Variety of Life

Question 1

what is biodiversity

Answer 1

• study of all variation that exists within and between all forms of life
• range and variety of genes, species and habitats within a particular region

Question 2

how can biodiversity be measured

Answer 2

• number and range of different ecosystems and habitats
• number of species and their relative abundance
• genetic variation within each species

Question 3

what is species rich

Answer 3

• an ecosystem that has a high number of different species

Question 4

ecosystems with high species biodiversity are usually more ____

Answer 4

• stable as they are more resilient to environmental changes

Question 5

what is genetic diversity

Answer 5

• diversity of alleles and genes in the genome of a species

Question 6

how is genetic diversity measured

Answer 6

• working out proportion of genes that have more than one allele and how many possible alleles each gene has

Question 7

how is genetic diversity in a species important

Answer 7

• can help population to adapt and survive to changes in the environment

Question 8

effects of limited genetic diversity

Answer 8

• inbreeding in small, isolated populations leads to high proportion of individuals being homozygous for many genes resulting in low genetic diversity
  so genetic diseases caused by recessive alleles are more common

Question 9

what is endemic/endemism

Answer 9

• certain species only occur in one particular area of the world
• they are particularly at risk of extinction due to their limited range

Question 10

what is evolution

Answer 10

• process of which natural selection has increased the variety of life

Question 11

effect on human population on biodiversity

Answer 11

• as human population increases, demand for resources increases which has negative effects on our aquatic and terrestrial ecosystems and climate

Question 12

main factors affecting biodiversity

Answer 12

• habitat destruction
• over exploitation
• hunting
• agriculture
• climate change

Question 13

habitat destruction

Answer 13

• when land is cleared for agriculture etc this results in habitat loss and habitat fragmentation
- habitat loss (plants and animals completely lose their habitat)
- habitat fragmentation (habitats are divided into small areas- population living within these separated habitat fragments are more likely to suffer from inbreeding or local extinction

Question 14

over expoloitation

Answer 14

• being used up faster than that they can be replaced

Question 15

hunting

Answer 15

• animals are being removed quickly than their wild populations can be replenished

Question 16

agriculture (modern farming practices)

Answer 16

• farms became more specialised so only grew one crop or raised one type of livestock (monoculture)
• fields were made bigger to accommodate machinery via the removal of hedgerows and stonewalls
• more land was made arable by draining wetland and filling in ponds
• use of fertilisers and pesticides massively increased

Question 17

monocultures

Answer 17

• they support much lower levels of biodiversity than natural habitats and natural grazing land (that has a large variety of plant species present that can support a much greater range and number of insect species and bird species)

Question 18

hedgerows

Answer 18

• important habitat for many insects, small mammals and birds which can nest there
• as they are being increasingly removed, habitat and biodiversity it supports is lost

Question 19

fertilisers

Answer 19

• can leach into waterways causing eutrophication which can lead to the death of many aquatic invertebrates and fish species

Question 20

pesticides

Answer 20

• used on crops kill insect pests but also kill many non target species including important insect pollinators like bees

Question 21

climate change

Answer 21

• ## occurring too fast for many species to be able to adapt to these changes which could result in many species becoming extinct and reduced bio diversity

Question 22

global warming

Answer 22

• causing many species to move to different poles to higher altitudes
• the species may not be able to compete with the species already there
• some species may not be able to move or change their distributions fast enough to adapt to increasing temperatures and may go extinct

Question 23

increasing atmospheric CO2

Answer 23

• more CO2 dissolving in sea water, decreasing its pH (ocean acidification) which negatively impacts organisms that need calcium carbonate for shells

Question 24

increased ocean temperatures

Answer 24

• increased frequency of coral bleaching effects where tiny organisms that live inside the corals and help keep them alive leave due to temperature stress

Question 25

what is a habitat

Answer 25

- place where an organism lives

Question 26

ways of measuring biodiversity within a habitat

Answer 26

- species richness - species abundance

Question 27

species richness

Answer 27

- number of species in a community - can be a misleading indicator of biodiversity as it does not take into account the number of individuals of each species