Convergent and Divergent Evolution Lesson

Types of Evolution

• Convergent vs Divergent

• Coevolution

Convergent

Evolution towards similar characteristic

• Analogous structures

• Similar functions

  • wings

  • aquatic mammals versus fish

Divergent

Closely related species that evoled in different directions

• Homologous structures (different function but similar ancestor)

• Speciation due to environmental adaptations

Multiple Choice

The three species pictured do not share a common ancestor, yet have evolved to have a similar anatomy and life style. This is an example of ?

• Homologous Structures

• Divergent Evolution

• Vestigial Organs

• Convergent Evolution

Coevolution

Two species evolve in response to changes in each other

• Evolutionary arms race

  • adaptations to prevent predation lead to adaptations of predators in response to prey adaptations

Trait Changes

Traits and allele frequencies can change over time in different ways

• Directional

  • the environment favors one trait over another

• Stabilizing

  • the environment finds a middle ground between two traits

• Disruptive

  • the environment favor two extreme variations of a trait

Multiple Choice

individuals with alleles for an extreme type are more likely to survive and reproduce

• stabilizing selection

• directional selection

• disruptive selection

• genetic drift

Multiple Choice

A fire has wiped out the vegetation that produces medium size seeds. As a result, the finches left can feed on seeds that are available in 2 sizes: small and large. What type of selection is likely to take place in this population?

• Disruptive Selection

• Artificial Selection

• Stabilizing Selection

• Directional Selection

Multiple Choice

Starlings produce an average of five eggs. If there are more than five the parents cannot adequately feed the young. Fewer than five and predators may destroy them. As a result, five eggs becomes the most common number.

• Stabilizing

• Directional

• Disruptive