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Biology A Level > Biodiversity > Flashcards

Biodiversity Flashcards

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1
Q

Define biodiversity

A

All of the variety in the living world (/another habitat)

Comprised of
• species diversity
• genetic diversity
• ecosystem diversity

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2
Q

Species diversity

A

Number of different species and the number of individuals of each species within a community

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3
Q

Genetic diversity

A

The variety of genes possessed by the individuals that make up the population of a species

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4
Q

Ecosystem diversity

A

The range of different habitats, from small -> plant earth

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5
Q

Measuring species diversity

A

d = N(N-1) / Σn(n-1)

N = total number of organisms of all species 
n = total number of organisms of each species
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6
Q

What does calculating species diversity show

A

Allows us to measure ecosystem stability (high value = stable; less affected by environmental change)

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7
Q

Species diversity in extreme environments

A
  • LOW
  • instable ecosystem
  • experiences greater change
  • fewer organisms have the adaptations to survive
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8
Q

How does agriculture reduce species diversity - the basics

A

• species and organism selection and rejection reducing species and genetic diversity

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9
Q

How does agriculture reduce species diversity - the specifics does

A
  • pesticides kill competing species
  • hedgerows removed, woodland grubbed out
  • monocultures
  • ponde and wetlands filled in
  • land over-grazed, preventing regeneration
  • no crop rotation, under-sowing
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10
Q

Why do we select plants/animals

A
  • financial stability

* high food demand

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11
Q

Describe agricultural reduction of species diversity

A

majority of biomass support used for selected species; lack of space, food, light, minerals for other species found in a natural ecosystem

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12
Q

Aim of conservation

A

To increase species and habitat diversity without raising food costs or lowering yield

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13
Q

Conservation techniques

A
  • maintaining hedgerows at most beneficial size and shape
  • plant hedges instead of fences as field boundaries
  • maintain + create ponds
  • not draining wetlands
  • plant native trees on land with low species diversity
  • reduce pesticide, biological control, and pesticide-resistant GMO usage
  • use organic fertilisers
  • rotate crops with nitrogen fixing crops rather than fertilisers
  • use intercropping rather than herbicides (controls weeds and pests)
  • create natural meadows; use hay rather than grass for silage
  • leave cutting off verges and field edges until after flowering + seed dispersal
  • introduce conservation headlands
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14
Q

Hedge shape

A

A is better than rectangular

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15
Q

Nitrogen fixing crops

A

Allowing nitrogen enrichment

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16
Q

Conservation headlands

A

Areas at the edges of fields where pesticides are used restrictively, so that wild flowers and insects can breed

17
Q

Hedgerows

A
  • remover to allow for increase in large farm machinery
  • removed to allow space for crop growth
  • increase species diversity
  • act are corridors along which species’ move to disperse themselves
  • provide food for animals inside + around
18
Q

Maintaining biodiversity

A

Allows a stable global ecosystem

19
Q

Community

A

The population of all the living organisms of a species present in a particular ecosystem at a particular time, interacting

20
Q

Population

A

Total number of individuals of one species (that can potentially interbreed) in a particular habitat at a particular time

21
Q

Ecosystem

A

All the biotic and abiotic components of a particular area (dynamic)

22
Q

Niche

A
  • how an organism responds/fits in to its environment

* governed by biotic + abiotic conditions

23
Q

Carrying capacity

A
  • the population size an ecosystem can support

* varies due to abiotic and biotic factors

24
Q

Describe population growth curve

A

1) lag phase
2) log phase
3) stable phase - population fluctuates due to limiting factors
4) death phase, esp. in sealed environments

25
Q

Natural factors affecting biodiversity

A
  • natural disasters
  • climate change
  • interactions between invasive and non-invasive species
26
Q

Man-made factors affecting biodiversity

A
  • pollution
  • deforestation
  • climate change
27
Q

Assessing genetic diversity

A

Compare:
• DNA
• RNA
• amino acids

28
Q

Assessing species diversity

A
  • use random/systematic sampling
  • don’t forget field guide!
  • mean average
29
Q

Assessing ecosystem diversity

A

Compare habitats and abiotic characteristics

30
Q

Species richness

A

The number of different species present in a habitat

31
Q

Species evenness

A

??

32
Q

Habitat

A
  • the place where an organism typically lives, characterised by the physical conditions and other organisms present
  • have microhabitats with microclimates

Biology A Level (45 decks)

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