in Ecosystems Energy Flow 6.L.2.1 Summarize how energy derived from the sun is used by plants to produce sugars (photosynthesis) and is transferred within a food chain or food web (terrestrial and aquatic) from producers to consumers to decomposers.

Obtaining Energy Every organism needs to obtain energy in order to live. For example, plants get energy from the sun, some animals eat plants, and some animals eat other animals.

Producers, Consumers, and Decomposers A producer (or an autotroph) is an organism, such as a green plant or alga, that uses an outside source of energy like the sun to create energy-rich food molecules (sugar). Examples: Grass, ferns, and trees

Organisms that cannot make their own energy-rich molecules are called consumers. Consumers obtain energy by eating other organisms.

There are four general categories of consumers: 1. Herbivores - are animals that eat plants. Herbivores are also called primary consumers. Most animals are herbivores. Examples: rabbits, deer, and cows.

There are four general categories of consumers: (Continued) 2. Carnivores - are animals that eat meat. Carnivorous animals often have sharp teeth and powerful jaws. Examples: lions, tigers, and penguins.

There are four general categories of consumers: (Continued) 3. Omnivores - are animals that eat both animals and plants. Examples are people, pigs, monkeys, chimpanzees, and most bears

There are four general categories of consumers: (Continued) 4. Decomposers - are organisms that break down organic matter. Examples: fungi, bacteria, and earthworms. (Decomposers help recycle once-living matter.)

Food Chains Food chains illustrate how consumers obtain energy from other organisms in an ecosystem. Each link in a chain is food for the next link. Food chains start with plant life and ends with an animal. The arrows in a food chain show the flow of energy. As the energy flows from organism to organism, energy is lost at each step. A network of many food chains is called a food web.

Trophic Levels: The trophic level of an organism is the position it holds in a food chain. Primary producers (organisms that make their own food from sunlight and/or chemical energy from deep sea vents) are the base of every food chain - these organisms are called autotrophs. Primary consumers are animals that eat primary producers; they are also called herbivores (plant-eaters).

3. Secondary consumers eat primary consumers 3. Secondary consumers eat primary consumers. They are carnivores (meat-eaters) and omnivores (animals that eat both animals and plants). 4. Tertiary consumers eat secondary consumers. 5. Quaternary consumers eat tertiary consumers. 6. Food chains "end" with top predators, animals that have little or no natural enemies.

FOOD WEBS show how plants and animals are connected in many ways to help them all survive. FOOD CHAINS follow just one path as animals find food. FOOD CHAIN (just one path of energy) FOOD WEB (everything is connected!)

Is this an illustration of a food chain or a food web?

Detrivores & Decomposers When any organism dies, it is eventually eaten by detrivores (like vultures, worms and crabs) and broken down by decomposers (mostly bacteria and fungi), and the exchange of energy continues. Detrivores Decomposers

Symbiotic Relationships Not all relationships among organisms involve food. Many organisms live together and share resources in other ways. Any close relationship between species is called symbiosis.

Symbiotic Relationships Mutualism is a symbiotic relationship between two organisms in which both organisms benefit from the relationship. Example: Pollination of flowers by honey bees. Commensalism is when one organism benefits while the other is neither harmed nor benefited. Example: Moss growing on trees benefits by being raised above forest floor competition, while the tree doesn't get much out of the deal either way.

Symbiotic Relationships Parasitism is a relationship in which one benefits, while the other is harmed. Example: A flea is a parasite on a coyote. The flea benefits by drinking the coyote's blood, but the coyote, by losing blood and acquiring discomfort and potential disease, is harmed.

Niches An organism’s niche is its role in its environment—how it obtains food and shelter, finds a mate, cares for its young, and avoids danger. Predators and Prey – Predators are consumers that capture and eat other consumers. The prey is the organism that is captured by the predator. Predators limit the size of prey populations. As a result, food and other resources are less likely to become scarce, and competition between species is reduced. Cooperation – Individual organisms often cooperate in ways that improve survival. Different individuals perform different tasks required for the survival of the species. Example: Soldier ants protect workers that go out of the nest to gather food. Worker ants feed and care for ant larvae that hatch from eggs laid by the queen.

Questions A basic food chain is shown above. Which organism will have the most energy available? A. Plant B. Grasshopper C. Bird D. Hawk

Which is always a first-order consumer. A. Carnivore B. Decomposer C Which is always a first-order consumer? A. Carnivore B. Decomposer C. Herbivore D. Omnivore

Which is a producer? A. Fungus B. Grass C. Mouse D. Rabbit

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