Animal Characteristics 1. Eukaryotes 2. Multicellular 3. No cell walls or chloroplasts 4. Heterotrophic

5. Many types of movement a. Sessile: don’t move (barnacles) b. Mobile early, sessile adults (coral) c. Sessile larvae, mobile adults (jellyfish) d. Mobile: able to move

6. 1 st evolved in water -more food than on land -needed to expend less energy 7. Ingest: digest food w/in body -digestive system is specialized to diet 8. Cells specialized into tissues & organs to carry out specific functions

Development 1. Fertilization: when egg & sperm join to form a zygote -occurs only during sexual reproduction

2. Cell division occurs by mitosis (cleavage) -embryo: mass of dividing & developing cells -org. at an early stage of growth/development -blastula: hollow ball of cells filled w/ fluid -humans-5 days after fertilization

3. Gastrulation: cells on 1 side of the blastula push inward -gastrula: structure of 2 layers w/ an opening at 1 end

-layers formed in gastrula a. ectoderm: outer cell layer that will develop into skin & nervous tissue b. endoderm: inner cell layer that will develop into digestive system c. mesoderm: middle layer that may form later, will develop into all other systems

-2 types of gastrulation a. Protostomes: opening of gastrula develops into mouth -snails, earthworms, insects b. Deuterostomes: mouth doesn’t form from gastrula opening -starfish, fish, amphibians, birds, reptiles, & mammals

4. Growth & Development -cells differentiate & become specialized for their specific function 5. Adulthood -org. reach sexual maturity, reproduce, & process begins again

Symmetry -arrangement of body structures -allows for specific movement 1. Asymmetry: not symmetrical, irregular body shape -usually sessile

2. Radial symmetry: can be divided into equal halves by multiple plans thru center -allows org. to detect & capture prey from many angles

3. Bilateral symmetry: can be divided into right & left halves along 1 plane -more effective movement

Body plans -develop 3 embryonic layers (ecto/meso/endoderm) -may have fluid-filled body cavity that allows for increased size

Types a. Acoelomates: no body cavity -flatworms -solid, compact body

b. Pseudocoelomates: space between endoderm & mesoderm filled w/ fluid -roundworms -allows for more effective movement -1-way digestive tract

c. Coelomates: fluid-filled space completely lined w/ mesoderm -one-way digestive tract -organs cushioned/protected -efficient movement

Protection & Support 1. Shells

2. Exoskeleton: hard outer covering that provides support for body framework -protect soft areas, prevent water loss -secreted by skin -place for muscles to attach -usually found in invertebrates: animal w/out a backbone

3. Endoskeleton: internal skeleton covered by cells that supports body -protects internal organs -muscle attachment

-e.g. -invertebrates-sea stars- made of calcium carbonate -Vertebrate: animals w/ endoskeleton & a backbone (bilateral sym.) -shark-made of cartilage -bony fish  mammals- made of bone