A.S Biology Unit 2.17.1 Species Diversity

aimee1234's version from 2015-04-11 12:52


Question Answer
What is species diversity?Species diversity is the number of different species and the abundance of each species within a community
The higher the species diversity of plants and trees....?The higher the species divsersity of plants and trees in an area, the higher the species diversity of insects, animals and birds. This is because there are more habitats (places to live) and a larger and more varied food source
Why can diversity be measured?Diversity can be measured to help us monitor ecosystems and identify areas where it has been dramatically reduced.
What is the simplest way of measuring diversity but what is the problem with this?The simplest way to measure diversity is to just count up the number of different species. But that doesn't take into account the population size of each species. Species that are in a community in very small numbers shouldn't be treated the same as those with bigger populations. The index of diversity takes different population sizes into account.
What is the index of diversity formula?Total number of all organisms of all species (N) x (N-1) / the sum of the total number of one species (n) x (n-1)
Why does deforestation affect diversity?1.Deforestation directly reduces the number of trees and sometimes the number of different tree species. 2.Deforestation also destroys habitats, so some species could lose their shelter and food source. This means that these species will die or be forced to migrate to another suitable area, further reducing diversity. 3.The migration of organisms into increasingly smaller areas of remaining forest may temporarily increase species diversity in those areas.
How does agriculture reduce diversity?1.Woodland clearance - this is done to increase the area of farmland. This reduces species diversity for the same reasons as deforestation. 2.Hedgerow removal - this is also done to increase the area of farmland by turning lots of small fields into fewer larger fields. This reduces species diversity for the same reasons as woodland clearance and deforestation. 3.Monoculture - this is when farmers grow fields containing only one type of plant. A single type of plant will support fewer species, so diversity is reduced. 4.Pesticides - these are chemicals that kill organisms (pests) that feed on crops. This reduces diversity by directly killing the pests. Also, any species that feed on the pests will lose a foodsource, so their numbers could decrease too. 5.Herbicides - these are chemicals that kill unwanted plants (weeds). This reduces plant diversity and could reduce the number of organisms that feed on the weeds.
Benefits of deforestation?1.Wood and land for homes to be built. 2.Local areas become more developed by attracting businesses.
Benefits of agriculture?1.More food can be produced. 2.Food is cheaper to produce, so food prices are lower. 3.Local areas become more developed by attracting businesses.
Risks of deforestation?1.Diversity is reduced - species could become extinct. 2.Less carbon dioxide is stored because there are fewer plants and trees, which contributes to climate change. 3.Many medicines come from organisms found in rainforests - possible future discoveries are lost. 4.Natural beauty is lost.
Risks of agriculture?1.Diversity is reduced - because of monoculture, woodland and hedgrow clearance and herbicide and pesticide use. 2.Natural beauty is lost

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