Each Species has a range of

environmental tolerances that determines its potential geographic distrubution

The temperature of an organism is determined by

exchanges of energy with the external environment.

Organisms have two options for coping with environmental variation, which are?

Tolerance and Avoidance

Potential geographic range of a species is determined by

the physical environment

Physical environment influences an organisms ecological success in two ways?

1. Availability of energy and resources

2. Extreme conditions can exceed tolerance limits

Actual geographic distribution of a species is

Ex. Dispersal, competition, etc

related to other factors as well

* Differs from its potential Distribution

Most likely to differ bc of geologic differences

Terrestrial biomes are categorized on the basis of

growth forms of dominant plant species

What are good indicators of the physical enviroment?

Plants because they do not move.

* ability to tolerate the full range of env conditions

Climate envelope

range of conditions over which a species occurs.

- Acclimatization can lead to a high breathing rate

- Acclimatization and adaptation may require an investment of Energy & Resources by the organism)

Adaptation is a transgenerational

genetic response of the population

Acclimatization is

short term reversible

Ecotypes are

Populations with adaptations to unique env.

- In both Abiotic and Biotic environmental factors

Andean Pop. have high rbc concentrations

Tibetans have faster breathing rates and

and large lung capacity

higher blood flows

Internal temp. influences

- rates of all rate processes

- cell membrane fluidity

- water turnover

Organisms temp. is determined by

the balance of gains and losses of energy to the external env.

Some organisms use behavior to

control exchange of energy with the environment

Behavioral thermoregulation

predominant mechanism of temp regulation in ectotherms

Heat exchange occurs across surfaces and

relative surface area decreases as organisms get bigger

Surface area:volume ratio decreases as organisms get bigger