Introduction to Ecology Table of Contents Identify a key theme in ecology. Describean example showing the effects of interdependence upon organisms in their environment. Identify the importance of models to ecology. Statethe five different levels of organization at which ecology can be studied. Interdependence: A Key Theme in Ecology Organisms and Their Environments Species interact with both other species and their nonliving environment. Ecological Models Ecological models help to explain the environment. Making an Ecosystem Model Levels of Organization Ecologists recognize a hierarchy of organization in the environment: biosphere, ecosystem, community, population, and organism.
Levels of Organization Levels of Organization, continued The Biosphere The broadest, most inclusive level of organization is thebiosphere,the volume of Earth and its atmosphere that supports life. Levels of Organization, continued Ecosystem Ecosystems The biosphere is composed of smaller units called ecosystems. An ecosystemincludes all of the organisms and the nonliving environment found in a particular place. Levels of Organization, continued Community Communities, Populations, and Organisms Acommunityis all the interacting organisms living in an area. Below the community level of organization is the populationlevel,where the focus is on the individual organisms of a single species.
Compareabiotic factors with biotic factors, and list two examples of each. Describetwo mechanisms that allow organisms to survive in a changing environment. Ecosystem Components Biotic and Abiotic Factors Bothbiotic, or living, factors andabiotic, or nonliving, factors influence organisms. Examples of abiotic factors are climate, sunlight, and ph. Explain the concept of the niche. Organisms in a Changing Environment Acclimation Some organisms can adjust their tolerance to abiotic factors through the process of acclimation. Organisms in a Changing Environment, continued Escape from Unsuitable Conditions Some species survive unfavorable environmental conditions by becoming dormant or by migrating. Section 2 Ecology Of Organisms The Niche Earthworm Niche A nicheis a way of life, or a role in an ecosystem.
Producers Summarize the role of producers in an ecosystem. Identify several kinds of consumers in an ecosystem. Most producersare photosynthetic and make carbohydrates by using energy from the sun. Explain the important role of decomposers in an ecosystem. Comparethe concept of a food chain with that of a food web. Explainwhy ecosystems usually contain only a few trophic levels. Consumers Energy Flow Consumersobtain energy by eating other organisms and include herbivores, omnivores, carnivores, detritivores, and decomposers. Food Chains and Food Webs A single pathway of energy transfer is afood chain. A network showing all paths of energy transfer is a food web. Food Chains and Food Webs Food Chain in an Antarctic Ecosystem
Food Web in an Antarctic Ecosystem Energy Flow, continued Energy Transfer Ecosystems contain only a fewtrophic levels because there is a low rate of energy transfer between each level. Energy Transfer Through Trophic Levels Energy Pyramid The Water Cycle List four major biogeochemical cycles. Summarize three important processes in the water cycle. Key processes in thewatercycleare evaporation, transpiration, and precipitation. Outlinethe major steps in the carbon cycle. Describe the role of decomposers in the nitrogen cycle. Summarize the major steps of the phosphorus cycle.
Water Cycle The Carbon Cycle Photosynthesis and cellular respiration are the two main steps in the carbon cycle. Carbon Cycle Nitrogen Cycle Nitrogen-fixing bacteria are important in the nitrogen cyclebecause they change nitrogen gas into a usable form of nitrogen for plants. Nitrogen Cycle