biodiversity

Question 1

define species richness

Answer 1

the number of different species in a community

Question 2

define biodiversity

Answer 2

the variety of living organisms within a habitat

Question 3

define species diversity

Answer 3

the number of individuals of each species and the number of different species in community

Question 4

how to obtain a more precise value for the index of diversity

Answer 4

• take more samples and find mean
• random sampling

Question 5

what is conservation

Answer 5

protection and management of earths resources and species and habitats

Question 6

give 3 examples of conservation

Answer 6

• using organic fertilisers
• not using pesticides
• not removing hedgerows

Question 7

give an advantage and disadvantage of maintaining hedgerows for farmers

Answer 7

:) increases species diversity so more predators for pests

:( less space for crop growth

Question 8

define population

Answer 8

a group of individuals of same species that live in the same habitat

Question 9

define community

Answer 9

all the different species that live in one area and interact with each other

Question 10

difference between biotic and abiotic

Answer 10

biotic- living factors e.g. predation, competition

abiotic- non living factors e.g. temperature, light

Question 11

give the equation for estimated population size using the mark-release-recapture technique

Answer 11

number of 1st captured x number of 2nd captured
/
number of marked recaptured in 2nd

Question 12

what is meant by a dynamic ecosystem

Answer 12

-populations rise and fall
- any small change may have a big impact
- biotic and abiotic factors may alter conditions of the ecosystem

Question 13

how does speciation happen (5)

Answer 13

1. geographical isolation
2. reproductive separation
3. different selection pressures
4. variation due to mutation in one population
5. advantageous allele passed on to offspring
6. different species cannot interbreed to form fertile living offspring

Question 14

suggest 1 precaution to take when marking animals

Answer 14

non toxic

Question 15

how would you estimate the size of a population of sundews in a meadow (5)

Answer 15

1. create a grid with 2 tape measures
2. use random generator to generate co-ordinate
3. place quadrat at co-ordinate and count number of sundew in quadrat
4. repeat 10 times and find mean
5. multiply by total number of quadrats

Question 16

suggest and explain how digesting insects helps the sundew grow in soil with low nutrients (2)

Answer 16

• insects contain proteins
• proteins break down into amino acids
• sundew uses amino acids to form proteins for growth

Question 17

explain how succession happens (5)

Answer 17

• pioneer species
• they provide food
• they increase then decrease in population as they are outcompeted by other species
• other species colonise
• overall there is an increase in species richness

Question 18

give two features of a climax community (2)

Answer 18

• same species present
• abiotic factors constant

Question 19

how should student use data from plot 1 to estimate total number of beetles in the meadow (4)

Answer 19

1. calculate the area of the plot
2. calculate area of the meadow
3. divide area of meadow by area of plot
4. multiply by number of beetles

Question 20

explain why it is more useful to calculate index of diversity rather than species richness

Answer 20

• index of diversity measures abundance of each species
• useful as they may be many of the same species

Question 21

what do the students need to collect to calculate index of diversity

Answer 21

total number of individuals of each species

Question 22

what are the 3 components of biodiversity

Answer 22

• species diversity
• genetic diversity
• ecosystem diversity

Question 23

define species diversity

Answer 23

number of different species and individuals of each species in a community

Question 24

define genetic diversity

Answer 24

number of different genes of a species in a population

Question 25

define ecosystem diversity

Answer 25

range of different habitats, from a small local habitat to the the whole Earth

Question 26

explain why it is more useful to calculate species diversity rather than just record number of species present

Answer 26

measures both number of species and number of individuals of each species

takes into account species that are present in small numbers

Question 27

give 4 examples of conservation techniques

Answer 27

• maintain hedgerows
• use biological control instead of pesticides
• don’t fill in ponds
• use organic fertilisers

Question 28

explain how agriculture has reduced species diversity

Answer 28

species with desired features are selected and grown
other species are excluded
small space left for other species
they compete for limited resources
they compete with the desired species for light,food,water
farmers remove other species with pesticides
number of different species decreases

Question 29

explain why species diversity decreases when forest is replaced by grassland for grazing sheep

Answer 29

forests have many layers
have many habitats with different species
grasslands have a single layer, fewer habitats, fewer species, and fewer species diversity

Question 30

suggest why draining of ponds on agricultural land might have a greater effect on biodiversity than removing a hedgerow

Answer 30

ponds provide a habitat for aquatic species which are unlikely to find alternative habitats
ponds are source of food and water for terrestrial organisms which may not be able to survive without them

hedgerow species are likely to find alternative habitats as most of the area around is terrestrial with other sources of food- fewer species are likely to be lost