A4.2 - biodiversity (1k)

Question 1

what is biodiversity?

Answer 1

biodiversity is the variety of life, in all its forms, levels and combinations

Question 2

what are the 3 types of biodiversity?

Answer 2

1. ecosystem diversity - the highest level, considering the number of types of ecosystems there are in a given location (e.g) the great barrier reef
2. species diversity - considers the variety of life within an ecosystem
   - it can be measured using species richness and species evenness
3. genetic diversity - is concerned with the variety in the gene pool of a population

Question 3

what is species richness and species evenness?

Answer 3

species richness - how many species there are in an area

species evenness - how similar in number the populations of each species are

• a given environmental disturbance may increase or decrease species richness and/or species evenness

Question 4

what does biodiversity of life result from?

Answer 4

biodiversity of life results from natural selection, where adaptive radiation occurs there is rapid divergence of multiple species from a single common ancestor

Question 5

what is a gene pool?

Answer 5

what is a gene pool?

Question 6

what is a positive of having a larger gene pool?

Answer 6

populations with more genetic diversity (bigger gene pool) are more stable and can better withstand environmental pressures (eg, extreme weather or disease) as at least some of the population is likely to survive
- low genetic diversity is particularly of concern in very small populations

Question 7

how can biodiversity of habitats be investigated?

Answer 7

using barcodes and environmental DNA allows the biodiversity of habitats to be investigated rapidly

Question 8

how can we compare and contrast current and past levels of biodiversity?

Answer 8

evidence from fossils suggests that there are currently more species alive on earth today than any time in the far past
- this can be explained by evolutionary theory, where speciation occurs in certain conditions
- however the number of species alive today is lower than it was a few hundred years ago, and the current biodiversity crisis has an anthropogenic cause

Question 9

why are the figures for biodiversity an estimate?

Answer 9

all figures used for analyses are based on estimates as millions of species are yet to be discovered and the fossil record is incomplete

Question 10

how can evidence be verifiable?

Answer 10

• comes from a peer-reviewed source
• comes from a published source
• methodology has to be checked

Question 11

what is classification and how can the same observations be classed differently?

Answer 11

classification is an example of pattern recognition but the same observations can be classified in different ways when considering taxonomic grouping

Question 12

what are splitters and lumpers?

Answer 12

“splitters”, who believe the differences between organisms are more important than the similarities, recognize more groups than “lumpers”, who believe the opposite, for a given group of organisms

Question 13

where might the IPBES have got their data from and how could we know to trust it?

Answer 13

results come from repeated, reliable surveys of biodiversity in a wide range of habitats around the world is required

Question 14

what are evaluations of using citizen-science for assessing biodiversity?

Answer 14

data recorded by citizens rather than scientists brings not only benefits but also unique methodological concerns

Question 15

what evidence is there about the biodiversity crisis?

Answer 15

• pollinator diversity has declined since 1970
• 66% of the ocean is experiencing “increasing cumulative impacts”, including half of live coral cover being lost since the 1870s, and over 85% of wetland area is lost
• the global rate of species extinction is already 10-100s of times higher than the average over the past 10 million years, and is accelerating
• around 25% of animal and plant groups are threatened, and around 1 million species (of an estimated 8 million total species) face extinction within decades
• over 500,000 terrestrial species (~9%) have insufficient habitat to survive long-term, and will become extinct unless the habitats are restored

Question 16

what are the causes of the current biodiversity crisis?

Answer 16

human population growth is the main cause of the biodoversity crisis, causing:
- hunting - removal of organisms
- over-exploitation of sustainable resources - removal of organisms
- urbanisation - loss of habitats
- deforestation - replacement with monoculture leaves soil infertile
- pollution - biomagnification and climate change
- global transport - spread of pests, disease and invasive species

Question 17

what is an example of the loss of terrestial megafauna?

Answer 17

North Island giant moas - New Zealand
- 3m in height with no wings
- herbivores who swallowed stones to grind plants and extract nutrients
- hunted to extinction within 100 years of the arrival of the Polynesians

Question 18

what is an example of a loss of marine species?

Answer 18

Caribbean monk seals - Gulf of Mexico
- European colonists killed the seals to eat, provide oil for lamps and to be taken as scientific specimens

Question 19

what is an example of a loss of UK species?

Answer 19

Great Auk - North Atlantic
- 80cm in height and flightless birds with small wings
- eggs were harvested and killed for meat and skins

Question 20

what are examples of anthropogenic ecosystem loss?

Answer 20

• loss of diptercarp forest in South-east Asia - deforestation means that only 500 species are found as the trees provide hardwood and clear-cutting (cheap) is used, leading to complete destruction of the local ecosystem as well as land being cleared for agricultural uses like palm oil
• loss of ferns in England - 99.7% of fens have been destroyed and are important as they are wetland ecosystems on peat-land soils that are carbon sinks and reduce the risk of flooding, but have been drained for agricultural land

Question 21

what is simpson’s reciprocal index?

Answer 21

measure combining both species evenness and species richness

D = ΣN(N-1) / Σn(n-1)
N - total number of organisms of all species found
n - number of organisms for each species
- higher value = more diversity