SB9g-h Flashcards
What is biodiversity?
A measure of how varied an ecosystem is and how many species the are in an ecosystem. The more the species in an area the more the biodiversity.
What are some examples of how humans can affect biodiversity?
- Fish farming
- Introducing new species in an area
- Eutrophication
What is the purpose of fish farming?
To produce more fish and stop overfishing of wild fish. This is done since overfishing has damaged some aquatic ecosystems.
What is the issue with fish farming?
- Causes problems to wild organisms living in the area which leads to a decrease in biodiversity
- Many fish are kept in a very small space so food that is not being eaten and faeces from fish sink to the bottom of the water which causes a change in conditions of the ecosystem, affecting wild organisms
What are the advantages and disadvantages for the fish in the fish farm?
Advantages:
- No predation
Disadvantages:
- Food given does not have all correct nutrients
- Diseases spread easily
What is the purpose of introducing a new species to an area?
When a native species population has increase a lot, it can harm the food chains. This is why we introduce a non-indigenous species to the area.
What is the issue with introducing a new species to an area?
The non-indigenous species does not have any natural predators in the area. Since there is nothing to eat it in order for its population to remain constant, it will start competing for food with other species. The non-indigenous species will keep increasing in population and will outcompete the other species, leading them to extinction due to starvation. This leads to a decrease in biodiversity in the area.
What is eutrophication?
The addition of more nutrients to an ecosystem than it normally has.
What is the process of eutrophication?
- Farmers add too much fertilisers in the fields and most of them remain in the soil
- Rain will dissolve the fertilisers and make them leak into nearby rivers and lakes
- Fertilisers contain nitrates and phosphates that are needed for plant growth
- When the fertilisers leak into the rivers and lakes, the algae naturally present will grow too much causing an algal bloom and covering the surface of the water
- Light cannot reach the plants inside the water and so photosynthesis cannot occur for plants to release oxygen into the water
- Lack of light will cause the plants to die and fall to the bottom of the lake
- The oxygen concentration starts to decrease
- Bacteria use oxygen in the water to break down the dead plants so oxygen concentration decreases even more
- Fish and other aquatic organisms die due to lack oxygen
- All that is left in the water are anaerobic bacteria leading to the pollution of the lake
Why does biodiversity have to be maintained?
So that different organisms do not become extinct.
What are the two ways of preserving biodiversity?
- Reforestation
- Conservation
What is reforestation?
Planting trees to make up for those lost.
Why do we perform reforestation?
Deforestation for building houses and agriculture land decreases biodiversity since many habitats situated in a forest are lost. By creating new forests, we increase the numbers of different habitats and the number of different species in the area.
What is conservation?
The study and protection of biodiversity and natural resources. When an effort is made to protect a rare or endangered species or habitat.
What are the two types of conservation?
- In situ conservation (on site)
- Ex situ conservation (off site)
What is in situ conservation?
It is preferred to protect and manage species and their habitat, so we help species that are at risk of extinction to recover in their natural environment. This means humans must enhance the available shelter and sources of food or introduce measures to reduce predation.
What are some examples of in situ conservation?
- Build nests on tall trees to encourage birds to nest
- Protect red squirrels by killing grey squirrels to reduce competition of food and sheleter
What is ex situ conservation?
When the habitat of species is damaged or destroyed, we remove the organism from their natural habitat. The species are then bred in captivity until they increase in population again. Once their habitat is fixed, they are then released back into their habitat.
