Ecology Chapter 4

tolerance

he only strategyavailable for immobilespecies

avoidance

can include behavioral and/or physiological changes

physiological ecology

the study ofinteractions between organisms and thephysical environment that influencessurvival and persistence

potential species distribution

determined by physical environment

actual species distribution

other factors: Dispersal, Disturbance, Competition

plants are good...

indicators of the physical environment

climate envelope

the range of climate conditions under which a species occurs

stress

environmental
change results in
decreased rates of
physiological
processes, lowering
the potential for
survival, growth, or
reproduction

acclimatization

Adjusting to stress through behavior or physiology.
- It is a short-term, reversible process.

adaptation

An affect of natural selection over time
- Individuals with traits that enable them to cope with stress are favored.
- Over time, these genetic traits become more frequent in the population.

ecotype

a population adapted to its unique local environmental conditions

physiology most senesitive to temperature

enzymes denature at high, membranes solidify at low, and water loss increases with temp

conduction

transfer of energy fromwarmer to cooler molecules. (diffusion)

convection

heat energy is carried bymoving water or air (movement)

latent heat transfer

water absorbs heatas it changes state from liquid to gas

Hmet

metabolic heat from chemical energy

Hevap

Heat transfer by evaporation (sweating, panting)

ectotherms

Primarily regulate body
temperature through energy exchange with the external environment

basking

control temperature with behavior by laying in the sun

mesotherms

generateenough heat to keep their blood warmer than theirenvironment, but do not maintain a constant bodytemperature (dinosaurs)

endotherms

Rely primarily on internal heatgeneration, mostly birds and mammals.

thermoneutral zone

Maintain a constant resting metabolic rate over arange of environmental temperatures

lower critical temperature

when heat loss isgreater than metabolic production

how do endotherms control their temeprature

torpor (dormancy), hibernation, denning

homeotherm

an animal with a constant body temperature

water is

essential for life- medium for all biochemical reactions
- is 60-90% of body mass

free water molecules

polarity frantically seeking amate! high energy!

salts =

a mate for H2O! Calm and happy (low energy)

what do dissolved solutes do to energy

decrease the energy of a solution

hypoosmotic

Water moves intohigh-solute cell andswells

hyperosmotic

Water moves out ofhigh-solute cell andswells

isosmotic

water is an equillibrium

marine organisms are _____ to their surroundings

isosmotic

osmotic adjustment

changing their solute concentration
- Synthesize organicsolutes
- Use inorganic saltsfrom environment
- Actively excrete salts

amphibians

have thin skin for gas exchange and therefore must live in moist environments, water reliant

reptiles

evolved thick outer skin and scales to prevent water loss

mammals

hair and feathers reduce evaporation (also have sweat glands for cooling)

insects

exoskeleton toprevent water loss

water potential

is the sum of all theseenergy components: Yo (osmotic potential (negative value)), Yp (pressure potential), Ym (matric potential (negative value))

water moves along

potential energy gradients (gravity) and water potential gradients

how do plants stay hydrated

The lower water potential of the atmosphere pulls water into the roots and out through the stomata

sand =

large pore spaces (high hydraulic conductivity) and low matric potential (low surface-to-volume ratio of particles)