integrated lec 15 Flashcards

1
Q

physiological ecology

A

Definition:

Study of how organisms acquire energy and nutrients while tolerating environmental conditions.
Examines physiological adaptations in an ecological context.

Core Concepts:

Tolerance Ranges: Distribution limits set by temperature, moisture, and other environmental factors.
Homeostasis: Maintaining stable internal conditions despite external variability.
Trade-offs: Adaptive compromises between competing functions

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2
Q

heat balance and thermal ecology

A

Key Principles:

Poikilotherms (e.g., reptiles, amphibians): Body temperature fluctuates with the environment.
Homeotherms (e.g., birds, mammals): Maintain constant internal temperature, requiring significant energy investment.

Modes of Heat Gain and Loss:

Radiation: Heat transfer via electromagnetic waves.
Conduction: Direct transfer through contact (e.g., feet on cold ground).
Convection: Heat exchange with moving air or water.
Evaporation: Cooling via water loss from surfaces.
Redistribution: Heat moved between body parts by the circulatory system.

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3
Q

Surface Area to Volume Ratio (SA:V)

A

Key Concept:
Smaller organisms (high SA:V): Lose heat quickly, equilibrate fast.
Larger organisms (low SA:V): Retain heat, equilibrate slowly.

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4
Q

bergmann’s rule

A

Homeotherms are larger at higher latitudes (colder climates) to reduce heat loss.

Example: Polar bear > Black bear > Sun bear.

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5
Q

shape and function

A

Adaptations:
Spherical shapes: Minimize SA:V for heat retention.
Specialized shapes: Enhance functionality (e.g., gliding snakes in warm tropics).

Allen’s Rule:
Appendages are shorter in colder climates to reduce heat loss (e.g., Arctic fox vs. Fennec fox).

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6
Q

insulation and cooling

A

Mechanisms:
Fur, Blubber, Feathers: Reduce heat loss in cold environments.

Countercurrent Circulation:
Heat conservation by transferring warmth between arteries and veins in appendages.

Evaporative Cooling:
Heat dissipated via sweating, panting, or other water-loss mechanisms.

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7
Q

Adaptive Trade-offs
Case Study: Weasel Body Shape:

A

Long, thin shape increases heat loss (high SA:V) but enhances hunting efficiency.
Trade-off: Energy cost of maintaining warmth is offset by improved predation success.

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8
Q

Constraints in Evolution

A

Limitations:
Adaptations are shaped by existing developmental pathways.
Evolution “tinkers” rather than creates entirely new designs.

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9
Q

What is Bergmann’s Rule?

A

A: Larger body sizes are found in colder climates to conserve heat, while smaller sizes occur in warmer climates.

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10
Q

What is Allen’s Rule?

A

A: Animals in colder climates have shorter appendages to reduce heat loss, while those in warmer climates have longer appendages for cooling

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11
Q

Why are spherical shapes beneficial in cold environments?

A

A: They minimize the SA:V ratio, reducing heat loss.

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12
Q

How does a snake’s elongated body shape benefit its function?

A

A: Enhances mobility and hunting efficiency, especially in warm environments.

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13
Q

How does countercurrent circulation conserve heat?

A

A: Warm blood from the body core transfers heat to cooler blood returning from extremities.

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14
Q

How does the weasel’s body shape illustrate trade-offs?

A

A: Its elongated shape increases heat loss but improves hunting agility in narrow spaces.

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15
Q

How does Bergmann’s Rule apply to fox species?

A

A: Arctic foxes are stockier with shorter ears, while fennec foxes have long ears to dissipate heat.

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16
Q

Why do desert animals rely on evaporative cooling?

A

A: To shed excess heat and maintain safe body temperatures in high ambient heat.

17
Q

What is the significance of the SA:V ratio for heat regulation?

A

A: High ratios increase heat exchange, critical for small or tropical species, while low ratios conserve heat in large or polar species.

18
Q

How do poikilotherms and homeotherms differ in energy requirements?

A

A: Homeotherms require more energy to maintain constant internal temperatures, while poikilotherms adapt to external conditions.