Bio Topic 4

• The function of phloem tissue is to transport organic solutes, mainly sugars like sucrose, from where they’re made in the plant to where they’re needed, and this is known as translocation.
• Biodiversity is the variety of living organisms in an area and it can be broken down into: Species diversity, genetic diversity.
• Species diversity is define as: The number of different species and the abundance of each species in an area.
• Genetic diversity is defined as : The variation of alleles within a species or population of a species.
• Population is defined as a group of organisms of same species living in a particular area.
• Endemism is defined as: When a species is unique to a single place.
• Species richness is the...

  Number of different species in an area.
• How are different things sampled?

  Plants: Quadrat

  Flying insects: Sweepnet

  Ground insects: Pitfall trap

  Aquatic life: Net
• What measures genetic diversity?

  Heterozygosity
• What is the equation of heterozygosity?

  H = Number of heterozygotes / Number of individuals in a population
• What is the Index of Diversity Equation?

  D = N(N-1) / (sum of) n(n-1)
• What do the "N's" represent in the Index of diversity equation?

  N = Total number of organisms of all species.

  n = Total number of organisms of one species.
• Niche is defined as the role a species performs within its habitat.
• What occurs if 2 species try to occupy the same niche?

  They will compete with each other, with one being more successful than the other until there is only one species left.
• Organisms can become adapted to their niches and the types of adaptions they form can be?


  Behavioural

  Physiological

  Anatomical
• Evolution is the change in the inherited characteristics of a population over time.
• Process of evolution:

  1. Mutations introduce new alleles into a population.

  2. Some alleles determine characteristics that can make the individual more likely to survive.

  3. Selection pressures like predation, disease, and competition create a struggle for survival.

  4. Individuals without advantageous alleles don't survive, leading to fewer individuals and less competition for resources.

  5. Individuals with advantageous alleles, better adaptions, are more likely to survive, reproduce, and pass on the advantageous alleles to offspring.

  6. Over time, the number of individuals with advantageous alleles increases.

  7. Over generations, evolution occurs as the frequency of advantageous alleles in the population increases and favorable adaptations become more common
• Speciation is defined as:


  The development of a new species.
• Species is defined as:

  A group of similar organisms that can reproduce to give fertile offspring.
• Speciation can occur when:

  Populations of the same species become reproductively isolated - The changes in the alleles and phenotypes of the populations prevent them for successfully breeding together.
• What are the examples of changes in alleles and phenotypes that cause speciation / reproductive isolation?

  Seasonal changes - Individuals from the same population develop different flowering or mating seasons, or become sexually active at different times of the year.

  Mechanical changes - Changes in genitalia prevent successful mating

  Behavioural changes - A group of individuals develop courtship rituals that aren't attractive to the main population.
• Geographical isolation can also lead to speciation when natural disasters create physical barriers that divides a population of a species.
• Evolution is a change in allele frequency.
• The Hardy-Weinberg principle predicts allele frequencies won't change from one generation to the next.
• The Hardy-Weinberg principle is only true under certain conditions, those conditions are:


  Large population, no immigration, no emigration, mutations or natural selection and there needs to be random mating.
• The first part of the Hardy-Weinberg equation is: p+q = 1.

  Where P = frequency of dominant allele,

  Q = frequency of recessive allele.

  This equation predicts allele frequency.
• The second part of the Hardy-Weinberg equation is: p^2 + 2pq + q^2 = 1

  This predicts genotype + phenotype frequency.

  p^2: Frequency of homozygous dominant genotype

  2pq: Frequency of heterozygous genotype

  q^2: Frequency of homozygous recessive genotype.
• Allele frequencies show that a population is changing overtime.
• The science of classification is known as taxonomy.
• The classification order is:

  Domain

  Kingdom

  Phylum

  Class

  Order

  Family

  Genus

  Species
• The five Kingdoms, and an example of each, are:

  Prokaryotae - Bacteria

  Protoctista - Algae

  Fungi - Mushrooms, moulds

  Plantae - Flowering plants

  Animalia - Insects, fish, reptiles mammals, etc.
• A new 3 domain classification has been proposed on new data:

  Bacteria

  Archaea

  Eukaryota
• Zoos + Seedbanks are used to conserve endangered species.
• Seedbanks are a store of lots of seeds from lots of different species of plant.
• Seedbanks also help to conserve genetic diversity. For some species they store a range of seeds from plants with different characteristics ( and so different alleles)
• Seedbanks create the cool and dry conditions needed for storage. This means that seeds can be stored for a prolonged period of time.
• Seedbanks also test seeds for viability, the ability to grow into a plant, where seeds are planted, grown and harvested and new seeds are harvested to put back into storage.
• Advantages of Seedbanks:

  • Cheaper to store seeds than fully grown plants and large number of seeds can be stored as they need less space than fully grown plants.
  • Less labour is required to look after seeds compared with plants.
  • Seeds can be stored anywhere provided the conditions are cool and dry, whereas plants would need original habitat conditions.
  • Seeds are less likely to be damaged by disease, natural disaster or vandalism than plants.
• Disadvantages of seedbanks:

  • Testing the seeds for viability can be expensive and time-consuming
  • It would be too expensive to store all types of seed and regularly test them all for viability.
  • It may be difficult to collect seeds from some plants as they may grow in remote locations
• Zoos use captive breeding programmes to help endangered species.