A Very Diverse Kingdom

Kingdom Animalia Characteristics All animals share the following characteristics 1. Eukaryotic 2. Multicellular 3. Reproduce sexually 4. Heterotrophic 5. Motile, at least for part of their life

Animals are taxonomically grouped based on three main features: Number of body layers Type of Body cavity Body Symmetry Kingdom Animalia Features

The 3 main layers appear very early in embryonic development. In humans the layers are: Endoderm – lungs, liver, gut lining Mesoderm – muscles, blood, kidneys Ectoderm – skin, nerves Feature 1: Number of body layers

The two main types of body cavities are: Coelomates –have a fluid filled body cavity that supports organ systems Acoelomates – lack a fluid filled body cavity like flatworms Feature 2: Type of Body Cavity

Text - Page 497

The three main types of symmetry are: Bilateral – can be cut into two mirror images through a central line. Radial – body is organized around a central axis. They are symmetrical around any central cut. Asymmetry – no distinctive symmetry Feature 3: Body Symmetry

8 Top Bottom Back Front

Animal Phyla Animalia phyla are spilt into two major groups based on the presence or absence of a spinal cord and vertebra 1. Non-chordates or invertebrates 2. Chordates or vertebrates

 These are animals without a notochord (backbone)  There are eight phyla of invertebrates 1. Porifera (Sponges) 2. Cnidarians (jellyfish) 3. Platyhelminthes (Flatworms) 4. Annelids (segemented worms) 5. Nematoda (Roundworms) 6. Mollusca (snails, clams) 7. Echinoderms (starfish) 8. Arthropods (insects, crabs) Invertebrate Phyla

1. Porifera: Sponges  Asymmetrical (no symmetry)  No coelom  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.

2. Cnidarians: Jellyfish and Corals  Have radial symmetry  No coelom  Have tentacles with stinging cells that they use to capture food.  Reproduce both sexually and asexually

3. Platyhelminthes: Flatworms  Have bilateral symmetry.  No coelom  Can be free-living or parasites  Free living worms are hermaphrodites, they generate a reproductive system only during breeding season.

4. Nematodes: Roundworms Have bilateral symmetry. pseudocoelomates (coelom was lost or reduced) Have long thin, round worm like bodies Simplest organisms to have a complete digestive tract Most are free-living, however some are parasitic Some reproduce sexually some asexually

5. Annelida: Segmented Worms  Have bilateral symmetry  Have a coelom  Have round, segmented bodies which is beneficial for movement, can move different parts at a time, increases flexibility.  Can reproduce sexually or asexually

6. Mollusca: Snails, Clams, Squid bilateral symmetry Have a coelom They are soft-bodied animals. Most cover their body with a shell for protection. Reproduce sexually or asexually

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

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