topic 7 biooo

• the hardy weinberg equations

  allele A = pallele a = qp + q = 1.0p² + 2pq + q² = 1.0
• What is the Hardy-Weinberg principle? (not the equations)


  There is an equilibrium between allele frequencies, and there is no change in this between generations. 
• What is differential reproductive success?

  Where not all the individials are as likely to reproduce.
• Define Niche


  The role of a species within its habitat
• What is InterSpecific Competition?


  When Organisms of different species compete with eachother for the same resources
• Explain how you would carry out an investigation on non-motile organisms using a Quadrat and Transect:

  1. Lie 2 tape measures at a right angle to create a gridded area
  2. Use a random number generator to create 2 random coordinates
  3. Place the quadrat and measure the percentage cover
  4. Repeat the experiment atleast 30 times and calculate a mean
• Explain how you would carry out a line transect along a shoreline?

  • Use a Interrupted belt transect; where you place the tape measures at a right angle to the shoreline
  • Place the Quadrat at regular intervals e.g. 5 metres
  • Collect the percentage cover
  • Repeat by placing another 30 transects along the shoreline at right angles.
• How would you calculate percentage cover?

  Count the number of squares, count one if it is more than 50%.Add into a percentage
• How would you calculate density?

  Count the number of species, Divide the area of the whole field by the total area (usually 0.25 m2)Will give you number of species in quadrat
• Species richness 


  how many species there are in a given area at a given time.
• Mark-Release Recapture method

  1. Collect the sample

  2. Mark & release

  3. Mark must be weather resistant

  4. Leave marked individuals for a period of time to randomly disperse

  5. Capture a second sample
• Mark-Release Recapture method

  The total number captured is recorded, along with the total number with the marking. The size of the population is then estimated on the principle that the individuals marked on the second sample equal the proportion of marked individuals in the population as a whole.
• What is meant by codominant alleles?

  
  

  Both alleles expressed in the phenotype
• What is a genotype?


  The genetic make up on an organism. It describes ALL the alleles that an organism has.
• What is an allele?


  A different version of the same gene
• What is a gene?


  A short section of DNA is made up of nucleotide bases, which codes for a specific order of amino acids which makes a protein.
• What is a phenotype?


  Observable characteristics due to environment and genetic makeup
• What is a homologous pair?

  A pair of chromosomes - maternal and paternal. Also known as a bivalent
• Suppose you obtained a chi squared value of 5 and the critical value was 5.99 (2dof) - what can you conclude?

  Because the chi squared value is SMALLER than the critical value - you accept the null hypothesis and there is greater than a 5% probability that the difference in the results are due to chance. There is no significant difference.
• Suppose you obtained a chi squared value of 8 and the critical value was 5.99 (2dof) - what can you conclude?

  Because the chi squared value is LARGER than the critical value - you reject the null hypothesis and there is less than a 5% probability that the difference in the results are due to chance. There is a significant difference.
• What is the difference between monohybrid inheritance and dihybrid inheritance?

  Monohybrid is the inheritance of a SINGLE gene, dihybrid is the inheritance of TWO genes (that are located on different chromosomes)
•  polymorphism


   the continued existence of two or more distinct phenotypes in species
• Disruptive selection


  a natural selection that maintains high frequencies of two different sets of alleles
• p+q = 1. What is this predicting?

  Frequency of alleles
• p2+2pq+q2 = 1. What is this predicting?

  Frequency of genotype
• which types of selection is being described: A baby born with a birth weight of more than 4kg and less than 2.5kg has a greater risk of dying

  stabilising
• Elephants have evolved longer trunks enabling them to reach leaves higher up in the trees

  directional
• small mammals can escape from predators by hiding in small places while large mammals can resist attack from predators

  disruptive
• Describe disruptive


  Preserve individuals with extreme phenotypes (both ends), not those around the mean. Opposite to stabilising. Environment changes taking 2 distinct forms
• Describe directional


  Phenotype of population changes, favouring phenotype at one direction from the mean (selection for one extreme phenotype). Environmental conditions change.
• Describe stabilising


  preserves the average phenotype, selection against extreme phenotypes. Environment pretty stable
• Name 3 types of selection

  stabilising, directional and disruptive
• identify 2 forms of speciation

  allopatric and sympatric
• Reproductive separation

  occurs when changes in the alleles and phenotypes of some individuals in a population prevent them from successfully breeding with other individuals in the population that don't have these changed alleles or phenotypes
• Examples of allele or phenotype changes that can lead to reproductive separation include...

  Seasonal, mechanical and behavioural changes
• speciation

  the formation of new species from pre-existing species over time, as a result of changes to gene pools from generation to generation