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OCR Biology A Level Module 4 > 4.2.1 Biodiversity > Flashcards

4.2.1 Biodiversity Flashcards

1
Q

Define biodiversity

A

measure of variation found in the living world

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2
Q

Define habitat biodiversity

A

range of habitats in which diff species live (sand dunes, woodland, meadow, streams)

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3
Q

Define species biodiversity

A

range of organisms found in a habitat (species richness and evenness)

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4
Q

What is species richness and species evenness?

A

richness: no. of species
evenness: no. of individuals in each species/the degree to which theyre represented.

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5
Q

Define genetic biodiversity

A

variation between individuals belonging to the same species -> breeds / number of different alleles in a population

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6
Q

Why is sampling important?

A

Impossible to count all fungi, bacteria and other single-celled organisms for example. So must SAMPLE -> select a small portion and then scale up

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7
Q

What is random sampling? State its advantages and disadvantages

A

randomly generating numbers as coordinates, or from a map

  • ensures data aren’t biased

-low presence species might be missed = underestimate
- might not cover all areas equally

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8
Q

What is opportunistic sampling? State its advantages and disadvantages

A
  • decisions based on prior knowledge - deliberate due to containing a species
  • easier and quicker

-may be biased
-may be an overestimate due to large and colourful species

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9
Q

What is stratified sampling? State its advantages and disadvantages

A
  • dividing a habitat into diff areas and sampling each separately
  • ensures species aren’t under-represented and that all areas are sampled
  • may lead to over-representation
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10
Q

What is systematic sampling? State its advantages and disadvantages

A
  • samples taken at fixed intervals using line and belt transects
  • useful when habitat shows a clear change in an environmental factor
  • species may be missed if not on line = underestimate
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11
Q

Explain how you use a quadrat

A

used to define size of sample area

generate random numbers as coords and place it there. Identify plants found.

estimation: some have grid which make them more accurate since percentage cover can be estimated
point frame: no. of long needles, lower it into quadrat and record any plants touching. best to use it at regular intervals. use no.of readings etc to calculate a %.

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12
Q

Explain how to use a transect. What is an interrupted vs continuous belt transect?

A
  • line taken across habitat, especially large ones
  • can be line (just tape) or belt (with quadrats)

interrupted: at intervals
continuous: move quadrat along the line to study in detail - no gaps

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13
Q

Why is it hard to sample animals by observation?

A

animals hide and often move too quickly

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14
Q

What is involved in careful observation?

A

footprints, DNA sequencing of droppings, burrows, damage to trees -> can estimate population sizes

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15
Q

What is capture recapture?

A

LONGWORTH TRAP
1. Capture a sample and mark each individual (C1)
2. Release them and leave traps for a period of time
3. Number captured on 2nd occasion = C2
4. Number of already marked that are captured = C3

TOTAL POPULATION = C1 x C2 / C3

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16
Q

Why is capture and recapture sometimes inaccurate?

A

some know it contains food, some know it’s harmless, or some might stay away

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17
Q

How are birds and larger mammals kept track of?

A

birds: ringing
larger mammals tagged

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18
Q

What is Simpsons index of diversity? What does a high and low value indicate?

A

measure of diversity of a habitat -> takes into account species richness and evenness

high: diverse. tends to be stable and able to withstand environmental changes
low: habitat dominated by a few species, less stable

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19
Q

How do you calculate genetic diversity in small, isolated populations?

A
  • Genetic diversity is found when there is more than one allele for a particular locus (position of a gene on a chromosome)
  • Genetic diversity = proportion of polymorphic gene loci (more than 2 allele) = no.of polymophic loci / total no. of loci
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20
Q

Explain how human population growth affects biodiversity

A

alter ecosystems to get food, clearing land for agriculture or building, deforestation, pollution, using more resources , destroy and fragment habitats

leads to EXTINCTION - no more living members of a species. many believe we are at start of mass extinction

21
Q

Explain how agriculture affects biodiversity

A
  • clear vegetation = decreases habitat size and reduces genetic diversity
  • reliance on monoculture -> one strain of species -> and selective breeding = decreasing genetic diversity

selecting for specific breeds means others may die out = genetic erosion

22
Q

What is genetic erosion?

A

limited gene pool of an endangered species diminishes even more

23
Q

Explain how climate change affects biodiversity

A
  • species less able to adapt as climate changes
  • extreme weather causes habitat destruction
  • barriers to migration (agricultural land, mountain ranges, water)
  • domesticated plants and animals very at risk due to little variation -> less food available
24
Q

Explain the ecological reasons to maintain biodiversity

A
  1. Interdependence: due to food chains, an effect on one species will affect other species.
  2. Keystone species: disproportionate effect upon its environment relative to its abundance, many species rely on them e.g. predators that limit herbivores, plants, beavers (dams causes water flooding where species can live, water slows = good for aquatic; felled trees allow light to reach ground)
  3. Maintaining genetic resource: may be able to breed new crop varieties that can cope with climate change, and use plants and microorganisms for new medicines ; huge potential in wide range of extant species
25
Q

Explain the economic reasons to maintain biodiversity

A

Food production:

Reducing soil depletion due to stopping monocultures = allows fertility and yields to increase

Biodiversity contributes to water purification, timber growth, recycling of nutrients, crop pollination, etc that food production relies on

26
Q

Explain the aesthetic reasons to maintain biodiversity

A
  • physical and emotional health
  • forests protect soils from erosion, trees take up water
  • protecting landscape for beautiful environments, e.g. by stopping soil exposure and severe flooding caused by deforestation
27
Q

What is conservation in situ?

A

management to maintain biodiversity in the natural environment

28
Q

What are wildlife reserves? What is the conflict?

A
  • designated areas established for conservation of habitats and species
  • animals raiding crops, poaching, tourists feeding/ littering
29
Q

What are marine conservation zones?

A

Conserve biodiversity of nationally rare, endangered and representative habitats in our seas

30
Q

What are other in situ methods?

A

National Parks (protected UK countryside), national nature reserves (protect sensitive features of environment) and local ones, SSSI’s (country’s best wildlife)

31
Q

What is repopulation?

A

Reintroducing a species once their habitat is suitable

32
Q

What are the advantages of in situ? (4)

A

Conservation in natural environment
Protect significant elements of natural and cultural heritage
Provide opportunities for sustainable land usage
Facilitates scientific research

33
Q

What are the disadvantages of in situ? (4)

A

Habitats may become fragmented
Genetic diversity may be lost already
Harmful conditions might be present still
Might attract poachers and ecotourists who cause disturbance

34
Q

What is conservation ex-situ?

A

management outside normal habitat of species

35
Q

What takes place in zoos?

A

Captive breeding -> breeding endangered species and conducting research

Artificial insemination, in vitro fertilisation and embryo transfer with wild animals

Some carry out research on domestic species SIMILAR to target ones to avoid experimental research on endangered species

36
Q

What are the advantages of zoos? (6)

A

protected from predation and poaching
genetic diversity can be measured
increased success of breeding due to reproductive tech
research made easier
education
attractions to raise funds

37
Q

disadvantages of zoos? (5)

A

limited genetic diversity
exposed to diseases
abnormal behaviour
correct environmental conditions might be hard to achieve
difficulties when reintroducing to the wild

38
Q

What are botanic gardens for?

A

Dormant plants = seeds.
Large numbers collected from wild, stored and germinated in protected surroundings
Huge numbers in little space
Often bred asexually
Individuals can be replanted in the wild

39
Q

What are the problems with botanic gardens? (4)

A

Difficult to fund
Samples may not have representative levels of genetic diversity
Seeds may not be viable
Decreases genetic diversity due to asexual breeding

40
Q

What are seed banks for? How are seeds stored?

A

Seeds that remain viable for decades. Provide them for crops, building materials and disease-resistant crops for agriculture. repopulation of endangered species + habitat reclamation

Storage: very dry and freezing conditions as they’re resistant to desiccation. tested at regular intervals to check their viability

41
Q

What are the aims of CITES?

A

Convention on International Trade of Endangered Species of Wild Fauna and Flora = international

Overall: Ensure international trade of specimens does not threaten their survival in the wild

  • ensure trade in wild plants for commercial purposes is inhibited
  • restrict trade of endangered species
42
Q

What are the aims of the Rio Convention on Biological Diversity?

A
  • International
  • promoting sustainable development
  • conservation of diversity
  • sustainable use of its components
    -appropriate shared access to genetic resources
  • appropriate sharing of knowledge and tech

states partner states must adopt ex situ facilities to complement in situ measures

43
Q

What were the aims of the Countryside Stewardship Scheme? What is it called now and what are its current aims?

A
  • improve natural beauty of countryside, restore targeted landscapes, and improve public access. all at a local level
  • Environmental Stewardship Scheme
  • provides funding to farmers in England to deliver effective environmental management on their land
  • help land managers to conserve and promote countryside by looking after wildlife, protecting natural resources, providing opportunities for learning
44
Q

What’s sweep netting

A

Sweep netting: through vegetation, (suitable for low, can be used in water) empty onto white sheet. A POOTER uses straw to ensure insects dont fly away

45
Q

Describe pitfall traps

A

Pitfall traps: in soil. any animals in plants/leaf litter will fall into container. Add water/scrunched paper to avoid them climbing up. Must be sheltered

46
Q

Describe tullgren funnels

A

Tullgren funnel: light above drives animals downwards as it warms up -> fall through mesh and collected

47
Q

Describe light traps

A

light trap: flying insects at night e.g. moths attracted to it and fall into collecting vessel with alcohol underneath

48
Q

The Madidi National Park, in the South American rainforest, is home to a wide variety of species.
The largest predator in the area is the jaguar. These large cats are well camouflaged and hunt
mostly at night. A single individual can cover a very large area.

(a) In 2007 the Wildlife Conservation Society (WCS) attempted to estimate the population of
jaguars in the Madidi National Park.
* Digital camera traps were placed in areas that jaguars were likely to visit.
* If an infrared beam was broken by an animal, the camera was activated.
* The camera then took a photograph of the animal.

(i) Suggest why it was not appropriate to estimate the number of jaguars using the
capture-recapture technique. (2)

A

estimate will be inaccurate (because of low numbers) 
dangerous (for collector or jaguar) 

49
Q

Most studies estimate the population density of jaguars in the South American rainforest
to be 5 individuals per 100km2.
In the 2007 study:
* 100 camera traps were set up covering an area of 271km2.
* 28 images of 9 different jaguars were recorded.
How well do these results support a population estimate of 5 individuals per 100km2? (4)

A

appropriate calculation of , observed / expected , population density 
lower than estimate 
so does not support 
low / unknown , repeatability / reproducibility 
(some) support because , figure / 3 , is close to estimate / 5 
some individuals not photographed 
idea that if many individuals not trapped population could be higher than estimate 

OCR Biology A Level Module 4 (3 decks)

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