Introduction to Ecology

• Course: Bio 94 – Lesson 18

• Focus: Figures 49.1, 49.2, 49.5, 49.6, 49.7, 49.8, 49.13 and Tables 49.1, 49.4

Learning Outcomes

• 18.1 Recognize different levels of ecological study

• 18.2 Describe how abiotic and biotic forces affect an organism’s niche

• 18.3 Analyze factors influencing global climate patterns

• 18.4 Identify main factors determining distribution and characteristics of terrestrial and aquatic biomes

Levels of Biological Organization

• Levels of ecological study:

  • Organism

  • Population

  • Community

  • Ecosystem

  • Globe

• Conservation biology: Field that aims to preserve and restore biodiversity and ecosystem functioning

• Study components include: Morphology, physiology, and behavior of individuals; populations of the same/different species; all biotic and abiotic components; and all ecosystems within the biosphere.

Factors Affecting Organism Abundance and Distribution

• Niche: Range of conditions and resources a species can tolerate and use

  • Influenced by factors:

    • Temperature

    • Sunlight

    • pH

    • Nutrients (N, P, K)

    • Moisture

    • Salinity

    • Soil texture

    • Wind

• No superorganisms due to fitness trade-offs

• Two-factor niche model involving abiotic factors (e.g., moisture, temperature)

Biotic Factors

• Biotic factors: Living components of the environment

  • Resources, Disease, Predators, Herbivores, Symbionts, Dispersers, Competitors, Consumers

Historical Biotic and Abiotic Factors

• Pangaea: Continental drift affects biogeography and species distribution

• Human legacies influencing past and current species

Climate vs Weather

• Climate: Long-term atmospheric conditions; predictable

  • Influenced by:

    • Latitudinal gradients

    • Seasonality

    • Ocean currents

    • Rain shadows

• Weather: Short-term conditions (temperature, precipitation, sunlight, wind)

Latitudinal Gradients in Temperature

• Temperature distribution:

  • North pole: Low sunlight per unit area

  • Equator: High sunlight directly overhead

Global Air Circulation

• Warm air rises, cools, and drops rain; affects rainfall and climate patterns

• Hadley Cells: Major circulation cells affecting tropical and desert regions

• Coriolis effect: Clockwise rotation in the Northern Hemisphere and counterclockwise in the Southern Hemisphere

Seasonality and Mountains

• Seasonality: Little variation at equator, more pronounced towards poles

• Mountains: Affect temperature and rainfall through elevation and rain shadows

Biomes

• Biomes: Defined by distinct abiotic characteristics and dominant vegetation types

• Net primary productivity (NPP): Total biomass generated minus carbon released during respiration

  • Varies by biome (e.g., tropical wet forest vs desert)

Aquatic Biomes

• Cover approximately 70% of Earth's surface

• Defined by abiotic characteristics: salinity, depth, water flow, nutrients

• Major types include: Lakes, ponds, freshwater wetlands, streams, estuaries, oceans

Human Land Use and Impacts

• Human impacts: Habitat conversion, fishing, invasive species, pollution leading to dead zones

• Increased nutrients can lead to algal blooms and decreased oxygen levels

Studying Climate Change Impacts

• Approaches include simulation studies, observational studies, historical studies, experiments

• Focus on terrestrial and aquatic impacts, future phytoplankton predictions.