Introduction to Biodiversity Flashcards

Introduction to Biodiversity

  • Objective: Understand levels of biodiversity and their importance to ecosystems.

Levels of Biodiversity

  • Genetic Diversity (ERT-2.A.1): Variability in genes among individuals of a population. Key for adapting to environmental stressors.
  • Species Diversity: Number of different species in an ecosystem and their abundance.
  • Ecosystem Diversity: Variety of habitats in a given area.
  • Importance: High biodiversity enhances ecosystem resilience and recovery from disturbances.

Species Richness and Evenness

  • Species Richness (S): Total number of different species in an ecosystem.
  • Evenness: Distribution of individuals across species.
    • High evenness implies a balanced ecosystem rather than dominance of any one species.
  • Indicators of Health: High richness and evenness are signs of ecological health, indicating available resources (e.g., water, soil).

Shannon Wiener Diversity Index

  • Measures community biodiversity by considering both species richness and evenness.
  • Example:
    • Community 1:
    • Proportions are equal (25% of 4 species).
    • Resulting Index (H) = 1.39
    • Community 2:
    • Unequal proportions (70% of 1 species, 6%, and 12% of others).
    • Resulting Index (H) = 1.06.

Genetic Diversity Significance

  • Genetic Diversity Benefits (ERT-2.A.2): More variation enables populations to better withstand drought, disease, etc.
  • Bottleneck Effect: Significant population reduction leads to decreased genetic diversity and increased vulnerability.

Inbreeding Depression

  • Occurs when closely related individuals reproduce leading to genetic diseases in offspring.
  • Example: Florida panthers' population suffered from inbreeding leading to health issues such as kinked tails and heart defects.

Ecosystem Resilience (ERT-2.A.3)

  • Definition: Ability to return to original state post-disturbance.
  • Higher species diversity increases resilience, enabling ecosystems to better adapt and stabilize after events like storms or fires.

Ecosystem Services (ERT-2.B)

  • Four types:
    1. Provisioning: Goods from ecosystems (food, timber).
    2. Regulating: Ecosystem processes stabilizing conditions (climate regulation).
    3. Cultural: Recreational and aesthetic benefits (tourism).
    4. Supporting: Processes sustaining ecosystems (nutrient cycling).

Human Disruption Effects (ERT-2.C)

  • Human activities can adversely affect ecosystem services, leading to ecological and economic impacts.
  • Examples: Deforestation, overfishing, pollution disrupt the balance of ecosystems.

Island Biogeography (ERT-2.D)

  • Examines species distribution on islands, which can vary significantly based on size and distance to the mainland.
  • Larger and closer islands tend to support greater biodiversity due to easier colonization.

Ecological Tolerance (ERT-2.F)

  • Refers to the ability of organisms to withstand varying abiotic factors (temperature, pH).
  • Example: Salmon have specific temperature tolerances influenced by genetic diversity.

Natural Disruptions to Ecosystems (ERT-2.H)

  • Natural events (hurricanes, wildfires) can drastically alter ecosystems, sometimes more so than human-induced changes.
  • These disturbances can follow patterns (periodic, episodic, random) and lead to significant shifts in community dynamics.

Ecological Succession (ERT-2.1)

  • Types:
    • Primary Succession: Occurs in lifeless areas (starting from bare rock).
    • Secondary Succession: Occurs where a disturbance has cleared existing vegetation but soil remains.
  • Pioneer Species: Initial species to colonize an area, aid in soil formation.
  • Progression to Climax Community: Over time, ecosystems mature and stabilize.