biodiversity

Question 1

importance of biodiversity

Answer 1

maintains balanced ecosystem for all organisms as all species are interconnected

Question 2

different levels of biodiversity

Answer 2

• habitat
• species
• genetic

Question 3

habitat biodiversity

Answer 3

• number of habitats found within an area
• the greater the habitat biodiversity, the greater the species biodiversity

Question 4

species biodiversity

Answer 4

• species richness- number of different species living in a particular area
• species evenness- comparison of the numbers of individuals of each species living in a community

Question 5

genetic biodiversity

Answer 5

• the variety of genes that make up a species
• including different alleles
• allow for better adaptation to a changing environment and individuals being more resistant to disease

Question 6

what is sampling

Answer 6

taking measurements of a limited number of individual organisms present in a particular area

Question 7

what is sampling used for

Answer 7

• to estimate the number of organisms in an area (abundance) without having to count them all
• to measure a particular characteristic of an organism
• after measuring the sample, generalisations are made to the entire habitat

Question 8

random sampling

Answer 8

• selecting individuals by chance where each individual has an equal chance of being selected as any other
• mark out grid on grass using 2 tape measures laid at right angles
• use random number generator to determine x and y coordinate on the grid
• take sample at the coordinates generated

Question 9

non-random sampling

Answer 9

• opportunistic
• stratified
• systematic:
• different areas within a habitat are identified then sampled separately
• line transect involves marking a line along the ground between 2 poles and taking samples at specified points
• belt transect involves marking 2 parallel lines and samples are taken of the area between them

Question 10

reliability of a sample

Answer 10

• sampling bias= selection process may be biased. this can be reduced by random sampling
• chance= organisms may not be representative of whole population. can be minimised by using large sample size

Question 11

techniques to study animals

Answer 11

• pooter to catch small insects by sucking on a mouthpiece
• sweep nets to catch insects in long grass
• pitfall traps to catch small crawling invertebrates where a hole is dug and insects fall into it
• tree beating where tree is shaken and invertebrates fall into sheet underneath
• kick sampling where river bank is kicked to disturb the substrate and a net held downstream captures organisms released into flowing water

Question 11

sampling plants

Answer 11

• point quadrat is a frame containing a horizontal bar. at set intervals along the bar, long pins are pushed through to reach the ground and each species touching the pin is recorded
• frame quadrat consists of square frame divided into grid of equal sections where the type and number of species within a section is recorded

Question 12

how to measure species richness

Answer 12

• list compiled of each species identified
• identification keys used with images or series of questions that identify organisms based on observable characteristics

Question 13

how to measure species evenness

Answer 13

frame quadrats:
- density- counting number of plants to give density by square metre
- frequency
- percentage cover - estimated by eye of the area within the quadrat that a species covers

Question 14

advantages of measuring abiotic factors with sensors

Answer 14

• rapid changes can be detected
• human error in taking a reading is reduced
• high degree of precision can be achieved
• data can be stored and tracked on a computer

Question 15

formula for proportion of polymorphic genes

Answer 15

proportion of polymorphic gene loci= (number of polymorphic gene loci)/(total number of loci)

Question 16

genetic bottlenecks

Answer 16

few individuals within a population survive an event or change reducing the gene pool as only the alleles of the surviving members are available to be passed onto the offspring

Question 17

founder effect

Answer 17

small number of individuals create a new colony (geographically isolated from the original) and the gene pool for this population is small

Question 18

gene flow

Answer 18

interbreeding between different populations when an individual migrates from one population and breeds with a member of another population, so alleles are transferred between the 2 populations

Question 19

how to calculate biodiversity

Answer 19

Simpson’s index of diversity

Question 20

Simpson’s index of diversity formula

Answer 20

D= 1 - SUM(n/N)^2
where N is total number of organisms of all species and n is total number of organisms of a particular species

Question 21

in situ conservation

Answer 21

conservation within the natural habitat

Question 22

ex situ conservation

Answer 22

conservation out of the natural habitat

Question 23

factors affecting biodiversity

Answer 23

• deforestation
• agriculture
• climate change

Question 24

reasons for maintaining biodiversity

Answer 24

- aesthetic reasons - economic - ecological