Biodiversity

• Biodiversity is the variety of living organisms and can be measured in terms of species diversity, habitat diversity, and genetic diversity
• Species richness refers to the number of species in an area, while species evenness indicates whether species have similar numbers
• Different types of sampling methods include:

  • Random: no particular system, but the aim is to be representative
  • Opportunistic: choosing encountered samples first
  • Stratified: dividing the population into smaller groups based on a characteristic, then sampling
  • Systematic: following a particular pattern
• Sampling is important because studying the whole population is impractical, so using a representative sample allows for easier investigation
• Simpson’s Index of Diversity measures the total number of organisms compared to the total number of organisms of each species, with a high index indicating several equally abundant species and a low index showing dominance of one or two species
• To assess genetic diversity, the proportion of polymorphic gene loci is calculated by dividing the number of polymorphic gene loci by the total number of loci
• Factors affecting biodiversity include population growth, deforestation for agriculture, and climate change affecting habitats
• Reasons to maintain biodiversity:

  • Ecological: protecting species and maintaining resources
  • Economic: reducing soil depletion
  • Aesthetic: protecting landscapes
• Conservation is the protection and management of species and habitats to maintain biodiversity, which can be in-situ (in an organism’s habitat) or ex-situ (outside an organism’s habitat)
• In-situ conservation examples:

  • Marine conservation zones
  • Wildlife reserves
• Ex-situ conservation examples:

  • Seed banks
  • Botanic gardens
  • Zoos
• Agreements aimed at protecting species and habitats:

  • Convention on International Trade in Endangered Species (CITES)
  • Rio Convention on Biological Diversity (CBD)
  • Countryside Stewardship Scheme (CSS)
• biotic factors: living things that can affect an organism, such as predators, parasites, pathogens
• Abiotic: non-living factors that affect an organism's environment e.g. light, temperature, soil moisture
• biotic: living features of an ecosystem that can affect the distribution and abundance of organisms e.g predictors, disease
• What is sampling?

  Selecting a group of individuals that will represent the whole target population. Allows to measure the distribution and abundance of organisms
• Quadrats:

  • used in small areas.
  • Randomly or regularly placed across habitat
  • frequency calculated
• Transects:

  • used in larger areas
  • sample taken along a line that crosses the habitat
  • can be combined with quadrats in the form of a belt transect
• Why do we conserve and preserve habitats?

  • Economic= food source, natural pest control, boosts tourism
  • social= many organisms can be used in medicine, aesthetics
  • Ethical= we have the responsibility to maintain habitats for future generations
• Sweeping nets:

  • these are large, strong nets with a very small holes
  • used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass
• pitfall traps: a type of pitfall trap that is placed in the ground and is used to catch insects and other invertebrates
• Pooters:

  • small plastic or glass containers with two tubes sticking out that are used to suck up small insects and other small invertebrates.
  • The first tube is placed over the insect and the second tube is used by the scientist to create suction
• Tullgren Funnel:

  • these are funnels with a light bulb above and a container below that are used to collect invertebrates that live in leaf litter or soil.
  • The leaf litter or soil is placed in the funnel and the light and heat forces the invertebrates to move down until they drop into the container
• Kick sampling:

  • this technique is used to invertebrates living in streams or rivers.
  • A net in placed on the stream-bed so that the water is flowing into it and the stream-bed just above the net is disturbed using their foot for a set period of time.
  • The invertebrates are carried by the stream into the net
• Factors affecting biodiversity:

  • human population growth
  • habitat destruction
  • deforestation
  • overexploitation
  • Hunting
  • agriculture
  • climate change
  • decline of the bumblebee
• Reasons for maintaining biodiversity:

  • Ecological: keystone species, a more diverse and diverse ecosystem increases their stability
  • Economic: contribute to: tourism, medicines, science and technology
  • aesthetic/ social: great joy in the beauty of nature, people spend a lot of time in the natural environment
  • Ethical: humans have a moral obligation to prevent loss of biodiversity
  • Environmental: Organisms provide essential environmental services (water cycle and absorption of CO2)
  • Agriculture: genetically diverse wild species can rescue crops from catastrophes
• Methods of maintaining biodiversity:

  • national parks: protecting endangered animal and plant species through strict regulations
  • marine parks: protecting endangered marine species through restrictions
  • zoos: captive breeding programmes for the reintroduction of animal species into the wild
  • botanic gardens: captive breeding programmes for the reintroduction of plant species into the world
  • frozen zoos: long term storage of animal genetic material at very low temperature
  • seed banks: long term storage of plant seeds in a temperature controlled environment
• Genetic diversity: The number of different alleles in a population of a species.
• the gene pool: the comprised of all the alleles of all the genes within a species
• How to assess genetic diversity:

  • the proportion of polymorphic gene loci (the number of loci that have 2 or more alleles)
  • the proportion of the population that is heterozygous
  • Allele richness (the number of different alleles that exist for specific genes)
• Calculating the proportion of polymorphic gene loci:

  • Genetic polymorphism - two or more alleles present at a single loci
  • A monomorphic locus - does not have multiple alleles
  • polymorphic locus - has multiple alleles
• polymorphic gene loci (P) equation:

  P = no. of polymorphic gene loci/ total number of loci investigated
• Limitations of polymorphic gene: Proportion of polymorphic genetic loci does not indicate allele richness
• Habitat: the natural home or environment of an animal, plant, or other organism
• niche: is the role of an organism in an ecosystem
• ecosystem: a biological community of interacting organisms and their physical environment
• In-situ conservation is the conservation of a species in its natural habitat, with the aim of preserving the species in its natural environment.
• Ex-situ conservation is when an organism is removed from its natural habitat and placed in a controlled environment