6.3.2 Populations and sustainability

Unfinished

Population growth curve image

When would the population grow exponentially

When all recources = avaliable in a plentiful supply

Limiting factors to population growth

Abiotic and biotic

Immigration and emigration

Immigration definition

Movement of organisms into an area

Emigration definition

Movement of organisms out of the area

Carrying capacity definition

The population is the max population size an environment can support.

The populations are not subject to further succession

Interspecific competition

Competition between two different species

Intraspecific competition

Competition between members of the same species

Predation

Biotic factor - influence pop size

Predators have evolved ways to catch their prey and prey has evolved ways to avoid capture (mimicry, camouflage..)

Population decrease

Death rete is higher than birth rate

Predator prey relationship graph

Interactions btw. the predator and prey relationships - simple

The population fluctuates

To do with the food availability of the predator and the over predation by the predator

Interactions btw. the predator and prey relationships - long winded.

As the rabbit population increases in size, more food for lynx. Therefore lynx pop. will increase. And as it increases, the hare pop. decreases cause its being eaten. And as the hare pop. decreases, the lynx = less food so it will decrease. And as there is less lynx, the hare pop can increase

Conservation definition

Maintenance/ management of nature to protect species/ habitats

Preservation definition

Leaves the environment/ lands not to be used by humans

(leaves the ecosystems untouched)

Why is conservation important for economic reasons

Ecotourism

A potential for future medicines

Why is conservation important for social reasons

Aesthetic

Stop the impact of deforestation

Why is conservation important for ethical reasons

Preserve biodiversity/ stop extinction

Support the indigenous populations

Sustaniablility deinition

Aims of sustainability

Preserve the environment

Ensure resources are available for future generations

Allow humans in all societies to live comfortably

Enable less economically developed countries to develop through exploiting their natural resources

Create a more even balance in the consumption of these resources in more economically developed countries and less economically developed countries

Sustainable timber production ways

Coppicing

Selective felling

Rotational felling

What is coppicing

Tree trunk cut close to ground level

Several new shoots grow from cut surface

Process repeated after a certain time

Can be repeated indefinitely

Need to protect young shoots from grazers

Advantages of coppicing

New stems grow more rapidly than saplings

Lifespan of tree extended

Provides variety of light levels

Fewer larger trees = more light for smaller plants

Proviedes a variteiy of habitats

Maintains biodiversity

Roots prevent soil erosion

Maintains soil quality

Prevents succession

Large machinery not needed therefore less disturbance

What is selective felling

The cutting down of selected mature trees in a forest

Allows other trees to grow and mature and also leaves enough habitats for animals

What is rotational felling