knowledge-14 SB

• Taxonomy is the science of naming, defining and classifying groups of organisms based on their shared characteristics.
• a phylogenetic classification system arranges species into groups based on their evolutionary relationships.
• An example of a phylogenetic classification system is the Linnaean classification system, it has the following groups:

  • Domain
  • kingdom
  • phylum
  • class
  • order
  • family
  • genus
• A species is a group of similar organisms that can reproduce to create fertile offspring.
• Each species has a scientific name ,a binomial, made up of its genus and species.
• Courtship:

  if members of a species are to reproduce they must recognize other individuals of the same species. Courtship is a mechanism of species recognition and is required for successful mating.
• All courtship enables individuals of a species to:

  • recognize members of their own species
  • identify a mate capable of breeding
  • synchronize mating
  • form a pair bond
• A large standard deviation means there is a lot of variation in the data, so the data is not reliable.
• Biodiversity relates to habitats that range from a pond to the whole earth.
• A habitat is the place where individuals of a species live, with a specific set of biotic and abiotic factors.
• Biodiversity is the variety of organisms living within a particular area or habitat. It includes ecosystems , species and the number of different alleles.
• Species richness is a measure of the number of different species in a community.
• A community is the number of organisms of all species that live in the same area.
• The biodiversity of a community can be calculated using an index of diversity:

  • d = N(N-1) / sum of n(n-1)
  • where:
  • n is number of individuals of a particular species
  • N is total number of all individuals of all species
• Index of diversity analysis:

  • A high index indicates that a habitat is diverse with many different species. The habitat will be stable and resilient to changes within the area
  • A low index indicates that a habitat has low diversity and is dominated by few species. These habitats can be affected by small changes such as drought or disease.
• impact of farming on biodiversity:

  in general most modern farming practices reduce biodiversity. For example:

  • ponds, hedgerows and woodland are removed
  • marshes and wetland drained
  • non-selective pesticides kill non-target species
• Genetic diversity within or between a species can be made by comparing :

  • the similarities of measurable or observable characteristics
  • the base sequence of DNA
  • the base sequence of mRNA
  • the amino acid sequence of proteins encoded by DNA and mRNA
• Quantitative investigations of variation within a species involve:

  • collecting data from random samples from a single population
  • calculating a mean value of the collected data and the standard deviation of that mean.
  • interpreting mean values and their standard deviations.