Topic 3: Biodiversity and Conservation

Subtopics

• 3.1 Biodiversity and Evolution

• 3.2 Human Impact on Biodiversity

• 3.3 Conservation and Regeneration

3.1 Biodiversity and Evolution

Guiding Questions

• How can biodiversity be explained and quantified, and why is it important?

• How does the unsustainable use of natural resources impact biodiversity?

What is Biodiversity?

• Definition: Biodiversity refers to the total diversity of living systems, which exists at different levels.

• Levels of Biodiversity:
    - Habitat Diversity: The variety of habitats in an ecosystem or biome.
    - Species Diversity: The range of different species present.
    - Genetic Diversity: The variation of genetic information within a population.

Habitat Diversity

• Description of habitats with varying ecological characteristics.
    - Example:
      - Rainforests (e.g., Reserva Nacional Huilo-Huilo)
        - High in habitat diversity due to multiple ecological niches resulting from the layering of the forest.
      - Woodland: Contains diverse habitats such as rivers, soil types, and trees, leading to high habitat diversity.
      - Deserts: Fewer habitats (e.g., sand, occasional vegetation), hence low habitat diversity.

Species Diversity

• Definition: The variety of species per unit area, encompassing both species richness and relative abundance.

• Key Concepts:
    - Species Richness: The total number of species present in a given area.
    - Species Evenness: The relative abundance of each species in a community.

• Example:
    - Community 1 may have greater evenness than Community 2, indicating higher species diversity despite the same number of species.

Species Abundance

• Definitions:
    - Species Abundance: The total number of individuals of a given species within a particular area.
    - Species Richness: The total number of different species found in an area.

• Example Calculation:
    - Community 1:
      - 17 individuals
      - 6 species
    - Includes species like tamarack ( ext{Larix laricina}), jack pine ( ext{Pinus banksiana}), and white-tailed deer ( ext{Odocoileus virginianus}).

Contribution of Species Diversity

• Benefits of higher species diversity:
    - Greater resilience to species loss as others can fill the ecological roles.
    - Increased habitat diversity through the presence of multiple species.
    - Enhanced ability of species to adapt to varying abiotic conditions.
    - Increased likelihood of survival through environmental changes.
    - Enhancement of interspecific competition, driving evolution.
    - Support of diverse predator populations and ecological niches.

Contribution of Species Abundance

• Benefits of greater species abundance:
    - Higher productivity that can support more populations.
    - Lower likelihood of extinction due to larger population sizes.
    - Enhanced support for predator populations due to larger prey bases.

Quantifying Species Diversity

• Simpson’s Reciprocal Index:
    - A numerical value utilized to measure species richness and evenness, allowing for comparison of different ecosystems over time.

• Formula Variables:
    - D = Diversity
    - N = Total number of organisms
    - n = Number of individuals of a single species

Activity: Calculating Simpson’s Index

• Scenario: Comparison of Forest A and Forest B for diversity analysis:
    - Forest A: 15 different species; 100 individuals of one species, 1 individual each of 14 others; total individuals = 114.
    - Forest B: 15 different species; 7 individuals of each of the 15 species; total individuals = 105.
    - Conclusion: Forest A exhibits low species diversity due to dominance, while Forest B shows high species diversity and more viable populations.

Genetic Diversity

• Definition: The variety of genetic information present within a population or species.
    - Involves different alleles for each gene.
    - A larger gene pool is associated with higher genetic diversity.

Advantages of High Genetic Variation

• Populations with high genetic variation can:
    - Adapt more effectively to environmental changes.
    - Evolve in response to threats, reducing extinction risk.

• Populations with low genetic variation are less likely to adapt and face extinction.

Evolution and Biodiversity

• Evolution: Defined as cumulative changes in heritable characteristics within a population over time.

• Key elements of evolution by natural selection:
    - Genetic diversity among individuals.
    - Variation within populations leads to competition.
    - Natural selection favors advantageous traits that enhance survival and reproduction.

• Continuous process occurring over billions of years, contributing to biodiversity.

Speciation and Biodiversity

• Speciation: The process through which new species arise due to evolutionary changes.
    - Takes place when a population becomes isolated and adapts to new environments, leading to reproductive isolation.

• Example: Adaptive radiation observed in the Galapagos finches, leading to diversification of species adapted to different niches.

Resilience in Ecological Systems

• Definition: Components of biodiversity contribute to the ecological resilience of systems.
    - Stable systems refer to those that can resist change, while resilient systems can recover from disturbances.

• Activity: Discuss and summarize the relationship between stable and resilient systems based on the article "Biodiversity, Stability, and Ecosystem Functioning".