Chapter 32-34: Animal DiversityObjectives1. Define common characteristics amongst all animals2. Animals can be characterized by “body plans”3. Molecular data is providing new data for phylogeny4. Understand life without a backbone5. 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 protists1. Specialized cells (nervous and muscular are not found in any other multicellular organism2. 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. Symmetty Tissue

1. Asymmetry = Sponges *Specialized cells isolated from other tissues by membranes (Called Germ layers during

2. Radial Symmetry development)

3. Bilateral Symmetry-Dorsal-Ventral-Anterior-Posterior-Cephalization

1. Ectoderm = Surface of embryo = becomes outer covering and nervous system

2. Endoderm = Inner surface = becomes inner wall of organs and digestive tract.

3. 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

Morphological and Developmental

Phylogenetic Tree

Molecular Data Phylogenetic Tree

Points of agreement of the two:1. Kingdom is Monophyletic and all animals

share a common ancestor2. Sponges branch from the base of both3. Clade opposite of Sponges (Eumetazoa)

includes organisms with true tissue4. Most animals are in the Bilateria clade5. Chordates are Deuterostomes

Invertebrates: No Backbone

1. Sponges lack true tissue (Basal or outgroup)

2. Eumetazoans contain true tissues (derived Characteristics)

3. Bilateria contains organisms with bilateral symmetry, triploblastic development, most are coelomates and contain three major clades1. Lophotrochozoa2. Ecdysozoa3. Deuterostomia(Deuterostome development andincludes chordates andvertebrates)

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, squidsand octopuses)

-Annelids (earth worms and

leeches)

Common Characteristics of Arthropods

1. Exoskeleton and Molts2. Well developed senses3. Open circulatory system4. Four major lineages

-Spiders, ticks, mites-Millipedes and

Centipedes-Insects-Crabs, lobsters, and

shrimp

Ecdysozoa a group defined by shedding of a tough external coat or molting.

-The Arthropods: most species rich animal group

Complete vs Incomplete metamorphosis

Deuterostomia includes both Echinoderms and Chordates-Based mostly on Molecular data

Derived Characteristics of Chordates

1. Notochord - Present in all embryos and turns into backbone/vertebrae

2. Presence of a hollow dorsal nerve chord that turns into the nervous system

3. Presence of Pharyngeal slits4. Presence of post anal tail

p. 734 for other derived characteristics