Download 15.2 PDQ - Biology with Radjewski

15.2 PDQ
1. Name and define 3 processes that affect the
genetic makeup of populations over time
• Gene flow – exchange of genes between
populations due to migration
• Genetic Drift – change in gene frequencies
from generation to generation due to random
processes
• Non-random mating – selection of mates on
basis of traits
• Mutation – change in DNA
• Selection – choosing preferential phenotypes
2. Explain, “natural selection acts on
individuals, but populations evolve”
• Changes that occur are developmental in a
single organism over the course of a life cycle.
• After breeding  populations will evolve
4. What is the difference between
natural selection and adaptation?
Natural Selection
• Difference in fitness among
organisms
Adaptation
• Enhances the fitness of the
organism
5. What is the raw material on which
mechanisms of evolution act upon?
• variation
6. What does it mean to say a
population evolves?
• It genetically changes over time
7. Why is genetic drift more apparent
in small populations?
• Because each individual’s genes represent a
large fraction of the gene pool
8. What is the net affect of a
population bottleneck?
• Loss of genetic
variation
9. Describe founder’s effect
• Loss of genetic variation that occurs when a
new population is established
10.Define sexual selection
• Preference by 1
sex for certain
characteristics