Topic 2: Natural Selection and Adaptation

Question 1

How did Lamarck suggest what we now know as evolution occured?

Answer 1

• “Use and disuse”
• we acquire characteristics thru lifetime via needs from the environments
• ex. for giraffes, as food got harder to obtain, they strained their necks to reach food higher up, which lead to longer necks.

Question 2

What are the three basics of Natural Selection?

Answer 2

1. Variation
   - individuals within a population vary (in genotype and phenotype)
2. Inheritance
   - some of this variation is heritable
3. Competition
   - reproductive capacity exceeds supply, competition for resources, mates. they need to fight for resources or else change will not occur

Question 3

What do the basics of natural selection result in?

Answer 3

• differential survival and reproduction (at the individual level)

Question 4

traits that contribute to improved survival and reproduction are termed …

Answer 4

Adaptations

Question 5

How does selection operate on variation?

Answer 5

• minor differences between individuals can yield differential survival and reproduction
• we don’t need major differences, often these differences are minor to create differential survival

Question 6

How does selection operate in individuals? not groups? explain with an example of infanticide

Answer 6

• there is no “for the good of the species” !
• male monkeys are often seen killing children within the group. This does not benefit the group, only the singular male. the male will only kill infants who are still nursing, as they prevent the female from entering repro viability.
• kills them so he can impregnate the female

Question 7

How is the concept of adaptation not good or bad?

Answer 7

• adaptations are defined in particular organisms in particular environments, and promote survival and reproduction
• ex. infanticide is not good, or striving for perfection. Only allows that male to perhaps achieve better fitness

Question 8

What is adaptation?

Answer 8

• arisen thru natural/sexual selection
• develops in members of the same species
• solves a problem

Question 9

What is the Williams criteria for adaptation?

Answer 9

1. Reliability (It CAN develop in all members of the species, not constrained)
2. Economy (Solves some kind of problem to promote survivability)
3. Efficiency (Must function well, ex be a good solution and works all the time)

Question 10

If behavior heritable?

Answer 10

• Yes! Some of it is!
• but it is not all genetic. If it was all genetic, it would be harder for selection to act upon it. If it is learned, it is more flexible to change.