Homologous Structures: Evidence for Evolution (Part 4)

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

adaptation
fossil record
species

Materials Needed

slides
onion skin
iodine stain
paper
colored pencils

Safety First

Dispose of materials properly after the experiment.
Handle glass items carefully to avoid breakage.
Do not mix unknown chemicals together.

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?