Biodiversity Flashcards
(53 cards)
1
Q
What is biodiversity?
A
The variety of species in an area.
The variety of genes in a population.
2
Q
Define habitat
A
The environment in which a species usually lives
3
Q
Define community
A
All the populations of living organisms in a particular habitat.
4
Q
Define species richness
A
Number of species living in a particular area
5
Q
Define species evenness
A
Number of individuals of each species living in a community
6
Q
What does species evenness indicate?
A
Higher species evenness indicates higher biodiversity.
Low species evenness indicates dominance by only a few species.
7
Q
Explain the importance of sampling in measuring the biodiversity of a habitat
A
- It is difficult to count every individual.
- Sample provides an estimate
- Representative of whole area
8
Q
Outline how to perform unbiased, random sampling with a quadrat
A
- Mark a grid in the area to be sampled using measuring tapes.
- Use a random number generator to provide coordinates on the grid.
- Place quadrat at coordinates and count species/organisms within a species.
- Determine abundance e.g. percentage frequency or percentage cover
- Repeat many times
- Calculate mean
9
Q
Determine methods of non-random sampling
A
Opportunity
- Use organisms that are conveniently available
- May not be representative of the population
Stratified
- Population divided into subgroups
- Random sample taken from each subgroup proportional to its size
Systematic
- Different areas in habitat identified
- Each area sampled e.g. belt transect
10
Q
Outline how to perform unbiased sampling with a transect
A
- Set up transect along area to be sampled
- Place quadrat at regular intervals and count species / organisms within a species
- Determine abundance e.g. percentage frequency or percentage cover
- Repeat many times
- Calculate mean
11
Q
How can representative samples be obtained when sampling?
A
- Unbiased method of selecting sample area e.g. random number generator
- Sample many times and calculate mean
- Standardised sampling procedure e.g. size of net, only count organisms completely in quadrat
- Use identification key
- Sample at different times/seasons.
12
Q
Simpson’s diversity index equation
A
D = 1 - (n/N2)
n = number of individuals of a particular species
N = total number of individuals of all species
13
Q
Outline the significance of a high value of Simpson’s Index of Diversity
A
- Many species present (high species richness)
- All species evenly represented (high species evenness)
- High biodiversity - More robust habitat
14
Q
Outline the significance of a low value of Simpson’s Index of Diveristy
A
- Habitat dominated by only a few species
- Habitat is unstable
- Less likely to cope with change
15
Q
Define genetic biodiverity
A
Differences in alleles within a population of a species
More alleles present = more genetically biodiverse
16
Q
Explain the importance of genetic biodiversity
A
- Greater genetic biodiversity = more likely to adapt to changes in environment
- Less likely to become extinct
- Likely to be some organisms with advantageous alleles
- These organisms more likely to survive and reproduce
- Advantageous alleles passed onto next generation
17
Q
What factors increase genetic biodiverity?
A
- Mutations in DNA create new alleles
- Interbreeding between populations increases gene flow
18
Q
What factors decrease genetic biodiversity?
A
- Genetic bottlenecks - major event leads to only few individuals surviving - leads to small gene pool
- Selective breeding
- Natural selection - less advantageous alleles lost
- Captive breeding e.g. zoos
19
Q
Define polymorphic gene
A
A gene with more than one allele e.g. human blood groups
20
Q
Define monomorphic gene
A
A gene with only one allele - most genes are monomorphic genes
21
Q
Define loci
A
The position of a gene on a chromosome
22
Q
How is genetic biodiversity measured?
A
- Using the proportion of polymorphic gene loci in a population
- The greater the proportion, the greater the genetic biodiversity
23
Q
How is the proportion of polymorphic gene loci in a population calculated?
A
Proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
24
Q
Why is human impact on biodiversity increasing?
A
- Population rapidly increasing
- Require more food, housing, resources etc
25
List human activities that can reduce biodiversity
* Deforestation
* Agriculture
* Pollution (climate change)
26
Explain how deforestation can reduce biodiversity
* Reduces number of trees
* Reduces species diversity
* Destroys animal habitat
27
Explain how agriculture can reduce biodiversity
* Removal of hedgerows destroys habitats and reduces prey for birds
* Monocultures reduce species diversity
* Removal of meadows reduces species diversity and habitats
* Pesticides and herbicides reduces species diversity
28
Explain how climate change could reduce biodiversity
* Global warming is melting polar ice caps - Could lead to extinction of species living in polar regions - Changes migration pattern of Arctic animals
* Rising sea levels could flood low lying land - Reduces terrestrial habitats - Salt water could reduce fresh water habitats in rivers
* Higher temperatures and less rainfall - Reduction in plant species - Xerophytes becoming more dominant - Impact on food chains
* Insect life cycles will change - Key pollinators of many plants - Could lead to extinction of plants - Greater spread of tropical diseases
29
Suggest how the excessive use of inorganic fertilisers can cause a reduction in biodiversity
* Fertiliser promotes growth of a few plant species
* Other plant species out-competed
* Leads to disruption of food chains
* Reduction in soil quality over time so plants cannot grow
30
Explain why a reduction in biodiversity may present problems for agriculture in the future
* Loss of genetic diversity in wild population
* Environmental requirements may change in future
* Lost alleles may have been useful to withstand change
31
Define keystone species
* Species that are essential for maintaining biodiversity
* Has disproportionately large effect on their environment relative to their abundance
32
Explain why keystone species are often predators
* Predators keep populations of prey at a consistent level
* Allows for balanced coexistence of other species
33
Why is it important to maintain biodiversity?
* Maintains complex, stable food chains
* Maintains variety of habitats for other organisms
* Ensures keystone species are not removed - avoids drastically changing habitat
* Aesthetic reasons e.g. natural beauty
* Economic reasons e.g. tourism
* Provides natural resources e.g. wood, medicine
34
Define *in situ* conservation
In natural habitat
35
Define *ex situ* conservation
Not in natural habitat
e.g. zoos, botanical gardens, seed banks
36
Define preservation
Protection of an area by restricting or banning human use
37
Give the benefits of *in situ* conservation in wildlife reserves
* Controlled grazing allows plant species to recover
* Human access restricted e.g. paths to prevent trampling of plants
* Control poaching of animals
* Reintroduction of species
* Removal of invasive species - ensure native species able to access resources
38
Give the benefits of *in situ* conservation in marine conservation zones
* Preserves species-rich areas e.g. coral reefs
* Control fishing areas and methods
39
What are the difficulties of setting up marine conservation zones?
* Large areas of sea required as aquatic species often move large distances
* Economic impact on fishermen
40
Explain why it is sometimes necessary to conserve a plant species outside of its natural habitat (*et situ*)
* Natural habitat lost due to climate change/human activity
* Number of plants in natural habitat is very low
* Reproduction is difficult in wild if numbers are low
* Breeding ex situ can maintain the gene pool
* Allows protection from grazers, plant collectors or competing species
* Protection from disease
41
What is the purpose of a seed bank?
* A store of plant genetic material
* Seeds dried and stored at cold temperatures to maintain viability
* Provides back-up against extinction
42
Why should the seeds of the same species in a seed bank be collected from several different sites in the wild?
* Maintains genetic variation in gene pool
* Reduces chance of future disease affecting the whole population
* Reduces chance of inbreeding
* Maintains geographical variation
43
Give advantages of conserving plant species as seeds and not as adult plants
* Can be collected with minimal damage to wild population
* Take up little space
* Can store greater genetic diversity
* Low maintenance costs
* Easier and cheaper to transport
* Remain viable for long periods
* Prevents fertilisation by undesired pollen
44
Explain why some species are conserved in captivity (ex situ) rather than in the wild (in situ)
* Protection from diseases or poisons
* Health of individuals monitored
* Reduced mortality of young
* Provision of mates
* Protection from hunting and predation
* Competition reduced between individuals and species
45
Why may organisms born in captivity not be suitable for release into the wild?
* May be loss of resistance to diseases present in wild
* Behaviour vital for survival in wild may not have been learnt
* Natural habitat may no longer be large enough to take more individuals
46
Discuss the advantages of captive breeding programs
* Maintains or increases endangered populations
* Allows for reintegration of species into its habitat
47
Discuss disadvantages of captive breeding programs
* Leads to loss of genetic diversity
* Leads to organisms not learning behaviours of their wild counterparts
* Genetic problems can occur in offspring due to inbreeding
* Can decrease the disease resistance of a population
48
State what CITES stands for
* Convention on International Trade in Endangered Species
49
What are the aims of CITES?
* Conservation of biodiversity
* Regulate trade of endangered species
* Ensure trade does not endanger wild populations
50
What are the aims of the Rio Convention on Biological Diversity?
* Sustainable use of organisms and habitats
* Share access to scientific knowledge and technology
* Promote international cooperation on biodiversity issues
* Promote ex situ conservation methods
51
What are the aims of the Countryside Stewardship Scheme?
* Sustain beauty and diversity of the landscape
* Improve, extend and create wildlife habitats
* Restore neglected land
* Improve opportunities for countryside enjoyment
52
Explain why local and international agreements can help preserve biodiversity
* Landowners have economic reasons for exploiting natural resources
* Exploitation leads to loss of biodiversity
* Financial incentives needed to replace income from exploiting a resource
* Animals do nor respect nation's boundaries
* To preserve number of species in natural habitat
53
Define sustainable development
Economic development that meets the needs of the people today.
Without limiting future generations' ability to meet their needs.
