1. Animals

2. Basic Characteristics
Eukaryotic
Multicellular
Heterotrophic
If mobile, get food by moving
If sessile, get food
by filter feeding
intracellular digestion

3. Symmetry = is the arrangement of body structures
Asymmetry= no symmetry
Example: Sea Sponge

4. Symmetry
Radial Symmetry= can be divided evenly along many different planes
Example: Hydra, Jellyfish

5. Symmetry
Bilateral Symmetry= can be divided equally only along length into Left and Right sides
Example: Human, Dog

6. Cephalization
Cephalization: sense organs are concentrated at the head end of the body
Can process info
from environment
much faster

7. Directional Terminology
Anterior - head end
Posterior - tail end

8. Directional Terminology
Dorsal - back side
Ventral - belly side

9. Development
Fertilization of egg cell by sperm cell produces a zygote

10. Development
Zygote divides by mitosis to form a blastula (hollow ball of cells)

11. Development The blastula is made of identical, unspecialized cells
These are embryonic stem cells
 Scientists would like to harvest these to do research because they can turn into any type of cell

12. Stem Cells

13. Development
One side folds inward, forming a gastrula

14. Germ Layers
The layers of the gastrula start to differentiate into different germ layers:
Cells on outer layer
are the ectoderm
Produce the skin
and nervous tissue

15. Germ Layers Cells on inner layer are endoderm
 Produce the digestive system

16. Germ Layers
A 3rd layer forming between the endo- and ectoderm is called the mesoderm
Produces the muscular,
respiratory,
circulatory, &
excretory systems

17. Skeletons
All skeletons allow movement and provide support & protection
Exoskeleton
= Hard outer
covering

18. Skeletons Endoskeleton
= Internal structure made of bone and/or cartilage