Threats To Biodiversity

Question 1

Threats to biodiversity

Answer 1

• direct exploitation
• eradication of predators and competition
• changing abiotic factors
• Changing biotic factors
• introduces species
• Habitat destruction

Question 2

Direct exploitation

Answer 2

-food
Cod, Sword fish, sharks, many herbivores endangered - dodo, great auk and passenger pigeon extinct.
- fashion
Animal skins clothing e. Fur coats fur seals extinct 1900s
- furniture and ornaments
Mahagany rainforest, Ivory piano keys and ebony wood, jewellery sea shells shark teeth etc
- traditional medicines
ESP. Asia parts of tiger for variety ailments - lil evidence, Rhinos horn illness ie small pox.
- pets and entertainment
Let’s - parrots, lizards, tortoise, tropical fish, plants like air plants, zoos, aquaria, marine life
- other products
Fine oil extracted from whale blubber lamp oils, candles, soaps

Question 3

Eradication of predators and competitors

Answer 3

Many species killed as they threaten humans or interfere with human activities e.g. sharks snakes crocodiles threatening humans pathogen factors like mosquitoes malaria
Predators of life stock
Agricultural pests
Wild herbivours and forest pests

Question 4

Changes in abiotic factors

Answer 4

Species range of tolerance
- water availability wetlands drained, wet and dry seasons needed river and sand banks nesting sites - hydroelectric schemes may suddenly change water level killing Eggs.
- dissolved oxygen
reduced by hot water discharges from power stations or organic wastes like sewage which deoxygenate water as decomposes can affect survival aerobic organisms
Anaerobic env.s like marshlands soil nitrogen levels trapping and digesting insects provides Son juice with a source of nitrogen in nutrient deficient soil Drainage schemes producing more aerobic soil may allow taller competitors to colonise area and sun dew plant die
- temp
growth and survival of species, GCC and hot effluent water.
- PH
Mine drainage water and pollutant gases From burning fossil fuels or smelting metals produce acidic conditions. Denature cell proteins of exposed tissues. Some animal particularly sensitive eg. Cray fish calcium based exoskeleton.
- water turbidity
Ploughing mining and judging increase water turbidity affect amount of light penetration and photosynthesis of submerged aquatic plants and kill filter feeders like bivalve molluscs
- physical damage
Wide range human actions cause physical damage like discarding litter or old fishing gear.

Question 5

Changes in biotic factors

Answer 5

Pollinators
Seed dispersal species
Often larger herbivores like elephants rhinos monkeys
Food chain impacts
Eg. Decline and see otters on West Coast USA had to increase and see actions their pray

Question 6

Introduced species

Answer 6

May have beneficial adaptations that give greater chance of survival then indigenous species or may predate on it as a species that have an adapted to survive new predators

  -  introduce competitors Grey squirrel introduced from North America but adapted to digest acorns from out trees which squirrels cannot and larger and can compete more successfully for nest sites
   - introduced predators  European waterfall threatened by American mink escape from the fur farms.
  - introduce pathogens  Maybe from humans.  White Claude crayfish indigenous to UK but instruction of signal crayfish North America Carry fungal  infection that killed white clawed ones.
   - species that hybridise  Natural gene pool will be changed - red deer native to UK threatened by hybridisation w sika deer.
   - loss of species that control abiotic factors E.g. beavers build dams aquatic habitats if lost other species decline

Question 7

Habitat destruction

Answer 7

Land use change

Deforestation, ploughing of grassland, reservoir creation, mineral extraction and urban expansion