Unit 2

• Random sampling is when every member in a population has equal chance of being selection
• Stratified sampling 


  Used to ensure that all subgroups within a population have an equal representation in the sample
• Systematic sampling 


  Is when samples are chosen at regular intervals
• Animal kingdom


  Chordata

  arthopoda

  nematoda

  platyhelminthes

  mollusca
• classification order


  Domain

  kingdom

  phyllum

  class

  order

  family

  genus

  species
• ethograms 


  Compare behaviours in different individuals of a species
• Latency 


  time between a stimulus and response
• Anthropomorphism 


  Applying human emotions to non human things/animals
• Taxonmoy


  Identification and naming of organisms and their classification into groups based on shared characteristics
• phylogenetics


  The study of evolutionary history and relationships among individuals or groups of organisms
• Methods for marking 


  Banding

  tagging

  surgical implantation

  painting

  hair clipping
• During evolution, changes in allele frequency occur through the non random processes of natural selection and sex selection, and random process of genetic drift
• Individual with variation that are better suited to their environment tend to survive longer and produce more offspring, breeding to pass on alleles that conferred an advantage to the next generation
• Sexual selection 


  Non random process involving the selection of alleles that increase the individual chances of mating and producing offspring
• Sexual selection may lead to sexual dimorphrism
• Sexual selection be due to male-male rivalry and female choice
• Genetic drift is more important in small populations, as alleles are more likely to be lost from the gene pool
• When selection pressures are strong, the rate of evolution can be rapid
• Absolute Fitness


  The ratio between the frequency of the individual of a particular genotype after selection, to those before selection
• Relative fitness


  The ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individuals of the most successful genotype
• Red Queen Hypothesis 


  In a co- evolutionary relationship, changes in the traits of one species can act as a selection pressure of the other species
• Cost of sexual reprodiction

  Makes unable to produce offspring

  only half of each parent genome is passed onto the offspring, disrupting successful parental genome
• Benefit out weights the cost due to an increase in genetic variation in the population
• Co-evolutionary interactions between parasites and host may select for sexually reproducing hosts
• If the host reproduce sexually, the genetic variability in their offspring reduces the chances that all will be susceptible to infection by parasites
• Vegetative cloning In plants and parthengenesis in lower animals that lack fertilisation are examples of aesexual reproduction in eukaryotes
• Parthenogenesis is more common in cooler climates, which are disadvantagous to parasite, or region of low parasite density or diversity
• meiosis I


  Two genetically identical chromatids attached at the centromere
• Meiosis I


  The chromosome condense and the homologous chromosome pair up
• Meiosis I


  Chiasmata form at point of contact between the non - sister chromatids of a homologous pair and sections of the DNA are exchanged
• Meiosis I


  This crossing over of DNA is random and produces genetically different recombinant chromosome
• Meiosis I


  Spindle fibres attach to the homologous pairs and line them up at the equator
• Meiosis I


  The chromosome of each homologous pair are separated and move towards opposite poles
• Meiosis II


  Each of the two cells produced in the meiosis I undergo a further division during which the sister chromatids of each chromosome are separated
• Cytokinesis occurs and two daughter cells are produced
• In most mammals the SRY gene on the Y chromosome determines development of male characteristics
• Heterogametic (XY) males lack most of the corresponding homologous alleles on the shorter (Y) chromosome
• This can result in sex linked patterns of inheritance as seen with carrier females (XBX b) and affected males (XbY)
• In homogametic females (XX) one of the two X chromosomes present in each cell is randomly inactivated at an early stage of development
• X chromosome inactivation prevents a double dose of gene products, which could be harmful to cells