Simple Animals L2 Biology A breakdown of the animal kingdom reveals many phyla
Porifera - sponges Cnidaria jellyfish, coral Platyhelminthes flat worms Nematoda round worms Annilida segmented worms Mollusca clams, snails, squid Echinodermata - starfish Arthropoda insect, spider, crustacean Chordata frogs,fish, humans SIMPLE ANIMALS Cnidaria (formerly called Coelenterata)
All have stinging cells (cnidocytes) Two body forms: Medusa like a jelly fish Polyp like a hydra Radial symmetry Have tentacles Cnidarian Cnidocyte Have you ever been stung by jellyfish? Cnidarian Life Cycle medusa and polyp alternate
egg larva JELLYFISH - MEDUSAS Hydra Hydroid Polyp body form Hydra on water plants Hydra Anatomy mouth tentacles testis bud ovary Basal disc
Gastrovascular cavity ovary Basal disc Coral is actually a colony of polyps, most of which are the size of a single hydra they just make a case around them for their home. Here are a variety of anemones polyp body form - Platyhelminthes Have flat bodies Some are parasitic
Most are free-living These are free-living flatworms
Planaria Scolex head with hooks and suckers
Tapeworms the ultimate parasite only highly developed system is its reproductive system - hermaphroditic Phylum Nematoda - roundworms
Mouth digestive tube anus Most free-living Some parasitic Look like threads in the microscope Some are parasitic to humans
Trichina From undercooked pork Causes severe muscle aches when larvae migrate from intestine to muscles Filaria Causes elephantiasis No treatment Carried by mosquitoes Hookworm Enters through soles of feet Larvae in human feces Causes fatigue may cause physical and mental retardation if children have it This lesion is caused by a nematode infestation Elephantiasis Caused by filaria the worm blocks the lympatic vessels and the area swells with lymph.Notreatment is available. Phylum Annelida Segmented worms Includes earthworms and leeches
Most are free-living Complex body with organ systems hermaphroditic LeechEarthworm Earthworm Anatomy Phylum Arthropoda Jointed legs Chitinous exoskeleton
Ventral nerve cord Must molt to grow Some undergo metamorphosis Includes insects, crustaceans, spiders, millipedes and centipedes Class Insecta Six legs May have wings Undergo metamorphosis
Varied mouthparts Breathe using spiracles Class Arachnida 8 legs, no antennae, simple eyes, chelicerae,
scorpion tick Dust mites spiders CCrustacea two body regions = cephalothorax most live in water Millipedes and Centipedes The End