Biodiversity

• Species 


  Are capable of breeding to produce living, fertile offspring.
• Binomial system 


  First name called the generic name denotes the genus to which the organism belongs. Like a surname.

  Second name called the specific name denotes the species the organism belongs. Like a first name.
• Rules of the binomial system

  Names are printed in italics or underlined.

  First letter of generic name is upper case, specific name is all lower case.

  If specific name not known it can be written as 'sp'.
• Courtship behaviour helps it achieve:

  • Recognise members of their own species
  • Identify a mate that is capable of breeding
  • Form a pair bond
  • Synchronise mating
  • Becomes able to breed
• Classification 


  The grouping of organisms
• Taxonomy 


  The theory and practice of biological classification.
• Artificial classification 


  Divides organisms according to differences that are useful at the time. E.g colour, size, number of legs and leaf shape. These are analogous characteristics. Where they have the same function but do not have the same evolutionary origins. E.g wings on butterflies and birds are both used for flight but they originated in different ways.
• Phylogenetic classification 


  Is based on the evolutionary relationships between organisms and their ancestors

  Classifies species into groups using shared features derived from their ancestors

  Arranges the groups into a hierarchy, in which the groups are contained within larger composite groups with no overlap
• Classification ranks 


  Kingdom

  Phylum

  Class

  Order

  Family

  Genus

  Species
• A domain is the highest taxonomic rank and three are recognised: Bacteria, Archaea and Eukarya.
• Bacteria 


  A group of single celled prokaryotes with:

  No membrane bound organelles

  Unicellular, cells may occur in chains or cluster

  Ribosomes 70s

  Murein cel wall

  Single loop of DNA made of nucleic acids but no histones
• Archaea 


  Group of single celled prokaryotes that were originally classified as bacteria which they resemble in appearance.

  Differ to bacteria because:

  Genes and protein synthesis are more similar to eukaryotes

  Membranes contain fatty acid chains attached to glycerol by ether linkages

  No murein in their cell walls

  Have a more complex form of RNA polymerase
• Eukarya 


  A group of organisms made up of one or more eukaryotic cells. Their features are:

  Cells possess membrane bounded organelles such as mitochondria and chloroplasts

  Have membranes containing fatty acid chains attached to glycerol by ether linkages

  Not all posses cells with a cell wall, when they do it contains no murein

  Ribosomes 80s
• Eukarya domain is divided into four kingdoms: 


  Protoctista, Fungi, Plantae and Animalia.
• Phylogeny 


  Evolutionary relationships between organisms.
• Biodiversity 


  General term used to describe variety in the living world. It refers to the number and variety of living organisms in a particular area.
• Species diversity 


  Refers to the number of different species and the number of individuals of each species within any one community.
• Genetic diversity 


  Refers to the variety of genes possessed by the individuals that make up a population of a species.
• Ecosystem diversity 


  Refers to the range of different habitats from a small local habitat to the whole of the earth.
• Species richness 


  Number of different species in a particular area at a given time (community).
• Impact of agriculture

  • Species are selected for particular qualities
  • Genetic variety of alleles is reduced to those expressing the desired features
  • Reduced species diversity and genetic diversity
  • Monoculture - focused on one species usually plants
  • Areas can only support a certain biomass
  • If most of the area is taken up by one species, the rest will need to compete for resources and space
  • Farmer may use pesticides against species which compete for resources required by the farmed species this reduces the index of diversity
• Practices that have directly removed habitats and reduced species diversity:

  • Removal of hedgerows and grubbing out woodland
  • Creating monocultures, replacing natural meadows for cereal crop or grass for silage
  • Filling in ponds and draining march and other wetland
  • Over grazing or land
• Practices that have an indirect effect of reducing species diversity and removing habitats:

  • Use of pesticides and inorganic fertilisers
  • Escape of effluent from slurry tanks into water courses
  • Absence of crop rotation and intercropping or under sowing
• Comparison of DNA base sequences

  More genetic diversity of a species by sampling the DNA. Can compare the DNA of different species. When new species occur due to evolution the initially similar DNA changes due to mutations. closely related species have more similar DNA.
• Comparison of base sequences of mRNA

  Base sequences of mRNA complementary to DNA we can measure genetic diversity.
• Comparison of amino acid sequences in proteins

  Genetic diversity can be measured by comparing the amino acid sequence of the same protein the degree of similarity will reflect how closely related organisms are. can count the similarities or differences. There are different forms of haemoglobin.