Lecture 2

Question 1

Could life on earth start again? Why or why not?

Answer 1

very unlikely as atmospheric conditions are much different today than before, however could possibly start again just highly unlikely. the chemical evolution would be hard to occur, organic evolution can easier

Question 2

Chemical Evolution

Answer 2

• Formation of complex organic molecules from simpler inorganic molecules through chemical reactions
• First step in the development of life on this planet.

Question 3

Organic Evolution

Answer 3

• The process by which changes in the genetic composition of populations of organisms occur in response to environmental changes
• Descent with modification

Question 4

True or false: Evolution as a theory was accepted before Natural Selection

Answer 4

True

Question 5

Five theories summarize Darwin’s views:

Answer 5

1. Perpetual Change
2. Common Descent
3. Multiplication of Species
4. Gradualism
5. Natural Selection

Question 6

Which of Darwins theories are not universally accepted/resolved?

Answer 6

Gradualism

Natural Selection

Question 7

Perpetual Change

Answer 7

Living world is always changing

Evidence: Fossil record

Question 8

Why is the fossil record is biased?

Answer 8

Hard structures (skeletons, shells, teeth)
are preserved best so soft-bodied animals such as jellyfish and worms are under-represented

Question 9

Common Descent

Answer 9

All organisms are descended from a common ancestor
(Last Universal Common Ancestor (LUCA))
Evidence: organismal form, cellular structure, and genetics

Question 10

Evidence for Common Descent (Shared characteristics of living things)

Answer 10

1. Chemical uniqueness
2. Complexity and hierarchical organization
3. Reproduction
4. Possession of genetic program*
5. Metabolism
6. Development
7. Environmental interaction
8. Movement

Question 11

Homology

Answer 11

Similarity of parts of different organisms caused by evolutionary derivation from a corresponding part or organ in a common ancestor

Question 12

Multiplication of Species

Answer 12

Evolution produces new species by splitting and transforming older ones
New species form through the appearance of reproductive barriers

Question 13

Gradualism

Answer 13

Small changes accumulate steadily over time

Question 14

Evidence against gradualism:

Answer 14

It is NOT supported by the fossil record

Animal breeding suggests that changes can be substantial and sudden

Question 15

Punctuated Equilibrium

Answer 15

Proposed in response to lack of evidence for Gradualism • Niles Eldridge and Stephen Jay Gould (1977)

Long periods of stasis (equilibrium), punctuated by brief events of speciation

Question 16

Natural Selection

Answer 16

the process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Question 17

How does Natural selection explain adaptation?

Answer 17

Adaptation = a change or the process of change by which an organism or species becomes better suited to its environment.

Question 18

Darwin’s observations

Answer 18

1 Natural populations do not normally increase exponentially but remain fairly constant
2 Variation occurs among individuals within populations
3 Variation is heritable
4 Organisms have great potential for fertility, which permits exponential growth of populations
5 Natural resources are limited