PART 3   Evolution and the Diversity of Life

10  •  The Origin and Diversification of Life on Earth 405

Understanding biodiversity

Life on earth most likely originated from non-living materials. 406

10.1

Complex organic molecules arise in non-living environments. 406

10.2

Cells and self-replicating systems evolved together to create the first life. 408

10.3

This is how we do it: Could life have originated in ice, rather than in a “warm little pond”? 409

Species are the basic units of biodiversity. 411

10.4

What is a species? 411

10.5

How do we name species? 413

10.6

Species are not always easily defined. 414

10.7

How do new species arise? 416

Evolutionary trees help us conceptualize and categorize biodiversity. 420

10.8

The history of life can be imagined as a tree. 420

10.9

Evolutionary trees show ancestor-descendant relationships. 421

10.10

Similar structures don’t always reveal common ancestry. 424

Macroevolution gives rise to great diversity. 426

10.11

Macroevolution is evolution above the species level. 426

10.12

The pace of evolution is not constant. 427

10.13

Adaptive radiations are times of extreme diversification. 428

10.14

There have been several mass extinctions on earth. 430

An overview of the diversity of life on earth: organisms are divided into three domains. 432

10.15

All living organisms are classified into one of three groups. 432

10.16

The bacteria domain has tremendous biological diversity. 434

10.17

The archaea domain includes many species living in extreme environments. 436

10.18

The eukarya domain consists of four kingdoms: plants, animals, fungi, and protists. 437

StreetBIO: KNOWLEDGE YOU CAN USE

Do racial differences exist on a genetic level? 438