Evolutionary Agents
The total collection of all the genes in a population.
Gene Pool
Scientist who wrote On the Origin of Species.
Charles Darwin
Mode where the "average" individuals survive best.
Stabilizing Selection
Differences between individuals in a population.
Variation
Human birth weights are an example of this mode.
Stabilizing Selection
When something random changes allele frequency by chance.
Genetic Drift
When a harmless animal looks like a dangerous one to stay safe.
Mimicry
Mode where the population shifts toward one extreme.
Directional Selection
A trait that helps an organism survive and reproduce.
Adaptation
Darwin’s famous birds that evolved different beak shapes.
Finches
When a few individuals start a brand new population elsewhere.
Founder Effect
When a harmless animal looks like a dangerous one to stay safe.
Artificial Selection
Rare mode where both extremes are good, but the middle ones die.
Disruptive Selection
Small-scale changes in a gene pool that are reversible.
Microevolution
These butterflies mimic each other to avoid birds.
Monarch and Viceroy
When a population size is crushed and then grows back with less diversity.
Bottleneck Effect
When two species evolve together, like a cheetah and a gazelle.
Coevolution
Bacteria becoming resistant to medicine is an example of this mode.
Directional Selection
Large, irreversible changes that lead to new species.
Macroevolution
These cattle were bred for milk or beef in England/Scotland.
Hereford or Ayrshire
When individuals move into or out of a population.
Gene Flow
Why inbreeding is bad for a gene pool over time.
Harmful alleles show up more
This is the most common mode of selection in nature.
Stabilizing
Environmental factors that decide which individuals survive.
Selection Pressure
The "Agent of Selection" in the Peppered Moth example.
Predators/Birds