3.4 Topic 4 - 3.4.6 Biodiversity within a community

Question 1

give a definition for biodiversity

Answer 1

the number and variety of living organisms in a particular area.

Question 2

what 3 components does biodiversity have?

Answer 2

species diversity, genetic diversity and ecosystem diversity.

Question 3

what does species diversity refer to?

Answer 3

refers to the number of different species and the number of individuals of each species within any one community.

Question 4

what does genetic diversity refer to?

Answer 4

refers to the variety of genes possessed by the individuals that make up a population of a species.

Question 5

what does ecosystem diversity refer to?

Answer 5

refers to the range of different habitats, from a small local habitat to the whole of the earth.

Question 6

what is the measure of species diversity called?

Answer 6

species richness.

Question 7

what does an index of diversity describe?

Answer 7

the relationship between the number of species in a community and the number of individuals in each species.

Question 8

give the index of diversity formula

Answer 8

d = N (N- 1) / £n(n - 1)

Question 9

what does the N in the index of diversity formula mean?

Answer 9

total number of organisms of all species.

Question 10

what does the n in the index of diversity formula mean?

Answer 10

total number of organisms of each species.

Question 11

what does the £ in the index of diversity formula mean?

Answer 11

the sum of.

Question 12

what does a high value of the index of diversity mean?

Answer 12

the species diversity is high.

Question 13

what techniques reduce biodiversity?

Answer 13

farming and agriculture.

Question 14

what do natural ecosystems become after developing over time?

Answer 14

complex communities with many individuals of a large number of different species – these communities have a high index of diversity.

Question 15

what happens to the number of species when farmers select species for particular qualities that make them more productive?

Answer 15

the number of species, and the genetic variety of allele they possess is reduced to the few which exhibit the desired features.

Question 16

list 4 ways agriculture can reduce biodiversity:

Answer 16

monoculture, deforestation, pesticides and herbicides.

Question 17

how do monocultures reduce biodiversity?

Answer 17

+ when crops are grown on a large scale for agriculture, a single crop (a monoculture) species covers many fields.
- monocultures directly remove species and fewer species can survive in monoculture environments.

Question 18

how does deforestation reduce biodiversity?

Answer 18

+ large regions of forests are cleared to provide space for farming.
+ forests are biodiverse environments because there are many different habitats for different species.
- direct removal of species and removal of habitats causing species to die.

Question 19

how do pesticides reduce biodiversity?

Answer 19

+ pesticides are sprayed onto crops to prevent pests e.g. slugs from feeding on crops.
- direct removal of pests and species that fee on the pests cannot survive.

Question 20

how do herbicides reduce biodiversity?

Answer 20

+ herbicides are sprayed onto crops to prevent growth of unwanted plants and weeds.
- direct removal of plants and species that feed on unwanted plants cannot survive.

Question 21

what schemes can help avoid the impacts of agriculture?

Answer 21

conservation schemes.

Question 22

how do conservation schemes help avoid the impacts of agriculture?

Answer 22

: endangered species can be protected to avoid extinction.
: specific areas with high biodiversity can be protected (cannot be developed into farmland).
: farmers are encouraged to balance agriculture with conserving biodiversity.

Question 23

what are 4 direct removals of habitats, reducing species diversity?

Answer 23

> removing hedgerows and grubbing out woodland.
creating monocultures, for example replacing natural meadows with cereal crops or grass for silage.
filling in ponds and draining marsh and other wetland.
over-grazing of land, for example, upland areas by sheep, thereby preventing regeneration of woodland.

Question 24

what are 3 indirect removals of habitats, reducing species diversity?

Answer 24

< use of pesticides and inorganic fertilisers.
< escape of effluent from silage stores and slurry tanks into water courses.
< absence of crop rotation and lack of intercropping or undersowing.

Question 25

what happens if biodiversity is reduced?

Answer 25

the global living system becomes increasingly unstable and we all rely on the global system for food and other resources.