Lecture 4

Question 1

Adaptive Radiation

Answer 1

The evolution of many diversely adapted species from a common ancestor upon introduction to new environments

Question 2

*Natural Selection

Answer 2

Alleles that contribute to success in survival and reproduction increase in frequency; results in adaptation

Question 3

Adaptation

Answer 3

Heritable trait that increases the fitness of an individual in a particular environment relative to individuals lacking the trait

Question 4

Fitness

Answer 4

Ability of an individual to produce surviving off spring relative to that ability in other individuals in the population

Question 5

*Genetic Drift

Answer 5

Causes allele frequencies to change randomly; May even cause some alleles to be lost from the population while other alleles may become fixed. (Fixed=100%)

• More pronounced in small populations
• Random with respect to fitness

Question 6

*Gene Flow

Answer 6

Causes allele frequencies to change randomly depending on what alleles are being brought into the population and what alleles are leaving
*Migration

Question 7

Key Points

Answer 7

• Natural Selection is still acting on the human population
• Natural Selection doesn’t always produce optimal results
• Population genetics models help explain how evolutionary forces interact to influence the genetic make up of populations