animal tissues what are tissues? groups of cells with common structure and function. 1.epithelial...

Bioenergetics• Food contains the energy that keeps ani

mals alive.– What do our bodies do with food?

Metabolic Rate

• Metabolic rate = total energy an animal uses per unit time

• BMR = basal metabolic rate of resting endothermic animal– Human adult males: 1600-1800 kcal/day– Human adult females: 1300-1500 kcal/day

• SMR= standard metabolic rate of ectotherm at a specific temperature

Bioenergetics• Metabolic rate = total energy an animal uses per

unit time• Endothermic animals are warmed by metabolism,

must work to keep body temp. constant– Birds, mammals– High energy expenditure– Capable of intense, long duration activity over wide range

of temps.

• Ectothermic animals warm themselves by absorbing heat from their environment– Fish, amphibians, reptiles, invertebrates– Lower energy expenditure– Not capable of endurance– When cold, cannot act quickly

Size and Metabolic Rate

• Amount of energy that it takes to maintain each gram of body weight is inversely related to body size– Ex. Each gram of mouse requires 20X as

many calories as a gram of elephant• Use proportionately more oxygen• Has higher breathing rate, blood volume, heart

rate, and eats proportionately more food

• WHY??

• Greater SA:volume in small animals, causes greater loss of heat. (maybe)– Fails to explain the inverse relationship in

ectotherms, which do not use energy to maintain body temp

Thermoregulation

• Countercurrent heat exchangers

• Nonshivering thermogenesis: hormones cause mitochondria to shift their metabolic production from ATP to heat– Can happen throughout the body, but

brown fat areas (in neck and between shoulders) specialize in this

• Torpor and hibernation

Body Plans

• Single celled organisms have entire surface area in contact with environment

• Simple multicellular organisms keep flat body plan with thin cells

• Larger more complex animals fold their internal surfaces to keep exchange with environment.

Homeostasis

• Interstitial fluid = internal fluid found between body cells

• Homeostasis = maintaining a steady state

• Feedback circuits help maintain homeostasis

Covers outside of

body and lines organs and

cavities.

Notice how structure fits

function.

Made of collagen, non-elastic does not tear easily