Temperature in animals Flashcards
1
Q
Range of temperatures inhabited
A
- Thermophiles (90C)
- Arctic animals: (-40C)
- Most organisms (10-30C)
2
Q
Species richness and temperature
A
- more amphibians seen in places where annual temperature is higher
- Generally there are more species of plants and animals where temperature is higher
3
Q
Importance of temperature on global scale
A
- Impact of extreme temperatures can range from discomfort to extinction
- Long-term temperature changes affect range and possibly survival/extinction of entire groups of fauna/flora
- Crucial to the study of ecology; temperature is one of the most important environmental factors in the lives or organisms
4
Q
Importance of temperature on cellular level
A
- proper cell membrane fluidity
- cellular fluidity influenced by phospholipids
5
Q
Saturated vs. Unsaturated fats
A
- Unsaturated; cannot pack together as tightly as saturated because kinked; maintain fluidity under lower temps)
- cholesterol helps regulate fluidity (buffers effect of temperature)
6
Q
Enzymes
A
- have specific ideal temperatures; most human enzymes function optimally at 37C, but most thermophile baceria enzymes optimal at 77C
7
Q
How is heat transferred?
A
- Evaporation
- Radiation
- Convection
- Conduction
8
Q
Evaporation
A
- heat is lost as water evaporates from surfaces (ex: sweating cools us off)
9
Q
Radiation
A
- Heat gained or lost through radiation (ex: sun radiates heat)
10
Q
Convection
A
- Heat gained and lost through convection (ex: blowing of colder or warmer air across a surface)
11
Q
Conduction
A
- Heat gained and lost through conduction (touch a colder or warmer surface; like radiation but required direct contact)
12
Q
Thermoregulation
A
Process of regulating internal temperature
13
Q
Genetic adaptations for thermoregulation
A
- Endotherms; regulate own body temperature through metabolic processes; little change in internal temperature, metabolic rate can vary greatly with temperature
- Ectotherms; animals rely on external environment to regulate body temperature; internal temperature slowly changes, but metabolic rate stays the same
14
Q
Benefits and drawbacks of ect vs endo
A
- Endotherms use more energy; have to regulate temp metabolically
- Endotherms are more widespread; they can adjust to a greater range of variation in temp
- Ectotherms can be smaller; small animals have higher surface area to volume ratio
15
Q
Bergmann’s Rule
A
- Body size increases with latitude, altitude or temperature (within species)
- ex: moose increase in body size with increasing latitude
- ex: woodrats have negative correlation; the colder it is, the bigger they get
- True for >72% of birds and 65% of mammals
16
Q
Exceptions to Bergmann’s rule
A
- Chilean foxes smaller at higher altitude (probably because smaller prey is available)
- Gerbils smaller at higher altitudes (because competitive displacement by larger species)
- Many ectotherms; maybe because their vulnerability to predation
17
Q
Allen’s Rule
A
- Mammalian body form: more linear in warm climates and rounder in cold climates (within species or between similar species)
- Ex: foxes, rabbits
- May be due to phenotypic plasticity
18
Q
Other genetic adaptations due to thermoregulation
A
- Fur
- Feathers
- Scales
- Shells
- Colour (dark colours allow absorption of more heat)
19
Q
Phenotypic plasticity
A
- temperature-size rule: colder climates, slower growth, larger adult body size, probably because of surface area to volume ratio
- this may be genetic or it may be a result of phenotypic plasticity
20
Q
Acclimitization
A
- adjustments to changes in temperature that occur over days to weeks are reversible (often seasonal)
- ex: weight gain in winter, increase in length and density of fur, horses left outside in winter grow thick coats, non-migratory finches put on weight in winter and lose it in summer
21
Q
Behaviour
A
- Changes that occur very rapidly in response to changes in temperature
- Some ex: reorientation, wallowing in water or mud, seeking shelter, gaping or panting, raising or lowering body to change conduction, dressing differently…
22
Q
Regulation
A
- Kind of like behaviour, but not a choice
- ex: sweating, mucus production, raising of hair, shivering, changing heart rate, vasoconstriction (less heat lost to cold), vasodilation (blood cooled)
23
Q
Cellular-level effects of temperature
A
- enzyme function
- protein denaturation
- cell membrane fluidity
- formation of ice crystals
24
Q
Temperature and enzymes
A
- optimal temperature for enzyme function
- tolerance for some temperature variation
- if temperature is too high: reaction rate drops, can experience thermal agitation, can become denatured
25
Q
Adjusting enzyme function - Isozymes
A
- Change isozymes (acclimation): two enzymes with same function but different genetic code; therefore can switch to other one under conditions (ex: carp can adjust to wide range of temp by using different isozymes)
26
Q
Adjusting enzyme function - Allozymes
A
- Change allozymes (genetic adaptation): same gene with different alleles coding for an enzyme (ex: closely-related polychaete species near heat vents have different allozymes than those farther away from heat vents)
27
Q
Avoiding protein denaturization
A
- Heat-shock proteins (HSPs)
- Produced in response to sudden increase in temperature
- Stabilize proteins that might otherwise be denatured by binding with them
- Ex: antarctic fish (Trematomus) does not produce HSPs in lab in response to temp spike
28
Q
Maintaining cell fluidity
A
- change concentration of unsaturated phospholipids in cellular membranes (genetic, phenotypic plasticity or acclimatization)
- cholesterol helps resist changes in temperature
29
Q
Freeze tolerance vs. Freeze intolerance/avoidance
A
- Freeze intolerance/avoidance: cannot survive ice crystal formation so avoid freezing
- Freeze tolerance: can survive formation of ice crystals; they freeze but survive
30
Q
Freeze tolerance in animals
A
- Temperature of freezing depends on solute concentration
- Between cells: hydrophilic ice-nucleated proteins (ice nuclei) attract water so ice crystals form b/w rather than in cells OR noncolligative (antifreeze) proteins inhibit crystal growth
- Within cells (Cryoprotectants): Colligative; sugars that raise solute concentration so cell does not freeze (ex: glycerol) OR Noncolligative; proteins and sugars than can replace water
- Blood of sea animals has freezing point similar to that of sea water
- Freshwater animals have a freezing point below that of freshwater; they maintain a higher solute concentration
31
Q
What happens while animal is “frozen” and what kind of animals are freeze tolerant
A
- little or no respiration or circulation of body fluids, extremely low metabolic rate
- common in insects, bivalves, gastropods, annelids, nematodes and intertidal organisms
32
Q
Freeze-intolerance/avoidance in animals
A
- Animals who life with body fluids below 0C but don’t freeze
- Supercooling; keeps body fluids unfrozen below freezing point
- Cryoprotectants; all solutes reduce freezing temperature, some solutes are particularly effective and don’t do damage (glycerol), animals must remove ice-nucleating agents from their bodies
33
Q
Freeze tolerance vs. intolerance (benefits and drawbacks)
A
- Tolerance is cheaper because decline in metabolic rate and consistent severe winter
- intolerance is more expensive, and best in a variable environment
34
Q
Regional heterothermy
A
o Different temperatures in different parts of a body
o In ectotherms:
- Occurs in some fish and reptiles
- Sometimes utilizing regional endothermy (even if they’re ectotherms)
- Ex: tunas and sharks maintain higher temperature in swimming muscles – allows more sustained locomotion
o In endotherms:
- Average internal temperature in endotherms is fairly stable (35-40), there are differences within the bodies of individuals, especially in their extremities
- Ex: humans have colder fingers than anywhere
35
Q
What allows for regional heterothermy and regional endothermy
A
- Countercurrent exchange; heat transferred between fluids moving in opposite directions
- Allows heat exchange along the length of limb axis
- increase in surface area for efficient heat exchange
- conserve core heat, allow limbs to cool or provides cooling
36
Q
Eurytherms
A
- organisms that function and are active within a wide range of body temperatures
- ectotherms (ex: mosquitoes)
37
Q
Stenotherms
A
- organisms that function and are active only under a very narrow range of body temperatures
- Edotherms AND ectotherms: mammals and birds, some lizards and insects, many aquatic animals (not that water temperature does not vary as much as air temperature so most aquatic organisms need not be able to function under a wide range of temp)
38
Q
Avoidance/Evasion - Temporal
A
- Torpor; physiological state of decreased activity and metabolism (hibernation in cold climates, estivation in deserts, warm climates)
39
Q
Avoidance/Evasion - Spatial (migration)
A
- May be relatively limited (spiders and bears seeking caves and holes, freshwater turtles and amphibians may seek deeper water)
- Long-distance (more common for those who swim or fly, many migrate using starts, magnetic sense - birds, whales, fish, butterflies)
40
Q
Migration in birds
A
- tiny birds may travel thousands of miles
- stop-over sites; need to stop for food; if these spots not available they may die
- Bar tailed godwits travel 10,000km non stop
- arctic terns 40,000km one way
41
Q
Migration in whales and anadromous fish
A
- Whales travel between resources (krill) in cold waters to breed in warmer waters
- ex: Humpback whale
- Fish live most of their adult lives in the ocean but swim upstream to breed in freshwater (salmon)
42
Q
Migration in monarch butterflies
A
- occurs over 5 generation
- importance of stop-overs
- not all monarchs migrate, those who do tend to have larger wings
43
Q
Predicting effects of climate change on species ranges
A
- prediction of invasive yellow star thistle expanding it’s range inland (toxic to horses)
- spread of diseases predicted this way (mosquito predicted to move north as climate warms)
- predict how composition of our forests will change (hardwoods north)
44
Q
Sociality and eusociality (microclimates)
A
- Insects; termites create huge mounds because they work together; inside these mounds temp is constant and cool
- Spiders; social spiders work together to build huge web masses, tem is constant
- Mammal: Naked mole rat; one reproductive female per colony - eusocial; work together to build a complex of burrows in which temperature is cool and constant
45
Q
Colouration
A
- change colour to lose or gain heat (especially in baskers)
- ex: south american frog changes melanin in response to background and temperature (dark when ambient temp is low)
- instant change in green tree frogs due to changes in chromatophores
- some insects differ in temperature with season (within species: ex: some butterflies darker in spring than in summer)
- Variations within the species of garden snails; light colour in areas with higher mean daily temperatures during hottest month
46
Q
Thermophiles
A
- live under extremely hot conditions (60-108C…and one species at 121C)
- Mostly archaea
- Live in water, often boiling
- have extremozymes
- differences in membrane structure; more kinked proteins
47
Q
Psychrophiles
A
- 20C to 10C
- Mostly bacteria and archaea
- fungi have been found under snowfields
- coldest living conditions (-20C for bacteria living in permafrost and sea ice)
- found in desert soil in Antarctica
- cold adapted enzymes and cryoprotectants
