Biology Ch 33: Animal Form and Function

asymmetrical body plan

aquatic, sessile, filter feeders

radial body plan

aquatic but often motile, filter feeders or actively search for food

bilateral body plan

all vertebrates (anterior, posterior, dorsal, ventral)

aquatic animals

constrained by the density of water, have a fusiform shape to minimize drag

terrestrial animals

constrained by gravity, evovled traits to counter gravity

Exoskeleton

hard covering or shell that protects the animal and provides attachment sites for muscles, made of chitin or calcium carbonate, limits animal size, must molt

apodemes

ingrowths where muscles are attached

endoskeleton

comprised of internal bone or cartilage that supports body weight and movement, determinant growth,

endothermic animals

use metabolism to maintain their body temperature, require 90% more calories

ectothermic animals

do not use metabolism to maintain body temperature, only require 10% of calories

homeothermic animals

maintain constant body temperature

Poikilothermic animals

allow body temperature to fluctuate depending on environment

metabolic rate

the amount of energy expended over a given time

small endotherms

greater surface area to body mass ratio, lose heat faster, higher BMR

Torpor

decreased activity and metabolism to conserve energy

hibernation

winter torpor, during coldest time of year, reduced body temp, no food intake

estivation

summer torpor, hibernate during times of extreme heat or decreased water availability