Human Impact on environment

Question 1

What are the reasons some species become threatened?

Answer 1

• Natural selection
• Non-contiguous populations- groups are isolated from each other so cannot breed. Lack of genetic diversity in each area
• deforestation
• drainage of wetlands
• loss of hedgrows in favour of agriculture
• farmers sow crops in autum rather than spring which means plants are an unsuitable height for the birds to build their nests
• over hunting by humans e.g. trophy hunting or over fishing
• competition from introduced species e.g. grey squirrels from America outcompeted UK red squirrels.
• pollution e.g. oil floats prevents the oxygenation of surface water and causes birds to chill to death as it causes their feathers to clump so they lack insulation. PCB’s can also accumulate in the food chain

Question 2

What is ‘NT’ on the International Union for Conservation of Nature (IUCN)?

Answer 2

Near threatened

Question 3

Why are oil floats bad for the environment?

Answer 3

they prevent oxygenation of the surface of the water