Lecture 7: Temperature and Light Flashcards
What is range of tolerance?
The range of an environmental condition in which an organism can survive. The organisms performance is negatively affected the further away it is from the range of optimal performance.
What is the optimal range of performance?
The range of an environmental condition in which an organism performs best in the absence of interactions with other species
What is the link between range of tolerance and the fundamental niche?
Environmental conditions that limit growth also affect the abundance and distribution of organisms. Organisms experience physiological stress at the niche margins of a limiting factor
What is the law of tolerance?
Species have optimal survival conditions within environmental thresholds, and beyond the optimum, survival decreases (forming a bell curve)
What is the difference between macroclimate and microclimate:
Macroclimate: large-scale climactic patters that prevail over entire regions, are determined by climate cells and topography (BIOMES)
Microclimate: small scale climate patterns, can deviate from macroclimate, due to small scale topography, landscape, vegetation
Do water temperatures fluctuate more or less than air?
LESS, especially in large water bodies, they only fluctuate between (-4) - 32 degrees.
What are three properties of water?
Higher capacity for absorbing heat energy (with intermittent stable temperatures between phase changes)
Heat is absorbed by water as it evaporates
Water gives up heat to the environment when it freezes
What is the principle of allocation?
Organisms have a limited amount of energy, and when energy is allocated to one function it reduces the energy available to other functions, and this has costs and benefits
What is an evolutionary tradeoff?
Adapting to one set of environmental conditions (within the range of tolerance) which generally reduces fitness in other environments
What are the four strategies for when you are at the margins of your tolerance?
- die
- migrate
- acclimate
- adapt to extreme temperatures
Why is death a viable solution to being at the outskirts of the range of tolerance?
You avoid extreme temperatures by funneling all your energy into reproduction, and thus your offspring have a better chance of survival
Why is migration a viable solution?
Avoid extreme temperatures by migrating to warmer regions, and the advantages outweigh the costs (birds, mammals, insects)
What is acclimation?
Physiological or morphological changes in an organism in response to changes in the environment.
NOT AN ADAPTATION (the ability to acclimate is an adaptation)
Phenotypic plasticity
What are some examples for adaptations to extreme environments”
Thick fur, short appendages, body fat, cryoprotection, prolonged state of metabolic activity (hibernation, estivation)
What does the heat equation consist of?
Hs: total heat stored is equal to
Hm: heat gained by metabolism
Hcv: heat gain/lost from convection (winds)
Hcd: heat gain/loss from conduction (roots)
He: heat loss by evaporation
Hr: heat gain/loss by radiation (sun)
What is the consequence of losing too much heat to evaporation?
DEHYDRATION, it is not the heat that kills you, it is the resulting dehydration that damages the body systems until death
What is the water budget equation for aquatic organisms?
Wi: internal water
Wd: water gained by drinking
Ws: water loss by secretion
Wo: water gain/loss by osmosis
What are diffusion and osmosis? What is the difference?
Diffusion is the movement of soluble salts or water due to random movement of particles, until salt concentrations are equalized in a solution
Osmosis is the movement of water through a semi-permeable membrane
What is osmolarity? What are the three types?
Osmolarity: amount of solute/water in a solution in relation to a reference (in this case it is the amount of solute/water in an organism in relation to its environment
Hypoosmotic: too much water in the fish and less solute compared to the environment, therefore the fish LOSES more water
Hyperosmotic: too much solute in the fish and not enough water, therefore the fish has a tendency to gain water
Isosmotic: equal concentration of solute across fish and environment
Most marine organisms have what type of osmolarity? What do other marine animals have?
Most are isosmotic
Others are hypoosmotic: not enough solute in the body and too much water, thus water leaves and salt comes in, leads to low osmotic pressure in the blood, and high risk or dehydration
What are 3 solutions to hypoosmotic issues in marine animals?
Drink constantly to counteract dehydration (increased Wd), low urination rates and volumes (decreases Ws), and get rid of excess salt through specialized chloride cells in the gills (to reduce water loss by osmosis)
Most freshwater animals have what type of osmolarity?
Hyperosmotic, they have a higher saly concentration in their blood compared to the environment. Have high osmotic pressure in blood, and they risk too much water entering the body and to many salts leave
What are three solutions to hyperosmotic in freshwater fish?
Do not drink much
Produce highly dilute urine in large amounts
Replace salts by absorbing sodium chloride in gills by ingesting food
What is is called when fish adapt to the salinity of their new environment?
ACCLIMATION
