Biodiversity

• Define species diversity


  The number of different species and individuals within each species in a community

  
• Define genetic diversity


  The variety of genes amongst all individuals in a population of one species

  
• Define habitat diversity


  The range of different habitats in an ecosystem/biome
• Give examples of habitat biodiversity


  Sand dunes

  Woodland

  Meadows

  Streams
• What species diversity be further classified as?


  Species richness
• Define species richness


  The number of different species in a particular area at the particular time

  
• What is the genetic diversity of a population reduced by?


  Captive breeding

  Inbreeding

  Genetic bottlenecks
• What does captive breeding result in?


  A small number of individuals breeding. There will be a limited gene pool
• What is a genetic bottleneck?


  When only a small number of a population have survived an event (such as a natural disaster/new disease). The gene pool is decreased and only the alleles in the remaining population can be passed on to future offspring

  
• What is a polymorphic gene?


  A gene that has more than one allele (for example, blood type).

  Most genes within a population have one allele (monomorphic)
• Calculating genetic diversity


  Genetic diversity is calculated by examining polymorphic genes within isolated populations like zoos (captive breeding).

  The higher the proportion of polymorphic gene loci, the larger the genetic diversity within the population

  
• What is used to calculate the biodiversity of a habitat?

  Simpson's Index of Diversity (D)
• Calculating biodiversity of a habitat


  N = the total number of organisms of all species

  n = total number of organisms of a particular species

  D = Simpson's diversity index

  1 is the lowest value for D. The larger the value of D, the greater the species diversity. It is typically a value between 1-10.

  
• When is sampling used?


  To measure the biodiversity of a habitat

  
• To ensure the sample is representative - taking a large sample...


  Can calculate a mean and statistical test to see any differences of correlations are significant
• To ensure the sample is representative - randomly sample...


  To avoid bias
• Random sampling


  A sample that fairly represents a population because each member has an equal chance of being selected.

  Method 1: Lay out 2 tape measures at right angles to each other to create a gridded area

  Method 2: Use a random name generator to generate 2 numbers to serve as coordinates on the grid

  Place your quadrat at the coordinates and record your data

  
• What are the 3 types of non-random sampling techniques?


  Opportunistic

  Stratified

  Systematic
• Opportunistic sampling


  This method involves sampling organisms that are conveniently available and therefore involve bias. They are the weakest form of sampling and is unlikely to result in data that accurately represents the population.
• Stratified sampling


  Separating the population into different subgroups. For example, when sampling a pond you may split the pond into 3: surface, shallow and deep-water regions and then take random samples within each group (strata)

  
• Systematic sampling


  This method involves identifying areas within a habitat to sample. Every nth item in the target population is selected It is used when there is a change in the distribution of species within the habitat and you want to investigate the impact of the change on biodiversity. It often involves a belt transect
• What is a belt transect?


  Place a single tape measure along the sample area and at a regular set distance along the tape measure you would place your quadrat and record the data

  
• Sampling techniques


  Quadrat

  Sweeping nets

  Pitfall traps

  Pooters
• What is a quadrat?


  A square frame enclosing a known area. It is used to sample plants and slow-moving organisms.

  
• Using a quadrat - Methods
• What are sweeping nets?


  Nets that can be used to capture insects with long grass

  
• What are pitfall traps?


  A hole is dug into the ground and a pot is placed within it. Small invertebrate may crawl into the trap and will be unable to crawl out. A roof-like structure is placed on top to prevent the trap from filling with rainwater and investigators will return daily to collect results and release the animals.

  
• What are pooters?


  Used to capture very small insects. Two tubes are connected to the closed pot. The investigator sucks on one tube and places the other tube over the insect . This creates suction and draws the insect into the pot

  
• Measuring species richness
• How to measure species eveness?
• What are factors affecting biodiversity?


  Human population growth

  Agriculture

  Climate change

  They all reduce biodiversity
• How is human population growth affecting biodiversity?


  Human population is continually increasing at an exponential rate. This has resulted in an increased need for housing, farming and industry (which all require deforestation)

  
• How is agriculture affecting biodiversity?


  There is increased agriculture to feed everyone. Clearing land for agriculture results the destruction of habitats, chemical pesticides or fertilisers may be added to the land and monocultures may be grown. All of this reduces the number of habitats and range of food sources

  
• How is climate change affecting biodiversity?


  The increase in global temperatures is melting polar ice caps (therefore destroying habitats).

  It is also resulting in sea levels rising, which is reducing biodiversity due to flooding.

  The higher the global temperatures and lower rainfall also mean that some plants and animals are unable to survive

  
• Reasons for maintaining biodiversity


  If an ecosystem experiences a loss in biodiversity, it is a cause of concern because a change is causing the loss of habitats therefore death and extinction of species often follow
• What are the main reasons for maintaining biodiversity?


  A reduction in biodiversity is undesirable for reasons ranging from:

  Ecological

  Economical

  Aesthetical
• What are the ecological reasons for maintaining biodiversity?


  Agriculture reduces biodiversity as it is removing natural habitats. All organisms are interdependent on each other and therefore the loss of one species impacts all the others.

  
• What are the economic reasons for maintaining biodiversity?


  Deforestation can result in soil erosion and monocultures can result in the soil becoming deficient in particular minerals that the crop absorbs a lot of. Both results in soil depletion and can negatively impact a country's ability to grow crops.

  Tourism often relies on people visiting areas of natural beauty and observing animals in their natural habitat. Extinction of habitats, plants and animals could reduce tourism and therefore impact the economy.

  Many medicines have been based on chemicals that naturally occur in plants, so species going extinct could have potentially held the molecules needed to cure diseases in humans

  
• What are the aesthetic reasons for maintaining biodiversity?


  Being in nature around animals and plants enriches people's lives and this is why many people may choose to visit rainforests and beaches.

  Nature is also a creative inspiration for art, music and writers

  Being amongst nature has also been shown to improve people's mental health.

  
• What are the 2 conservation methods for maintaining biodiversity?


  In situ

  Ex situ