Chapter 33
The Ancestors Protists: Choanoflagellates
The Ancestors Colonies of choanoflagellates
The Ancestors Colonies of choanoflagellates
Porifera – The Sponges
Sessile filter feeder Grouped based on “skeleton” type. Can form gemmules for protection.
Porifera – The Sponges Asymmetrical No tissue layers.
Porifera – The Sponges Sexual reproduction - hermaphrodites Can grow whole new sponges if cut in pieces
Cnidaria Examples: jellyfish, anemones, hydra and coral
Cnidaria Named for cnidocytes
Cnidaria Diploblastic Two body forms: polyp & medusa Grouped based on amount of life spent as polyp or medusa
Cnidaria Reproduces asexually by budding.
Cnidaria
Platyhelminthes - Flatworms Examples: planaria, liver flukes, tapeworms
Platyhelminthes - Flatworms Most are parasitic
Platyhelminthes - Flatworms Bilateral symmetry Simplest phylum with a head Simple organ systems Reproduce sexually and asexually
Platyhelminthes - Flatworms Acoelomates Triploblastic
Rotifera Named for feeding rotors Pseudocoelomates Have an anus! Images from
Rotifera Usually reproduces by parthenogenesis
Nematoda – Roundworms Found in most aquatic habitats, soil, and in plant and animal tissues
Nematoda – Roundworms Many are parasitic – hookworms, roundworms, pin worms, heartworms, etc.
Nematoda – Roundworms Pseudocoelomates Simple organs
Annelida – Segmented Worms Examples: earthworms, fireworms, leeches
Annelida – Segmented Worms “Little rings” –repeating segments, some specialized Coelomates Setae Parapodia
Annelida – Segmented Worms Fairly complex anatomy
Mollusca Largest classes: Gastropods Bivalves Cephalopods
Mollusca Muscular foot
Mollusca Head
Mollusca Visceral mass
Arthropoda “Jointed foot”
Arthropoda Most successful animal phyla – 67% of all species!
Arthropoda Four main groups: Cheliceriforms Myriapods Hexapods Crustaceans
Arthropoda Exoskeleton - ecdysis
Arthropoda Open circulatory system
Arthropoda Tracheal tubes Spiracles vs. book lungs
Arthropoda Malpighian tubules
Echinodermata “Spiny skin”
Echinodermata Radial symmetry
Echinodermata Water vascular system Tube feet
Echinodermata No head or brain Simple anatomy Deuterostomes Endoskeleton