biodversity

Question 1

Explain the importance of sampling in measuring the biodiversity of a habitat. (2)

Answer 1

1. sample provides estimate
2. sample representatve of whole area

Question 2

Why was it important to take samples in fenced and unfenced areas? (1)

Answer 2

to comapre 2 areas

Question 3

Explain the difference between species richness and species evenness and why both measurements are needed to assess biodiversity. (3)

Answer 3

1. species richness is the number of species in a habitat
2. species eveness is the number of individuals in each species in a habitat
3. both are needed to reveal dominance
4. high biodiversity needs both

Question 4

Outline the significance of a low value of Simpson’s Index of Diversity. (2)

Answer 4

1. habitat dominated by one or few species
2. habitat is unstable/ less likey to cope with change

Question 5

Define the term phylogeny and explain how phylogeny is related to classification. Use the two lynx species as examples. (4)

Answer 5

1. phylogeny is the veolutionary relationship between organisms
2. phylogeny is the baisis of classification
3. example of molecular evidence used to classify
4. organisms within the same group have common ancestors
5. l,lynx . l patdinus are sufficently different to be palced in seperate species , but simialr to be placed in same genus

Question 6

Outline three reasons why it is important to conserve the Iberian lynx. (3)

Answer 6

1. impact on food chain
2. preserving species for future generations
3. economic reason e,g tourism

Question 7

Explain why it is sometimes necessary to conserve a plant species, such as N. thermarum,
outside its natural habitat (ex situ). (3)

Answer 7

1. protection from gene
2. habitat may be destroyed/ under threat deu to environmental impacts e,g climate change
3. protection from predators
4. breeding can maintain gene pool

Question 8

Give three advantages of conserving plant species as seeds and not as adult plants. (3)

Answer 8

1. less space taken up so more can be stored
2. remaining viable for long periods
3. less susceptible to disease
4. lower maintenance

Question 9

Outline an unbiased sampling method that can be used to measure the biodiversity of plant species in grassland. (4)

Answer 9

1. use of quadrat
2. random sampling
3. place at regular intervals along a transect (systematic sampling)
4. abundance, count how many plants appear in qudrat or % cover
5. repeat many times
6. sample at different times/ times of year

Question 10

Scientists try to estimate the total number of species on Earth.
Suggest three reasons why such estimates are not likely to be accurate. (3)

Answer 10

1. not found all species
2. many have become extrinct
3. some species difficult to distinguish

Question 11

simpsons index of biodiversity

Question 12

Outline the implications for a habitat if the Simpson’s Index of Diversity is low. (2)

Answer 12

1. habitat is unstable and not able to withstand change
2. habitat domianted by one/few species
3. change in one species is likley to affect whole habitat

Question 13

When collecting data on the field trip, the students placed quadrats in 15 locations and calculated a mean number of plants for each species.
-Suggest two other steps they could have taken to ensure that their value for Simpson’s Index of Diversity was as accurate as possible (2)

Answer 13

1. random sampling
2. survey at different times of year
3. standartisation of techniques

Question 14

Define the term biodiversity. (2)

Answer 14

range of species in an area
a combination od species eveness and richness

Question 15

Suggest two specific reasons why the government feels it is important to conserve red squirrels in a particular area, such as Northumberland. (2)

Answer 15

1. part of food chain
2. toruism

Question 16

Environmental groups have asked members of the public to report sightings of grey and red squirrels. In parts of Northumberland, the reported number of sightings of grey squirrels is higher than that of red squirrels.
Suggest two reasons why the actual number of grey squirrels might not be higher than the actual number of red squirrels in these areas. (2)

Answer 16

1.hard to see
2. wrongly identified

Question 17

sate three criteria that would have been considered when the EIA was carried out. (3)

Answer 17

1. potential damage to area/organisms
2. size of devlopment
3. idea of potential strategies to minimise impact
4. which species present (environmental sensitivity )

Question 18

A study of the biodiversity of an area considers not only the total number of species but also the relative number of individuals within each species.
State one further factor that could be taken into account when describing the biodiversity of an area. (1)

Answer 18

1. number of habitats
2. genetic variation withon species

Question 19

In any attempt to protect global biodiversity, cooperation between countries is important.
Two examples of such international cooperation are:
* Convention on International Trade in Endangered Species (CITES)
* Rio Convention on Biological Diversity.
Other than the conservation of biodiversity, state two aims for each of these conventions.

Answer 19

1. CITES
   - regulate trade in endagered species
   - ensure international trade doesn’t endager wild populations
   - prohibit trade in wild plants
2. RIO convention
   - share genetic resources
   - sustainable use of organisms
   - share access to scienfic knowledge
   - promoting ex situ conservation

Question 20

This ram gave rise to a breed which grew more quickly, producing more wool and meat than other varieties of sheep.
(i) Explain how it would be possible for farmers in the eighteenth century to produce a larger, more profitable variety of sheep from an existing flock of sheep. (3)

Answer 20

1. selective breeding
2. select male and female that have the strongest desirable trait
3. breed together
4. select best offspring
5. and breed them
6. repeat fro several generations

Question 21

State one further way of improving productivity that is used by modern farmers. (1)

Answer 21

pesticdies
genetic modifciations

Question 22

Suggest how organic fertilisers improve the yield of plant crops. (3)

Answer 22

1. broken down by decomposers/ bacteria
2. add minerals ,like nitrate and phsophates
3. nitrates for proteins

Question 23

Suggest how the excessive use of inorganic fertilisers on farmland can cause a reduction in its biodiversity. (2)

Answer 23

1. fertilisers promotes groeth of one / few species
2. other species outcompeted
3. disruption of food chains
4. reduction in soil quality over time

Question 24

Explain why a reduction in biodiversity may present problems for agriculture in the future. (3)

Answer 24

1. loss of genetic diversity
2. environment requirements may change
3. lost alleles that may have been useful

Question 25

Suggest three reasons why the conservation of the black poplar is important. (3)

Answer 25

1. resource for research 2. potential source of genetic variation 3. part of food chain 4. part of ecosystem

Question 26

Suggest why it is important to ensure that, for each species, the seeds in a seed bank have been collected from several different sites in the wild. (3)

Answer 26

1. increases genetic variation 2. reduces change of disease/ environment affecting whole population 3.reduces change of inbreeding

Question 27

explain why nitrogen fertiliser needs to be applied to farmland. (3)

Answer 27

1. without fertilisers yield will fall over time 2. replaces lost nitrates ]3. needed for proteins

Question 28

Insect pests, such as aphids, can reduce yield in rye plants by piercing the phloem and removing materials. Aphids can be killed using an insecticide. However, over a period of time, an increasing concentration of insecticide is required to control the aphid population. Explain why this is the case. (4)

Answer 28

1. natural selection 2. random mutaion allowing insect to be resistant 3.survives , non resistant dies 4. pass on alleles

Question 29

This male bird, having lost its partner, mated with a Blue-winged Macaw, Propyrrhura maracana. (a) Explain why eggs produced by this mating did not hatch. (2)

Answer 29

1. different species 2. genetically incompatible

Question 30

The insects were sampled using a sweep net method. Fig. 3.1 shows a sweep net being used. With this method, a net is swept through the vegetation. Insects are removed, identified and counted.Describe three ways in which the sampling procedure could be designed to try to make sure that a representative sample was obtained. (3)

Answer 30

1. random selection of areas 2. different times of day, weather 3. sample many times and calulate mean 4. ensure insects don't escape before counting 5. method to prevent recounting

Question 31

Species evenness also contributes to the measurement of biodiversity. Explain the importance of species evenness in determining the biodiversity in a habitat. (3)

Answer 31

1. number of indiviudals in each species 2. more quantative than richness 3. higher eveness , higher biodiversity 4. low species eveness means domiannce of one/ few species

Question 32

One such development is the proposed extension to the M27 motorway in Hampshire. This extension would cut through an important heathland ecosystem. Suggest three aspects of this development that would need to be considered when carrying out the EIA. (3)

Answer 32

1. biodiversity of heathland 2. effect on species 3. rarituy if habitat 4. method of minmising impact

Question 33

An ecologist carried out a survey of butterfly species on the heathland. The ecologist walked along a marked path on four different days in June. She counted * the number of butterfly species * the number of individual butterflies of each species. (i) Suggest how this method of collecting data could be improved. (3)

Answer 33

1. wider area 2. different tumes of day / weather conditions 3. method of ensuring individuals not counted again

Question 34

State why Small Heath and Large Heath butterflies both share part of their scientific name. (2)

Answer 34

1. same genus 2. have simialr features, biochemistry , pysiology 3. share common ancestor

Question 35

Explain why the white-backed vultures in the captive breeding programme were, * collected from several different areas * housed in three separate centres. (3)

Answer 35

1. increase genetic variation 2. reduces risk of inbreeding 3. les likeye to loose all indiviudals to change

Question 36

Suggest three measures that could be taken in the long term to preserve the numbers of white-backed vultures, once the captive bred individuals have been released into the wild. (3)

Answer 36

1. educate people 2. ban 3. no hunting 4. provide breeding sites

Question 37

Suggest why, despite the low genetic variation, the average yield of potato plants varied from year to year. (2)

Answer 37

1. environmental factor 2. lacl of soil mineral content

Question 38

Describe how it is possible to use selective breeding to improve the overall disease resistance of a crop, such as potatoes, in both the short and long term. (7)

Answer 38

1.cross / breed, with disease resistant variety ; 2 method to test offspring for disease resistance ; 3 select , best offspring / offspring with resistance ; 4 (inter)breed, offspring with resistance / best offspring ; 5 6 (continue process) for (many) generations ; idea of avoid breeding, closely related / AW , 7 8 from different field / area’ 9 method / prevention of self-pollination / asexual reproduction of desired variety PhysicsAndMathsTutor.com individuals to preserve genetic diversity ; ora (regularly back) cross with, wild variety ;