1. Chapter 32 – Animal Diversity

2. Animals have the following characteristics:
32.1 – Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers
Animals have the following characteristics:
Multicellular heterotrophs
Most have muscle & nervous tissue
Most reproduce sexually, with a flagellated sperm & a large egg which unite to form a diploid ZYGOTE
The diploid stage dominates the life cycle
1.3 million living species

3. Vocab Zygote Cleavages Blastula Fertilized egg
Successive mitotic cell divisions without cell growth between cycles
Blastula
Hollow ball of cells surrounding a cavity called the blastocoel

4. Gastrula Ectoderm Endoderm
As the blastula is “punched in”, the embryonic tissue layers will form
Ectoderm
The outer tissue layer
Endoderm
The inner tissue layer

5. Blastopore Archenteron Opening into the gastrula
Becomes the mouth in protosomes
Becomes the anus in deuterostomes
Archenteron
Blind pouch formed by gastrulation

8. Some animals have larvae
Immature form distinct from the adult stage they will undergo metamorphosis
Animals share HOX GENES
Unique family of genes that play important roles in development
Can produce a wide diversity of animal morphology

9. 32.3 – Animals & Their “Body Plans”
Symmetry
None (sponges)
Radial
Bilateral

10. Radial occurs in:
Jellyfish
Any cut through the central axis would produce mirror images

11. Bilateral occurs in
- Lobsters
Humans
Have a right & left side
Single cut would divide the animal into 2 mirror image halves
Dorsal side (back)
Ventral side (belly)
Anterior (head)
Posterior (tail)
Cephalization

12. Tissues
Animal body plans vary according to the organization of the animal’s tissues
Tissues are collections of specialized cells isolated from other tissues by membranous layers
During development, three germ layers give rise to the tissues and organs of the animal embryo

13. Ectoderm is the germ layer covering the embryo’s surface
Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron
Mesoderm is the middle layer

14. Diploblastic animals have ectoderm and endoderm
Triploblastic animals also have an intervening mesoderm layer; these include all bilaterians

15. Body Cavities Most triploblastic animals possess a body cavity
3 types:
1) A coelomate possesses a true body cavity
Derived from mesoderm
Filled with fluid
Separates an animal’s digestive tract from the outer wall
Earthworms

17. 2) Pseudocoelomate Triploblastic animals
Cavity formed from mesoderm & endoderm
Roundworms

18. ----- Meeting Notes (3/30/12 15:00) -----
Mr.Norman
joey
joseph
donald

19. 3) Acoelomates
No cavities between alimentary canal & outer wall of body
Flatworms

21. Functions of Body Cavities
1) Cushion suspended organs
2) Act as a hydrostatic skeleton
3) Enable internal organs to grow & move independently

22. Protostome & Deuterostome Development
3 major differences:
1) Cleavage
2) Coelom formation
3) Fate of the blastopore

23. Cleavage:
P = begins with spiral, determinate cleavage
D = radial, indeterminate cleavage

24. Begins in the gastrula stage
Coelom Formation:
Begins in the gastrula stage
P = coelom forms from splits in the mesoderm
D = coelom forms from mesodermal outpocketings of the archenteron

25. Fate of the Blastospore:
P = mouth forms from the blastopore
D = mouth forms from a secondary opening