Genetic diversity & adaption

• Define genetic variation

  The small differences in DNA base sequence between individual Organisms within a species population
• define genetic diversity

  the number of different alleles within a population
• define fitness of an organisms

  its ability to survive and pass on its alleles to offspring

  organisms with higher fitness possess adaptations that make them better suited to their environment
• the theory of natural selection

  under certain environmental conditions, individuals with certain alleles with have an increased chance of survival and reproduction
• what are the principles of natural selection ?


  -random mutation can produce new alleles of a gene

  -new alleles may be advantageous, leading to an increased chance of survival and increased reproductive success

  -advantageous allele passed onto next generation

  -new allele frequency will increases in population over several generations
• what is natural selection ?

  the process by which an organism better adapted to their environment survive and reproduce and pass on their advantageous alleles to their offspring.
• what are the other processes that can affect allele frequencies in a population?

  founder effect

  genetic drift

  bottleneck effect
• what is the founder effect 


  occurs when only a small number of individuals from a large parent population start a new population
• what is genetic drift

  the alleles that are passed on by random chance. it is easier to see the effect of genetic drift within a small population.
• what is the bottleneck effect ?

  occurs when a previously large population suffers a dramatic fall in numbers. which in turn reduces the genetic diversity in the population as alleles are lost.
• What are selection pressures ?

  And what are the two types of selection ?

  -environmental factors that affect the chance of survival or an organisms are selection pressures

  • stabilising
  • directional
• what is stabilising selection ?

  • Stabilising selection is natural selection that keeps allele frequencies relatively constant over generations
• what is directional selection ?

  • Directional selection is natural selection that produces a gradual change in allele frequencies over several generations
  • This usually happens when there is a change in environment/selection pressures or a new allele has appeared in the population that is advantageous

  for exampe - antibiotic resistant bacteria strains
• define allele frequency 


  how common an alleles is in the population.
• what are the different types of adaptations

  anatomical adaptations

  • structural /physical feature

  physiological adaptations

  • biological processes within the organisms

  behavioural adaptations

  • the way an organism behaves ( migration)
• what is evolution ?

  the change in adaptive features of a population over time as a result of natural selection
• what are some aseptic techniques ?

  aseptic techniques - ensure the mircrobes being investigated dont escape or become contaminated with anotherr unwanted, and possible pathogenic, microbe.

  1. washing hands thoroughly
  2. not allowing the growth of microorganisms at body temperature
  3. using flamed loops or stériles swabs when transferring cultures
  4. sterilising or disposing of all used equipment
  5. having a lit Bunsen burner in the room
• testing for bacterial antibiotic resistance using the disc diffusion method

  • The disc diffusion method is commonly used to test for antibiotic resistance in bacteria
  • It allows for multiple antibiotics to be tested at once
• what is the minimum inhibitory concentration (MIC)

  the lowest concentration of a substance that will inhibit the growth of a microorganism.
• What is the index of diversity formula ?

  Where :

  • n = total no. of organisms for a single species in the community
  • N = total no. of organisms in the community
  • Σ = sum of

  The larger the number obtained, the higher the level of diversity

  
• using measurable and oBaer able characteristics to d’hermine genetic diversity

  Characteristics that coule be measured :

  • Number of legs
  • Number of seeds in a berry
  • Number of petals
  • Number of leaf indentations

  Characteristics that could be observed:

  • Colour
  • Patterns on fur/scales/feathers
  • Habitat
  • Presence of hair/wings/fins