Classification and biodiversity

• Major groups of living organisms


  • Plants
  • Animals
• Plants

  • Flowering (e.g. daisy, rose, dandelion)
  • Non-flowering (e.g. mosses and ferns)
• Animals

  • Vertebrates (have a backbone, e.g. birds, snakes, humans)
  • Invertebrates (do not have a backbone, e.g. insects, spiders)
• Classifying and naming organisms

  Traditionally based on morphological features, but more recently DNA analysis has been used to more accurately group organisms to show how related they are
• Domains

  • Eukarya (which contains 4 of the 5 kingdoms), Bacteria, Archaea
• Kingdoms

  • Animals, plants, fungi, single celled organisms, bacteria
• Phylum, Class, Family, Genus, Species


  Groups get smaller and organisms become more similar as they have more morphological features (body structures) in common
• Scientific names

  Used as they are universal, avoiding confusion from language barriers or common names
• Adaptations

  Living things become adapted to their habitat, which may be morphological or behavioural
• Morphological adaptations

  • Fennec foxes have large ears to radiate heat, Arctic foxes have small furry ears to reduce heat loss
• Behavioural adaptations

  • Fennec fox is mostly nocturnal and burrows under sand to avoid heat
• Competition

  • Animals compete for food, territory and mates
  • Plants compete for light, water and minerals
• Interspecific competition


  Competition between different species
• Intraspecific competition


  Competition between members of the same species
• Other factors affecting population size

  • Predation
  • Pollution
  • Disease
• Biodiversity

  Measure of the variety of different species and the numbers of each in a particular area
• Importance of biodiversity


  • Provides food and potential foods
  • Provides industrial materials
  • Provides new medicines
  • Enhances human well-being
• Ways to conserve and protect biodiversity and endangered species

  • Convention on International Trade in Endangered Species
  • Sites of Special Scientific Interest
  • Captive breeding programmes
  • National parks
  • Seed/sperm banks
  • Local biodiversity action plans
• Measuring plant biodiversity using quadrats

  1. Randomly throw quadrat

  2. Count different species and number of each

  3. Take mean number of each species

  4. Multiply up to estimate whole area
• Measuring animal biodiversity using capture-recapture

  1. Carefully collect organisms

  2. Mark and return them

  3. Leave time for reintegration

  4. Recollect marked and unmarked samples

  5. Use equation to calculate estimated population size
• Biological control


  Use of one organism to control the population size of another species by eating it, often a predator controlling a pest
• Predator


  An animal that hunts and eats another for food
• Prey


  An animal that is eaten by a predator
• Pest


  An organism that eats a crop plant
• Native species

  An organism that lives in the country
• Alien species


  An organism introduced into a country in which it does not normally live
• Invasive species


  An alien organism that has had a negative effect on the native species