KINGDOM ANIMALIA

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

Symmetry A balance in proportions of an

object or organism. 3 types

Asymmetry Radial Symmetry Bilateral Symmetry

Asymmetry Irregular Body

Shape Often sessile

organisms Ex. sponges

Radial Symmetry Can be divided along

any plane, into roughly equal halves.

Ex. Sea Star, Ex. Sea Anemone

Bilateral Symmetry Can be divided

into similar left and right halves that form mirror images of each other.

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

3 Different Body Plans 1. Acoelomate

2. Pseudocoelomate

3. Coelomate All three body plans exhibit bilateral

symmetry

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

Pseudocoelomate Fluid filled

cavity- partly lined

A “real” body cavity

Ex. Roundworm

Coelomate True body

cavity Ex. Insects, fish,

humans

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.

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)

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)

Protection and Support 1. Exoskeleton- hard, waxy

covering on outside of body. ( ex. Crabs, spiders)

2. Endoskeleton- support housed within the body. (ex. Humans)