APES 2.1-2.3

2.1: INTRO TO BIODIVERSITY

Biodiversity is measured in 3 levels

Ecosystem diversity: the number of different habitats available in a given area

Species diversity: the number of different species in an ecosystem and the balance or evenness of the population sizes of all species in the ecosystem

  • Higher species diversity = higher ecosystem resilience

Genetic diversity: how different the genes are of individuals within a population

  • There is genetic diversity in all populations because random mutations in copying of DNA and recombination of chromosomes in sex cells of parents leads to new gene combinations and new traits in offspring

  • The more genetic diversity in a population, the better the population can respond to environmental stressor

    Bottleneck Event: an environmental disturbance that drastically reduces population size and kills organisms regardless of their genome

  • Because individuals died randomly, it does not represent the genetic diversity of the original population

    Imbreeding: Organisms mate with closely related family members

  • Leads to higher chance of offspring having harmful genetic mutations because they are getting similar genotypes from both parents

  • Smaller populations are more likely to experience imbreeding

2.2: ECOSYSTEM SERVICES

Provisioning services: Goods taken directly from ecosystems or made from natural resources

  • Disrupted by overharvesting, water pollution, clearing land for agriculture/urbanization

Regulating services: natural ecosystems regulate climate/air quality, reducing storm damage and Healthcare costs

  • Disrupted by Deforestation

Supporting services: natural ecosystems support processes we do ourselves, making them cheaper and easier

  • Disrupted by pollinator habitat loss and filling in wetlands for development

Cultural services: revenue from enjoyment activities such as hunting/fishing and profits from scientific discoveries made in ecosystems

  • Disrupted by Deforestation, pollution, and urbanization

2.3: Theory of Island Biogeography

Island Biogeography: study of ecological relationships and community structure on islands

Larger islands support more total species

Islands closer to the mainland support more species

  • Easier for colonizing organisms to get to Island from mainland

  • More colonizing organisms = more genetic diversity in new population

Adaptive radiation: single species rapidly evolving into several new species to use different resources and reduce competition