Pt 5 Struggle for existence Flashcards
Homeostasis and Regulation:
Homeostasis: Maintenance of internal stability in response to external fluctuations.
Key examples include:
Thermoregulation:
Endotherms: Maintain constant internal temperature (e.g., mammals, birds).
Ectotherms: Depend on external temperature for body heat (e.g., reptiles, amphibians).
Water Balance:
Evaporation and water loss regulation critical for plants and animals in arid environments.
physiological constraints
Tradeoffs and Constraints:
Limited resources lead to tradeoffs (e.g., reproduction vs. survival).
Examples include:
Resource allocation in plants between growth and reproduction.
Mammals balancing heat loss and thermoregulation.
Scaling and Surface Area to Volume (SA/V) Ratios:
Smaller organisms have higher SA/V ratios, leading to faster heat and water loss.
Larger organisms can buffer environmental changes due to lower SA/V ratios.
Tradeoffs in Rabbits and Pikas:
Rabbits in hot climates have large ears for heat dissipation.
Pikas in cold climates have small ears to minimize heat loss and avoid mechanical damage.
Heat Regulation in Plants:
Leaves balance sunlight absorption for photosynthesis and heat dissipation to avoid enzyme denaturation.
Discuss the significance of SA/V ratios in determining an organism’s physiological constraints.
Significance: SA/V ratio influences heat, gas, and nutrient exchange with the environment.
Small Organisms (High SA/V): Efficient exchange but prone to rapid heat and water loss.
Large Organisms (Low SA/V): Retain heat better but slower exchange rates, requiring specialized systems (e.g., lungs, circulatory systems).
Key Constraint: SA/V ratio limits size and shapes adaptations for survival
Explain the difference between homeothermy and poikilothermy with examples.
Homeothermy:
Maintains a stable internal body temperature regardless of environment.
Example: Mammals like humans regulate temperature via metabolism.
Poikilothermy:
Body temperature varies with the environment.
Example: Reptiles like snakes depend on external heat sources for temperature regulation.
Key Difference: Homeotherms use internal mechanisms; poikilotherms rely on external conditions.
How do physiological adaptations in animals reflect their ecological niches?
Definition: Physiological traits enable animals to survive and thrive in specific environments.
Examples:
Camels: Water storage and heat tolerance for deserts.
Penguins: Fat layers and countercurrent heat exchange for cold climates.
Fish in Low-Oxygen Waters: Efficient gill systems for oxygen uptake.
Key Link: Adaptations align with resource availability, climate, and survival needs in an animal’s niche.
What is physiological ecology?
The study of how physiological processes in organisms interact with their environments.
Define homeostasis.
The maintenance of stable internal conditions despite external changes.
What is the difference between endothermy and ectothermy?
Endothermy: Internal heat production (e.g., mammals).
Ectothermy: Dependence on external heat (e.g., reptiles).
Example of a tradeoff in animals.
Rabbits: Large ears in hot climates to dissipate heat; small ears in pikas for insulation and mechanical protection.
Why is the SA/V ratio important in physiological ecology?
Determines heat and water exchange rates, influencing metabolic needs and survival in varying climates.
Key function of stomata in plants.
Facilitate gas exchange and regulate water loss through evaporation.
Provide an example of thermoregulation in animals.
A: Rabbits in hot climates have large ears for heat dissipation, while pikas in cold climates have small ears to retain heat.
