6.3.2 sustainability

Explain population and time graph

Slow population growth birth rate is higher than death rate

Rapid growth few limits on population growth

Stable phase and further growth is limited

End of graph fluctuates and is called carrying capacity

Carrying capacity - population has reached maximum size that the environment can support

Factors that affect population size

Biotic and abiotic factors

Immigration

Emigration

What is Interspecific competition

What is Intraspecific competition

Interspecific competition - between different species

Intraspecific competition- between same species

Explain a predator prey graph

Initially number of predators increase as there is more prey available

The number of prey then decrease as there are now more predators

The number of predators decrease as less prey

As a result the number of prey increases as there are now fewer predators

What is conservation

To maintain/manage nature to protect species/habitats

What is preservation

Leaves the environment/ lands not to be used by humans

Economic reasons for conservation

Ecotourism- Potential for future medicines

Social reasons for conservation

Aesthetic - to stop impact of deforestation

Ethical reasons for conservation

Preserve biodiversity/stop extinction

Supports indigenous tribes

What is coppicing

The trunk is cut close to the ground level, several new shoots will grow from cut surface, process is repeated after certain time. Young shoots need to be protected from grazers

Advantages of coppicing

New stems can grow rapidly than saplings

Lifespan of tree extended

Fewer trees mean more light for smaller plants

Provides a variety of habitats

Maintains biodiversity

Roots prevent soil erosion

Maintains soil quality

prevents succession

What is selective felling

The cutting down of selected mature trees in a forest. This allows other trees to grow to maturity.

What is rotational felling

This consists of planting a site and felling tree when it has reached maturity

What is strip felling

The cutting down of selected, mature trees in a forest in a strip allowing other trees to grow to maturity

What is pollarding

The tree trunk is cut high above the ground so there is less chance of damage by herbivory

What is something important to do after cutting down a tree

Replant after felling

How can we contribute to sustainable fishing

Introduce quotas - limits the number of certain species of fish that can be caught

Certain hole size - allow smaller fish to escape and reach maturity

Fishing only allowed at certain times of the year - allow the population to reach a sustainable level

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