Natural Selection

Question 0

According to Darwin, what 3 things have to be present in order for evolution to occur?

Answer 0

1. Variation
2. Selection
3. Inheritance

Question 1

How did Darwin explain the theory of natural selection?

Answer 1

Natural selection state that characteristics that increase survival and reproduction will get passed on from generations and will be more common in populations over time.

Question 2

What did Darwin’s theory say about selective pressures?

Answer 2

That there are a lot of different types of selective pressures besides competition, in order to reproduce. The ultimate test of selection is reproductive success.

Question 3

What are the 2 main types of selective pressures that might operate?

Answer 3

1. Selective pressure of finding food

2. Selective pressures of finding mates

Question 4

What is sexual selection?

Answer 4

Sexual selection is the selective pressure of finding a mate based on their traits and characteristics that are likely to aid in reproduction of healthy offspring and pass on from generation to generation

Question 5

What are 3 reasons for variation?

Answer 5

1. Mutations
2. Founder effects –> small portion of a large population will isolate away and be the baseline for future change
3. Genetic bottlenecks/catastrophes: when natural disasters wipe out almost all the population but only a few survive and become the baseline for future change

Question 6

What are 3 products of natural selection?

Answer 6

1. Adaptation: allows organisms to meet reoccurring environmental challenges to their survival
2. By-products: follows from another functional adaption but is useless now like belly buttons
3. Evolutionary noise: certain characteristics that get passed on and have no effect on the species however, it could be beneficial in the future

Question 7

Is language a by product or an adaption?

Answer 7

Language is a by-product occurring from our previous ancestral adaptation to high order cognition like developing a bigger prefrontal cortex.

Question 8

What are 2 criticisms of Darwin’s natural selection?

Answer 8

1. How are traits inherited? –> darwin didnt know much about genetics because it was observed after his theory
2. How do partial structures provide adaptive value? –> why do animals develop partial wings (like penguins) instead of full wings and what value does it have