Ecology Exam

Endotherms

Organisms that can generate their own heat.

Ectotherms

Organisms that need to find external heat sources.

Threshold value

The point at which the developmental rate is zero (y=0).

Day degrees

A measure of heat accumulation over time, calculated by subtracting the threshold value from the developmental rate value.

Temperature size rule

The principle that warmer temperatures lead to faster growth but result in smaller final sizes.

Dry mass

A measure of the size of an organism, often used in relation to growth.

Endothermic organisms

Examples include birds, mammals, bluefin tuna, porbeagle sharks, swordfish, sea turtles (phylum Chordata), bumblebees, termites, honey bees (phylum Arthropoda), and some squid and octopus (phylum Mollusca).

Energy cost for endotherms

The energy used to conserve heat instead of for other functions like hunting.

Performance cost for ectotherms

Sub-optimal performance leading to lower reproduction rates and slower growth.

Freeze-avoiding strategy

A survival strategy that allows organisms to withstand temperatures below freezing.

Benefits of freeze-avoiding strategy

Ability to survive in sub-freezing temperatures.

Costs of freeze-avoiding strategy

Energy demand for producing anti-freeze components.

Temperature as a stimulus

Organisms respond to temperature changes with specific biological responses.

Examples of temperature responses

Trees shedding leaves, hibernating animals starting hibernation, plants producing seeds from dormancy, mammals growing or losing winter fur.