Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 16 Ecosystems Section 1- What is an Ecosystem? • Ecology – study of interactions of living organisms with one another and with their physical environment. – Soil – Water – Climate – Etc. • Habitat – place where a particular population of a species lives. • Community – the many different species that live together in a habitat. • Ecosystem – consists of a community and all the physical aspects of its habitat. – Soil – Water – Weather • Abiotic Factors – non-living parts of an ecosystem. • Biotic Factors – living parts of an ecosystem Diverse Communities in Ecosystems • Biodiversity – variety of organisms, their genetic differences, and the communities and ecosystems in which they occur. Change in Ecosystems Over Time • Pioneer Species – first organisms to live in a new habitat where soil is present tend to be small, fast-growing plants. • Succession – somewhat regular progression of species replacement • Primary Succession – succession where life has never existed before • Secondary Succession – succession that occurs in areas where there has been previous growth, such as abandoned fields or forest clearings *No 2 successions are the same Section 16.2 Energy Flow in Ecosystems Movement of Energy Through Ecosystems • All activities that organisms perform in ecosystems require energy • The flow of energy in an ecosystem determines what kind and how many organisms an ecosystem can support. Primary Energy Source • Most life on earth depends on photosynthetic organisms • Primary Productivity – Rate at which organic material is produced by photosynthetic organisms in an ecosystem • Producers – Organisms that first capture energy • Plants, bacteria, and algae • Consumers – Organisms that consume plants or other organisms to obtain energy Trophic Levels • Used to study how energy moves through an ecosystem. • Trophic Level – Graphic organizer based on the organisms source of energy – p. 345 – fig. 6 Trophic Levels • First Level – This level is occupied by producers – Get their energy from the sun • Food Chain – The path of energy through the trophic levels of an ecosystem • p. 346 – fig. 7 Trophic Levels • Second Level – Primary consumers – Organisms that are able to digest cellulose • Herbivores – Animals that eat plants or other primary producers Trophic Levels • Third Level – Secondary consumers • Carnivores – Animals that eat other animals • Omnivores – Eat plants and animals • Detritivores – Obtain energy from organic wastes and dead organisms – Decomposers Trophic Level • Food Web – Develops from organisms feeding at several different trophic levels Loss of Energy in a Food Chain • When organisms obtain energy they are never able to obtain 100% of the resource’s supply. Energy Transfer • Large amount of energy lost as heat as various organisms capture/obtain energy. • Plants capture about 1% of the sun’s energy. • Herbivores obtain about 10% of plant’s energy. • Carnivores obtain about 10% of herbivores energy. The Pyramid of Energy • Used to illustrate the flow of energy in an ecosystem • Energy Pyramid – Diagram in which each trophic level is represented by a block with the lowest trophic level on the bottom. Limitations of Trophic Levels • Not much available energy as levels increase – Usually only 3 trophic levels • Limited by the amount of available resources • Ability of digestive system • Size of organism • Biomass – Dry weight of tissue and other organic matter found in an ecosystem – Decreases with each trophic level • Think of the animals and other organisms in our area. • Construct a food chain of at least 10 animals and plants that you can find in our area. Food Web • Use the same organisms you chose for your food chain to create a food web. Section 3 Cycling of Materials in Ecosystems Biogeochemical Cycles • Materials are constantly cycling through our ecosystems – Energy – Water – Carbon – Phosphorus – Nitrogen • Biogeochemical Cycle – Pathway of substances that enter living organisms, stay for a period of time within the organism, then return to the nonliving environment and starts over. The Water Cycle • Has the largest impact on the organisms of an ecosystem. • Ground Water – Water that is retained beneath the surface of the earth – Nonliving part of environment • Transpiration – Water that evaporates from the leaves of plants – Living part of the environment The Water Cycle • Condensation • Precipitation • Evaporation/Transpiration