Biodiveristy (4A)

• Biodiversity


  The variety of living organisms in an area
• Components of biodiversity


  • Species diversity
  • Genetic diversity
• Species diversity


  The number of different species and the abundance of each species
• Genetic diversity


  The variation of alleles within a species
• Natural selection and evolution have increased biodiversity on Earth over time
• Human activities, such as farming and deforestation, are reducing species diversity and causing biodiversity to fall
• Conservation is needed to help maintain biodiversity
• Conservation is particularly important for endemic species as they are vulnerable to extinction
• Endemism


  A species that is unique to a single place and isn't naturally found anywhere else in the world
• Species richness


  The number of different species in an area
• Index of diversity


  A calculation used to measure species diversity that takes into account both the number of species and the abundance of each species
• Sampling to measure species diversity

  1. Choose an area to sample

  2. Ensure the sample is random

  3. Count the number of individuals of each species in the sample area

  4. Repeat the process to take multiple samples

  5. Use the results to estimate the total number of individuals or the total number of different species in the habitat
• Phenotype


  The observable characteristics of an organism
• Genetic diversity within a species


  The variety of alleles in the gene pool of a species
• Measuring genetic diversity within a species

  1. Look at the different phenotypes in a population

  2. Analyse the DNA sequence of individuals to look at similarities and differences
• Alleles


  Different versions of the same characteristics
• By looking at the different phenotypes in a population of a species, you can get an idea of the diversity of alleles in that population
• The larger the number of different phenotypes, the greater the genetic diversity
• Eye colour in humans

  • Blue, grey, green or brown eyes in northern Europe
  • Usually brown eyes outside this area
• Analysing DNA sequence


  1. Samples of DNA taken

  2. Sequence of base pairs analysed

  3. Look at similarities and differences in alleles within a species

  4. Measure number of different alleles for a characteristic
• Heterozygosity index (H)


  • Measures genetic diversity within a species
  • Calculated as the number of heterozygotes divided by the number of individuals in the population
• Index of diversity (D)


  • Measures species diversity in an area
  • Calculated using the formula: D = Σ(ni(ni-1))/(N(N-1)) where ni is the number of individuals of species i and N is the total number of individuals
• Calculating index of diversity

  • Field 1: 3 species, 11 organisms total (3 red, 5 white, 3 blue)
  • D = 11(11-1)/(3(3-1)+5(5-1)+3(3-1)) = 3.44
  • Field 2: 3 species, 11 organisms total (9 red, 1 white, 1 blue)
  • D = 11(11-1)/(9(9-1)+1(1-1)+1(1-1)) = 1.72
• Niche


  The role of a species within its habitat, including its interactions with other species and the environment
• Niche examples


  • Common Pipistrelle Bat: Lives in farmland, woodland, hedgerows, urban areas, feeds on insects using echolocation at 45 kHz
  • Soprano Pipistrelle Bat: Lives in woodland near lakes/rivers, feeds on insects using echolocation at 35 kHz
• Adaptations


  • Behavioural (e.g. playing dead, mating dances)
  • Physiological (e.g. hibernation, antibiotic production)
  • Anatomical (e.g. streamlined shape, blubber)
• If two species try to occupy the same niche, they will compete and one will be more successful
• Enhanced field margins are thick bands of land around the edges of fields that are not farmed but instead are planted with plants that are good for wildlife
• Species diversity refers to the number of different species within an ecosystem or region.
• Biodiversity refers to the variety of living organisms on earth, including plants, animals, fungi, bacteria, and other microorganisms.
• The biosphere is the part of Earth where life exists.
• Niche


  The role of a species within its habitat
• Adaptation


  Changes in an organism's structure, physiology, or behaviour that improve its chances of survival and reproduction in a particular environment
• Types of adaptations


  • Behavioural
  • Physiological
  • Anatomical
• Behavioural adaptations are ways an organism acts that increase its chance of survival
• Physiological adaptations are processes inside an organism's body that increase its chance of survival
• Anatomical/structural adaptations are features of an organism's body that increase its chance of survival
• Adaptations become more common in populations through evolution by natural selection
• How adaptations become more common

  1. New alleles introduced into a population

  2. Individuals with advantageous alleles survive and reproduce more

  3. Frequency of advantageous alleles increases

  4. Advantageous adaptations become more common
• Speciation


  The development of a new species