Topic 4

• What is biodiversity?


  the variety of living organisms in an area. includes species diversity and genetic diversity
• What is species diversity

  The number of different species and the abundance of each species in an area
• What is genetic diversity?

  The variation of alleles in the gene pool of a species
• What is endemism?


  When a species is unique to a single place
• How is species richness counted?

  counting the number of species in a known area using a quadrat
• 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
• Why is little genetic diversity bad?

  no selective advantage when the environment changes, less likely to survive, so this increases risk of extinction
• 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
• How does the use of Hardy Weinberg equation allow us to see if evolution has occurred?

  identify changes in the allele frequency over time, if allele frequency has changed then evolution has occurred
• Species evenness is...


  relative abundance of each species
• Species richness is...


  the number of different species
• A niche is...


  The role of a species within its habitat. It includes its interactions with other living organism (biotic( and its interactions with the non living (abiotic) environment
• Define behavioral adaptations


  Ways an organism acts that increase its chance of survival.
• Define physiological adaptations


  Processes inside an organism's body that increase its chance of survival
• Define anatomical adaptations


  Structural features of an organism's body that increase its chance of survival
• Why may individuals of the same species vary?

  they have different alleles
• What is a gene pool?


  complete set of alleles in a species
• 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
• 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
• Define heterozygote


  Have two different alleles at a particular locus
• A higher proportion of heterozygotes in a population means...

  the population has greater genetic diversity
• What do selection pressures do?

  create a struggle for survival
• Why is there variation in the phenotypes of individuals of a population?

  random mutations introduce new alleles
• What happens to individuals with the advantageous alleles?

  they are more likely to survive, reproduce and pass on their advantageous alleles to their offspring
• Why has the theory of evolution become increasingly accepted?

  there has been more evidence that supports it and no evidence to disprove it. evidence increases scientists confidence in a theory.
• What is a species?

  A group of similar organisms that can reproduce to give fertile offspring
• What is reproductive isolation?

  The changes in the alleles and phenotypes of the populations prevent them from successfully breeding together
• Why does speciation occur?

  when populations of the same species become reproductively isolated
• How can seasonal changes result in reproductive isolation?


  individuals from the same population develop different flowering or mating seasons or become sexually active at different times of the year
• How can mechanical changes result in reproductive isolation?

  changes in genitalia prevent successful mating
• How can behavioural changes result in reproductive isolation?


  A group of individuals develop courtship rituals that aren't attractive to the main population
• Why might a population become reproductively isolated?

  due to geographical isolation or random mutations
• What is geographical speciation?

  When a physical barrier divides a population of a species
• How does geographical isolation lead to speciation?

  Conditions on either side of the barrier are slightly different. Different characteristics will be advantageous on each side so the allele frequencies change in each population. Mutations occur independently in each population, also changing the allele frequencies. The changes in allele frequencies lead to changes in phenotype frequencies. Eventually, the different populations become genetically distinct and are reproductively isolated
• What does it mean when organisms are genetically distinct?


  The individuals from the different populations will have changed so much that they won't be able to successfully breed with each other to produce fertile offspring
• Define allele frequency


  How often an allele occurs in a population
• Under what conditions is the Hardy Weinberg principle true?

  Large population, random mating, no natural selection, no mutations, no immigration or emigration
• What does p stand for in p + q = 1?

  the frequency of the dominant allele
• What does q stand for in p + q = 1?

  the frequency of the recessive allele
• what does p^2 stand for in p^2 + 2pq + q^2 = 1?

  the frequency of the homozygous dominant genotype