chapter 32: intro to animals

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the nature of animals

animals- multicellular heterotrophic organisms that lack cell walls

vertebrates- animals that have a backbone and a skull

fishes

mammals

amphibians

reptiles

birds

5% are vertebrates

invertebrates- animals without a backbone

sponges

worms

arthropods

mollusks

echinoderms

-make up the greatest number of animal species

characteristics of animals

multicellularity

no cell walls

heterotrophy

mobility

sexual reproduction

nervous tissue

muscle tissue

-unicellular and multicellular-

specialization- the evolutionary adaptation of a cell for a particular function

digesting food

removing waste

reproducing

differentiation- process in which specialized cells form

tissue is a group of similar cells that perform a common function

(cell junction form tissues from individual cells where cells connect to each other)

organs are body structures that are made from more than one type of tissue and are specialized for a certain function

-multicellularity has allowed organisms to evolve and adapt

ingestion- an animal takes in food , digestion occurs and carbohydrates, lipids, amino acids and other organic molecules are taken from the food.

zygote- diploid cell that comes from the fusion of the two gametes

differentiation- cells become specialized and different from each other, this is the path to cell specialization.

muscle tissue and nervous tissue hp many animals move.

-invertebrate animals may have evolved from protists

-phylogenetic diagram- shows how animals are related through evolution

chordate- refers to animals with a notochord

notochord- firm, flexible rod in the tissue located in the dorsal part of the body

dorsal nerve cord- hollow tube above the notochord

pharyngeal pouches- small outpockets of the anterior digestive tract

in vertebrates to the dorsal nerve chord develops into the brain and spinal chord, notochord is then the backbone

the pharyngeal pouches in aquatic vertebrates turn into gills

symmetry-

bialateral symmetry-

radial symmetry- organized around the center

asmmetry-

asymmetrical- no symmetry

dorsal vs ventral

anterior vs posterior

cephalization- concentration of sensory organs and nerves in the anterior

-know what 3 germ layers are-

body cavity functions

provides a firm base for muscles to pull

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