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A Level Bio > 4.2.1 Biodiversity > Flashcards

4.2.1 Biodiversity Flashcards

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1
Q

What is biodiversity?

A

The variety of living organisms present in a certain area

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2
Q

What is habitat biodiversity?

A

Refers to the number of different habitats in an area. The greater the habitat biodiversity, the greater the general biodiversity

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3
Q

What is species biodiversity?

A

Refers to the number of different species present in an area.
Species evenness - the proportion of each of the different species within the area
Species richness - the abundance of different species in the area

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4
Q

What is genetic biodiversity?

A

Refers to the number of alleles within the population gene pool. High genetic biodiversity allows for greater variation & adaptation to a changing environment

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5
Q

Describe sampling techniques for plants.

A
  1. Frame quadrat - divide area into grid of particular size (quadrats), record amount of organisms in each quadrat
  2. Point quadrat - horizontal bar with pins stuck through at set intervals, record organisms that touch the pin
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6
Q

Describe sampling techniques for animals.

A
  1. Pooter
  2. Sweeping net
  3. Pitfall trap
  4. Capture-Mark-Release-Recapture (greater number of organisms at recapture without marks, the greater the population size)
  5. Tree beating - white cloth under tree, tree beaten to dislodge organisms
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7
Q

State and describe non-random sampling techniques.

A
  1. Opportunistic: organisms that are readily available are tested - not representative, convenient and quick
  2. Stratified: organisms split into groups based on characteristics then random sample taken of groups in relation to their size - time-consuming, but does do even coverage of area
  3. Systematic: samples taken at fixed intervals along the habitat - line transect: count organisms that touch the line, belt transect: two parallel lines marked, sample are between the lines - can miss out species
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8
Q

Why is it important to sample a range of organisms in a habitat?

A

So you can use the data to generalise to the whole population so you don’t have to analyse each organism in the habitat.

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9
Q

What are the three different ways of using quadrats?

A

Measure density: count number of visual plants in 1x1m quadrat for density per square metre - absolute measure
Measure frequency: count the number of squares a particular organism is in to find % occurrence
Measure percentage cover: estimate by eye the abundance of an organism in an area - used for speed

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10
Q

Why is Simpson’s Index of Biodiversity a better measure of biodiversity?

A

It takes into account both species evenness and species richness

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11
Q

What do low and high biodiversity index values tell us about the habitat?

A

Low biodiversity - UNSTABLE, few successful species, large effect from change in environment, very specific adaptations to their environment, few ecological niches

High biodiversity - STABLE, many successful species, more ecological niches, small effect from change in environment, few specific adaptations to environment

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12
Q

How do you calculate genetic biodiversity?

A

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

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13
Q

State and describe factors that increase genetic biodiversity.

A
  1. Mutations in DNA - different proteins synthesised

2. Interbreeding - individual migrates and breeds with another population, alleles are transferred (gene flow)

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14
Q

State and describe factors that decrease genetic biodiversity.

A
  1. Selective breeding/Artificial selection - few individuals selected due to desirable characteristics
  2. Captive breeding programmes - small number of individuals available for breeding, reduces allele variation
  3. Natural selection - those with advantageous characteristic out compete others, reduces variation
  4. Genetic drift - frequency occurrence of an allele decreases until it complete disappears from the population
  5. Founder effect - small number of individuals create colony isolated from original population - small gene pool
  6. Genetic bottleneck - only few individuals survive event - reduces gene pool
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15
Q

Explain agricultural factors that decrease biodiversity.

A
  1. Selection of species based on characteristics that give a high yield
  2. Deforestation
  3. Removal of hedgerows - support large diversity of species, are natural windbreakers - soil could be blown away if removed
  4. Chemicals - pesticides and insecticides
  5. Monoculture - only one species dedicated to an area
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16
Q

Explain the effect of global warming on biodiversity.

A
  1. Melting of polar caps - extinction of the species
  2. Rising sea-levels flood low land - reduce available habitats
  3. High temps and rainfall - non-xerophytes can’t survive, organisms that feed on them die
  4. Insect life cycles/populations change to adapt - affect organisms that rely on insects
17
Q

How has the climate changed over the years?

A
  1. Warming trend in 50yrs twice that for previous 100yrs
  2. Average temp of ocean has increased since 1961 - seawater expanding, sea-level rising
  3. Fluctuations in the Earth’s surface temp
  4. CO2 levels significantly increased since industrial revolution
  5. Average amount of water vapour in atmosphere has increased significantly
18
Q

State aesthetic reasons to maintain biodiversity.

A
  1. Humans feel joy from nature - inspires creativity

2. Studies show exposure to natural environments help patients recover quickly

19
Q

State economic reasons to maintain biodiversity.

A
  1. Deforestation causes soil erosion - reduces crops to feed people
  2. Species with potential economic benefit may become extinct before discovery
  3. Continuous monoculture causes soil depletion (reduction in nutrient diversity) - weaker crops, dependent on chemicals
  4. Highly bio-diverse areas are more attractive for tourism
  5. Greater potential for manufacturing different products in the future
20
Q

State ecological reasons to maintain biodiversity.

A
  1. Organisms are interdependent of each other (rely on each other) e.g. plants and bees
  2. Keystone species - have a dis-proportionally large effect on environment relative to their abundance, affect many organisms
21
Q

State human activities that aim to maintain biodiversity,

A

Human intervention in creating a habitat manages ecosystems e.g. hedge planting, grazing. Without this, some species would begin to dominate within the area, lowering the biodiversity

22
Q

Describe marine conservation zones as an ‘in situ’ method of maintaining biodiversity.

A

Marine conservation zones: vital for protecting areas rich in a species from unsustainable fishing. Creates refuge for population to build up for sustainable fishing - invasive species removed. Requires a large area

23
Q

Describe captive breeding/zoos as an ‘ex situ’ method of maintaining biodiversity.

A

Zoos: endangered species bred to stable population size and released into natural habitat, suitable breeding partners/semen can be from other zoos. Difficult to maintain genetic biodiversity - few breeding partners, keep genetic record for individuals to ensure mating with greatest diversity. Organism may not be suitable for release if: lost resistance to disease, complacent behaviour, genetic divide, or an unsustainable habitat.

24
Q

What is succession?

A

When a species is replaced over time until a stable population is achieved

25
Q

What are reasons for unsuitable release to the wild?

A
  1. Disease - either loss of resistance or they haven’t developed resistance yet
  2. Behaviour - organisms could become complacent e.g don’t search for food
  3. Genetic races - genes could veer so far from original population that they can’t interbreed anymore
  4. Habitat - may not be large enough to support all - lead to tension over resources
26
Q

What did the countryside stewardship scheme do?

A

Offered government payments to farmers and land managers to conserve English land to: sustain beauty and diversity, extend and create wildlife habitats, restore neglected land

27
Q

What was agreed at CITES (Convention of International Trade in Endangered Species)?

A

Aimed to regulate trading with select species and encourage trade that doesn’t endanger species - resulted in more than 35,000 species being protected

28
Q

What do the International Union for the conservation of nature (IUCN) do?

A

Publish ‘Red List’ of endangered species every year

29
Q

What was agreed at the United Nations Framework convention on climate change (UNFCCC)?

A

Stabilise greenhouse gas concentrations

30
Q

What was agreed at the United Nations convention to combat desertification (UNCCD)?

A

Prevent transformation of fertile land into desert and reduce drought effects

31
Q

What are the aims of an Environmental Impact Assessment (EIA)?

A
  1. Avoid intense impact
  2. Help developers to develop their proposals to be more environmentally friendly
  3. Ensure local authorities are aware of potential environmental threats
32
Q

Describe seed banks as an ‘ex situ’ method of maintaining biodiversity.

A

Seed bank: most temperate and tropical seeds stored this way, back-up if wild plants become extinct. Seeds dried and stored at -20c - slows rate of loss of ability to germinate. Some seeds die when dried/frozen - tropical rainforest trees

33
Q

Describe botanic gardens as an ‘ex situ’ method of maintaining biodiversity.

A

Botanic gardens: provide best resources for growth (nutrients, watering, removal of pests). Many wild species are unrepresented within gardens (very low %) - could be potential genetic resources

34
Q

Describe wildlife reserves as an ‘in situ’ method of maintaining biodiversity.

A

Wildlife reserves: actively managed through controlled grazing, restricted human access, removal of invasive species, and halting succession (through controlled grazing)

35
Q

What was agreed at The Rio Convention on Biological Diversity (CBD)?

A

Three main goals: 1) protect biodiversity
2) use biodiversity without destruction
3) share benefits from genetic diversity equally
Lead to UNCCD and UNFCCC

A Level Bio (8 decks)

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