Unit 2; Continuity of Life; Biodiversity

  • Created by: LibPinch
  • Created on: 18-11-16 13:38
View mindmap
  • Biodiversity
    • Refers to:
      • species richness: number of species
      • number of organisms in a species
    • Varies spatially due to:
      • light intensity; high = more plants = more herbivores = more carnivores
      • amount of energy in region; equatorial regions have more energy to support life
      • environmental changes
    • Variance Over Time
      • Succession
        • change in composition of community over time
        • makes more suitable for particular species
        • increases animal biodiversity but decreases that of plants
      • natural selection
      • Human Influences
        • farming
        • over-fishing
        • eutrophication
        • deforestation
        • urbanisation
        • conservation benefits
    • needed for food, raw materials & medicines
    • Assessing Biodiversity
      • Simpson's Index
        • describes bio-d of motile organisms
        • numerical value, higher=better
      • Number of Alleles
        • locus is genes position on chromosome
        • polymorphism if 2+ alleles at frequencies greater than mutation alone
        • > alleles = > biodiverse
      • Proportion of Alleles
        • if 98% have recessive allele then low bio-d
        • if 50% have recessive allele then high bio-d
      • Molecular Assessment
        • mutations change base sequence, sometimes only 1 base
        • regions of DNA that often repeat many times are hyper variable regions or short tandem repeats
        • more mutations = different DNA fingerprint
          • many varying fingerprints in biodiverse population
    • Natural Selection
      • 1. mutation occurs causing difference in DNA
      • 2. there's variation in the population due to different characteristics
      • 3. individuals with specific characteristics have competitive advantage & out-compete for resources
      • 4. Survival of the fittest means individuals most suited to habitat survive
      • 5. the survivors can reproduce
      • 6. advantageous alleles passed to offspring so they can also out-compete
      • habitats continually change so biodiversity occurs
    • Adaptations
      • change in a species as a useful characteristic becomes common
      • Anatomical Traits
        • different body structures can make organism more adept e.g. stream-lined dolphin
      • Physiological Traits
        • different characteristics are better e.g. polar bears are endothermic so save energy in cold
      • Behavioural Traits
        • different behaviours cause better suitability e.g. mating rituals

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Ecology and biodiversity resources »