Water and Temperature Regulation Flashcards
What is the theory of tolerance?
There is a zone of tolerance where an organism is capable of surviving, an optimal zone where it is capable of reproducing. Outside the tolerance zone is death
How do animals gain and lose water?
Gain mostly by drinking and eating. Can absorb through the skin, but some organisms are better than others at this. Lose by evaporation and in secretions
How do plants gain and lose water?
Gain by absorbing through the roots and from moist air. Lose from evapotranspiration.
How do plants regulate water in a dry environment?
Roots are deeper with more hairs, most biomass is below the ground.
How do plants prevent water loss? 6 ways
- open the stomata when it’s cooler
- reduced leaf area compared with root area
- thick leaves with very few stomata
- periodic dormancy
- wilting leaves
- cuticle
How do animals prevent water loss? 8 ways
- raise body temperature
- reduce metabolic rate
- have a more efficient large intestine to reabsorb water
- enlarged nasal passages that condense leaving water vapour
- Water-proof skin, fur, feathers, scales
- Be active when it’s cooler
- burrows and microclimates
- migrate
How do animals regulate their salt balance?
- get more by licking salt, eating plants high in salt
- eliminate excess salts through urine or drink more water
- Concentrate urine
- Salt glands in marine species (modified tear glands)
What is an energy budget?
Describes how an organisms allocates energy to essential life activities -> growth, reproduction, activity, and maintenance. All can’t be simultaneously maximized if energy supplies are limited, have to compromise
Why does adapting to one environment reduce fitness in another?
A trait can be beneficial in one environment and detrimental in another
What is the law of toleration?
Distribution and abundance of a species depends on the deviation between local conditions and the optimal conditions of a species
How does temperature affect animal performance?
Driven by effect on enzyme function. Optimal temperature is usually an intermediate temperature that allows fast functioning and some shape flexibility
What are 4 ways animals regulate their temperature?
- Body size
- body shape
- pigmentation
- activity (behaviour)
What is an ectotherm?
Most heat comes from external sources
What is an endotherm?
Most heat comes from metabolism
What is a poikilotherm?
Body temperature changes directly with the environment temperature
What is a homeotherm?
Maintains a relatively constant internal environment
What kinds of animals are endotherms?
Birds and mammals
How do animals conserve heat? 4 ways
- reduce evaporation by ceasing to sweat, or by having scales, fur, or feathers
- Hibernation or torpor
- Change activity levels
- Reduce convection and/or conduction
- Lower surface area: volume ratio (larger body)
How are plants different from animals in terms of how heat is lost and gained?
Not much heat is generated through metabolic functioning, not much heat is lost through evaporation
How do plants gain and lose heat through conduction and convection?
Conduction: gained through the roots, colour of the ground
Convection: long stems and open leaves increases heat gain and loss from the wind
How does altitude, aspect, vegetation, and ground colour and structure affect how a plant regulates its temperature?
The microclimate
Lower temperatures at higher altitudes, whether facing north or south affects the amount of sun exposure and water loss, stratification of plant layers, dark ground absorbs more heat, structure of surface can provide heating and sheltering
How do arctic and alpine plants minimize heat loss?
Dark leaves, plant is squat and close to the ground to stop cooling from convection, leaves perpendicular to the sunlight, flowers are white and shaped to project sunlight on the reproductive organs
How do desert plants decrease heat storage?
Stems and leaves open to cool from convection, light coloured leaves, leaves parallel to sunlight, white flowers, can have reflective hairs on the leaves, small leaves
How do understory plants maximize the amount of light received?
Dark, broad leaves that capture any light that reaches the forest floor
