Animals and the Environment

Výukový materiál EK 01 - 11Tvůrce: Ing. Marie Jiráková

Tvůrce anglické verze: Mgr. Milan SmejkalProjekt: S anglickým jazykem do dalších předmětů

Registrační číslo: CZ.1.07/1.1.36/03.0005Tento projekt je spolufinancován ESF a SR ČR

. Organisms and the environment

• The organism is an open system (between the organism and the environment there is an exchange of materials and energy)

• each organism is influenced by abiotic and biotic factors

The ecological valence

• it specifies the range of conditions in which the organism is able to survive

The Gaussian bell-shaped curve of the ecological valence

The minimum of the ecological valence

• The lowest value of the conditions (lower limit) at which the organism can still survive

The maximum of the ecological valence

• The highest value of the conditions (upper limit) at which the organism is still alive

Optimum ecological valence

• The value of the environmental conditions that are best suited for the life of the organism

Liebig's law of the minimum

• no environmental factors (condition) are acting separately

• the organism is influenced by the sum of all factors (conditions)

• the exceeding of the border at one lethal factor (conditions) can lead to the demise of an individual or all the population

The limiting factor

• the component which is the most important in the environment for the survival of the organism

• (can easily exceed the lethal threshold of the ecological valence) e.g. oxygen in water, temperature in the polar regions.

The distribution of the organisms according to the ecological valence

• stenovalent - organisms with narrow ecological valence

• euryvalent- organisms with wide ecological valence

Species with narrow ecological valence

• bounded to a single type of the environment

• no fluctuations in environmental conditions

• little tolerance for the environment e.g. koala, kiwi

• can function as bioindicators e.g. crayfish, trout

Species with wide ecological valence

• comes in different environments e.g. a rat• tolerates variations in environmental

conditions

Worksheet - revision

Between the organism and the environment there is an exchange of materials and energy. Therefore the organism is an ………..system.Each organism is influenced by …………….and …………conditions.The ecological valence specifies ……………………………….. .The most suitable conditions for life are called …………………… .The exceeding of the border at one lethal factor (conditions) can lead to the …………….of an individual or all the population.Species with narrow ecological valence can function as …………………… .

SourcesPAPÁČEK, Miroslav a kol. Zoologie. Praha: pedagogické nakladatelství, 2000, ISBN 80-7183-203-0. KVASNIČKOVÁ, Danuše. Základy ekologie. Praha: Scientia,spol.s r.o., 1994, ISBN 80-85827-84-0.