Refer to Chapter 37
Biology: The Study of Life. 5th ed. Schraer and Stoltze © 1993
Define producer, autotroph, consumer, heterotroph, and decomposer.
Producers are organisms, like green plants, that produce organic compounds from inorganic compounds. These are also a type of autotroph. THen green plants, for example, are are eaten by consumers in this case, grazing animals like the zebra.
An autotroph is an organism that makes its own food from inorganic substances. It is then eaten by a consumer if it is a plant for example.
A consumer is the organisms that obtain nutrients from other organisms. This is also a heterotroph.
A heterotroph is an organism that cannot synthesize their own food and must obtian it ready made.
A decomposer is an organism of decay. These are also called saprobes. They break down the remaines of dead animals and plants, releasing the substances that can be used by other members of the ecosystem.
Define and give examples of each of these heterotrophic types: herbivores, carnivores, omnivores, and saprobes.
There are several groups of heterotrophs. Heterotrophs are all organisms that obtain their food from the environment. All animals and certain types of micro-organisms are heterotrophs. These organisms must take in, or ingest, food containing already made organic nutrients from other plants or animals. It all depends on what they eat and how they obtain it. Heterotrophs include herbivores, carnivores, omnivores and saprobes.
Herbivores are animals that feed only on plants. Rabbits, cattle, horses, sheep and deer are all herbivores.
Carnivores are animals that feed on other animals. Some carnivores may be predators (such as lions, hawks, and wolves who attack and kill their prey and feed on their bodies) and some may be scavengers (they feed on dead animals that they find).
Omnivores are animals that feed on both plants and animals. Examples of omnivores are humans and bears.
Saprobes are organisms that get nutrients by breaking down the remains of dead plants and animals. Examples of saprobes are bacteria and fungi.
Explain the role played by decomposers in an ecosystem.
Decomposers are an essential component of any ecosystem. Their main role is to recycle nutrients in dead organisms and their wastes. Most decomposers are bacteria and fungi. Without the decomposers, there could be no life since plants would run out of nutrients.
Differentiate between scavengers and predators as two types of carnivores.
A carnivor is a type of heterotroph that feeds only on other animals. There are two different ways to classify carnivors. The first group are known as predators. Predators hunt and kill other animals for food. Animals like lions, wolves, snakes, and sharks are all classified as predators. Another group of animals that are considered carnivors are scavengers. Scavengers are animals that feed on the dead bodies of other organisums. Animals such as vultures, hyenas, and griffins and all classified as scavengers. Scavengers eat the food that has been killed and left behind by predators. Scavengers are a very important group because they dispose of the carcus's of animals that have been left to decompose.
Recognize that the routes by which the flow of energy and the recycling of matter through the ecosystem occur are called food chains.
The ultimate source of energy for life on Earth is the sun. Solar energy is trapped during the process of photosynthesis and converted into a chemical form that we normally call food. Food contains both materials (the elements carbon, hydrogen, nitrogen, and the other essential elements) as well as stored energy. The materials within the food are recycled. They pass from the producers to the consumers and finally are recycled back to the producers by the action of the decomposers. Energy, unlike the materials, is not recycled. As the food is passed through the food web, energy is lost. In general terms, only 10% of the energy stored in one trophic level (such as producers) is actually transferred t the next trophic level (for example the herbivores). This is known as the pyramid of energy. Eventually there is so liitle energy remaining in the top trophic level that no highr trophic level can be supported. This is why there are few if any fourth order consumers in any ecosystem.
Explain how autotrophs are the basis of energy flow in all food chains (and food webs) by capturing solar energy and making it available to consumers.
Autotrophs are organisms that are able to make their own food using carbon dioxide. Most autotrophs carry on photosynthesis. Photosnythesis is the process by which organic compunds are synthesized from inorganic carbon, in the presence of light or solar energy. Autotrophs provide food for the primary consumers, which are heterotrophs. heterotrophs such as herbivores, omnivores, saprobes feed on autotrophs. The heterotrophs are in turn eaten by the secondary consumers, which are carnivores.
Autotrophs are organisms that are able to make their own food using carbon dioxide, they can also be called producers. Most autotrophs carry on photosynthesis. Photosnythesis is the process by which organic compunds are synthesized from inorganic carbon, in the presence of light or solar energy. Autotrophs provide food for the primary consumers, which are heterotrophs. heterotrophs such as herbivores, and omnivores,feed on autotrophs. The heterotrophs are in turn eaten by the secondary consumers, which are carnivores.
Producers are eaten by the primary consumers which are eaten by the secondary consumers, when all of these die the saprobes break down their reamins which then can be reused by other members in the cycle.
Summarize the roles of producers, consumers, and decomposers in relation to a food chain and all of the food web interactions.
Producers (photosynthetic organisms) capture solar energy and take in materials (elements such as carbon, hydrogen, oxygen, nitrogen, etc.) and make food which is then passed on to the consumers. Consumers generally carry on a process of cellular respiration which releases the energy for use for their own life functions. Both the producers and the consumers die and produce waste products which are then passed on to the decomposers (saprophytes). Decomposers are mainly bacteria and fungi that break down the materials in the waste and dead bodies and recycle them back to the producers. Note that materials are recycled but energy is not. For this reason, it is important that the Earth receive solar energy since it is the solar energy that drives the entire cycle of life, that is all the interactions and feeding relationships that we refer to as the food web.