/sub} and CO{sub}2{/sub}
Summary
Muscle and Movement
33.1: Muscle Cells Develop Forces by Means of Cycles of Protein–Protein Interaction
33.2: Skeletal Muscles Pull on Skeletal Elements to Produce Useful Movements
33.3: Skeletal Muscle Performance Depends on ATP Supply, Cell Type, and Training
33.4: Many Distinctive Types of Muscle Have Evolved
Summary
Neurons, Sense Organs, and Nervous Systems
34.1: Nervous Systems Are Composed of Neurons and Glial Cells
34.2: Neurons Generate Electric Signals by Controlling Ion Distributions
34.3: Neurons Communicate with Other Cells at Synapses
34.4: Sensory Processes Provide Information on an Animal’s External Environment and Internal Status
34.5: Neurons Are Organized into Nervous Systems
Summary
Control by the Endocrine and Nervous Systems
35.1: The Endocrine and Nervous Systems Play Distinct, Interacting Roles
35.2: Hormones Are Chemical Messengers Distributed by the Blood
35.3: The Vertebrate Hypothalamus and Pituitary Gland Link the Nervous and Endocrine Systems
35.4: Hormones Regulate Mammalian Physiological Systems
35.5: The Insect Endocrine System Is Crucial for Development
Summary
Water and Salt Balance
36.1: Kidneys Regulate the Composition of the Body Fluids
36.2: Nitrogenous Wastes Need to Be Excreted
36.3: Aquatic Animals Display a Wide Diversity of Relationships to Their Environment
36.4: Dehydration Is the Principal Challenge for Terrestrial Animals
36.5: Kidneys Adjust Water Excretion to Help Animals Maintain Homeostasis
Summary
Animal Reproduction
37.1: Sexual Reproduction Depends on Gamete Formation and Fertilization
37.2: The Mammalian Reproductive System Is Hormonally Controlled
37.3: Reproduction Is Integrated with the Life Cycle
Summary
Animal Development
38.1: Fertilization Activates Development
38.2: Cleavage Creates Building Blocks and Produces a Blastula
38.3: Gastrulation Produces a Second, then a Third Germ Layer
38.4: Gastrulation Sets the Stage for Organogenesis and Neurulation in Chordates
38.5: Extraembryonic Membranes Protect and Nourish the Embryo
38.6: Development Continues throughout Life
Summary
Immunology: Animal Defense Systems
39.1: Animals Use Innate and Adaptive Mechanisms to Defend Themselves against Pathogens
39.2: Innate Defenses Are Nonspecific
39.3: The Adaptive Immune Response Is Specific
39.4: The Adaptive Humoral Immune Response Involves Specific Antibodies
39.5: The Adaptive Cellular Immune Response Involves T Cells and Their Receptors
Summary
Animal Behavior
40.1: Behavior Is Controlled by the Nervous System but Is Not Necessarily Deterministic
40.2: Behavior Is Influenced by Development and Learning
40.3: Behavior Is Integrated with the Rest of Function
40.4: Moving through Space Presents Distinctive Challenges
40.5: Social Behavior Is Widespread
40.6: Behavior Helps Structure Ecological Communities and Processes
Summary
Ecology
The Distribution of Earth’s Ecological Systems
41.1: Ecological Systems Vary over Space and Time
41.2: Solar Energy Input and Topography Shape Earth’s Physical Environments
41.3: Biogeography Reflects Physical Geography
41.4: Biogeography Also Reflects Geological History
41.5: Human Activities Affect Ecological Systems on a Global Scale
Summary
Populations
42.1: Populations Are Patchy in Space and Dynamic over Time
42.2: Births Increase and Deaths Decrease Population Size
42.3: Life Histories Determine Population Growth Rates
42.4: Populations Grow Multiplicatively, but the Multiplier Can Change
42.5: Immigration and Emigration Affect Population Dynamics
42.6: Ecology Provides Tools for Conserving and Managing Populations
Summary
Ecological and Evolutionary Consequences of Interactions within and among Species
43.1: Interactions between Species May Increase, Decrease, or Have No Effect on Fitness
43.2: Interactions within and among Species Affect Population Dynamics and Species Distributions
43.3: Species Are Embedded in Complex Interaction Webs
43.4: Interactions within and among Species Can Result in Evolution
Summary
Ecological Communities
44.1: Communities Contain Species That Colonize and Persist
44.2: Communities Change over Space and Time
44.3: Community Structure Affects Community Function
44.4: Diversity Patterns Provide Clues to What Determines Diversity
44.5: Community Ecology Suggests Strategies for Conserving Community Function
Summary
The Global Ecosystem
45.1: Climate and Nutrients Affect Ecosystem Function
45.2: Biological, Geological, and Chemical Processes Move Materials through Ecosystems
45.3: Certain Biogeochemical Cycles Are Especially Critical for Ecosystems
45.4: Biogeochemical Cycles Affect Global Climate
45.5: Rapid Climate Change Affects Species and Communities
45.6: Ecological Challenges Can Be Addressed through Science and International Cooperation
Summary
The Tree of Life
Making Sense of Data: A Statistics Primer
PRACTICE EXERCISES
Some Measurements Used in Biology
Illustration Credits
Index