Introduction to Ecology

Introduction to Ecology

• Ecology is the scientific study of interactions between organisms and their environments
• Abiotic factors are physical aspects of the environment (e.g., sunlight, temperature, water)
• Biotic factors are other organisms (e.g., plants, animals, bacteria)

Levels of Ecological Organization

• Organism: a single individual
• Population: a group of individuals of the same species in the same area
• Community: all the populations of different species in a given area
• Ecosystem: all the living organisms (biotic) and nonliving components (abiotic) in a particular area

Factors Influencing Climate

• Solar radiation: uneven heating of the Earth's surface drives atmospheric circulation
• Atmospheric circulation: global patterns of air movement impact moisture and temperature distribution
• Ocean currents: influence regional temperatures and climates
• Regional geography: mountains, valleys, and coastlines affect local climates
• Seasonal variation: changes in temperature and precipitation throughout the year determine species presence

Rain Shadow

• A dry region on the leeward side of a mountain range
• Warm, moist air rises on the windward side, cools, and releases precipitation
• As air descends on the leeward side, it warms and dries

Biomes

• Large-scale ecosystems categorized by dominant vegetation type
• Each biome has a characteristic climate, defining factors that determine species distribution
• Descriptions of each biome include temperature, precipitation, fire, and typical plant and animal species

Aquatic Ecosystems

• Photic zone: upper layer of water that receives enough sunlight for photosynthesis
• Freshwater ecosystems: lakes, ponds, streams, rivers
  • Depth and area determine communities
• Marine ecosystems: oceans, estuaries, coral reefs, kelp forests, rocky intertidal, pelagic zone, and benthic zone
  • Categorized by location relative to shorelines and ocean bottom

Human Impacts on Biomes

• Humans affect biome distribution through population size, land development, and resource use
• Deforestation: logging removes trees for wood and conversion of land to agriculture
• Desertification: conversion of grasslands to desert due to unsustainable grazing practices

Additional Information

• The biosphere is the zone of life on Earth.
• Terrestrial biomes include various ecosystems (e.g., deserts, grasslands, forests)
• Freshwater ecosystems include lakes and ponds
• Marine ecosystems include oceans, estuaries