AB’s Lectures

Question 1

What is an endotherm?

Answer 1

An animal that produces it’s own body temperature independent from its environment

Question 2

What is an ectotherm?

Answer 2

An animal that relies on the environment for internal body temperature

Question 3

What is a poikilotherm?

Answer 3

An animal that has a body temperature that varies a lot due to environmental variation

Question 4

What is a homeotherm?

Answer 4

An animal whose body temperature is stable (little variation)

Question 5

What is a heterotherm?

Answer 5

An animal in between a homeotherm and poikilotherm where their body temperature varies slightly

Question 6

What is Topt?

Answer 6

The optimum body temperature where performance is maximised (100%)

Question 7

What is the critical thermal min and max?

Answer 7

Critical body temperature at which the animal is dead and performance is therefore 0

Question 8

What is B80?

Answer 8

The range of body temperature where performance is at 80% or above

Question 9

What is the tolerance range?

Answer 9

The range of temperature an individual animal can tolerate

Question 10

What are generalists (in terms of TPC)?

Answer 10

Animals that are favoured in variable environments where they have a broad tolerance range but a lower Topt/maximum performance

Question 11

What are specialists (in terms of TPC)?

Answer 11

Animals that are favoured in stable environments that have a narrow tolerance range but a high max performance and Topt

Question 12

What is acclimation?

Answer 12

A slow and reversible change to the body that allows an organism to handle different environments (in a controlled environment). This can happen over a few days, weeks, or months

Question 13

What is acclimitisation?

Answer 13

A process where an organism changes in their natural environment due to seasons. This happens during the organisms lifetime

Question 14

What is adaptation?

Answer 14

Mutations and natural selection that cause changes to organisms and accumulate over generations

Question 15

What are some fish adaptations to maintain thermal balance?

Answer 15

Behavioural adjustments e.g., moving horizontally or vertically
Anatomical features e.g., regional endothermy

Question 16

What is an example of regional endothermy in sharks?

Answer 16

Warmer muscles (increases their power and speed)

Question 17

What is an example of regional endothermy in opahs?

Answer 17

Produces heat from its pectoral muscles

Question 18

What is an example of regional endothermy in billfish?

Answer 18

Thermogenic eye muscle

Question 19

What are some advantages of regional endothermy?

Answer 19

Enhanced muscle performance
Improved sensory abilities
Extended range and habitat flexibility
Enhanced digestion and metabolism

Question 20

What are some freeze avoidant strategies in arctic fish?

Answer 20

Migration
Hypoosmotic
Production of antifreeze proteins

Question 21

What are the effects of warming temperatures on marine fish?

Answer 21

Seasonal changes in timing of life cycle events
Latitudinal shifts in species distribution
Growth rate/size

Question 22

What is freeze avoidance?

Answer 22

The evasion of freezing by lowering the temperature at which water freezes in the body (supercooling)

Question 23

What is freezing tolerance?

Answer 23

The ability to tolerate frozen tissues by limiting the presence or location of ice in the body

Question 24

What is a crystal-seed?

Answer 24

A small particle used as a starting point for ice to attach onto and grow

Question 25

What is an ice nucleator?

Answer 25

A particle which acts as the nucleus for the formation of an ice crystal Another name or crystal-seed

Question 26

What are three ways that animals can lower their supercooling point (SCP)?

Answer 26

1. Rid the body of ice nucleators (e.g., food, impure water, etc) 2. Produce antifreeze/ice-binding proteins 3. Produce cryoprotectants (e.g., glycerol, glucose, and urea)

Question 27

What is the function of ice binding proteins?

Answer 27

They bind to ice crystals and prevent the from growing, keeping biological fluids in a liquid state

Question 28

What is the function of cryoprotectants?

Answer 28

They prevent precipitation of water out of the cells to stop dehydration from happening

Question 29

What are mechanisms animals use to be freeze tolerant?

Answer 29

1. Nucleating proteins/ice nucelators 2. Ice-binding proteins 3. Cryoprotectants 4. Membrane transporters

Question 30

Is freeze avoidance or freeze tolerance the ancestral trait?

Answer 30

Freeze avoidance

Question 31

What environment do you see freeze avoidance in?

Answer 31

Predictable, moderately cold environment (freezing is lethal)

Question 32

What environment do you see freeze tolerance in?

Answer 32

Cold, unpredictable environments

Question 33

What is an example of freeze tolerance in vertebrates?

Answer 33

Wood frogs that freeze 65-70% of their extracellular fluid

Question 34

What are the ecological advantages of freeze tolerance?

Answer 34

They can breed earlier than other species They can breed in safer places than other species They can detect the warming of the environment around them and thaw out earlier

Question 35

What is the lower lethal temperature (LLT)?

Answer 35

The temperature at which a given percentage of individuals die

Question 36

What is the supercooling point?

Answer 36

The temperature at which ice formation begins

Question 37

What is the range of SCP in insects?

Answer 37

-1’C to -54’C

Question 38

What is the range of the lower lethal temp in insects?

Answer 38

-11.5’C to -196’C - Note, insects can tolerate up to 80% of their body water being converted to ice

Question 39

What do recrystallisation-inhibiting proteins (RIPs) do?

Answer 39

Stabilise ice crystals - stop them from growing and spreading

Question 40

What is an example of freeze tolerance in insects?

Answer 40

The NZ stick insect