Component 1: Human Impacts Flashcards
What is the definition of biodiversity?
Variety of species present in an ecosystem. This can be calculated as the number of species in a specific area.
Why does natural selection lead to species becoming endangered (+ examples)?
Existing species do not have the ability to survive in a changing environment.
- Saber Tooth cat, woolly mammoth, cave bear
Why does deforestation lead to species becoming endangered (+examples)?
Removal of large areas of forests for a variety of reasons such as for oil palm plantations in Borneo
- Orangutan
Why does habitat destruction lead to species becoming endangered (+examples)?
Wetland drainage for agricultural land or land for building, reducing habitable areas, so population declines
- Western Black Rhino
Why does loss of hedgerows lead to species becoming endangered (+examples)?
To increase field size for the use of machinery and wildlife in hedgerows are adapted for life in that environment specifically
- dormice
Why does pollution (such as PCBs and Oil) lead to species becoming endangered?
Unregulated industry polluting rivers, pollution can change the environment that it becomes uninhabitable for organisms living there
- Baiji River Dolphin
Why does hunting and collecting lead to species becoming endangered?
They collect for profits or food, can prevent mating seasons that restore numbers, so population declines
- elephants are hunted for ivory
Why does competition from domestic animals lead to species becoming endangered?
Introduced domesticated animals for food competing with native species for prey , can transmit diseases and kill wild animals
- Goats on the Galapagos competing for grazing sites with tortoises
What is conservation?
the maintenance of the biosphere and enhancement of biodiversity locally
What does the conservation of species ensure?
Ensures the conservation of existing gene pools
Conservation method: Nature reserves
- Nature reserves protect areas rich in biodiversity from being damaged or destroyed from development
- Managed to improve and maintain the quality of habitat, ensuring species action plans are having intended results
Conservation method: SSSIs
- SSSIs cover 50% of habitat considered to be of conservation priority in ENGLAND (e.g. coastal, woodland, wetland, heathland, etc)
- Usually managed privately leading to less human disruption
Conservation method: Restriction on trade
- e.g. CITES
- International agreements between governments that prevents the trade in organisms whether dead, alive or part of the organism
- This reduces the number of species killed, less harvesting of the organism and increases biodiversity
- E.g. a ban of elephant ivory
Conservation method: Zoo breeding programmes
- Animals on the edge of extinction can be taken into zoos and bred before being returned to the habitat
- allows animals from several subspecies to be bred
- Captive breeding means that animals can be outbred with animals from different zoos (preventing inbreeding and no genetic deformation)
Conservation method: Sperm or seed banks
- Sperm and seed banks store material in a safe environment and insure against damage or loss of a habitat (conserves rare species)
- Damage to ecosystems can be repaired and animals which have small populations may be boosted by using sperm from a wider variety of individuals increasing the potential gene pool and avoiding bottleneck problems. (increase genetic variation)
Conservation method: Reintroduction
- Releasing species into the wild from captivity to establish healthy wild populations
- Individuals can be reintroduced to where a species has been lost of the conditions are still favourable for the success of the species (e.g. Large blue butterfly)
Conservation method: Pollution Control
- Eutrophication from transport and agriculture
- acid rain from air pollution (acidifies soil and water)
- chemical pollutants leach into the soil and water
- oil pollution affects marine ecosystems
- reducing pollution improves health and state of the environment
How do pesticides increase agricultural production?
Reduces competition from other plants or weeds. Reduces damage & disease, increases yield & quality
How do pesticides affect the environment?
- Less biodiversity as weeds and animals they support are killed.
- May kill pollinators (kills bees) & natural predators of pests.
- Can spread to other areas leading to contamination (e.g. water), animals are poisoned and effects the food chain
How do artificial fertilisers increase agricultural production?
Higher yields.
Nutrients no longer limiting.
No need to rotate crops allows constant growth of most valuable crop.
How does artificial fertilisers affect the environment?
- Reduces biodiversity in pastures as grass grows rapidly and out-competes wild crops.
- Wash to watercourses cause eutrophication
- Fossil fuels required to manufacture and transport them
- Alter soil pH reducing the quality of the soil
How does the removal of hedges increase agricultural production?
Allows large machines to work efficiently. Reduces labour / labour costs. Faster harvesting. More land for crops to grow Reduces breeding ground for pests
How does the removal of hedges affect the environment?
- Loss of habitat / nest sites/ food for wildlife.
- No wildlife corridors connecting isolated woods.
- Animal populations can inbreed
- Increases flooding potential (decreases infiltration)
How does the drainage of water meadows increase agricultural production?
More land can be farmed.
More fertile soil as aerobic nitrifying bacteria do well
