Exam Flashcards

1
Q

What are the biological scales from smallest to largest?

A

Molecules -> Cells -> Tissues -> Organs -> Organisms -> Populations -> Communities -> Ecosystems -> Biotas

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2
Q

What are the spatial scales from smallest to largest?

A

Local -> Regional -> Continental -> Global

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3
Q

What are the temporal scales from smallest to largest?

A

Acute -> Chronic -> Generational -> Macroevolutionary

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4
Q

Acute Time Scale

A

Minutes to hours; ex. Daily fluctuation in temperature, hottest day on record.

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5
Q

Biological Response to Acute Pressures

A

Behavioural adjustment (e.g. sit in water); Physiological response (e.g. sweating); Death; Immediate response.

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6
Q

Chronic Time Scale

A

Weeks to years; ex. Seasonal fluctuation in temperature, hottest seasons on record.

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7
Q

Biological Response to Chronic Pressures

A

Migration, Acclimatization, Death; Change in physiology to adjust set points in relation to prolonged changes in the environment.

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8
Q

Generational Time Scale

A

Multiple generations; ex. Gradual climate change (e.g. ice ages), Rapid climate change.

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9
Q

Biological Response to Generational Pressures

A

Habitat tracking, Adaptation, Extinction.

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10
Q

Conformers

A

Allow internal environments to follow external changes; as external environment changes, internal environment changes in the same manner.

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11
Q

Regulators

A

Attempt to maintain constant internal environments in the face of varying environmental conditions; internal environment stays consistent along zone of stability, changing at extremes.

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12
Q

Hyper-Regulation

A

Maintaining an internal environment higher than external environment.

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13
Q

Hypo-Regulation

A

Maintaining an internal environment lower than external environment.

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14
Q

What processes are regulated by regulators?

A

Ions, temperature and metabolic depression can be affected.

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15
Q

How do mammals conform/regulate?

A

Regulate ions and temperature; some species go into hibernation or torpor where metabolic depression occurs.

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16
Q

How do birds conform/regulate?

A

Regulate ions and temperature; some experience torpor.

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17
Q

How do reptiles/amphibians conform/regulate?

A

Conform to temperature; regulate ions.

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18
Q

How do fishes conform/regulate?

A

Conform to temperature; regulate ions; exceptions include icefishes.

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19
Q

How do invertebrates conform/regulate?

A

Conform to ions and temperature.

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20
Q

Where do polar bears release heat?

A

Eyes and mouth.

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21
Q

Where do elephants release heat?

A

Along entire body, especially large trunk and ears.

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22
Q

Why would photoperiod evolve to be a trigger for anti-freeze protein production, if it’s actually an adaptation to changing temperature?

A

The antifreeze proteins are readily available when they are needed. Photoperiod is also more consistent than temperature. Maybe it’s easier for cues based on photoperiod to evolve.

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23
Q

What materials must arctic plants/animals exchange?

A

Gases (O2 for metabolism), Nutrients (foods), Wastes (balance ion composition).

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24
Q

How does exchange occur in cells?

A

Across membranes; rate depends on membrane surface area; amount needed depends on volume. In multicellular animals, every cell must be in contact with aqueous environment (interstitial fluid) where dissolved substances can be exchanged. Complex animals must have circulatory fluid to carry things to interstitial fluid. Respiratory and digestive systems have direct contact with external environment.

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25
Q

Homeostasis

A

To varying degrees, animals maintain relatively constant internal conditions in the face of a fluctuating external environment. Neural/hormonal processes are involved in keeping internal variables constant. Regulatory systems based on negative feedback.

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26
Q

Negative Feedback

A

Results in a decrease in a variable that is too high or an increase in a variable that is too low.

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27
Q

What happens in endotherms when temperatures rise?

A

Vasodilation, increased sweating and panting, behavioural changes that limit heat gain. (signals from hypothalamus)

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28
Q

What happens in endotherms when temperatures fall?

A

Vasoconstriction, shivering, behavioural changes that limit heat loss. (signals from hypothalamus)

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29
Q

Temperature Set Point

A

Temp. set point is not fixed but may vary on a daily/monthly/seasonal cycle. Hibernating endotherms do not lose complete control, but maintain a lower set point.

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30
Q

Positive Feedback

A

Not as common because it pushes system father from initial state (ex. oxytocin stimulating uterine contractions in mammals. Must be a natural endpoint.

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31
Q

Acclimatization

A

Adjustment by individual organisms to chronic stresses.

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32
Q

Adaptation

A

Evolution of populations across generations under natural selection.

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33
Q

Range of Tolerance

A

Temperature range where the organism functions best.

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34
Q

How do temperature changes affect the molecular/macromolecular level?

A

Can alter cellular function (especially in ectotherms). An increase in temperature increases molecular movement and can denature proteins if extreme. A decrease in temperature can make an enzyme still and unable to function.

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35
Q

Lactate Dehydrogenase (LDH)

A

Final enzyme in anaerobic glycolysis. If cell temperature changes, LDH activity or rate of lactate production will change. Ectotherms modify LDH activity to maintain cell function by altering expression of LDH isoforms.

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36
Q

How are cell membranes affected by a change in temperature?

A

In ectotherms, cell membrane composition is changed to maintain fluidity.

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37
Q

Homeoviscous Adaptation

A

The maintenance of relatively constant membrane fluidity regardless of tissue temperature.

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38
Q

Circadian Rhythms

A

Pattern that follows rhythm over 24 hours. Controlled by endogenous (or internal) mechanism that acts like a clock. The internal biological clock is set by external light conditions, but is not dependent on light.

39
Q

Circannual Rhythms

A

Proceed over a year (e.g. hibernation in small mammals).

40
Q

What changes have been made in arctic plants to survive?

A

Thicker cuticle to limit H2O loss, take full advantage of light during short growing season, plants stunted to avoid wind damage.

41
Q

What are some consequences of tying seasonal changes to photoperiod?

A

Seasonal patterns of photoperiod don’t change, no matter how much warming occurs; camouflage mismatch could occur (e.g. arctic hare).

42
Q

Freeze Avoidance

A

Use strategies to avoid freezing even at subzero temperatures. Species that use this strategy are freeze-intolerant. (Ex. migration, anti-freeze proteins, hibernation, supercooling, dehydration). Promote conditions where cellular water can be cooled to below 0C before ice crystal formation.

43
Q

Freeze Tolerance

A

Use strategies to promote controlled freezing to minimize tissue damage. (Ex. cellular dehydration, ice nucleating proteins in intercellular spaces).

44
Q

Supercooling

A

Making antifreeze (bind microscopic ice crystals); make cryoprotectants glycerol, sugars and proteins which lower the freezing point.

45
Q

Wood Frog

A

Freeze-Tolerant. Freezes solid, uses glucose as cryoprotectant, and organs dehydrate.

46
Q

What does an endotherm do in the cold?

A

1 - Try to find someplace warmer, 2 - Try to prevent heat loss, 3 - Try to generate more heat, 4 - Allow certain parts of the body to cool, 5 - Allow the entire body to cool (in a controlled manner).

47
Q

Heat Production

A

1 - Muscle activity, 2 - Shivering, 3 - Non-shivering thermogenesis, 4 - Digestion.

48
Q

How does brown adipose tissue differ from normal white adipose tissue?

A

More numerous, smaller droplets; higher number of mitochondria with high levels of iron; higher vascularization. It is mainly found in small animals who undergo torpor/hibernation.

49
Q

Do humans have brown adipose tissue?

A

Infants do, but adults do not.

50
Q

Why is freezing bad?

A

There is no cellular activity, ice crystals are jagged and may rupture cell membrane, as ice expands it may rupture cells, lack of movement.

51
Q

Regional Heterotherms

A

Flukes and flippers of whales, seals, walrus. Legs of wading birds, northern birds, caribou, wolves.

52
Q

Countercurrent Heat Exchange

A

Arteries give up heat to veins; blood going to the extremity is pre-cooled; little heat is lost.

53
Q

Controlled Hypothermia

A

Reduction in body temperature, metabolism, heart rate and other bodily functions.

54
Q

If you are an endotherm, what are your options when you do not have the energy to heat up?

A

CONSERVE ENERGY. Ex. Regional heterotherms, controlled hypothermia, metabolic depression, torpor, hibernation.

55
Q

Daily Torpor

A

Seen in small endotherms with high metabolism; often occurs on a daily basis; body temperature drops rapidly 10-20C; reheat with shivering or oxidation of brown fat; state of decreased physiological activity in an animal.

56
Q

Hibernation

A

Deep torpor/winter dormancy; in marsupials, rodents, insectivores, bats; sufficient food stores to survive periods of no food; marked reductions in metabolic rate and blood flow; body temperature can near 4-6C; seasonal state of heterothermy; multiple episodes of torpor and arousal.

57
Q

During hibernation, what physiological processes are affected?

A

Blood pressure, temperature, heart rate, and oxygen uptake.

58
Q

How do black bears hibernate?

A

Reduced metabolic rate, NOT deep hibernators, fat -> water, recycle. With a lower heart rate, the left ventricle heart wall is stiffened, the myosin structure is changed, which maintains heart function.

59
Q

Do polar bears hibernate in winter?

A

No, as food is available in winter.

60
Q

How does body size affect requirements?

A

Absolute requirements are proportional to body size, and relative metabolic requirements are proportional to the inverse of body size.

61
Q

How is the surface area to volume ratio related to exchange?

A

Exchange with the environment is not efficient for large animals (who have smaller surface area to volume ratios). To compensate, many organs have folded membranes to give more surface area.

62
Q

Metabolic Rate

A

An overall indication of how much energy or O2 is being consumed per unit time.

63
Q

What is Q10?

A

Temperature quotient; describes the change in rate with an increase in temperature of 10 degrees. (Rate at T/Rate at T-10). For most physiological process, Q10 values are between 2 and 3. Hibernation is an exception (more profound decrease).

64
Q

Why do endotherms hibernate?

A

Once ambient temperature start to fall, there is a larger temperature gradient between internal/external temperature and greater heat loss.

65
Q

How does hibernation differ in small animals?

A

Need to supply more energy for each cell than large mammals, and they lose heat faster than larger animals.

66
Q

Hibernation vs. Arousal

A

HIBERNATION: Lower metabolism, little/no food, burn stored white fat. AROUSAL: Higher metabolism, burn brown fat (generate 10x more heat).

67
Q

Non-Shivering Thermogenesis

A

Process whereby brown fat is used to generate body heat

68
Q

How is brown fat metabolism regulated?

A

Prevent overheating. Key switch is release of adrenaline. Brown adipose tissue has a fine meshwork of blood vessels that supply O2 and carries heat away to warm body.

69
Q

Is hibernation more advantageous for small or large animals?

A

Small animals, as they require relatively constant supplies of food to maintain a high metabolic rate/body temperature while active. White fat stores provide sufficient fuel to sustain low metabolic activity, then non-shivering thermogenesis is used to restore active metabolism.

70
Q

Active Overwintering Small Mammals

A

Voles and lemmings construct long tunnels under the snow, where they rely on twigs/shrubs/old grasses for food.

71
Q

How is the woolly mammoth haemoglobin molecule unique?

A

The haemoglobin could unload oxygen more efficiently in cold conditions than haemoglobin from living elephants.

72
Q

What makes the icefish haemoglobin unique?

A

There is none. Instead, they have a high blood volume, large blood vessels, and less efficient heart muscle. (Haemoglobin gene has been lost).

73
Q

Environmental Facilitation

A

Species with weak adaptation or even maladaptive traits or can survive only in a particular environment.

74
Q

What is a non-adaptive explanation for the loss of haemoglobin in icefish?

A

A mutation that destroyed Hb function but was not fatal due to high oxygen content of Antarctic water.

75
Q

Stenothermal

A

Able to live in narrow range of temperatures.

76
Q

Adaptations to the Cold in Polar Bears

A

Thick fur, blubber, large size (low surface area to volume ratio), hollow hairs that trap heat emitted from skin.

77
Q

What new biotic interactions could occur in a warmer climate?

A

Ranges of other predators could expand or shift (e.g. grizzly bear).

78
Q

Differences Between Brown Bear and Polar Bear

A

POLAR: longer skull and nose, sharper teeth, longer canines (more stress on skull), smaller ears; specialist (100% carnivore), can fast for several months during late summer.

79
Q

Are polar bears and brown bears in distinct lineages?

A

Nuclear DNA says yes, mitochondrial DNA says no. Hybridization is possible.

80
Q

What did the Arctic look like in the past?

A

Lush forests and terrestrial/aquatic habitats. Global climate change marks major transitions in evolution of life.

81
Q

Osmosis

A

Passive movement of water across a membrane from a solution of low solute concentration to a solution of high solute concentration; occurs from a solution with lower osmotic pressure to one with higher osmotic pressure.

82
Q

Hypertonic solutions cause cells to…

A

Shrink.

83
Q

Hypotonic solutions cause cells to…

A

Swell.

84
Q

Isotonic solutions cause cells to…

A

Remain constant.

85
Q

What happens when ice crystals form in the extracellular fluid?

A

Amount of free water outside cell is reduced, which creates an increase in osmotic pressure, which in turn shrinks cell.

86
Q

Resting Eggs

A

Remain dormant during harsh winter and are very resistant to cold and desiccation. Adults do not survive, but resting eggs do and then hatch when conditions become favourable.

87
Q

What will be the effects of reduced time on sea ice?

A

Decreased feeding period (reduce stored fat), increased fasting period (increased need for stored fat), reduce number of successful pregnant females able to rear young, and reduce survival rates of dependent young (population decline).

88
Q

What are the global patterns in biodiversity?

A

EQUATOR: high species richness, lower abundance per species. POLES: lower species richness, higher abundance per species.

89
Q

Arctic Biodiversity

A

Terrestrial Arctic biodiversity was thought to be lower than in temperate or tropical regions, but there is probably more insect diversity in low Arctic sites than previously thought, and unique and diverse marine fauna.

90
Q

Refugium

A

Pocket where habitat remains when climate changes (e.g. polar bears).

91
Q

Where is the speciation rate highest in marine fishes?

A

Poles. However, still low richness here, so extinction rate must also be high.

92
Q

What is the argument for the Arctic being hit especially hard by climate change?

A

Highest species turnover. High temperature changes. Gamma diversity will go down. Treeline expansion.

93
Q

What is the argument for the Arctic NOT being hit hardest by climate change?

A

Tropical insects are relatively sensitive to temperature change. Species at higher latitudes have broader thermal tolerance, and warming may enhance their fitness. Ectotherms may do better in warm temperatures.

94
Q

What is the argument that Arctic will be hit just as hard as other areas by climate change?

A

It is complicated - many components. Overly simplistic.