1. Introduction to Animals

2. Characteristics Multicellular Eukaryotic (with no cell walls!)
Heterotrophic

3. Multicellular Organization
Most animals contain large numbers of cells.
Humans contain 50 trillion cells!
In most animals, cells are specialized.
cells  tissues  organs  organ systems
Cell specialization has allowed organisms to evolve and adapt to many environments.

4. Animals are Heterotrophic
Heterotrophs must obtain complex organic material from other sources.
The animal eats (ingests) and then digests. This process extracts the carbohydrates, protein and lipids from the food eaten.

5. Sexual Reproduction and Development
Sexual reproduction restores the diploid number and increases genetic variation.
During the developmental process, the zygote undergoes many mitotic divisions. These identical cells must undergo differentiation.
Differentiation is process of cell becoming different from each other and being specialized.

7. Movement Most animal are able to move.
The ability to move results from the interrelations of two types of tissues found only in animals: nervous tissue and muscular tissue.
There are a few animals that are sessile.

8. Origin and Classification
The first animals probably arose from the sea.
Taxonomists have grouped animals into several phyla based on evolutionary relationships.
Many taxonomist recognize 30 or more animal phyla!
(We will investigate 9 major phyla. Eight of these phyla include invertebrates and only Phylum Chordata includes the vertebrates.)

9. Animal Body Structure
Symmetry
Germ layers
Body Cavities

10. Symmetry
Symmetry refers to the consistent overall pattern of structure of an animal.
Animals have three patterns of symmetry:
Asymmetry – no symmetry
Radial Symmetry – similar parts branch in all directions from a central point
Bilateral Symmetry- similar halves on either side of a central plane.

11. Patterns of Symmetry

12. Identify the Type of Symmetry

13. Most animals have a dorsal, ventral, anterior and posterior side or orientation.
Dorsal – top (topside or back)
Ventral – bottom (underside or belly)
Anterior – head
Posterior – tail
Most animals exhibit cephalization, the concentration of sensory and brain structures in the anterior. Animals with cephalization have a head!

14. Germ Layers
Germ layers are fundamental tissue types found in all animals except sponges (no true tissues).
Ectoderm
Mesoderm
Endoderm

15. Body Cavities
Most animals have a fluid filled space that forms between the digestive tract and the outer wall of the body during development.
This body cavity is known as a COELOM.

16. Animal Diversity 95% Invertebrates (animals without a backbone)
Phylum Porifera (sponges)
Phylum Cnidaria (jellyfish & corals)
Phylum Platyhelminthes (flatworms)
Phylum Nematoda (roundworms)
Phylum Annelida (segmented worms)
Phylum Mollusca (mollusks)
Phylum Echinodermata (spiny sea creatures)
Phylum Arthropoda (insects & spiders)
5% Vertebrates (animals with a backbone)
Phylum Chordata (Fishes, birds, reptiles, amphibians and mammals)