Human Impacts On Biodiversity Flashcards
what is biodiversity
the variety of living organisms in an ecosystem
what abiotic factor can often affect biodiversity
human interactions
what are some of the positive impacts that humans have in biodiversity
- carrying out conservation schemes
- or reforestation
how do nitrates find their way into rivers and lakes
- nitrates are put into fields as fertilisers
- if too much is applied and it rains afterwards
- nitrates can find their way into rivers and lakes
what is the result of nitrates finding their way into rivers and lakes
eutrophication
what is eutrophication
the excess of nutrients in water
what is the effect of eutrophication
- it can lead to the death of many of the species present in the water
- reducing the biodiversity of a habitat
what is stage 1 of the eutrophication process
- fertilisers enter the water
- adding excess nitrates (more than plants in the water can take in)
what is stage 2 of the eutrophication process
- the excess nitrates cause algae to grow fast
- which blocks out the sunlight as they float on the surface
what is stage 3 of the eutrophication process
- plants can photosynthesise due to the lack of light
- and start to die and decompose
what is stage 4 of the eutrophication process
- with more food available
- microorganisms that feed on decomposing plants increase in numbers
- and use up the oxygen in the water
what is stage 5 of the eutrophication process
organisms that need oxygen for aerobic respiration such as fish die
how does fish farming contribute to eutrophication
- food is added to the nets of the fish which produce large amounts of waste
- both the food and waste can leak into the open water
- causing eutrophication and the death of wild species
what is the effect of fish farms in open water acting as large breeding grounds for parasites
- the parasites can get out of the farm and start infecting animals
- sometimes killing them
how does fish farming disrupt the natural food chain
- predators are attracted to the nets
- but they become trapped in them and die as a result
why is is bad for farmed fish to escape into the wild
because it causes problems for wild populations of indigenous species
why do people prefer to farm fish in large tanks rather than in open water nets
- the farms are low in biodiversity as often only one species is farmed
- tanks are often kept free of plants and predators
- and any parasites or microorganisms are usually killed
what is a non-indigenous species
a species that doesnt naturally occur in an area
what re the two ways non-indigenous species can be introduced into an area
- intentionally (like for food or hunting)
- or unintentionally (like a stowaway in international cargo)
what problems can non-indigenous species cause for indigenous species in terms of competiton
- they compete for resources like food and shelter
- sometimes the non-indigenous are better at competing which decreases the number of indigenous species
- meaning they can eventually die out and have their place taken
what is an example of competition being an issue between non-indigenous and indigenous species
- signal crayfish were introduced into the UK for food
- but they prey on and out-compete many indigenous river species
- which reduces biodiversity
what problems can non-indigenous species cause for indigenous species in terms of disease
- non-indigenous species can sometimes bring new diseases to a habitat
- these often infect and kill lots of indigenous species
- reducing the habitats biodiversity
