Biodiversity and Ecosystems Unit 2

Unit 2: Biodiversity and Ecosystems

• The Basics: Understanding ecosystems involves understanding species interactions, primarily competition for limited resources. Competition drives an "arms race" in the natural world.
• Biodiversity: The variety of life on Earth, measured in several ways. Biodiversity is crucial for ecosystem stability.
  • Habitat diversity refers to the variety of biological communities (lakes, rivers, grasslands, deserts)
  • Species diversity is the different species in an ecosystem.
  • Genetic diversity is the variety of genes within a species. More diverse populations are better able to adapt to environmental changes.
• Ecological Niche: The total way of life of a species in an ecosystem, including all the physical, chemical, and biological conditions it needs to survive and reproduce.
  • Resource Partitioning: Species share resources to avoid competition.
  • Habitat Loss: The biggest threat to biodiversity. Not all species are impacted equally or at the same rate.
  • Generalists vs Specialists:
    • Generalists live in diverse conditions and are more adaptable.
    • Specialists live in narrow conditions and have very specific requirements.
• Genetic Diversity: The variety of genes within a species. More diverse populations are better equipped to withstand changes in the environment.
  • Mutations: Accidental changes in DNA. Non-lethal mutations provide the genetic variation for natural selection to act upon.
  • Fitness: The ability to reproduce successfully, a trait passed on to offspring.
• Natural Selection: The process by which traits that enhance survival and reproduction are passed on more frequently to future generations.
• Ecological Succession: The process of ecosystem recovery from disturbance.
  • Primary succession: Begins on bare rock (e.g., lava fields). Pioneer species (e.g., lichens) break down rock to form soil, allowing other species to grow.
  • Secondary succession: Starts on soil that already exists (e.g., after a forest fire).
• Natural Disturbances: Events like fires, floods, and storms can shape ecosystems. Some natural disturbances can benefit biodiversity in the long term.
• Climate Change: Earth's climate is not fixed; significant changes in the biosphere have occurred.
  • Adaptation: Species adapt to environmental changes through biological and behavioral modifications, but this process takes time.
  • Migration: Movement of species between locations.
  • Extinction: A natural process. Extinction rates can increase due to human activity, exceeding the natural background rate. Mass extinction events have also occurred in Earth's history, often due to climate changes.
• Species Diversity: Reflects not only the number but also the relative abundance of species in an ecosystem. Low species evenness indicates a few dominant species.
• Island Biogeography: The biodiversity on islands is influenced by their size and distance from the mainland. Bigger and closer islands tend to have more species diversity.
• Ecological Services: Benefits that ecosystems provide to humans, including food, regulation of climate, and provision of recreation.

Dive into Unit 2 of Biodiversity and Ecosystems, where we explore the fundamentals of ecosystems and the importance of biodiversity. Learn about species interactions, ecological niches, and the significance of habitat and genetic diversity in maintaining ecosystem stability. Understand how competition and resource partitioning shape the natural world.