Introduction to Ecology

Introduction to Ecology

  • Introduction to Chapter 49 (section 49.5) and Chapter 51 (51.1).

  • Objectives of discussion: Understanding ecology and its significance; bring a calculator for upcoming population ecology activity.

Ecology and Its Importance

  1. Definition of Ecology

    • Study of interactions between organisms and their environment (living and non-living components).

  2. Importance of Ecology

    • Understanding geographic distribution, abundance, and diversity of organisms.

    • Applications:

      • Preserve and restore ecosystems (e.g., sustainable fisheries).

      • Protect human health through disease ecology insights.

      • Evaluate human impacts on the biosphere and propose corrective actions.

Geographic Distribution of Species

  • Discussion on geographic distribution factors using the deer mouse presence at ISU campus as an example.

  1. Factors Influencing Species Distribution:

    • Geographic origins (regional species pool).

    • Dispersal capacity

    • Abiotic (non-living) factors

    • Biotic (living) factors

Historical Context of Species Distribution

  1. Geographic Origins and Dispersal Capacity

    • Historical changes (e.g., land bridges and continental shifts) influenced species distribution.

  2. Stages of Geographic Distribution:

    • Pacific Ocean's separation of regions; the influence of Pangaea on species origins and climates.

Abiotic Factors Influencing Distribution

  • Abiotic factors affecting distribution include:

    • Sunlight: Essential for photosynthesis.

    • Temperature: Influences enzyme function and metabolic rates.

    • Water: Essential for nutrient transport and physiological functions.

    • Nutrients: Needed for biosynthesis (e.g., nitrogen and phosphorus).

    • Habitat: Non-living forms provide essential features for shelter and reproduction.

  • Abiotic factors can be either resources (positive) or stressors (negative).

Survival Limits of Species

  • Each species can survive only in a limited range of abiotic conditions; these limitations shape distribution (e.g., temperature constraints on enzyme function).

Biotic Factors Influencing Distribution

  • Biotic factors affecting species abundance include:

    • Prey/Host Availability: Essential for feeding and reproduction.

    • Negative Interactions: Competition, predation, and other adverse relationships.

    • Positive Interactions: Beneficial relationships such as commensalisms and mutualisms.

Summary of Distribution Factors

  • A species’ occurrence at a location depends on:

    • Geographic origins

    • Dispersal capacity

    • Available abiotic and biotic factors

Species Diversity and Abundance Across Biomes

  1. Terrestrial Biomes Overview

    • Ecosystem types characterized by dominant plant growth forms, influenced by climate.

    • Greater plant diversity correlates with high temperatures and abundant water.

    • Animal diversity aligns with plant diversity patterns.

Tropical Wet Forests

  • Characterized by high species diversity and abundance:

    • Factors contributing:

      • Ample sunlight.

      • Warm temperatures.

      • High water availability (considerable precipitation).

Arctic Tundra

  • Low species diversity and abundance are influenced by:

    • Limited sunlight.

    • Cold temperatures.

    • Low water and nutrient availability (permafrost and low precipitation).

Human Impact on Species Diversity

  1. Anthropogenic Biomes

    • Replacement of natural biomes leads to reduced species diversity and biological productivity.

  2. Effects of Urban and Agricultural Ecosystems

    • Unfavorable abiotic conditions lead to:

      • Habitat fragmentation.

      • Distanced and reduced dispersal capabilities.

      • Resulting in extinction events and diminishing regional species pools.

Aquatic Biomes and Species Diversity

  1. Conditions for High Diversity in Aquatic Biomes

    • Highest diversity and abundance in shallow waters (littoral zones) where light penetrates and nutrients are available.

Human Activities Impacting Aquatic Diversity

  1. Degradation of Aquatic Biomes

    • Pollution, habitat degradation (e.g., wetlands), and excessive nutrient input (nitrogen and phosphorus) lead to:

      • Algal blooms, reduced diversity, and altered habitat conditions.