Lecture 11

Question 1

What happens to the ratio of pectoral muscle mass and the body mass of red knots when they reach 60g’s what is an issue with this?

Answer 1

What happens here is that the animal gets bigger but the pectoral muscle doesn’t increase as much.
The problem for the bird is that it cannot increase the pectoral muscle mass to the same extent at these higher body masses and because of that they can’t fly as well, they are less manoeuvrable which means they are more prone to predation

Question 2

What is thought to be the reason that red knots fly in very big flocks?

Answer 2

Because when they get about 160g’s then their pectoral muscle mass cannot increase too the same extent as the body mass at these higher body masses, so they can’t fly as well and are less manoeuvrable which means they are more prone to predation so perhaps flying in big flocks can hide some of this vulnerability so the behaviour may be linked to the physiology

Question 3

Hoary bat migrating individuals have more fat than non-migrating individuals but what is the difference between females and males?

Answer 3

. Migrating female individuals certainly have more fat
. Males don’t show a difference in pectoral muscles
. and in males and females the capacity of the lungs are bigger and smaller intestines so they are reducing the load that they have to take with them.

(These migrating bats were caught post migration so the duration over which they have been at their wintering site when they were caught may be variable which may explain why the males had less mass than the females)

Question 4

Energy costs of migration are very difficult to measure, we can measure heart rate in large birds but what is the issue with most birds?

Answer 4

Most birds that migrate are small, less than 100g and more likely 20-50g, so we can’t put devices on them

Question 5

We can’t put devices on small birds to measure energy costs of migration, but what can we use?

Answer 5

Can use the doubly labelled water technique, this gives us the ability to measure the energy expenditure of small animals

Question 6

What is the issue with using doubly labelled water to measure energy expenditure of small animals?

Answer 6

All depends on being able to inject at one point but then being able to recapture that individual within 48 hours at most but probably 24 hours

Question 7

If you are wanting to measure energy expenditure of the actual flight of migrating birds using doubly labelled water then what do you want to do?

Answer 7

You want to catch them immediately before they take off for their migration and as soon as they arrive to estimate the energy cost

Question 8

What is the issue with wanting to measure small animals immediately before they take off for their migration and as soon as they arrive to estimate their energy cost using doubly labelled water?

Answer 8

It is difficult to estimate where it is going to turn up and the time in which it will take to get there and catch them again

Question 9

Using experiments they found that birds that stayed where they were and didn’t migrate were having to expend just as much just as energy as an animal that was able to fly 2 and a half hours. Why is this?

Answer 9

There is a good relationship between the ambient temperature and their energy expenditure. As it gets cooler they are having to thermoregulate, they are having to produce extra energy to produce the heat they need to maintain their body temperature
(For some it would probably have been better if they didn’t stay because they have used a lot of energy and gotten nowhere)

Question 10

In birds that fly in V formation flight why don’t they all flap at the same time?

Answer 10

Because if they did then they wouldn’t benefit from the back air draft that is produced by the wing of the bird in front.
(So then being at different stages the synchronisation suggests the birds are trying to benefit from the air steam produced by the bird in front)

Question 11

If you measured the heart rate at the same time as wing beat frequency when a bird is alone and flying well above the water (e.g. 50m) and when they are flying closer to the water (e.g. 1m) how would the heart rates differ?

Answer 11

When they are flying closer to the water then their heart rate is reduced

Question 12

Why do lone birds that fly closer to the water have a lower heart rate than those that are flying well above the water? Give an example

Answer 12

This is because they get updraft from the waves which helps it with its flight which is why albatrosses are able to do dynamic soaring so have a slight saving by flying close to the water

Question 13

Explain how heart rate changes through a group of V formation flying birds

Answer 13

. The one at the front has the same heart rate as if it were alone
. However, the one behind has a low heart rate
. And the one behind is lower etc.
. Until it plateaus off

(So is we use heart rate as a proxy for energy expenditure then the one at the front is working as hard as it would if it were alone but the ones behind are saving energy)

Question 14

When they recorded the body temperature before migration began it started to decline and carried on throughout migration, why do they think this is?

Answer 14

This decline of 3-4 degrees may represent a huge decline in the animal’s metabolic rate so therefore they won’t be using up the fuels as much as they would if they were maintaining their body temperature

Question 15

Other than migrating birds what else decreases its temperature to save energy? What declined with it?

Answer 15

Animals in torpor decreases their mean ambient temperature, the energy saved decreases also

Question 16

What happens to the fat required as metabolic rate decreases?

Answer 16

It decreases also

Question 17

What happens to the ambient temperature as fat required and mean metabolic rate decline?

Answer 17

Mean ambient temperature increases gradually and then at a point suddenly declines

Question 18

Define the ‘emergency life history stage’

Answer 18

A specific physiological and behavioural response to perturbation that enhances survival

Question 19

Describe the ‘emergency life history stage’ (what it applies to, behaviour and what happens after)

Answer 19

. Can apply to any bird and interrupt any stage of the annual cycle
. Redirect behaviour (e.g. stop breeding behaviour)
. Seek refuge or move away
. Mobilise stores energy reserves: gluconeogenesis
. Recovery: return to normal once perturbation finishes (e.g. move back to original habitat and resume breeding behaviour)

Question 20

What are the Acute (short term effects) beneficial (anti-stress) mechanisms of glucocorticoids in animals?

Answer 20

. Suppression of reproductive behaviour without affecting reproductive system
. Altered immune function
. Increased gluconeogenesis (mobilisation of energy stores
. Increased foraging behaviour
. Promotion of escape (irruptive) behaviour during day
. Promotion of night restfulness

Question 21

What are the chronic (long term effects) pathological mechanisms of glucocorticoids in animals?

Answer 21

. Inhibition of the reproductive system 
. Immune suppression, impaired disease resistance 
. Loss of protein from skeletal muscle 
. Accelerated neuronal degeneration 
. Suppression of growth

Question 22

What do the acute (short term) effects of glucocorticoids in animals correspond with?

Answer 22

The emergency life history stage (applies to any bird at any time of year)

Question 23

What does poikilotherm mean?

Answer 23

Variable temperature

Question 24

What does homeothermic mean?

Answer 24

Stable temperature

Question 25

What is slow metabolic rate referred to as?

Answer 25

Bradymetabolism

Question 26

What is fast metabolic rate referred to as?

Answer 26

Tachymetabolism

Question 27

Describe ectotherms

Answer 27

Their temperature is dependent of that of their environment, these animals still produce heat just don’t produce enough to maintain the heat in their bodies (all organisms produce heat it is the rate in which they produce heat that is different)

Question 28

What is it called when you generate heat internally?

Answer 28

Endothermic

Question 29

What is heterothermy?

Answer 29

When their body temperature changes- the temperature of the core is very different to the temperature of the periphery

Question 30

What are the types of heterothermy?

Answer 30

. Partial endothermy
. Facultative endothermy
. Regional endothermy
. Regional heterothermy

Question 31

Give an example of an animal that shows partial endothermy

Answer 31

Bats in torpor

Question 32

Give example of an animal that shows facultative endothermy

Answer 32

Bees- maintain a temperature in certain parts of their body

Question 33

Give an example of an animal that shows regional endothermy

Answer 33

Tuna muscles- are able to elevate the heat of the muscles and keep it in the muscles

Question 34

Give an example of an animal that shows regional heterothermy

Answer 34

Bird legs- regional differences in temperature

Question 35

What happens in poikilothermic ectotherms as ambient temperature changes?

Answer 35

Temperature goes up or down depending on the ambient temperature, there are also changes in their metabolic rates.
So, as the ambient temperature increases in the ectoderm their body increases in temperature, their cellular mechanisms increase and that speeds up the rate in which reactions take place and their metabolic rate rises

Question 36

What happens to homeothermic endotherms as ambient temperatures change?

Answer 36

The homeotherm keeps its temperature steady. The metabolic rate is variable as they are trying to maintain that steady body temperature, they are having to manipulate the rate at which they produce heat

Question 37

Describe a eurythermic thermoconformer with an example

Answer 37

They change their body temperature according to that of the environment and are able to withstand huge ranges in temperature, e.g. sea enemany

Question 38

Describe eurythermic thermoregulators

Answer 38

Are able to thermoregulate but over a wide range of temperatures

Question 39

Describe stenothermal’s. Give an example

Answer 39

Ones that perhaps can thermoregulate but only over a small range of temperatures.
E.g. ice fish, they have a very small range of temperatures in which they can survive

Question 40

When looking at the oxygen consumption of a barnacle goose flying in a wind-tunnel it is about 15x more than it’s resting level. Just before the end it increases a bit more, why is this

Answer 40

It is because the bird tries to hover as the wind speed is reduced

Question 41

After recording the oxygen consumption of a barnacle goose flying in a wind tunnel it’s metabolic rate remains high even after its flight, what is his mostly down to?

Answer 41

Is because they produce a lot of heat that has to be dissipated

Question 42

After recording the oxygen consumption of a barnacle goose flying in a wind tunnel it’s metabolic rate remains high even after its flight, what is his mostly down to?

Answer 42

Is because they produce a lot of heat that has to be dissipated

Question 43

What is the adrenocortical response to stressors inhibited on arrival in the artic hypothesis?

Answer 43

It is that because the breeding season is short switching off stress response may be energetically costly but reproductive fitness could be enhanced (avoid entering emergency life history stage)