Evidence for Evolution

Question 1

Evolution vs. Natural Selection

Answer 1

• Evolution: genetic changes (allele frequency) over time, through generations in a population
• Natural Selection: operates on phenotypes, not genotypes

Question 2

Evidence: fossils

Answer 2

• Show morphological changes over millions of years
• Vestigial structures show evidence of previously important body parts

Question 3

Evidence: bad design

Answer 3

• Ex: left recurrent laryngeal nerve runs from the brain to the larynx by looping around
• Inefficient design today, but originated in fish, where it was a direct link

Question 4

Biogeography

Answer 4

• Distribution of life across continents (Pangaea)
• Ex: marsupials in Australia and the Americas

Question 5

Convergent evolution

Answer 5

• Similar adaptations without a common ancestor (it was beneficial to evolve with a similar morphology)
• Ex: non-crabs converging into crab-like forms

Question 6

Humans inadvertently create selection

Answer 6

• Peppered moths, harvesting, hunting
• Those with traits most fit for survival will be seen at a higher frequency over time

Question 7

Molecular genetics

Answer 7

• DNA suggests a universal origin of life
• Speciation (observed through genetic differences) appears to accumulate at a constant rate
• Ex: increase in pseudogenes for olfactory receptors in cetaceans when they returned to the water