Biodiversity and Classification

• Groups organisms can be broadly classified into

  • Plants (flowering and non-flowering)
  • Animals (vertebrate and invertebrate)
  • Fungi
  • Protoctists (single celled organisms)
  • Bacteria
• Classification


  The organisation of organisms into groups
• Importance of classification


  • Makes it easier to identify organisms
  • Aids communication between scientists
• Scientific name


  • Given in two words
  • First name (genus) begins with a capital letter
  • Second name (species) begins with a lowercase letter
  • Words written in italics, or if handwritten underlined
• Types of adaptation


  • Morphological (structural)
  • Behavioural
• Adaptation


  Characteristics of an organism that increase its chance of survival, maintained by natural selection
• Resources organisms require from the environment

  • Light
  • Food
  • Oxygen
  • Carbon dioxide
  • Water
  • Minerals
• Resources are limited, creating competition between organisms
• Competition, as well as predation, disease and pollution, limits population sizes within a community
• Competition is the driving force of evolution by natural selection
• Ways to maintain biodiversity

  • Protection of endangered species
  • Conservation schemes to protect ecosystems
  • Reforestation
  • Sustainable farming
  • Minimising global greenhouse gas production
  • Legislation to protect habitats
  • Seed banks
• Passing legislation to protect habitats can be difficult because the needs of the human population sometimes conflict with the conservation of the environment
• It is important to balance the need for resources with the need to preserve the biodiversity of ecosystems
• Quadrats


  • Square frame divided into smaller square sections
  • Used to count members of each species present or estimate % coverage
• Capture-recapture technique


  • Used to sample animal populations
  • Capture and mark individuals, then recapture and count marked individuals to estimate total population
• Biological control


  Introduction of a new organism into an ecosystem to control a pest or pathogen
• Alien species introduced for biological control may grow out of control, outcompete or prey on existing species, or carry new diseases
• Detailed research and trials must be carried out before introducing alien species
• Using quadrats to study plant cover

  1. Count the number of each species of plant inside it

  2. Calculate the percentage cover of a plant
• How to find out how many organisms there are in an area

  1. Select a random sampling method

  2. Place a 1m2 quadrat randomly and count the number of living organisms (or percentage cover)

  3. Repeat at least twice or until the numbers are consistent

  4. Calculate the average

  5. Multiply the average to calculate the total number in the whole area
• How to see if the numbers of organisms have changed

  1. Use the quadrat method to calculate the number of organisms in an area at the start of the study

  2. Use the quadrat method to study the same area after a set period of time

  3. Note the change to identify a pattern
• Transect


  A series of quadrat samples taken in a line
• Transects can show


  • Frequency of a species in a habitat
  • Distribution of species in a habitat
• Capture-recapture technique


  Capturing a number of individuals from a species, marking them, releasing them back into the wild, then capturing another sample and using a mathematical equation to estimate the population
• Living organisms


  • Plants
  • Animals
  • Microorganisms (microbes)
• Plants


  • Flowering plants
  • Non-flowering plants
  • Algae
  • Fungi
  • Bacteria
• Animals


  • Vertebrates
  • Invertebrates
• Common names


  The names we use everyday for animals and plants, which are usually based on appearances
• Classification


  Putting things into groups
• Classification methods


  • Morphological features (5 kingdoms)
  • DNA analysis (3 domains)
• Binomial system


  Organisms are given two names - the first refers to the genus, the second refers to the species
• The advantage of using the scientific/Latin name is that it is always the same all over the world and in all languages
• Adaptations


  • Morphological (shape) and behavioural adaptations that enable organisms to survive in their environment
• Population size


  How many of one type of plant or animal (species) there is in a given ecosystem
• Factors affecting animal population size

  • Competition for food and water
  • Number of predators
  • Disease
  • Pollution
• Factors affecting plant population size

  • Competition for light, water or minerals
  • Number of herbivores
  • Disease
  • Pollution
• Organisms that are better adapted to the environment are more successful and usually reproduce more and have more offspring
• Predator


  Animals that kill and eat other animals
• Prey


  Animals that are killed and eaten by predators
• Within a natural environment there is a delicate balance between the population of the predator and prey


  As the prey population increases, the predator population increases, then the prey population decreases, and the cycle repeats