1. Invertebrates

2. Kingdom Animalia Characteristics
Review
What were the 5 characteristics of Animalia?
Name the 3 body layers and state what human tissues develop from each layer.
Name the 2 types of body cavities and state an example organism.
Name the 3 types of body plans. 2

3. Invertebrates
Most animals are invertebrates. Invertebrates lack bones, especially the vertebra that cover and protect the spinal cord.
Over 95% of animals are invertebrates. The phyla with the most species is Arthropoda or the insects, spiders and crabs. 3

4. Invertebrate Phyla There are eight phyla of invertebrates:
Porifera: sponges
Cnidarians: jellyfish
Platyhelminthes: flatworms
Annelids: segmented worms
Nematoda: roundworms
Mollusca: snails, clams
Echinoderms: starfish
Arthropods: insects, crabs and spiders

5. 1. Porifera: Sponges Lack any definite symmetry
Sponges are the simplest animals, lack defined tissues and organs
Are hermaphroditic
Fertilized eggs become free-swimming larvae, which then attach to the ocean floor, metamorphose and become fixed in one place

6. 2. Cnidarians: Jellyfish and Corals
Have radial symmetry
Reproduce both sexually and asexually
Many have tentacles with stinging cells that they use to capture food

7. 3. Platyhelminthes: Flatworms
Have bilateral symmetry
Free living worms are hermaphroditic and they generate a reproductive system only during breeding season
Can be free-living or parasites

8. 4. Nematodes: Roundworms
Have bilateral symmetry
Have long thin, round worm like bodies
Most are free-living, however, some are parasitic and can cause major health concerns
Simplest organisms to have a complete digestive tract

9. 5. Annelida: Segmented Worms
Major evolutionary change - have a coelom
Have bilateral symmetry
Have round, segmented bodies which is beneficial for movement, can move different parts at a time, increases flexibility

10. 6. Mollusca: Snails, Clams, Squid
Have bilateral symmetry
Are coelomic
They are soft-bodied animals
Most cover their body with a shell for protection

11. 7. Echinodermata: Starfish
Have radial symmetry
Have spiny outer covering for protection
Move by changing water pressure inside tubes in the arms
Can be stationary or burrowing
Have a coelom

12. 8. Arthropoda: Insects, Spiders and Crustaceans
Have bilateral symmetry
Ecologically important part of food chains due to their abundant numbers
Have a coelom
Have simple respiratory, circulatory and excretory systems
There are four group of arthropods:
Arachnids (spiders)
Centipedes & Millipedes
Crustaceans (crabs, shrimp)
Insects (have 6 legs)

13. The order of evolution of different animal characteristics
The order of evolution of different animal characteristics. You will learn about this in the next unit.

14. The number of species in each phyla.