1. KINGDOM ANIMALIA

2. Characteristics of an Animal
1. Multicellular
2. Eukaryotic
3. No cell wall
4. Heterotrophic
5. Motile or sessile
6. Digestion (internal or external)

3. Symmetry A balance in proportions of an object or organism. 3 types
Asymmetry
Radial Symmetry
Bilateral Symmetry

4. Asymmetry
Irregular Body Shape
Often sessile organisms
Ex. sponges

5. Radial Symmetry
Can be divided along any plane, into roughly equal halves.
Ex. Sea Star,
Ex. Sea Anemone

6. Bilateral Symmetry
Can be divided into similar left and right halves that form mirror images of each other.

7. More terms Anterior- Head End Posterior- Tail End Dorsal – Back End
Ventral- Belly Surface
Radial Symmetry
Oral- underside (mouth)
Aboral – top side (anus)

8. 3 Different Body Plans 1. Acoelomate 2. Pseudocoelomate 3. Coelomate
All three body plans exhibit bilateral symmetry

9. Acoelomate
1. 3 cell layers
2. No body cavity
Ex. Flatworm

10. Pseudocoelomate Fluid filled cavity- partly lined A “real” body cavity
Ex. Roundworm

11. Coelomate
True body cavity
Ex. Insects, fish, humans

12. Animal Development
Most develop from a single fertilized egg called a zygote.
2 Stages of development
Blastula- single layer of cells around a fluid-filled space.
Gastrula- structure made of two cell layers.

13. 3 Different Cell Layers
1. Ectoderm- cell on outer surface of gastrula (ex. Skin, nervous tissue)
2. Endoderm- layer of cell lining inner surface of gastrula. (develops into digestive tract)
3. Mesoderm- b/w the ecto and endoderm (forms muscles, repro. Organs, circulatory vessels)

14. 2 Ways to Develop
1. Protostome- an animal with a mouth that develops from the opening in the gastrula.
(ex. Insects, earthworms)
2. Deuterostome- an animal in which the anus develops from the opening in the gastrula. (ex. Fish, birds, humans)

15. Protection and Support
1. Exoskeleton- hard, waxy covering on outside of body. ( ex. Crabs, spiders)
2. Endoskeleton- support housed within the body. (ex. Humans)