Homologous Structures Activity

Name______

Date______

Period____

Standard(s):

  • BI.7 a. Students know why natural selection acts on the phenotype rather than the genotype of an organism.
  • BI. 8. a. Students know how natural selection determines the differential survival of groups of organisms.

Objectives: SWBAT…

  • Explain how natural selection determines the differential survival of groups of organisms.
  • Describe how natural selection acts on the phenotype of an organism

Introduction:The prefix homo- means the same. Homologous structures refer to structures that have a shared embryonic origin or ancestry. The forelimbs of a human, the wing of a bird, the wing of a bat and the flipper of the dolphin have the same embryonic origin during development and they have the same basic bones. Homologousstructures are used as anatomical evidence of evolution.

Procedure:

Part I. Identifying Common Bones

1.)Examine the diagram of the bones of the 6 vertebrate organisms.

2.)Using the human arm as a key locate and label the carpals,ulna, radius, and humerus bones in each organism.

3.)Using the following coloration key color the bones of each organism its correct color.

Humerus=Yellow

Carpals=Red

Radius=Blue

Ulna=Green

Part II. Limb Function

1.)Examine the limbs and discuss with your partner the function of each type of limb.

2.)Cut-out and paste each limb into the correct column in the table on the back of the sheet.

Follow-up Questions:

  • Answer the questions below in complete sentences.
  • You may use the resources below to help with this.

Resources:

Questions:

1.)What does the presence of homologous structures in the limbs of vertebrates tell us?

2.)Which of the animals do you think are the most closely related? Why?

3.)How have limbs of the different organisms changed over time?

4.) What is the difference between homologous structures and analogous structures?

Walking/Climbing / Flying / Swimming / Grasping
Name of Organism: / Name of Organism: / Name of Organism: / Name of Organism:
Name of Organism: / Name of Organism: / Name of Organism: / Name of Organism: