2005_campbl33

2005_campbl33 - Porifera Characteristics Animal...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 33: Invertebrates Animal Phylogeny (compacted) Some Animal Phyla Porifera “Sponges are simple, sessile animals that lack true tissues. They live as suspension feeders, trapping particles that pass through the internal channels of their bodies.” p. 639, Campbell and Reece (2005) Porifera Characteristics ± Sponges ± Sole member of the Parazoa ± Lack true tissues, simplest of animals, no nerves or muscles ± Choanocytes (collar cells) Æ “Unique flagellated cells that ingest bacteria and tiny food particles” ± Choanocytes look a lot like Choanoflagellates ± Amoebocytes transfer food to rest of cells ± Adults sessile, larvae non-sessile ± “Cells tend to be totipotent (retain zygote’s ability to form the whole animal)” Sponge Anatomy
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Cnidaria “Cnidarians include corals, jellies, and hydras. These animals share a distinctive body plan that includes a gastrovascular cavity with a single opening that serves as both mouth and anus.” p. 639, Campbell and Reece (2005) Cnidaria Characteristics ± Hydras, Jellies, Sea Anenomies, Corals ± One member of the Radiata (also Ctenophora) ± Diploblastic, Carnivorous, Tentacled ± Lack true muscles (since no mesoderm) ± Possess nerve net ± Cnidocytes Æ Cells that shoot stinging or grasping threads at potential prey ± Grastrovascular cavity (only one opening) = Hydrostatic Skeleton ± Polyps vs. Medusa Various Cnidarians Cnidaria Anatomy Don’t forget that cnidarians are carnivorous Cnidocytes Cnidaria Classes
Background image of page 2
3 Obelia Life Cycle Platyhelminthes “Flatworms (including tapeworms, planarians, and flukes) have bilateral symmetry and a central nervous system that processes information from eyes and other senory structures. They have no body cavity or organs for circulation.” p. 639, Campbell and Reece (2005) Platyhelminth Characteristics ± Flatworms (including Flukes and Tapeworms) ± Bilaterally symmetrical acoelomates ± Flat, unsegmented, single opening to gastrovascular cavity ± Eyespots, flaps on head involved in sense of smell ± No circulatory system (instead diffusion) ± The flat shape makes diffusion a very real option for movement of stuff (digestive products, nitrogenous waste, oxygen, CO 2 about the animal or relative to the outside world)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/03/2011 for the course BIO 113 taught by Professor Swenson during the Spring '08 term at Ohio State.

Page1 / 10

2005_campbl33 - Porifera Characteristics Animal...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online