Biodiversity

• Sampling


  Used to provide information concerning biodiversity in a habitat
• Biodiversity


  Indication of both the range of species in a habitat and also how evenly balanced the numbers of individuals are across the different species
• Biodiversity is not the same as species richness
• A particular habitat can be species-rich but not show much biodiversity, for example, a habitat may be species-rich but has very small numbers of most species, with only one or two species dominating the community
• Simpson's index (D)


  A measure of biodiversity that takes into account both the number of species and the number of individuals of each species
• Calculating Simpson's index


  1. Identify the number of different species present

  2. Measure the abundance of each species

  3. Use the formula: D = Σ(ni(ni-1)) / N(N-1) where ni is the total number of organisms of each individual species and N is the total number of organisms of all species
• The value of D ranges from 1 to 0, where 0 represents infinite biodiversity and 1 represents no biodiversity. The lower the value of D (ie the closer to 0), the greater the diversity
• Types of diversity


  Species diversity, ecosystem diversity, genetic diversity
• Habitat


  The places where organisms live, can be small scale like an individual leaf
• Environment


  The conditions that affect organisms in a habitat, can be abiotic (physical and non-living) or biotic (living)
• Ecosystem


  A community of organisms, interacting with one another and the associated environment, forming a balanced self-sufficient ecological unit
• Population


  All the members of the same species that occur in a particular area at a particular time
• Community


  A group of species which occur in the same place at the same time
• Many major ecosystems are at risk due to the action of man, such as the melting of ice in polar regions and deforestation of the Amazon rainforest
• Much of the ecosystem diversity in Northern Ireland has been lost due to the intensification of agricultural practices
• Genetic diversity


  The genetic variability of a species, influenced by factors like how long the species has existed and the degree of directional selection
• Genetically diverse species are more likely to remain adapted if the environment changes
• Species


  A group of individuals of common ancestry that closely resemble each other, and are normally capable of interbreeding to produce fertile offspring
• Binomial system


  Gives each species two names: the generic name indicating the genus, and the specific name identifying the species
• Taxonomy


  The arrangement of organisms into hierarchical groups of increasing size: species, genus, family, order, class, phylum, kingdom
• Phylogenetic taxonomy


  The classification of species and larger groups according to their ancestral relationships, based on evidence from morphology, anatomy, cell structure, biochemistry, etc.
• Phylogenetic taxonomy is now a much more scientific process due to a greater understanding of the evolutionary development of life on Earth
• There is exponential progress in the techniques available to elucidate relationships among organisms at the microscopic and biochemical level, as well as the more obvious physical and behavioural characteristics of organisms
• Techniques used to establish phylogeny


  • Morphology and anatomy
  • Cell structure
  • Biochemistry
• Morphology


  The external features of an organism
• Anatomy


  The internal features of an organism
• Morphology and anatomy have been very important in the early classification systems and are still important today
• The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers
• The presence of a modified form of pentadactyl limb clearly identifies different species as a member of the Phylum Chordata (vertebrates)
• Bats and birds have wings that can look very similar, but they belong to different classes (Mammalia and Aves) and are not as closely related as their morphology suggests
• Prokaryotic


  Cells without a nucleus or membrane-bound organelles
• Eukaryotic


  Cells with a nucleus and membrane-bound organelles
• The first cells were prokaryotic and for many millions of years life on Earth was entirely prokaryotic
• Eventually, eukaryotic cells evolved and four out of five kingdoms in the most common classification system used today are eukaryotic
• The organisms in the four eukaryotic kingdoms (Protoctists, Plantae, Fungi and Animalia) are more closely related to each other than they are to the organisms in the kingdom Prokaryotae
• Cell structure is important in classifying organisms as plants, fungi or animals
• In recent years, biochemistry has become increasingly important in classification
• Genome analysis and other biochemical techniques have confirmed the phylogenetic relationships already established by more traditional methods, but occasionally they have resulted in species taking up a new position in the classification system
• The biochemical basis of life is similar in all organisms. They all contain carbohydrates, lipids, nucleic acids and proteins
• The more closely related species are, the more similar their DNA, RNA and protein sequences will be