control of body temperature PART 1

normal body temperature of human and why it’s important to maintain this temperature

37°C→it is the optimum temperature for enzymes so ensures they function in metabolic reactions

ectotherms

organisms that rely on external sources to regulate their body temperature.

ectotherms examples (3)

-reptiles

-fish

-amphibians (frog)

what does the internal temperature of ectotherms depend on

depends on the external temperature of their surroundings

how do ectotherms control their body temperature

they can't maintain their body temperature internally so they control their temperature by changing their behaviour

behavioural response to low temperature [ectotherms] (3)

-move to a warmer area/ bask in the sun

-Lie on warm surfaces to absorb heat

-reduce activity to conserve energy

[ectotherms do this to increase their body temperature]

behavioural response to high temperature [ectotherms] (2)

-move to a cooler, shaded area

-burrow underground

[ectotherms do this to decrease their body temperature]

when is activity level higher and lower for ectotherms? (explain)

-they are more active in higher temperatures→ bcs metabolic reactions happens faster so more energy is available for movement/activity. Also enzymes can work more efficiently

-they are less active in lower temperatures→ bcs metabolic reactions occur at a slower rate so less energy is available for movement

what is metabolic rate like for ectotherms? (3)

what is metabolic rate like in warmer and colder conditions?

-metabolic rate varies with external temperature

-they generate less heat

-have a lower metabolic rate than endotherms.

In warm conditions: metabolic rate increases

In cold conditions: metabolic rate decreases

why do aquatic ectotherms (e.g. fish) struggle less when maintaining body temperature?

water has a high specific heat capacity so it changes temperature slowly. This makes the temperature of water relatively stable, allowing aquatic ectotherms to maintain their body temperature more easily.

advantages (3) and disadvantages (3) of ectotherms

advantages

-require less food (don’t use energy to generate heat)

-more energy can be used for growth

-can survive in habitats with low availability of food

disadvantages

-less active at lower temperatures

-vulnerable to predation when body temperature is low

-less able to hunt for food when body temperature is low

endotherms

organisms that use heat from metabolic processes to maintain their body temperature

[can maintain their body temp internally, ectotherms cannot]

examples of endotherms (2)

-mammals (humans)

-birds

do endotherms rely on the external environment to maintain their body temperature?

no

what is metabolic rate like for endotherms?

-have a constantly high metabolic rate bcs they can keep their internal temperature constant.

-they generate a lot of heat through metabolic reactions 

what is the activity level like for endotherms? (2)

-can be active at any temperature

-there activity is not dependent on the external environment

advantages (2) and disadvantages (2) of endotherms

advantages

-constant body temperature

-can be active at any temperature

disadvantages

-need more food

-less energy used in growth

responses of endotherms to maintain body temperature

-physiological response

-behavioural response

How do changes in external temperature affect internal temperature of endotherms and ectotherms?

draw graph

-as the external temperature increases, the internal temperature of ectotherms increases [as its internal temperature depends on the external temperature]

-as the external temperature increases, the internal temperature of the endotherm remains relatively constant [as its internal temperature does not depend on the external temperature]