Topic 4: Biodiversity & Natural sciences

• 4.1: how has the variety of life change overtime


  life has become extensive but is now being threatened by human activity
• 4.2: what is biodiversity


  the variety of living organisms in an area
• 4.2: what does biodiversity include

  • genetic diversity

  • species diversity
• 4.2: define species diversity


  the number of different species and the number of individuals of each species within any one community
• 4.2: define genetic diversity

  the number of different alleles of genes in a population
• 4.2: define endemism


  when a species is unqiue to a single place
• 4.2: what are the two ways species diversity in a habitat can be measured

  • count the number of different species in an area

  • count the number of different species and the number of individuals in each species
• 4.2: define species eveneness

  relative abundance of each species
• 4.2: define species richness

  the number of different species
• 4.2: how can species diversity be calculated

  index of diversity
• 4.2: what is the formula of index of diversity


  D = N(N-1)/Σn(n-1)
• 4.2: what is N in the formula of index of diversity


  N = total number of organisms of all species
• 4.2: what is n in the formula of index of diversity


  n = total number of organisms of one species
• 4.2: what is Σ in the formula of index of diversity

  Σ = sum of
• 4.2: if the index of diversity scores an index of 1..

  all the individuals are of the same species
• 4.2: describe the process of measuring a habitat


  1) choose an area to sample by using random sampling

  2) count the number of individuals of each species in the sample area

  3) repeat the process

  4) use the results to estimate the total number of individuals/total number of different species
• 4.2: what do you use to count the number of plants

  quadrat
• 4.2: what do you use to count the number of flying insects

  sweepnet
• 4.2: what do you use to count the number of ground insects

  pitfall trap
• 4.2: what do you use to count the number of aquatic animals

  net
• 4.2: why does biodiversity need to maintained


  • loss of biodiversity means there are fewer species.

  • loss of endemic species leads to extinction.

  • some species have not yet been discovered that may be useful
• 4.2: How is species richness counted

  counting the number of species in a known area using a quadrat
• 4.2: what is a gene pool


  complete set of alleles in a species
• 4.2: what are the two ways to measure genetic diversity

  • phenotypes

  • genotypes
• 4.2: define phenotypes


  describes the oberservable characteristics of an organisms
• 4.2: how can phenotypes be used to measure genetic diversity


  • look at different phenotypes in a population of a species

  • the large the number of different phenotypes, the greater the genetic diversity
• 4.2: define genotypes


  complete set of genetic material of an organism
• 4.2: how can genotypes be used to measure genetic diversity

  • samples of an organism's DNA are taken and bases pairs are analysed

  • order of bases in different alleles is slightly different

  • the larger the number of different alleles, the greater the genetic diversity

  • use heterozygosity index
• 4.2: how do we calculate genetic diversity

  heterozygosity index
• 4.2: what is the formual for heterozygosity index

  H = number of heterozygotes/number of individuals in the population
• 4.2: a higher proportion of heterozygotes in a population....


  means that the population has greater genetic diversity
• 4.2: why is little genetic diversity bad


  no selective advantage when the environment changes, less likely to survive, so this increases risk of extinction
• 4.2: why is increased genetic diversity good


  greater chance of survival as higher chance of having beneficial alleles, increased mating with genetically different individuals decreases inbreeding
• 4.2: How can looking at phenotype help to measure genetic diversity of a species

  different phenotypes are coded for by different alleles, so the larger the number of different phenotypes, the greater the diversity of alleles so the greater the genetic diversity
• 4.2: how can looking at genotype help to measure genetic diversity of a species

  analyse the sequence of base pairs in DNA samples of organisms. the order of bases in different alleles is slightly different. by sequencing the DNA of individuals of the same species, you can look at similarities and differences in the alleles. The larger the number of dif alleles the greater the genetic diversity
• 4.2: Define heterozygote


  Have two different alleles at a particular locus
• 4.3: what is a niche


  the role of a species within its habitat
• 4.3: what does a niche include


  It includes its interactions with other living organism (biotic( and its interactions with the non living (abiotic) environment
• 4.3: what happens when two species try and occupy the same niche

  they will compete with each other, one will be more successful than the other
• 4.3: how can organisms adapt to their niche

  • behavioural

  • anatomical

  • physciological