Animal diversity 28

Question 1

Ectothermy strategies

Answer 1

1) basking in the sun
2) ancient but effective strat
3) more food energy available to increase biomass
4) v. low energy requirements, however limits where they can live

Question 2

Endothermy strategies

Answer 2

1) heat body using metabolism
2) derived state (birds = mammals)
3) low energy efficiency - 1% energy available for biomass increase
4) wider range of habitats available, temp independent of environment

Question 3

How does body size affect endotherms/ectotherms

Answer 3

1) metabolic rate increases with decreasing body size (more so for endotherms)
2) heat loss is higher for smaller animals (SA/volume ratio) - don’t see v. tiny endotherms
3) ectotherms are smaller then endotherms (on average)

Question 4

Example of ectotherms having for energy for biomass

Answer 4

E.g. Desert tortoise

• east hardly anything + inactive a lot
• Biomass increase by 25% each year
• cant excrete salt without losing water, instead retains salt and is osmotically stressed
• uses burrows to thermoregulate

Question 5

Ectotherm adaptation for temp reg

Answer 5

1) e.g. desert iguanas change colour throughout the day to change absorption

Question 6

How do ectotherms cope with extremely low temperatures

Answer 6

1) avoid freezing - produce anti-freeze and become “supercooled”
2) Tolerate freezing- produce cryoprotectant in cell glycerol , cells maintain low level of anaerobic activity, avoids cells becoming completely frozen

Question 7

Example of a completely endothermic fish

Answer 7

E.g. Opah-sunfish

-distributes warm blood throughout the body

Question 8

Ectothermy

Answer 8

Body temp relies on environmental sources

Question 9

Poikilothermy

Answer 9

Internal temp varies considerably - opposite of homeothermy

Question 10

Homeothermy

Answer 10

Retains an entirely stable internal temp under normal conditions - includes fishes

Question 11

Endothermy

Answer 11

all endotherms are homeotherms, not al homeotherms are endotherms

body temp relies on metabolic activity

Question 12

How does ectotherm and endotherm growth rate compare

Answer 12

• although endotherms aren’t very efficient at growth they can grow all year round
• ectotherms , efficient but low growth rates
• endotherms -> high growth rate
• mesotherms = middle growth rate (mostly seen in dinosaurs )

Question 13

Insulation

Answer 13

• a way to cope with the cold

- insulation value of pelts higher value for arctic species

Question 14

How do aquatic mammals deal with cold

Answer 14

• wet fur loses all insulative properties

- aquatic mammals have thick layer of blubber to conserve heat

Question 15

Torpor

Answer 15

a state of physical or mental inactivity; lethargy.

Question 16

How is torpor used to deal with temp variance

Answer 16

• Adaptive hypothermia OR hibernation
• Body temp + respiration + heart rate all decrease in activity significantly
• Relative to body size, torpor easier for smaller bodies as takes less time to warm up

Question 17

How do endotherms cope in the desert

Answer 17

• heat gradient reversed, heat becomes a problem not cold
• cooling by evaporation increases dehydration
• behavioural + physiological solutions
  E.G. camels