Chapter 32-34: Animal Diversity Objectives 1. 2. 3.

Chapter 32-34: Animal Diversity Objectives 1. 2. 3. 4. 5. Define common characteristics amongst all animals Animals can be characterized by body plans Molecular data is providing new data for phylogeny Understand life without a backbone Understand life with a backbone What does it mean to be an animal? -Animals get food by; 1. Ingesting - Differs from absorption (Fungus)

2. Rely on other organism for food or are heterotrophic unlike plants -Animals are multicellular unlike protists 1. Specialized cells (nervous and muscular are not found in any other multicellular organism 2. Cells are held together by proteins (mostly collagen which is only found in animals) -Reproduction is mostly sexual with the 2n version dominating life -Development into layers - leads to organs and tissue -Some development includes a larval stage -sexually immature stage and undergoes metamorphosis -Use of Homeoboxes or gene regulatory genes are common to all animals - many have similar DNA sequences Body Plan: Set of morphological and developmental traits that work together as a whole. *Research suggests gastrulation has remained unchanged for 500 million years but other aspects of body plans have changed. 1.

2. 3. Symmetty Asymmetry = Sponges tissues by Radial Symmetry Bilateral Symmetry -Dorsal -Ventral -Anterior -Posterior -Cephalization Tissue *Specialized cells isolated from other membranes (Called Germ layers during

development) 1. 2. 3. Ectoderm = Surface of embryo = becomes outer covering and nervous system Endoderm = Inner surface = becomes inner wall of organs and digestive tract. Mesoderm = middle layer = becomes other organs and muscles between the digestive tract and outer layer -Organisms that only have endo and ecto are considered diploplasts -Organisms that have all three are considered triploblasts

**All bilaterally symmetrical Body Cavities of Triploblasts -Coeloms prevent injury to organs -Allow organs to move and grow indpendently of outer shell -Humans are ????? Determinate Cleavage means cells are differentiated very early. Ex. Take one cell out and the organism will develop missing many parts and inviable Cells retain ability to turn into any type of cell

Ex. Identical Twins in humans Points of agreement of the two: 1. 2. 3. 4. 5. Kingdom is Monophyletic and all animals share a common ancestor Sponges branch from the base of both Clade opposite of Sponges (Eumetazoa) includes organisms with true tissue Most animals are in the Bilateria clade Chordates are Deuterostomes

Morphological and Developmental Phylogenetic Tree Molecular Data Phylogenetic Tree Invertebrates: No Backbone 1. 2. Sponges lack true tissue (Basal or outgroup) Eumetazoans contain true tissues (derived Characteristics)

3. Bilateria contains organisms with bilateral symmetry, triploblastic development, most are coelomates and contain three major clades 1. Lophotrochozoa 2. Ecdysozoa 3. Deuterostomia (Deuterostome development and

includes chordates and vertebrates) Sponges p. 670 -Thought to have been plants -Suspension Feeders -Water is drawn through pores and a current provided by the flagella -Ameobocytes take food particles to the rest of the cells Cnidarians (Jellyfish, Coral) -Simple diploblast radial body plan -Polyp adheres to something

-Medusa free moving form -Carnivores -No brain but responds to stimuli from all directions Lophotrochozoans -Clade includes 18 phyla -Most diverse animal clade (very different body plans) -Clade is molecularly monophyletic Phylums include: -Tapeworms -Mulluscs (snails, slugs, mussels, clams, oysters, squids

and octopuses) -Annelids (earth worms and leeches) Ecdysozoa a group defined by shedding of a tough external coat or molting. Complete vs Incomplete metamorphosis -The Arthropods: most species rich animal group Common Characteristics of Arthropods 1. 2.

3. 4. Exoskeleton and Molts Well developed senses Open circulatory system Four major lineages -Spiders, ticks, mites -Millipedes and Centipedes -Insects -Crabs, lobsters, and shrimp Deuterostomia includes both Echinoderms and Chordates -Based mostly on Molecular data

Derived Characteristics of Chordates 1. 2. 3. 4. Notochord - Present in all embryos and turns into backbone/vertebrae Presence of a hollow dorsal nerve chord that turns into the nervous system Presence of Pharyngeal slits Presence of post anal tail p. 734 for other derived characteristics