Animal Diversity: Invertebrates Chapter 25

Animal Diversity:Invertebrates

Chapter 25

Sponges

Jelly fish

Coral

Worms

Mussels

Insects

What makes an animal an animal?What are the evolutionary milestones that led to bodies of modern animals?Tissue FormationFormation of a three-layer animal embryo

Formation of a three-layer animal embryo

Body Symmetry

Gut and Body Cavities

Bilateral organisms develop in one of two waysProtostomeDeuterostomeBoth represent distinct evolutionary groups within bilateral animalsCirculation

Segmentation

Understanding Evolution. 2011. http://evolution.berkeley.edu/evolibrary/article//arthropods_05

AbsoluteAstronomy. 2011. http://www.absoluteastronomy.com/topics/Segmentation_(biology)Choanoflagellates

Science Notes. 2008. New York Times. http://sciencenotes.wordpress.com/2008/03/06/choanoflagellates-to-sponges-to-metazoa/

Carroll, Sean B. 2010. http://www.nytimes.com/2010/12/14/science/14creatures.html?_r=1

Devitt, Terry. 2001. University of Wisconsin-Madison News. http://www.news.wisc.edu/6920Choanoflagellates

Relationships and Classification

The Simplest Living AnimalPlacozoans, the simplest known animals, have no body symmetry, no tissues, and just four different types of cells Example: Trichoplax adherens

14Phylum Porifera - Sponges Only animal to lack tissuesIndividual cells have specialized functions but do not act as a specialized group of cells or tissueSuggests that the evolutionary split between sponges and all other animals occurred early Ancient common ancestor gave rise to both sponges and tissue containing animals

2 Major Categories of AnimalsVertebrates (vertebral column)Invertebrates (no vertebral column)Major Invertebrate PhylaPoriferaCnidariaPlatyhelminthes Nematoda Rotifera AnnelidaMolluscaArthropodaEchinodermata

Sponges Phylum Porifera

Sponge Body Plan

Phylum Cnidaria

Hydrozoan

Jellyfish

Corals

Sea anemone

Two Cnidarian Body Plans

Cnidarian Diversity

Flatworms Phylum Platyhelminthes

Phylum Platyhelminthes Schistosoma Blood Fluke

Phylum Platyhelminthes - Tapeworm