Dinosaur Endothermy (Thermoregulation)

Question 1

What is the metabolic rate?

Answer 1

Energy expenditure per time

Measure how much oxygen is used up/respired per unit of time (min etc.) (mg/min) -> (J/S)

Question 2

Energy used up @ rest - endothermic

Answer 2

Basal metabolic rate (endothermic)

Question 3

Which is greater? Basal metabolic rate or exercise metabolic rate?

Answer 3

Basal metabolic rate < exercise metabolic rate

Question 4

How does the metabolic rate change with temperature in reptiles?

Answer 4

Metabolic rate is oxygen consumption
Warmer you are -> more oxygen consumed

For reptiles, there’s a big direct correlation b/t Body temperature w/ air temp
Based on air temperature

Becauses reptiles Use external heat (sun) to warm up
The sun minimizes heat loss (blood flow pattern, etc.)

Question 5

What’s the relation (graph wise) between air temperature and body temperature? For reptiles/ectothermic animals?

Answer 5

Linear

Question 6

How much oxygen is being consumed in relation to the body temperature? What kind of graph is this?

Answer 6

Ambient temp = air temp
Body temp higher ↑ uses more oxygen metabolic rate ↑

Depends on outside temp
Not linear, looks more like ex or 2x

Question 7

Warm blooded?

Answer 7

Homeothermy
Endothermy
(stenothermy)

Question 8

Homeothermy

Answer 8

(warm blooded)

Body temp constant regardless of outside temp

Question 9

Poikilothermy

Answer 9

(antonym of Homeothermy)

applies to reptiles because Reptiles temp depends on outside temp

Question 10

Lethal temperature

Answer 10

Max temp before you die
37 °C for monotreme
Birds have higher (lethal) temp than humans

Question 11

Endothermy

Answer 11

“Inside temp”

Mechanism to facilitate homeothermy

Question 12

What does Endothermy or “Inside temp” really mean?

Answer 12

Internal organs make up most of heat inside body (72.4%)
Skin and muscle (27.6%) of heat produced inside body
High heat generation inside body

Question 13

Ectothermy

Answer 13

“Outside temp” (sun)

Reptiles

Question 14

In Warm blooded animals, what is the general body temperature? What kind of animals are warm blooded?

Answer 14

Warm blooded maintain high body temp (>30 °C) w/ endothermy - mammals and birds

Question 15

stenothermy

Answer 15

Stenothermy is implied if homeothermic and endothermic then stenthermic

Both mammals and birds

Chemical reactions require core temp to be within a specific body temp range

Works best within that range

There is a cost - (use 10x more oxygen than reptiles who don’t do this)

Resting (Basal or standard) metabolic rate - mammals higher than reptiles

Question 16

Gigantothermy

Answer 16

“Scaling effect”
Ratio b/t surface & volume differs
Generation of heat in gigantic animals

Question 17

What would happen to an alpaca 2x its normal size

Answer 17

Big alpaca (2x big alpaca) will suffer from overheating)

Heat generation proportional to volume x8

Heat removal proportional to surface x4

Heat generation > heat removal -> overheating

Question 18

What would happen to a Shrunken alpaca (2x smaller)

Answer 18

Overcooling

Heat generation proportional to volume x0.125
Heat generation proportional to surface x0.25
0.25 > 0.125 -> overcooling

Lose heat more
Surface heat loss
Volume heat generation

Question 19

surface/volume ratio

Answer 19

is loss/generation

Question 20

what kind of animal is Gigantothermy most important for?

Answer 20

Very important for bigger animals

Question 21

Metabolic rate and bigger animals

Answer 21

Metabolic rate per 1 kg of body mass: slope -0.25

Bigger you are, get less b/c you don’t lose as much heat

Larger animals have smaller metabolic rates per body mass

Question 22

total metabolic rate, per individual animal, is _______ in larger animals

Answer 22

total metabolic rate, per individual animal, is larger in larger animals

Question 23

heat loss/heat generation and larger animals

Answer 23

Larger animals smaller heat loss/heat generation

Question 24

Gigantothermy, and body temperature in low and high ambient heat?

Answer 24

Easier to keep constant body temp in low ambient temp

Easier to overheat in high ambient temp

Question 25

Is Gigantothermy Homeothermic, stenothermic or endothermic?

Answer 25

Homeothermic and stenothermic but NOT endothermic

Question 26

Saltwater crocs and Gigantothermy

Answer 26

``` Saltwater crocs (very big) Larger crocs are warmer ``` Thermally stable (doesn’t lose heat) Ectothermy (relies on outside temp but loses less heat) Less fluctuation of temp Body temp stable in large crocs Not warm blooded

Question 27

Leatherback turtle and Gigantothermy

Answer 27

Leatherback turtle (very heavy) Body temp stable in turtles Lives in very low ocean temp Homeothermic Don’t have to be endothermic to be homeothermic! Not warm blooded True gigantothermic

Question 28

Do you have to be endothermic to be homeothermic?

Answer 28

no, Don’t have to be endothermic to be homeothermic!

Question 29

Body Equipment to maintain constantly high metabolic rate

Answer 29

Nasal turbinates | NOSE TURBINATE BONES/CARTILAGE IS NECESSARY

Question 30

Why do Warm blooded animals suffer from heat loss and moisture loss?

Answer 30

Warm blooded animals need a lot of air -> heat loss and moisture loss

Question 31

Nasal turbinate

Answer 31

Thin sheets of bone in nose covered by membrane Keeps moisture inside body Cold air in inhaled in -> warmed up -> go to inside of body so it’s safer Mammals have bone Birds have cartilage Exhale air -> air is cooled to maintain heat and moisture inside body Happens in mammals and birds, ex. Dog and ducks in pres Nose chambers bigger than crocs

Question 32

Crocs and Nasal turbinate

Answer 32

Cold temp in High temp out No changing of temp in croc Nose chamber tiny Doesn’t breathe as much as mammals Ectothermic nose

Question 33

Ectothermic nose

Answer 33

Ectotherms do not burn as much energy inside the body -> do not need as much oxygen. difference could be five to ten times.

Question 34

Air sac system? Is it necessary as nasal turbinate

Answer 34

UNIDIRECTIONAL AIRFLOW IN LUNGS NOT NECESSARY NOR SUFFICIENT

Question 35

Why are air sacs helpful?

Answer 35

Sufficient system? Humans don’t have it so it’s not necessary Lung airflow is unidirectional Getting oxygen is better if air is moving Humans stop air, birds don’t -> why birds get oxygen better than us Crocs- unidirectional airflow in crocs’ lungs Also happens in lizards -> multiple lobes to help unidirectional flow

Question 36

Are dinosaurs warm blooded? - Nasal Turbinates

Answer 36

“In b/t situation” not as small as reptiles but has no turbinates suggesting not warm blooded Air flow cold -> in Air flow hot -> out like in crocs/reptiles not like mammals like humans

Question 37

Are dinosaurs warm blooded? - Insulation

Answer 37

``` Insulation (feathers) Helps approach homeothermy Some dinosaurs were evolving Dinosaur insulation Evolving toward homeothermy ```

Question 38

Are dinosaurs warm blooded? - Growth rate

Answer 38

Growth rate Dinosaurs fast growers as marsupials Some not as fast tho Some dinosaurs grew as fast as mammals

Question 39

Are dinosaurs warm blooded? - Body temp

Answer 39

Body temp They were big so did they overheat? (32-38 °C) measurements of temp from teeth Did not really overheat

Question 40

Dinosaurs and Gigantothermy?

Answer 40

Some dinosaurs had high body temp but it’s gigantothermy Theropods - eggs like ectotherm (smaller and cooler than others) Larger animals - warm - gigantothermy (homeothermic but not endothermic) Smaller animals - insulation (by feathers) advancing toward homeothermy - expanded nose cavity Mesotherm - transitional stage b/t ectotherm and endotherm

Question 41

Are Dinosaurs mesotherms?

Answer 41

Leaving cold blooded and transitioning towards warm blooded but not completely there (in the middle)

Question 42

Basal metabolic rate

Answer 42

(endothermic)

Question 43

Standard metabolic rate

Answer 43

(ectothermic)

Question 44

Energy used up @ rest - ectothermic

Answer 44

Standard metabolic rate (ectothermic)

Question 45

Reptilian temperature fluctuation throughout the day?

Answer 45

Reptiles fluctuate temperature throughout day (15-20 °C)

Question 46

What is core temperature? What is the physical number? Does it stay constant or does it fluctuate?

Answer 46

``` Core temp (most hot in body, most internal): 38°C Core temp fluctuates throughout day (a few degrees C) ```

Question 47

Why is the resting metabolic rate of mammals higher than reptiles?

Answer 47

Mammals are warm blooded and have sternothermy. So they consume 10x more oxygen (because that's what happens when you have sternothermy) than reptiles do which do not have sternothermy because reptiles are ectothermic (they depend on the sun and do not generate their own heat) Because warm blooded (mammals/birds) consume much more oxygen, their resting metabolic rate is therefore higher.