Homologous Structures: Evidence for Evolution

What You'll Learn

Homologous structures are similar body parts in different species that suggest a common ancestor. The arm bones of humans, whales, bats, and dogs share the same basic structure.

Key Words

fossil record
species

Materials Needed

colored pencils
coins (for Punnett squares)
tape
index cards

Safety First

Do not mix unknown chemicals together.
Tie back long hair before starting the experiment.

Steps

Step 1 — Read

Read and learn: Homologous structures are similar body parts in different species that suggest a common ancestor. The arm bones of humans, whales, bats, and dogs share the same basic structure.

Step 2 — Do

Compare your results with a partner.

Step 3 — Observe

Watch carefully for any changes and note the time.

Step 4 — Record

Create a data table to organize your measurements.

Check Your Understanding

Question 1

1 of 3

What are homologous structures?