Homeostasis And Communication

Question 1

homeostasis

Answer 1

Maintaining a constant internal environment despite changes in external and internal factors

Question 2

Negative feedback

Answer 2

The mechanism that reverses a change, bringing the system back to the optimum

Question 3

Positive feedback

Answer 3

The mechanism that increases a change, taking the system further away from optimum

Question 4

Ectotherms

Answer 4

Not able to control their body temperature as effectively as endotherms
-use behavioural techniques

Question 5

Endotherms

Answer 5

Control their body temperature within very strict limits
-independent to external temp

Question 6

Temp control in ectotherm

Answer 6

-move into sunny area
-lie on warm surface
-move underground if too hot

Question 7

Adv of ectotherms

Answer 7

Don’t use up energy trying to keep warm
-less of their food is used in respiration
-more of the energy and nutrients gained from food can be used for growth
-can survive longer without food

Question 8

Disadv of ectotherms

Answer 8

They are less active in cool temperatures - more at risk of predators

Question 9

why do multicellular organisms need communication system

Answer 9

to respond when their internal and external environment change

Question 10

what is cell signalling

Answer 10

paracrine signalling between adjacent cells occurs directly or aided by extracellular fluid
autocrine- cell releases signals to stimulate its own receptors and triggers response within itself

Question 11

what is the role of skin in thermoregulation

Answer 11

constriction of arteries to reduce blood flow to skin which prevents heat loss
-evaporation of sweat cools skin surface