Coping with Environmental Variation: Temperature and Water

A set of flashcards covering key concepts from Chapter 4 on coping with environmental variation, specifically focusing on temperature and water.

What determines the potential geographic distribution of a species?

Each species has a range of environmental tolerances.

How is the temperature of an organism determined?

Through exchanges of energy with the external environment.

What influences an organism’s water balance?

Exchanges of water and solutes with the external environment.

What is cryonics?

The preservation of bodies by freezing.

How do certain Arctic frog species survive winter?

They can remain in a semi-frozen state with no heartbeat or breathing.

What happens to most organisms when they freeze?

They experience tissue damage due to ice crystals perforating cell membranes.

What are two options for coping with environmental variation?

Tolerance and avoidance.

What is physiological ecology?

The study of interactions between organisms and their environment.

What ultimately determines a species' geographic range?

The physical environment.

Name a key indicator of the physical environment in ecological studies.

Plants.

What influences the actual geographic distribution of a species?

Other factors such as competition.

Define climate envelope.

The range of conditions over which a species occurs.

What happens to physiological processes at the extremes of temperature?

Their functioning may be reduced or cease.

What is the process of acclimatization?

Adjusting to environmental stress through behavior or physiology.

What is the difference between acclimatization and adaptation?

Acclimatization is short-term and reversible, while adaptation is a long-term genetic change.

What is the significance of ecotypes?

They are populations with adaptations to unique environments.

How do ectotherms typically regulate body temperature?

Through energy exchange with the external environment.

What is the main challenge for ectotherms in hot environments?

Gaining too much heat that can lead to lethal body temperatures.

How do endotherms maintain internal temperature?

Through internal heat generation, mostly by metabolic processes.

What is a thermoneutral zone?

The range of environmental temperatures for maintaining a constant basal metabolic rate.

What adaptations do kangaroo rats have for arid environments?

Active at night, waterproof skin, minimal water loss in urine.

What are osmotic environments?

Conditions where water flows according to solute concentrations.

How do freshwater organisms deal with hypoosmotic environments?

They lose solutes and gain water.

What adaptations do marine bony fishes have?

They are hypoosmotic to seawater and regulate salt and water balance.

Why do terrestrial organisms need to manage water loss?

They lose water to the dry atmosphere.

What effects can low water availability have on plants?

Loss of turgor pressure and potential wilting.

How do some plant species prevent water loss?

By closing stomates or shedding leaves during dry seasons.

What is turgor pressure important for?

It gives form to plants and promotes growth.

What do mycorrhizae do for plants?

Enhance the absorption of water and nutrients.

Why do amphibians rely on stable water supplies?

To maintain water balance and facilitate gas exchange.

How do adaptations in reptiles help them in dry environments?

Thick skin that minimizes water loss.

How do birds and mammals regulate evaporative water loss?

By sweating, panting, and using fur or feathers.

What is the role of boundary layers in heat exchange?

They affect how much heat is lost or gained by leaves.

What is the role of insulation in endotherms?

To limit conductive and convective heat loss.

What are the costs of being endothermic?

High energy demands for metabolic heat production.

How do small mammals deal with high metabolic rates?

By entering a state of torpor to conserve energy.

What happens to ectotherms when they experience cold temperatures?

They must avoid or tolerate freezing.

What is the significance of evaporative cooling in animals?

It helps regulate body temperature during heat exposure.

How do terrestrial animals minimize gas exchange resistance?

By having skin resistance in dry environments.

How do plants cope with low soil water availability?

By altering root growth and shedding leaves.

How does seasonal shedding of leaves help plants?

It reduces transpirational water loss.

What is osmotic adjustment in microorganisms?

Altering osmotic potential to maintain water balance.

How do organisms withstand freezing conditions?

By limiting freezing water to areas outside the cells.

What do desiccation-tolerant organisms do when facing aridity?

They synthesize sugars that protect cellular structures.

Why are small organisms more desiccation-tolerant?

They have favorable surface area-to-volume ratios for water loss.