Evolution (Part 2) – Types of Evolution

How can you tell if two parents belong to the same species? What is speciation?

• If two animals mate and produce fertile offspring (offspring can reproduce), they are considered the same species.

• If they cannot produce offspring, or the offspring is sterile (cannot reproduce), they are considered different species.

• Speciation: The process by which one species splits into two or more new species over time.

• Evolution: The change in inherited traits of a population over generations.

What are convergent evolution, divergent evolution, coevolution, and analogous structures?

• Convergent Evolution: Unrelated species independently evolve similar traits because they live in similar environments or face similar selective pressures.

• Divergent Evolution: Related species become increasingly different after adapting to different environments.

• Coevolution: Two or more species influence each other’s evolution through close interactions.

• Analogous Structures: Structures with similar functions but different evolutionary origins (e.g., bird wings and insect wings).

Under what conditions do convergent evolution and divergent evolution happen? Given a scenario, how can you tell which type it is?

Convergent Evolution

• Happens when unrelated species live in similar environments or experience similar environmental pressures.

• They evolve similar adaptations independently.

Divergent Evolution

• Happens when related species become separated or live in different environments.

• Different environmental pressures cause them to develop different adaptations.

How to identify them:

• Unrelated + become similar → Convergent

• Related + become different → Divergent

• Two species affecting each other → Coevolution

How do organisms influence each other’s evolution? (Bird, monarch butterfly, mimic butterfly; plant and insect)

The plant involves chemical defense against the insects and the insect evolves ways to resist the plant’s defense, and the race goes on