Module 1 Flashcards
What is evolution?
Descent with inherited modification
Gain and loss of traits
What is small scale evolution?
Changes in allele frequencies in a population
What is large scale evolution?
The descent of different species from a common ancestor
How do we know evolution occurs?
Fossil evidence
Homologous structures (& vestigial structure- pelvic bone in whales)
Observing evolution
What are the four mechanisms of evolution?
Mutation
Genetic drift
Migration
Natural selection
What is mutation?
RANDOM changes in DNA sequences
Can be good, bad, or neutral
Is mutation heritable?
Depends, if the mutation occurs in a reproductive cell it can be passed on to offspring
What causes mutation?
Mutation occurs at a predictable rate, the body has mechanisms to correct this, some factors increase the risk that mutations will slip past the body’s corrective mechanisms (UV light, nicotine, alcohol, etc.)
Why is mutation important for natural selection?
All variation- the raw material for natural selection- must initially come from mutation
What is genetic drift?
Random change in allele frequencies in a population
How does genetic drift occur?
Founder effect & bottleneck effect
Genetic drift does not provide advantage or disadvantage for reproductive success
What is fixation?
A consequence of genetic drift when an allele frequency reaches 100%
Reduces variation in a population
What is the founder effect?
When a subgroup splits off from a main population and set the alleles of the new population
What is the bottleneck effect?
A population size is reduced (natural disaster) and variation is reduced
What is migration?
Gene flow into or out of a population changing the allele frequencies in both original and recipient populations