B10 biodiversity

• members of a species are able to breed to produce living, fertile offspring
• to name species we use a binomial naming system which identifies each organism by a two-part name
• in the binomial naming system, the first half of the name is the generic name which is the genus of the organism, and the second half of the name is the specific name which is the species of the organism
• rules for the binomial naming system are:

  • names should be in italics if typed
  • names should be underlined if handwritten
  • only the first letter of generic name should be uppercase
  • if specific name not known, use 'sp.'
• courtship behaviour is ways in which species can recognise each other and differentiate themselves from other species, particularly during mating
• courtship behaviour enables organisms to:

  • recognise members of their own species
  • identify a mate that is capable of breeding
  • form a pair bond
  • synchronise fertility
  • become able to breed
• classification is the process of naming and organising organisms into groups based on their similar and different characteristics
• the two forms of biological classification are artificial and phylogenetic
• artificial classification divides organisms based on characteristics that are useful at the time
• phylogenetic classification divides organisms based on their evolutionary relationships, using shared features derived from their common ancestors, and arranges the groups into a hierarchy with no overlap between groups
• a typical phylogenetic classification system uses the following taxa:

  domain, kingdom, phylum, class, order, family, genus, species
• biodiversity is the range and variety of genes, species and habitats within a particular region
• the three components of biodiversity are:

  • species diversity
  • genetic diversity
  • ecosystem diversity
• species diversity is the number of different species and number of individuals of each species within any one community
• genetic diversity is the variety of genes possessed by the individuals that make up a population of a species
• ecosystem diversity is the range of different habitats
• biodiversity can be measured and compared using the index of diversity
• the equation to calculate index of diversity is:

  d = N(N-1) / the sum of n(n-1)
• in the index of diversity equation, N represents total number of organisms, and n represents the total number of organisms in each species
• agriculture reduces biodiversity because humans select for particular characteristics, reducing the number of alleles in the gene pool, and therefore reducing the genetic diversity of the population, also because it creates monocultures which prevent other species from living there
• techniques to maintain biodiversity in agriculture are:

  • maintain hedgerows and plant hedgerows instead of fences
  • maintain ponds and where possible create new ponds
  • reduce use of pesticides
  • use organic fertilisers rather than inorganic
  • include nitrogen-fixing crops in crop rotation
  • use intercropping instead of monocultures
  • create natural meadows
• genetic diversity within or between species can be determined by comparing:

  • base sequence of mRNA
  • base sequence of DNA
  • frequency of measurable and observable characteristics
  • amino acid sequence of proteins encoded by DNA and mRNA
• genetic diversity used to be determined by comparing observable characteristics, but this has limitations as the characteristics could be coded for by more than one gene, the same characteristics could have arisen separately, and the characteristics could be influenced by the environment and not the genes
• interspecific variation is differences between species
• intraspecific variation is differences between individuals of the same species
• sampling is the random selection of individuals
• sampling may not be representative due to chance and sampling bias
• to eliminate sampling bias, use a quadrat or transect and randomly generated coordinates
• to increase reliability of a sample, use a bigger sample size
• the features of a phylogenetic classification system are:

  • no groups overlap
  • smaller groups are within larger groups