classification and evolution qp4

Question 1

when more organisms occupy a larger area than before, how would you describe the distribution of the organism

Answer 1

spread over a larger area/ more widespread

Question 2

explain the importance of sampling in measuring the biodiversity of a habitat

Answer 2

-its impossible/ difficult to count every individual
-sample provides an estimate
-sample is representative of the whole area

Question 3

why is it important to take samples in fenced and unfenced areas

Answer 3

-to compare the two areas

Question 4

1. explain the difference between species richness and species evenness
2. explain why both measurements are needed to assess biodiversity

Answer 4

-species richness is the number of species in a habitat

-species evenness is the abundance of individuals of each species in a habitat

-both richness and evenness are used to reveal dominance
-there is a high biodiversity associated with high species richness and high species eveness

Question 5

how would diversity be affected if grass was removed

Answer 5

diversity would decrease because plants are the basis of all foodchains
they are food for insects/ animals/ birds
may provide as a nesting site or for coverage

Question 6

outline the significance of a low value of the simpsons index of diversity

Answer 6

-habitat dominated by one/ few species
-ecosystem/ habitat is unstable/ less likely to cope with change (change in food chain)

Question 7

describe the term phylogeny and how its related to classification

Answer 7

-phylogeny is the evolutionary relationships between organisms
-phylogeny is the basis of classification
-example of molecular evidence used to classify (base sequence, amino acid sequence, cytochrome C)
-species in the same group have shared phylogeny/ common ancestor

Question 8

why in the last 10 years have more organisms been classed as separate species

Answer 8

-more molecular/ biochemical/DNA/ genetic evidence
-modern/ new/ better technology to distinguish between closely related species

Question 9

why is it important to conserve species

Answer 9

-impact on food chains
-right to exist/ duty of humans to care for other species/ ethical reasons/ preserving species for future generations
-aesthetic reasons - beautiful creatures
-economic reason- tourism/ might provide a useful resource

Question 10

why is it necessary to conserve a plant species outside its natural habitat sometimes

Answer 10

-natural habitat lost/ under threat from climate change/ human activity
-number/ population in natural habitat is very low
- wild (sexual) reproduction is difficult
-breeding ex situ can maintain the gene pool/ genetic diversity
-allows protection from grazers/ herbivores/ plant collectors/ competing species
-protection from pathogens/ parasites/ disease

Question 11

give advantages of conserving plant species as seeds and not adult plants

Answer 11

-can be collected with minimal damage to the wild population/ habitat/ ecosystem
-take up little space/ large numbers can be stored
-can store greater genetic diversity
-lower maintenance cost
-easy/cheaper to transport
-remains viable for long periods
-less susceptible/ vulnerable to disease/ pests/ environmental change
-prevents fertilisation by undesired pollen

Question 12

suggest reasons why estimating the total number of species on earth is likely to be inaccurate

Answer 12

-reasons for not having found all species (e.g. microscopic species missed)
-some species may have become extinct recently
-evolution is ongoing/ new species are being formed
some species are difficult to distinguish/ some species may be reclassified

Question 13

suggest how the information obtained by DNA analysis can be useful to taxonomists

Answer 13

-information used to decide which group/ taxon an organism/ species fits in.
-compares the proportion of different bases
-compare the DNA/genes/ sequence of bases.
-the more simmilar the DNA/ genes, the closer the relationship

Question 14

what types of evidence other than biochemical evidence, can be used by taxonomists when classifying organisms

Answer 14

-fossil records
-observed characteristics
-anatomy/ physiology/ behaviour

Question 15

suggest why some people are concerned about the plan to introduce pine martins from other areas into wales

Answer 15

-introduced pine martins may not be adapted to local conditions
-local habitat might have changed/ is not suitable
-introduced pine martins may outcompete native population/ pine martins
-introduced pine martins may bring disease
-welsh pine martin may lose its distinctiveness/ identity because of interbreeding

Question 16

what needs to be considered when carrying out an EIA for a habiat were a motorway wants to be constructed on

Answer 16

-looking at the effect of a reduced size of habitat
-method of minimising impact/ named example
-effect of movement/ spread of species
-example of current legal status
-rarity of this habitat
-rare/ endangered species
-biodiversity
-build toad tunnels so that toads can still move between the two areas