1. Introduction to Animals

2. Characteristics Multicellular Organization Heterotrophic
Sexual reproduction and development
Movement

3. Multicellular Organization
Most animals contain large numbers of cells.
Humans contain 50 trillion cells.
In most animals, there is a division of labor.
Specialization is the adaptation of a cell for a particular function.
Tissues are the organization of cells. Cell are able to organize by the joining of cells by cell junctions.
Cell specialization has allowed organisms to evolve and adapt to many environments.

4. Animals are Heterotrophic
They must obtain complex organic material from other sources.
Most accomplish this through ingestion.
Digestion is accomplished within the animal. 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.

6. 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.

7. 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 11 phyla. Ten of the phyla include invertebrates and only Chordata includes the vertebrates.

8. Animal Body Structure
Symmetry
Germ layers
Body Cavities

9. Symmetry
Asymmetry 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.

10. Patterns of Symmetry

11. Identify the Type of Symmetry

12. Most animals have a dorsal, ventral, anterior and posterior side or orientation.
Dorsal – top
Ventral – bottom
Anterior – head
Posterior - tail
Most animals exhibit cephalization, the concentration of sensory and brain structures in the anterior. Animals with cephalization have a head!

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

14. 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 space is known as a COELOM.

15. Acoelomate (without a coelom)
2 germ layers
ectoderm and endoderm
not separated by a cavity
least complex body plan
sponges and cnidarians
3 layer acoelomate
3 germ layers
endoderm, mesoderm and ectoderm
flatworms
Pseudocoelomate
pseudocoelom
cavity formed between mesoderm and endoderm
roundworms and rotifers
Coelomate
cavity developed within the mesoderm
most complex body plan
mollusks, annelids, arthropods, echinoderms, and chordates

16. Animal Diversity Invertebrates Chordates 10 phyla 95% of animals
Notochord
Dorsal nerve cord
Pharyngeal pouches
Postanal tail
Vertebrates
Include fishes, birds and mammals

17. What is the difference in a vertebrate and an invertebrate?
A vertebrate is an animal with a backbone and invertebrates do not have a backbone.

18. Comparison of Invertebrates and Vertebrates
symmetry
germ layers
Body cavities
Segmentation
support
Respiratory/
circulatory
Digestive/excretory
Nervous
reproduction