1. Complexity of the Animal Kingdom
Learning Outcome G1

2. Learning Outcome G1
Analyse how the increasing complexity of animal phyla represents an evolutionary continuum

3. Student Achievement Indicators
Students who have fully met this learning outcome will be able to:
Compare phyla in terms of:
levels of organization
cephalization
development of a coelom
symmetry
reproduction
Describe the life functions animals need to survive, including: (Examined in depth with specific phyla)
feeding
respiration
internal transport
excretion
response and motility

4. Student Achievement Indicators
Compare the advantages and disadvantages of different ways animals carry out their life functions (e.g., filter feeding vs. fluid feeding, parasitic vs. free-living, asexual vs. sexual reproduction, sessile vs. motile)

5. Characteristics of Animals
Heterotrophic - eats other organisms or organic material that is decomposing
Animal cells do not have a cell wall
Animal cells are held together by structural proteins such a collagen
Have muscle tissue
Have nervous tissue

6. Characteristics of Animals
Generally reproduce sexually, although more primitive animals may have life cycles that include an asexual phase.
The lifecycle of animals is generally diploid (2n) and only the gametes are haploid (n)
All animals are multicellular eukaryotes

7. Theory of Origin of Animal Kingdom
The animal kingdom is monophyletic
If we could trace all animal lineages back it would lead to one common ancestor

8. Complexity & Diversity
Lower invertebrate such as jellyfish or sponges lack a mesoderm, therefore they do not have a complex circulatory, muscular or urinary system
More complex animals have a large mesoderm which allows the formation of more complex systems.

9. Embryonic Development
Small flagellated sperm and large non-motile egg
Zygote (2n) - A fertilized egg
Mitotic divisions start to occur, this is known as cleavage
Blastula forms
This is a multicellular state
In many animals the blastula looks like a hollow sphere

10. Embryonic Development
Gastrulation occurs when the blastula folds inward
Embryonic tissues are produced by this folding
These tissues will eventually become adult body parts
Gastrulation forms germ layer
There are three germ layers:
Ectoderm (outer layer) - forms the skin and nervous system
Mesoderm (middle layer) - forms the circulatory, reproductive, urinary and muscular systems
Endoderm (inner layer) – forms the gut

12. Body Cavity & Symmetry Body Cavity
Both type of body cavity and symmetry are used to classify animals
There are two types of body cavities:
Simple
A gut with one opening formed from the endoderm.
The opening serves as both a mouth and an anus
This type of cavity is present in simple animals
Example - flatworm

15. Body Cavity & Symmetry Complex Gut with both a mouth and anus
Having both a mouth and an anus allows one way movement of food through the gut.
Allows greater regional specialization
Development of chewing mechanisms
This occurs in more complex animals
Development of coelom, which is a body cavity of space lined with a layer of cells and peritoneum
Peritoneum – is a covering membrane that lines the body cavity and covers the internal organs
The coelom is located between the gut and wall and is found in all vertebrates and many invertebrates.

16. Body Cavity & Symmetry Animals with a coelom are known as coelomates
Less complex invertebrates may lack a coelom and are known as acoelomates
Some animals are known as pseudocoelomates
They have an intermediate structure known as a pseudocoelom (“fake-coelom)
It is known as a pseudocoelom because the body cavity is not covered by a peritoneum.

18. Body Cavity & Symmetry Symmetry
There are two types of symmetry in Kingdom Animalia:
Radial asymmetry
Symmetrical around a central axis
Not highly adapted for movement
Can not move quickly
No definite head region or anterior end
Example – hydra/ jellyfish

19. Body Cavity & Symmetry Bilateral symmetry
Right and left hand sides of the organisms are identical
Designed for speed
Have definite head region
Gives more immediate information about the environment
Have cephalisation
Concentration of nerve cells in the anterior region of the body
Example – fish/cow/Human