A4.2 Conservation of diversity

• Biodiversity


  The variety of life in all its forms, levels and combinations
• Types of biodiversity


  • Ecosystem diversity
  • Species diversity
  • Genetic diversity
• Ecosystem diversity


  Diversity of species living in communities- due to the variation in environments across the planet
• Species diversity


  Variety in the number of species of living organism
• Genetic diversity


  Variety in the gene pool of each species, including variation within and between populations
• There are uncertainties involved in estimating the number of prokaryotes, making a reliable estimate almost impossible
• There have been 5 major mass extinction events in geological history, with the most recent being 66 million years ago that wiped out the dinosaurs
• Biodiversity is likely higher than in the past


  There has been sustained growth, speciation, and evolution since the last mass extinction event
• Fossil evidence would support the idea that biodiversity is higher than in the past
• Humans may be causing a sixth mass extinction event through their impacts on species and ecosystems
• Anthropogenic impacts causing species extinction

  • Hunting and overexploitation
  • Urbanisation
  • Deforestation and clearance of land for agriculture
  • Pollution
  • Spread of pests, diseases and invasive alien species
• Human population growth is the principal cause of the current biodiversity crisis
• Strategies for conservation of biodiversity

  • In-situ conservation
  • Ex-situ Conservation
  • Management of nature reserves
  • Rewilding
  • Reclamation of degraded ecosystems
  • Zoos
  • Botanic Gardens
  • Seed/tissue banks for storage of germ plasm
• The EDGE of Existence Programme highlights and protects some of the most unique species on the planet, which are on the verge of extinction
• Factors involved in prioritising which species to allocate resources to for conservation include evolutionary distinctness and global endangerment
• Biodiversity


  All the variety in life
• Levels of biodiversity


  • Ecosystem diversity
  • Species diversity
  • Genetic diversity
• Estimating the number of species on Earth is very difficult
• Current estimate is between 2 and 10 million species
• Counting current species is difficult, counting extinct species is even harder
• There have been cycles of increasing biodiversity followed by mass extinctions throughout Earth's history
• The current increase in biodiversity is likely to end in a mass extinction
• Anthropogenic


  Caused by humans
• The current mass extinction is anthropogenic in cause, unlike previous mass extinctions
• Causes of the current biodiversity crisis include overharvesting, habitat loss, invasive species, pollution, and climate change
• Ecosystem


  The biotic (living) and abiotic (non-living) factors in a given area
• Ecosystem loss is a major problem driven by human activities like dams, mining, and land exploitation
• The current biodiversity crisis is unprecedented in scope compared to past mass extinctions
• Simpson's diversity index


  A measure of biodiversity that considers both species richness and evenness
• Calculating Simpson's diversity index

  1. Total number of organisms * (total number - 1)

  2. Divide by sum of (number of each species * (number - 1))
• A higher Simpson's diversity index indicates higher biodiversity
• The root causes of the current biodiversity crisis are related to human overpopulation and increased scale of human activities
• Conservation strategies


  • In-situ (conservation in natural environment)
  • Ex-situ (conservation outside natural environment)
• In-situ conservation


  Protecting natural environments and allowing natural processes to continue
• Ex-situ conservation


  Removing organisms from natural environment and conserving them in captivity
• With massive biodiversity loss, conservation efforts must focus on evolutionarily distinct and globally endangered (EDGE) species