Transcript Document
Food Relationships Food web • describes the eating relationships between species within an ecosystem or a particular living place. • Many types of food chains or webs are applicable depending on habitat or environmental factors. Food web Trophic Levels • describes the position that an organism occupies in a food chain • what an organism eats, and what eats the organism. Producers • An autotroph is an organism that produces complex organic compounds from simple inorganic molecules • using energy from light (by photosynthesis) • plants & algae • or inorganic chemical reactions (by chemosynthesis) • Bacteria in hydrothermal vents Consumer • A Heterotroph is an organism that uses organic substrates to get its chemical energy for its life cycle. • This contrasts with autotrophs such as plants which are able to directly use sources of energy such as light to produce organic substrates from inorganic carbon dioxide. • Animals, Fungus eat other things Consumers Herbivores • Herbivory is a form of predation in which an organism, known as a herbivore, consumes principally autotrophs • such as plants, algae and photosynthesizing bacteria. • Herbivory is generally restricted to animals eating plants. • Organisms that feed on autotrophs are known as primary consumers. Herbivore Carnivore • A carnivore means meat eater • An animal that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of vertebrate and/or invertebrate animal tissue, whether through predation or scavenging • A carnivore that sits at the top of the foodchain is an apex predator. Carnivores omnivore • Omnivores are species that eat both plants and animals as their primary food source. • They are opportunistic, general feeders not specifically adapted to eat and digest either meat or plant material exclusively • Crows are another example of an omnivore that many people see every day • There are reported cases of herbivores eating meat matter as well as examples of carnivores eating plants, the classification refers to the adaptations and main food source of the species in general so these exceptions do not make either individual animals nor the species as a whole omnivores. detritivore detrivore • Detritivores are heterotrophs that obtain nutrients by consuming detritus • decomposing organic matter) • They contribute to decomposition and the nutrient cycles. • Detritivores are an important aspect of many ecosystems. • They can live on any soil with an organic component, and even live in marine ecosystems where they are termed interchangeably with bottom feeders. • Typical detritivorous animals include millipedes, woodlice, dung flies, many terrestrial worms, burying beetles, some sedentary polychaetes such as amphitrite, terebellids and fiddler crabs. primary vs secondary vs tertiary • Primary Consumer - organism which gets its food from plants (rabbit, squirrel, deer, mouse, honey bee, aphid, grasshopper, tadpole, duck, black bear, mosquito, humpback whale, other animals at times). Secondary Consumer - organism which gets its food mainly by eating primary consumers, but can also be prey itself. (weasel, shrew, mole, merganser, snake, spider, frog, most fish, other animals at times). • Tertiary Consumer - organism which gets its food mainly by eating other consumers, but rarely becomes prey itself. (hawk, wolf, shark, fox, dragonfly, orca, human). APEX PREDATOR Decomposer • Decomposers and scavengers break down dead plants and animals. • They also break down the waste (poop) of other organisms. • Decomposers are very important for any ecosystem. • If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up. • There are two kinds of decomposers, scavengers and decomposers. decomposers biomass pyramid • pyramid of biomass is a diagram of different trophic levels in an ecosystem • usually plotted as dry matter per unit area or volume. • Typically this gives a gradually sloping pyramid, except where the sizes of organisms vary dramatically from one trophic level to another. Biomass pyramid Energy and Nutrients • pyramid of energy is a diagram of the rates of flow of energy through the different trophic levels of an ecosystem. • Each bar of the pyramid represents the amount of energy per unit area or volume which flows through that trophic level in a given time period. • The pyramid reflects the rates of photosynthesis, respiration, etc. • pyramid of numbers is a diagram of the numbers of individual organisms present at each trophic level of an ecosystem. Energy Pyramid Energy Flow • Energy flows in a one way direction • At each level of the food chain, about 90% of the energy is lost in the form of heat. • The total energy passed from one level to the next is only about one-tenth of the energy received from the previous organism. • Therefore, as you move up the food chain, there is less energy available. • Animals located at the top of the food chain need a lot more food to meet their energy needs. • NOTE!! Each organism in the food chain is only transfering onetenth of its energy to the next organism. Nutrient Cycling • • • • • • Energy does NOT cycle through an ecosystem, chemicals (Nutrients) do. Nutrients cycle through the organisms, the atmosphere, the oceans, and rocks. Since these chemicals cycle through both the biological and the geological world, we call the cycles biogeochemical cycles. Each chemical has its own unique cycle, but all of the cycles do have some things in common. Reservoirs are those parts of the cycle where the chemical is held in large quantities for long periods of time. The energy for transportation of chemicals is provided either by the sun or by the heat released from the mantle and core of the Earth. Sand County Almanac/Aldo Leopold • Aldo Leopold died in 1948 without seeing his book in print, but when A Sand County Almanac was published in 1949 it spoke his voice clearly and plainly, and has had a profound effect on its readers ever since • A Sand County Almanac is built around three main ideas: • Land is a community of living things. This idea argues for the study of ecology. • Land is to be loved and respected. This idea argues for conservation ethics. • Land yields a harvest of culture. Leopold calls this "a fact long known, but forgotten recently."