Chapter 21

Question 1

Organisms that produce their own food from simple raw material

Answer 1

Autotrophs

Question 2

Time period from 600 to 542 million years ago

Answer 2

Ediacaran Period

Question 3

Ancient remains of microscopic life

Answer 3

Microfossils

Question 4

The largest divisions of the geological time scale

Answer 4

Eons

Question 5

Organisms that live symbiotically inside a host cell

Answer 5

Endosymbionts

Question 6

The time period that began 542 million years ago and lasted 291 million years

Answer 6

Paleozoic Era

Question 7

According to this model, the chemistry of prebiotic Earth gave rise to self-replicating RNA molecules that functioned as both enzyme and substrates for their own replication

Answer 7

RNA World

Question 8

The oldest known fossils of multicellular animals

Answer 8

Ediacaran Fossils

Question 9

Type of fossil evidence which are rock like columns composed of many minute layers of prokaryotic cells

Answer 9

Stromatolites

Question 10

According to this type of hypothesis, organelles such as mitochondria and chloroplasts may have originated from mutually advantageous symbiotic relationships between two prokaryotic organisms

Answer 10

Serial Endosymbiosis

Question 11

The Earth’s beginning, 4.6 to 2.5 billion years ago

Answer 11

Archaeaneon

Question 12

Photosynthetic autotrophs that obtain hydrogen electrons by splitting water

Answer 12

Cyanobacteria

Question 13

How old do astrophysicists and geologists estimate Earth is?

Answer 13

4.6 billion years old

Question 14

What hypothesis proposes that life began as a self-sustaining organized system consisting of chemical reactions between simple molecules that are enclosed within a boundary

Answer 14

Metabolism First Hypothesis

Question 15

Divisions of the geological time scale based primarily on organisms that characterized each time period

Answer 15

Eras

Question 16

Cells that obtain organic molecules from the environment

Answer 16

Heterotrophs

Question 17

2500 to 542 million years ago

Answer 17

Proterozoic Eon

Question 18

What hypothesis proposes that organic molecules formed near Earth’s surface?

Answer 18

Prebiotic Soup Hypothesis

Question 19

The oldest subdivision of the paleozoic era

Answer 19

Cambrian Period

Question 20

A type of protobiont formed by adding water to abiotically formed polypeptides

Answer 20

Microspheres

Question 21

What are the six periods in the Paleozoic era?

Answer 21

1. Cambrian
2. Ordovician
3. Silurian
4. Devonian
5. Carboniferous
6. Permian

Question 22

Vertebrates with four limbs

Answer 22

Tetrapods

Question 23

The hypothesis that life developed from nonliving matter

Answer 23

Chemical Evolution

Question 24

This time period from the Paleozoic era that much land was covered by shallow seas

Answer 24

Ordovician Period

Question 25

A transitional form between fishes and tetrapods

Answer 25

Tiktaalik

Question 26

Vesicle-like appendages of abiotically produced organic polymers

Answer 26

Protobionts

Question 27

What hypothesis proposes that organic precursors formed at cracks in the ocean’s floor

Answer 27

Iron-Sulfur World Hypothesis