Chapter 22

Question 1

What is evolution?

Answer 1

Heritable change in a population over generations.

Evolution refers to the process through which species undergo changes over time.

Question 2

What is an adaptation?

Answer 2

An inherited trait that improves survival or reproduction.

Adaptations enhance an organism’s ability to thrive in its environment.

Question 3

What is natural selection?

Answer 3

Individuals with favorable traits survive and reproduce more.

Natural selection is a key mechanism of evolution.

Question 4

Does selection act on individuals or populations?

Answer 4

Selection acts on individuals; evolution occurs in populations.

This distinction is crucial for understanding evolutionary processes.

Question 5

What did Hutton & Lyell propose?

Answer 5

Uniformitarianism—Earth changes slowly via continuous processes.

Their ideas laid the groundwork for understanding geological time.

Question 6

Why were Hutton & Lyell important for evolution?

Answer 6

They showed Earth is old enough for evolution to occur.

Their work provided the necessary time frame for evolutionary changes.

Question 7

What were Lamarck’s incorrect ideas?

Answer 7

Use/disuse; inheritance of acquired traits.

Lamarck’s theories were later disproven by Darwin’s findings.

Question 8

What key ideas came from Darwin?

Answer 8

Descent with modification and natural selection.

Darwin’s theories revolutionized the understanding of biological diversity.

Question 9

What influenced Darwin’s thinking?

Answer 9

Adaptations and variation (finches, tortoises).

Observations during his voyage led to his formulation of natural selection.

Question 10

What 3 conditions are required for natural selection?

Answer 10

• Variation
• Heritability
• Differential reproduction

These conditions are essential for the process of natural selection to occur.

Question 11

What is a selective pressure?

Answer 11

Environmental factor determining which traits are beneficial.

Selective pressures shape the evolution of species.

Question 12

Why are selective pressures important?

Answer 12

They determine which individuals survive and reproduce.

Understanding selective pressures helps explain evolutionary outcomes.

Question 13

Similarities between natural and artificial selection?

Answer 13

• Both require variation
• Heritability
• Differential reproduction

Both processes lead to changes in traits within populations.

Question 14

Difference: natural vs artificial selection?

Answer 14

Natural = environment chooses; artificial = humans choose.

This distinction highlights the role of human intervention in artificial selection.

Question 15

Example of artificial selection?

Answer 15

• Dog breeds
• Agricultural plants
• Livestock

These examples illustrate how humans influence the traits of species.

Question 16

Five categories of evolutionary evidence?

Answer 16

• Fossils
• Biogeography
• Convergent evolution
• Selective breeding
• Homologies

These categories provide a comprehensive understanding of evolutionary processes.

Question 17

What does the fossil record show?

Answer 17

Extinction, new groups, change over time.

Fossils are crucial for understanding the history of life on Earth.

Question 18

What does biogeography show?

Answer 18

Distribution of species; continental drift; endemic species.

Biogeography helps explain how species are related and adapted to their environments.

Question 19

What is convergent evolution?

Answer 19

Unrelated species evolving similar traits.

This phenomenon occurs due to similar environmental pressures.

Question 20

What causes analogous structures?

Answer 20

Convergent evolution.

Analogous structures serve similar functions but arise from different evolutionary paths.

Question 21

What does selective breeding show?

Answer 21

Species change when certain traits are selected.

Selective breeding demonstrates the power of human choice in shaping species.

Question 22

What are homologous structures?

Answer 22

Traits inherited from a common ancestor.

Homologous structures provide evidence for common descent.

Question 23

What are analogous structures?

Answer 23

Similar function; different ancestry.

These structures highlight how different species can adapt similarly to environmental challenges.

Question 24

Convergent evolution produces what structures?

Answer 24

Analogous structures.

This reflects how unrelated species can develop similar adaptations.

Question 25

Divergent evolution produces **what structures**?

Answer 25

Homologous structures. ## Footnote Divergent evolution illustrates how species can evolve different traits from a common ancestor.

Question 26

What is **horizontal gene transfer (HGT)**?

Answer 26

Gene transfer between non-parent/offspring organisms. ## Footnote HGT is significant in microbial evolution and antibiotic resistance.

Question 27

Why is **HGT** important?

Answer 27

Increases genetic diversity; spreads antibiotic resistance. ## Footnote Understanding HGT is crucial for addressing challenges in medicine and evolution.

Question 28

What are the **three HGT mechanisms**?

Answer 28

* Transformation * Transduction * Conjugation ## Footnote These mechanisms describe how genetic material is exchanged between organisms.

Question 29

What is **transformation**?

Answer 29

Uptake of free DNA. ## Footnote Transformation is one way bacteria can acquire new genetic traits.

Question 30

What is **transduction**?

Answer 30

Phages transfer DNA. ## Footnote This process involves viruses that infect bacteria and facilitate gene transfer.

Question 31

What is **conjugation**?

Answer 31

Direct DNA transfer via sex pilus. ## Footnote Conjugation is a common method of genetic exchange in bacteria.