Lecture 2 - Homestasis, Scale, and Tradeoffs

Homeostasis

Keeping the inside of your body stable, even when the outside changes.

Trade-offs

Making choices where you can't have everything, so you have to give up some things for others.

Ectotherm

Animals that depend on outside heat to warm up.

Endotherm

Animals that can create their own heat to keep warm.

Negative feedback

A system that helps bring things back to normal after a change.

Positive feedback

A system that pushes things to go further from normal.

Sensors

Parts of the body that notice changes around you or in you.

Integrators

Parts of the body that think about what the sensors tell them and decide what to do.

Effectors

Parts of the body that act to fix things that sensors notice.

Metabolic rate

How fast your body uses energy.

Homeotherm

Animals that keep their body temperature the same all the time.

Poikilotherm

Animals whose body temperature changes with the environment.

Regulation vs. conformity

Regulation means keeping things stable inside, while conformity means allowing changes inside based on outside conditions.

Scaling

How an animal's size affects how its body works and uses energy.

Surface area to volume ratio

A principle that says as animals grow, their inside space grows faster than their surface area.

Basal metabolic rate (BMR)

How much energy an animal uses when it's resting.

Torpor

A state where warm-blooded animals slow down and use less energy.