biodiversity

• sampling


  not practical often to observe all species present in an area. instead, a representative sample can be taken
• random sampling


  sample sites inside a habitat are randomly selected
• non-random sampling


  sample sites inside a habitat are not randomly selected
• opportunist sampling


  researcher deliberately chooses sampling sites
• stratified sampling


  different areas are sampled in proportion to their area in habitat as a whole
• systematic sampling 


  sampled taken at fixed intervals often along a line
• biodiversity


  variety of living organisms in an area
• habitat biodiversity 


  area inhabited by a species. includes physical factors and biotic factors
• species


  group of similar organisms able to reproduce to produce fertile offspring
• genetic diversity 


  variation of alleles within a species or population of species
• species richness


  number of different species in an area
• species evenness


  abundance of different species in an area
• simpsons index of diversity 


  quantitative measure of biodiversity of a habitat which takes into account both species richness and evenness
• simpsons index of diversity equation

  • n=number of individuals of one species
  • N=total number of individuals in an area
  • $D=$$1-(+(n/N)squared)$
• measuring biodiversity

  1. capture sample of animals and mark then (C1 marked)
  2. release animals and wait to recapture
  3. capture another sample of animals (C2) (marked and unmarked)
  4. marked animals (C1) also appeared in second sample (C2) are grouped as (C3)
• population estimate equation


  (C1 x C2)/C3
• • C1: first sample captured (marked)
  • C2: second sample captured (marked and unmarked)
  • C3: marked individuals in C2
• genetic diversity


  accumulated in species where there are multiple alleles for a particular locus
• locus


  where a gene is located on a chromosome
• polymorphic locus/loci


  genes whose more than one alleles are found at the same location on a chromosome
• proportion of polymorphic loci equation

  (number of polymorphic gene loci / total number of loci )x 100
• drivers of biodiversity: pollution

  • plastic pollution
  • wildlife eating plastics
  • garbage patches
• drivers of biodiversity: changes in sea and land use

  • agriculture
  • habitat destruction
  • industry or residential buildings
• drivers of biodiversity: overexploitation

  • overfishing
  • hunting and poaching
• drivers of biodiversity: invasive species


  out competing 'native species'
• drivers of biodiversity: climate change

  • extreme weather conditions - water level rise, storms, forest fires
  • global warming - temperature rise, habitats, migration patterns (species unable to adapt and species migrate)
• monoculture


  farms have become more specialised, so they grow only one crop or raise one type of livestock
• monoculture reasons

  • support lower levels of biodiversity compared to natural habitats
  • fertilisers can leach into waterways which lead to death of many aquatic invertebrate and fish species
  • pesticides used on crops kill insect pests but kill many non target species
• reasons to maintain biodiversity

  • economic reasons - discovery of medicines, chemicals, vaccines, tourism (ecotourism), food security (pollinators), flood defences(mangrove forests)
  • ecological reasons - more species - more resilient ecosystem (disease, natural disasters)
• necrosis


  cell suicide in plants
• interdependence


  the way species in an ecosystem depend upon eachother
• keystone species


  species that has a disproportionate effect on its environment, relative to its abundance e.g beavers (dam building)
• conservation in situ


  active management to maintain biodiversity in natural environment
• conservation ex situ 


  conservation outside normal habitat of species
• agricultural yield and monoculture

  1. monoculture reduces genetic diversity of crops, making them more vulnerable to environmental change
  2. monoculture leads to soil depletion by reducing nutrient cycling - this can lead to reduced agricultural yield and increase in natural disasters
• conservation in situ

  1. establishing protected areas - restricting industrial, urban or agricultural development
  2. controlling invasive species e.g grey squirrels
  3. habitat protection and management - scottish highlander cattle to conserve grassland
  4. legal protection - hen harriers uk
• conservation in situ: advantages

  • both species and their habitats are conserved at same time
  • larger populations of organisms protected
  • less disruptive for organisms than ex situ
  • greater chance of population recovery than ex situ
• conservation in situ: disadvantages

  • endangered habitats may already be fragmented
  • populations may already have lost much of its genetic diversity
  • difficult to manage threats (poaching, disease)
  • public engagement required
  • ecotourism may cause disturbance
• conservation ex situ: advantages

  • zoo - monitor and study behaviour and health of endangered species
  • can measure genetic diversity and selectively breed to increase it
  • research in modern technology
• conservation ex situ: disadvantages

  • animals kept outside natural habitat
  • exposed to more diseases
  • difficult to recreate natural environment
  • if ever integrated into wild population can have issues integrating