2.1 - biodiversity and classification

• Adaptation


  A feature of an organism that increases its chance of survival in its environment. Adaptations may be anatomical, physiological or behavioural.
• Anatomical adaptations


  Changes to the physical features of an organism that increase its chance of survival in its environment.
• Animalia


  A biological kingdom consisting of multicellular, heterotrophic eukaryotes that do not have a cell wall.
• Archaea


  One of the three domains made up of primitive bacteria existing in extreme environments, e.g. extremophile prokaryotes.
• Bacteria


  One of the three domains that consists of true bacteria.
• Behavioural adaptations


  The ways in which an organism acts differently to increase its chance of survival in its environment.
• Binomial system


  The universal system of naming organisms using their genus and species.
• Biodiversity


  The number and variety of living organisms in a given region. It is affected by environmental, genetic and human factors.
• Classification


  The organisation of organisms into groups.
• DNA profiling


  A method of determining the characteristics of an individual's DNA. The percentage of DNA or proteins shared by organisms can be used to estimate relatedness.
• DNA sequencing


  Determining the entire DNA nucleotide base sequence of an organism. Comparisons between members of the same species can identify variation in base sequences and hence estimate genetic diversity.
• Domain


  The highest taxonomic rank. There are three domains; Archaea, Bacteria and Eukaryota.
• Eukarya


  One of the three domains that consists of all eukaryotic organisms.
• Five kingdom classification system

  The classification of organisms into five major kingdoms: Animalia, Fungi, Plantae, Prokaryotae and Protoctista.
• Fungi


  A biological kingdom consisting of heterotrophic eukaryotes that have chitin cell walls and reproduce asexually by producing spores.
• Genetic biodiversity


  A measure of the variety of genes that make up a species. It can be assessed by determining the proportion of the population that possess a certain allele or the number of alleles at a locus.
• Kingdom


  The second highest taxonomic rank. There are five kingdoms: Animalia, Fungi, Plantae, Prokaryotae and Protoctista.
• Linnaean system


  The classification of organisms into kingdom, phylum, class, order, family, genus and species.
• Morphological convergence


  The independent evolution of analogous features in unrelated organisms due to exposure to similar environments or selection pressures.
• Natural selection


  The process by which the frequency of 'advantageous' alleles gradually increases in a population's gene pool over time.
• Physiological adaptations


  The internal body changes that an organism undergoes to increase its chance of survival in its environment.
• Plantae


  A biological kingdom consisting of multicellular eukaryotes that have a cellulose cell wall and can photosynthesise.
• Prokaryotae


  A biological kingdom consisting of unicellular prokaryotes which lack a true nucleus and membrane-bound organelles.
• Proportion of polymorphic gene loci


  A measure of genetic biodiversity. Calculated using:
• Protoctista


  A biological kingdom consisting of unicellular eukaryotes.
• Simpson's Index of Diversity (D)


  A measurement of diversity that considers both species richness and evenness. A value between 0 and 1 is found and the greater the value, the greater the diversity. Calculated using the formula:
• Species


  A group of similar organisms that are able to breed with one another to produce living, fertile offspring.
• Species evenness


  The number of individuals of each species living together in a community.
• Species richness


  The number of different species found within an area.
• Taxonomic hierarchy


  The arrangement of organisms into successive levels of classification known as taxonomic groups.
• Three-domain system


  A method of classification in which organisms are categorised into three groups; Archaea, Bacteria and Eukaryota.
• Classification is based on the information available at the time and is subject to change as new information comes to light
• Species


  A group of similar organisms that can interbreed to produce fertile offspring
• Classification


  • Division of living organisms into groups based on their evolutionary relationships
  • Hierarchical, meaning that large groups are split into groups of decreasing size
  • Phylogenetic, meaning that organisms in the same group are more closely related
  • Discrete, an organism cannot belong to more than one group at the same taxonomic level
  • Each group is called a taxon
• Binomial name


  • A name in two parts, the first is the genus and the second is the species name
  • Organisms in the same genus are more closely related to each other than to organisms in a different genus
  • Conventionally, the binomial of an organism is italicised
• Binomial names are the same the world over, thus avoiding issues with local names and language differences
• Domains


  • Larger taxon than a kingdom
  • All organisms evolved along three separate lineages
• The three domains


  • Eubacteria - 'true' bacteria
  • Archaea - prokaryotic extremophiles
  • Eukarya - all eukaryotic organisms
• Extremophiles


  Organisms that live where environmental conditions are harsh, e.g. very high or low temperatures, acidic or alkaline environments, high salinity or pressure
• Taxonomic groups


  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species