Factors Affecting Biodiversity Flashcards
Why has human population risen so quickly?
-improved healthcare
-improved diet
-people living longer
-lower infant mortality
Explain how human population growth is decreasing biodiversity through habitat loss. Give an example
As the human population grows, we need to develop more land for housing and to produce food, but this is destroying habitats
E.g deforestation in the Amazon for grazing and agriculture
Explain how human population growth is decreasing biodiversity through over exploitation. Give an example
A greater demand for resources means a lot of resources are being used up faster then they can be replenished , either destroying habitats or directly affecting the species.
E.g Industrial fishing can deplete the population of certain fish species, potentially causing extinction
Explain how human population growth is decreasing biodiversity through urbanisation. Give an example
Sprawling cities and major road developments can isolate species, meaning populations are unable to interbreed and genetic diversity is decreased
E.g snakes may living in areas isolated by roads show lower genetic diversity than populations living in areas of continuous habitat because they re unable to migrate and breed.
Explain how human population growth is decreasing biodiversity through pollution. Give an example
As the human population grows, were producing more waste and more pollution, high levels of which can kills species or destroy habitats
E.g high levels of fertiliser flowing into a river from nearby fields can lead to a decrease in fish species, decreasing biodiversity
When does eutrophication occur?
It results from an increase of nutrients in freshwater lakes and rivers and therefore affects aquatic habitats. This may be from fertilisers being applied to nearby farmland and when it rains the fertiliser is washed from the fields and into the water (leaching) or a discharge of sewage or slurry into the river
What is an algal bloom? Explain how it occurs, and how it has a damaging impact to the pond.
-Its the green biomass covering the surface of the water.
-It occurs when the nutrients encourage the growth of aquatic plants and algae.
-It is opaque and prevents the transmission of light to the aquatic plants which stop them from photosynthesising, so production of oxygen stops.
-This causes a large number of plants to die and the large amounts of dead plant tissue causes a big increase in population size of bacteria which are acting as decomposers
-The pond is left in hypoxic conditions (low o2) due to bacteria respiring, meaning the aquatic animals can’t do gas exchange and suffocate.
What is monoculture? Give an example
The growing of a single variety of a single crop
E.g In Africa large areas of land are used for palm oil plantations
Explain how monoculture is decreasing biodiversity through habitat loss. Give an example
Habitats are lost as land is cleared to make way for the large fields, reducing habitat diversity. Marine fish farms are often built in locations that are ideal for wild fish
E.g Mangrove forests are areas of trees that grow in tropical and subtropical coastal regions, but one of the biggest threats is clearance to make space for shrimp farms
Explain how monoculture is decreasing biodiversity through loss of local plants and animals. Give an example
Local and naturally occurring plants and animals are seen as weeds and pests, so are destroyed with pesticides and herbicides, reducing species diversity.
E.g Use of herbicides on corn farms in the USA kills the local milkweed plant, which is the main source of food for the monarch butterfly.
Explain how monoculture is decreasing biodiversity through loss of heritage varieties.
Traditional varieties of crops are lost because they dont make enough money so are not planted any more, reducing the species diversity.
Explain what climate change is and how humans are contributing to it.
A significant long term change in an areas climate. It occurs naturally, but the climate change that we’re currently experiencing at the moment is thought to be caused by humans increasing emissions of greenhouse gases. This causes global warming causing other types of climate change.
Explain how changing environmental conditions is affecting global biodiversity
Climate change affects the environmental conditions in different areas differently. This affects global biodiversity because because most species need a particular climate to survive, therefore a change may make an area which was previously inhabitable become uninhabitable, changing biodiversity.
What is extinction and how are humans contributing to it?
When the last living member of a species dies and the species ceases to exist. Humans may hunt animals for food for example
