Names: ______

Animal Evolution and Body Plans

In this activity, you will:

  • Make models of the three body cavity types into which the triploblastic animals are classified
  • Make models of the three body symmetry types into which animals are categorized.
  • Identify dorsal, ventral, anterior and posterior ends
  • Use models to show differences in protostome and deuterstome development.

Directions:

Part 1: Germ Layer Activity

1. Choose three different colors of modeling clay, and designate which color you will use for each of the three embryonic layers that give rise to all adult body parts:

Endoderm layer:

Medoderm layer:

Ectoderm layer:

2. Divide these three colors up into three smaller portions so that each body cavity type will include the same colors for comparison.

3. Using the above diagrams of the three body cavity types, make a model of each of the following and give an example of an animal (or phylum) that represents each type of body plan. When complete, show the models to your teacher for a grade:

Acoelomate Example:Grade: ______

Pseudocoelomate Example:Grade: ______

Coelomate Example:Grade: ______

4. Determine what each of the following gastrula germ layers become:

Ectoderm:

Mesoderm:

Endoderm:

5. Use your model of a coelomate to identify the endoderm, ectoderm, and mesoderm for a grade. ______

Part 2: Body Symmetry Activity

6. Use modeling clay to make a model of an imaginary animal with the following three symmetry types. Give an example of an animal (or phylum) that has each type of symmetry. When complete, show your models to the teacher for your grade.

Asymmetry Example: Grade: ______

Radial Symmetry Example:Grade: ______

Bilateral Symmetry Example:Grade: ______

7. Draw your creation of an animal with bilateral symmetry. Label the dorsal, ventral, anterior, and posterior ends.

Part 3: Protostomes versus Deuterostomes

8. Use modeling clay to identify the differences in protostome and deuterstome development.

First, create a model of a zygote to differentiate between spiral and radial cleavage (this will be hard to model – be ready to explain it to the teacher). Also differentiate between determinate and indeterminate cleavage when explaining the differences in the eight-cell stage of the zygote

Model and explanation grade: ______

Finally, use the modeling clay to identify a blastopore, and explain the varying fates of the blastopore in protostome and deuterostome development.

Model and explanation grade: ______

Complete the following table.

Protostomes / Deuterostomes
Examples phylums: / Example phylums:
1. Cleavage: / 1. Cleavage:
2. Coelom Formation: / 2. Coelom Formation:
3. Fate of blastopore: / 3. Fate of blastopore: