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OCR Biology AS H020 > Biodiversity > Flashcards

Flashcards in Biodiversity Deck (63):

Define biodiversity...

The variety of living organisms present in an area.


What are the 3 levels that biodiversity can be studied?

Habitat, species, genetic.


What is habitat biodiversity?

The number of different habitats found within an area. Each habitat can support a number of different species eg. Meadow, woodland, streams, sand dunes. Habitat diversity is in correlation with species biodiversity.


What are the 2 components of species biodiversity?

Species richness and species evenness.


What is species richness?

The number of different species living in a particular area.


What is species evenness?

A comparison of the numbers of individuals of each species living in a community.


What is a community?

The population of a particular habitat.


What is genetic biodiversity?

The variety of genes that make up a species.


What does greater genetic biodiversity within a species allow for?

Better adaption to a changing environment and more likely to contain individuals who are resistant to disease.


What is sampling?

Taking measurements of a limited number of individual organisms present in a particular area.


What can sampling be used to estimate?

The number of organisms (abundance), particular characteristics of a species to be able to make generalisations.


What are the 2 ways sampling can be done?

Random and non-random.


What is random sampling?

Selecting individuals by chance, each individual in a population has an equal chance of selection.


Name 2 ways to randomise selection...

Random number tables, computers.


What is non-random sampling?

The sample is not chosen at random, an alternative to random sampling.


What are the 3 methods of non-random sampling...

Opportunistic, stratified and systematic.


What is opportunistic sampling?

The weakest form of sampling as it is not representative. Uses organisms that are conveniently available.


What is stratified sampling?

Dividing populations into a number of strata (sub-groups) based on a particular characteristic. A random sample is taken from each sample proportional to its size.


What is systematic sampling?

Different areas within an overall habitat are identified and sampled separately.


What is the difference between a line and belt transact?

A line transact involves making a line along the ground between 2 poles and sampling at specified points. A belt transect occurs between 2 parallel lines and sampling occurs at specified locations.


What reduces sampling reliability and how can this be resolved?

Sampling bias - random sampling
Chance - large sample


Name 5 methods of sampling animals...

Pooter, sweep nets, pitfall traps, tree beating and kick sampling.


Describe and explain the 2 types of quadrat...

A point quadrat consists of a frame containing a horizontal bar, a set intervals a pin can be pushed through. A frame quadrat consists of a frame divided into a grid of equal sections.


What are 3 ways a frame quadrat can be used?

Density in a square, frequency of square, percentage cover.


How is an animal population size estimated?



What are abiotic factors?

Non-living conditions in a habitat.


Name 6 abiotic factors and how they can be measured...

Wind speed - anemometer
Light intensity - light meter
Relative humidity - humidity sensor
pH - pH probe
Temperature - temperature probe
Oxygen content in water - dissolved oxygen probe


What are sensors advantageous when measuring abiotic factors?

Rapid changes can be detected, human error in taking a reading is reduced, a high degree of provision can be achieved, data can be stored and tracked on a computer.


The diversity of the organisms present in an area is proportional to...

The stability of the ecosystem.


Why is Simpsons Index of Diversity a good measure of biodiversity?

It takes into account both species richness and evenness.


How is Simpsons index of biodiversity calculated?

1 - The sum of (n/N)2


The higher the value of Simpsons index of biodiversity...

The more diverse the habitat (0-1)


What are alleles?

Different versions of the same gene.


What makes a population more genetically bio diverse?

The more alleles present in a population.


How can genetic biodiversity increase?

Mutations creating a new allele AND gene flow (interbreeding between different populations).


How can genetic biodiversity decrease (8)?

1) selective breeding/artificial selection
2) captive breeding programmes
3) rare breeds
4) artificial cloning
5) natural selection
6) genetic bottlenecks
7) the founder effect
8) genetic drift


How do scientists quantify genetic biodiversity?

Measuring polymorphism.


What are polymorphic genes?

Genes that have more than one allele.


What are monomorphic genes?

A gene where only a single allele exists.


What is the locus/loci(pl.) of a gene?

The position of a gene on a chromosome.


What are the 3 broad themes of human influence on biodiversity?

Deforestation, agriculture and climate change.


How does deforestation affect biodiversity?

1) directly reduces the number of trees in an area
2) specific tree removal decreases species diversity
3) reduces the number of animal species present as it destroys their habitat and food source.
4) forced animal migration causes the biodiversity of an neighbouring area to increase.


How does agriculture reduce biodiversity?

1) deforestation
2) removal of hedgerows (mechanisation)
3) use of chemicals
4) monoculture


How does climate change affect biodoversity?

1) melting of polar ice caps
2) migration of animals north as sea temps rise
3) thermal expansion/sea level rise leads to low land level flooding hence xerophytes become more dominant.
4) insect lifecycles and populations due to climate change, pollination?


What are the 3 broad themes for the reasons for maintaining biodiversity...

Aesthetic, ecological and economic.


What are the aesthetic reasons for maintaining biodiversity?

1) life enrichment
2) inspiration
3) rapid patient recovery


What are the economic reasons for maintaining biodiversity?

1) soil erosion/desertification due to deforestation which can lead to low crop yields and dependence on other countries.
2) conserve organisms that we use to make things.
3) species with potential economic importance may become extinct before they are even discovered.
4) continuous monoculture leads to soil depletion, the farmer becomes increasingly dependant on costly chemicals.
5) high biodiversity provides protection against abiotic stresses and disease.
6) tourism
7) the potential for the manufacture of different products in the future
8) plant varieties needed for cross breeding which can lead to better characteristics eg disease resistance/high yield.


What are the ecological reasons for maintaining biodiversity?

1) interdependence - serious consequences on complex food webs
2) keystone species have a disproportionately large effect on their environment relative to their abundance, they can help determine species richness and evenness.
3) maintaining genetic resources


What is in-situ conservation?

Within the natural habitat


What is ex-situ conservation?

Out of the natural habitat


What is conservation?

The preservation and careful management of the environment and of natural resources.


What are the classifications of abundance of species?

Vulnerable, endangered, extinct in the wild, extinct.


What is sustainable development?

Economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs.


Describe wildlife reserves...

In-situ conservation

1) controlled grazing
2) restricting human access
3) controlling poaching
4) feeding animals
5) reintroduction of species
6) culling of invasive species
7) halting succession


Describe marine conservation zones...

In-situ conservation

Prevent fishermen. Create areas of refuge where repopulation can occur in adjacent zones. Large areas of sea are usually needed as target species are mobile.


What are the advantages of in-situ conservation?

Maintains genetic diversity and evolutionary adaptions, preserves interdependent relationships, it is cheaper than ex-situ.


Describe botanic gardens...

Ex-situ conservation

Plant species actively managed to provide them with the best resources.


Describe seed banks...

Ex-situ conservation

A store of genetic material p, seeds are carefully stored so new plants can be frown in the future.


Describe captive breeding programmes...

Produce offspring of species kept in human controlled environments often run by zoos and aquatic centres. They aim to create a healthy population and gradually reintroduce them to the wild.


Why are some organisms born in captivity not able to be released into the wild?

Loss of resistance to local disease, innate behaviour stops survival as animals become domesticated, genetic makeup becomes so different that interbreeding cannot occur, the natural habitat must first be restored as there is limited territory and resources.


International Union for the Conservation of Nature (ICUN)

Publishes the red list detailing the current status of threatened animals. Involved in the establishment of the convention on international trade of wild plant and animal specimens and their products (CITES).


The Rio Convention...

1992, 172 nations 'Earth Summit' resulting on new agreements:

1) the convention of biological diversity (CBD) - national strategies for sustainable development maintaining biodiversity.
2) the United Nations framework convention on climate change (UNFCCC) - stabilise greenhouse gas concentrations within the atmosphere.
3) the United Nations convention to combat desertification (UNCCD) - prevent the transformation of fertile land into desert and reduce he effects of drought.


Countryside Stewardship Scheme...

A local level, government payments to farmers to enhance and conserve the English landscapes.

1) sustaining the beauty and diversity of the landscape
2) improving wildlife habitats
3) restoring neglected land and conserving archeological and historic features
4) improving countryside enjoyment.