chapter 10 - biodiversity

• what is a species?

  a group of similar organisms that can breed together to produce fertile offspring
• what is a binomial system?

  a universal method & is the way organisms are named
• what does the first & second name of an organism present

  1st name - genus

  2nd name - species
• what does having the same genus show?

  most recently shared a common ancestor
• why do different species look similar?

  1. live in a similar environment
  2. have similar selection pressures
  3. similar alleles will have the selective advantage
  4. produces similar/same proteins & therefore have similar characteristics
• what is a hierachy?

  • smaller groups arranged within larger groups
  • no overlap between groups
• what is an example of a hierachy?

  classification system
• order of a classification system

  1. domain
  2. kingdom
  3. phylum
  4. class
  5. order
  6. family
  7. genus
  8. species
• what is each group in a classification system called?

  taxa
• what is phylogenetic classification?

  it arranges species into groups according to their evolutionary origins & relationships
• what does phylogeny tell?

  who is related to whom & how closely related they are
• where have all organisms evolved from?

  a shared common ancestor
• why is courtship behaviour essential?

  successful mating and species recognition
• what does courtship behaviour enable individuals to do?

  1. recognise members of their own species
  2. identify a mate capable of breeding
  3. form a pair bond
  4. able to breed
• what are courtship rituals?

  a sequence of actions which is unique to each species & is how animals identify members of their own species to reproduce with
• the more similar a courtship sequence is between different species, the more closely related a species are
• courtship rituals are genetically determined so the more similar a species sequence is, the more similar their DNA base sequence is
• what does biodiversity mean?

  the number & variety of living organisms in a particular area
• what are 3 components of biodiversity?

  1. genetic diversity,
  2. species diversity,
  3. ecosystem diversity
• what is species diversity?

  the number of different species & individuals within each species in a community
• what is species richness?

  a measurement of a number of different species in a particular area at a particular time
• what is genetic diversity?

  variety of genes amongst all the individuals in a population of one species
• what is ecosystem diversity?

  range of different habitats
• what does the index of diversity describe?

  the relationship between the number of species in a community & the number of individuals in each species ( SPEC POINT - 3.4.6)
• what often causes a decrease in diversity?

  farming practices
• what are examples of farming practices that cause a decrease in diversity?

  1. destruction of hedgerows - hedges provide a habitat for birds and insects however makes farming difficult & so are removed
  2. selective breeding - plants or animals with displayed characteristics get selected to breed to produce offspring however this narrows down gene pool
  3. monocultures - only growing one species leads to less diversity
  4. overgrazing - animals left to overgraze reduces plants
  5. filling in ponds & draining wetlands - provides space for farming
• SPEC POINT 3.4.7

  genetic diversity within, or between species, can be made by comparing:

  • base sequence of DNA
  • base sequence of mRNA
  • base sequence of amino acid sequence
  • frequency of measurable/observable characteristics
• what is the problem with comparing amino acid sequences?

  2 species may have the same amino acid sequence but different DNA base sequences because the genetic code is degenerate so less useful