Biodiversity

• Define the terms "ecosystem", "community", "habitat", "population" and "species"

  Ecosystem - All the interacting living organisms and non-living conditions in an areaCommunity - All the populations of living organisms in a particular habitatHabitat - the natural home or environment of an animal, plant or other organismPopulation - all the individuals of one species living in a specific area at a specific timeSpecies - the smallest and most specific taxonomic group. Can interbreed to produce fertile offspring.
• Define the terms "biodiversity", "habitat biodiversity", "species biodiversity" and "genetic biodiversity"

  Biodiversity - The variety of living organisms present in an areaHabitat biodiversity - The number of different places with different communities of organisms found in an areaSpecies biodiversity - The number of different types of organism found in an area, as well as the evenness of the population sizeGenetic biodiversity - The variety of alleles in a gene pool
• State the 3 levels of biodiversity

  habitat, species, genetic
• Name 3 examples of different habitats

  Desiduous woodland, Fen, Lake etc.
• Define the term "sampling" and explain why it is important.

  Taking measurements of a limited number of individual organisms or locations within a larger population or area.Whole population/are too large to be able to collect data from. Samples are quicker and cheaper and can provide good estimates for entire populations.
• State the two general ways in which sampling can be undertaken.

  Random sampling and non-random sampling
• Define the terms "random sampling" and "non-random sampling"

  Random sampling - Selecting individuals or locations to be sampled by chance. This ensures that each individual or location has equal likelihood of being in the sample.Non-random sampling - Sampling when there is some method to the individuals or locations being sampled. Each individual or location does not have equal likelihood of being int he sample.
• Outline how to randomly sample an area.

  Place tape measure down each sideUse a random number generator to create coordinatesPlace centre of quadrat on coordinateCount the relevant organisms within the quadratRepeat for as many as possible within time
• Name and describe the 3 main techniques of non-random sampling.

  Opportunistic - sample conveniently available organisms/areasStratified - population divided into groups (strata) and a sample taken from each group proportional to its sizeSystematic - Sampled areas follow a pattern. Sections of area identified and sampled separately.
• Define the terms "frame quadrat", "point quadrat", "line transect", "belt transect", and "interrupted belt transect"

  Frame quadrat - A square, rigid structure of fixed size used to identify an area to be sampled. It is usually divided into a grid of equal sections.Point quadrat - A frame containing a horizontal bar. At set intervals along the bar, long pins can be pushed through the bar to reach the ground. Each species of plant the pin touches is recorded.Line transect - This involved marking out a line along the ground between two poles and recording the location and type of each species that touches the lineBelt transect - Two parallel lines are marked and samples are taken of the area between the two lines.Interrupted belt transect - Sampling using a frame quadrat at specific intervals along a line transect.
• Outline how to sample an area using an interrupted belt transect.

  Mark a line along the ground between two poles. At regular intervals, place a frame quadrat against the line and take a sample.
• Explain when random sampling would be appropriate and when systematic sampling would be appropriate.

  Random sampling appropriate for a large area of the same type.Systematic sampling such as using transects looks for change across an area.
• Describe 5 ways to sample animals.

  Pooter - used for small insects - sucked into the chamberSweep nets - used to catch insects in long grassPitfall traps - used to catch small crawling invertebrates - hole dug in ground deep enough that they cannot crawl out and covered so does not fill with rain waterTree beating - used to sample animals living in tree or bush - large sheet under tree which is then shaken and animals fall out onto sheetKick sampling - used to sample organisms in a river - river bed is 'kicked' to move substrate, net held downstream to collect any creatures that are dislodged
• Describe 2 ways to sample plants (and sessile, or very slow moving, animals)

  Quadrats - point or frame
• Describe 3 ways of collecting data using a frame quadrat (that could be applied to either random or non-random sampling).

  Density - counting number of individuals to give a number per metre squaredFrequency - Count number of small divisions the species is present in. If quadrat divided into 100 small squares and organism is present in 65 of them, frequency is 65%Percentage cover - estimate by eye the percentage of the quadrat area that is covered by the organism
• Define the terms "biotic factor" and "abiotic factor"

  Biotic factor - The presence of, the population size of, and the interactions between the living organisms in an ecosystemAbiotic factor - The non-living or physical characteristics of an ecosystem
• Name, and state the equipment used to measure, 6 abiotic factors that could be measured when studying the abundance and distribution of organisms in an area.

  Wind speed - anemometer Light intensity - light meterRelative humidity - humidity sensorpH - pH probeTemperature - temperature probeOxygen content in water - dissolved oxygen probe
• Explain why a temperature probe linked to a data-logger may be advantageous over the use of a thermometer when investigating factors affecting the abundance and distribution of organisms in an area.

  Can record rapid changes and high precision measurements with reduced chance of human error.
• Name and describe 2 ways of measuring species biodiversity.

  Species richness and species evenness
• State the information needed to determine the species richness and species evenness of an area.

  Richness - a list of all the species of organisms present in an area then a total can be calculatedEvenness - Need to know the population sizes of each species to compare whether one is much more abundant than another or whether they are all of similar sizes
• Suggest how the population size of plants can be estimated

  Samples taken with quadrats to find average per metre squared. Then multiply up by total area to find population size.
• Suggest how the population size of animals can be estimated

  Capture - mark - release - recapture method
• Explain why measuring species diversity allows us to obtain information about the stability of an ecosystem or the degree of pollution in an ecosystem.

  Stable ecosystems tend to have high biodiversity with lots of different species with even population sizes and reasonably large population sizes.
• Name one measure of species diversity that takes into account both species richness and species evenness.

  Simpson's Index of Biodiversity
• Describe the meaning of each of the symbols in the equation for calculating Simpson's index of diversity.


  D=1-∑[(N/n)^2]∑ - sum of N - total number of organisms of all speciesn - total number of organisms of a particular species
• Describe the range of values that Simpson's index of diversity can take and explain how to interpret the value calculated.

  Values between 0 and 1 where 0 represents no biodiversity and 1 represents infinite diversity.
• Draw a table to show typical habitat features for areas with low and high biodiversity


  Low: few successful species, extreme conditions with few ecological niches, few species with specific adaptations, relatively simple food webs, a change majorly affects the ecosystemHigh: many successful species, relatively benign conditions with many ecological niches, many species with few specific adaptations to the environment, complex food webs, change has relatively small effect
• Explain why a greater genetic biodiversity increases a species chances of long term survival.


  More likely for some individuals to survive a change in environment to continue to reproduce if there is variation within the population as some individuals are likely to have an advantageous allele that means they are adapted to the change.
• Name and describe the two ways in which the genetic biodiversity of a population can be increased.

  Mutations in DNA of an organism creating new allelesInterbreeding between populations - alleles transferred between populations - gene flow
• Describe 6 factors that may cause a decrease in genetic diversity.

  Selective breeding - specific alleles being selected for so reduces number of possible alleles within populationCaptive breeding - only a small number of individuals available for breedingRare breeds - small number of individualsArtificial cloning - asexual reproductionNatural selection - species evolve to contain primarily the alleles which code for advantageous characteristicsGenetic bottlenecks - few individuals survive an event, reducing the gene poolThe Founder effect - small number of individuals create new colony geographically isolated from originalGenetic drift - random nature of alleles being passed on - frequency of allele varies. Genetic drift more pronounced in small populations with low genetic diversity
• Explain why captive breeding programmes for rare species in zoos and for rare breeds of domestic animal are likely to have low genetic biodiversity.

  Small number of individuals therefore limited number of different alleles
• Define the terms "polymorphic" and "locus" in relation to genes.

  polymorphic genes - genes with different possible alleleslocus - the position of a gene on a chromosome
• Write an equation that provides a measure of genetic diversity

  Proportion of polymorphic gene loci = (Number of polymorphic gene loci)/(Total number of loci)
• Describe the range of values that the "proportion of polymorphic gene loci" can take and explain how to interpret the value calculated

  Between 0 and 1 or converted to a percentage.0 represents no diversity, 1 implies all genes are polymorphic
• Describe the change in the human population since 1800.

  Human population double that in 1960 and 7 times the size of 1800.
• Explain why the human population is increasing so rapidly.

  Improvements in medicine, hygiene, housing and infrastructure
• Describe 3 main issues for biodiversity that have come about due to an increased human population size.

  Deforestation, Agriculture, Climate Change
• Describe 4 ways in which deforestation affects biodiversity.

  Reduces number of treesTakes out one species leaving the restReduces the number of animal species Animals forced to migrate - increased biodiversity of other areas
• Describe 5 methods associated with agriculture which affect biodiversity.

  DeforestationRemoval of hedgerowsPesticides and herbicides Removing weeds - plants growing where unwanted and therefore competing with crops for nutrientsMonocultureAnimal biodiversity reduced as a result of removal of plant food sources
• Define the terms "global warming" and "climate change"

  Global warming - a gradual increase in the overall temperature of the earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutantsClimate change - a change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.