Chapter 13: Organisms and the Environment Foundations Ms. Johnson

Objectives Living things interact with their surroundings, called the environment. Living things and the nonliving factors of their surroundings make up an ecosystem. There is a continual exchange of materials between an organism and its environment; this includes food, water, oxygen, and wastes. Green plants use sunlight to make their own food. They are called producers. Animals depend on other organisms for food. They are called consumers. Decomposers are organisms that break down the remains of dead plants and animals. Decomposers return nutrients to the environment. All organisms get their energy directly or indirectly from the sun. Producers, consumers, and decomposers may be linked in a sequence called a food chain. Disturbing any part of a food chain affects other organisms in the food chain.

Vocabulary Organisms Environment Community Ecosystem Producers Consumers Food chain Decomposers Food web Symbiotic

Organisms and Their Environment How would you classify the following things? ▫Living versus nonliving Organisms: living things that have characteristics that set them apart from nonliving things ▫Life processes

Organisms and Their Environment Environment: the surroundings that living things interact with ▫Includes all living and nonliving things around an organism Organisms obtain their food, water, and oxygen from the environment In return they release wastes such as CO 2 There is a continual exchange between organisms and their environment

Communities and Ecosystems Habitat: the particular environment in which an organism normally lives ▫Desert, jungle, prairie, coral reef, etc. Habitats vary in the amount of water, light, temperature, wind, etc. Each habitat has different types of organisms, but those organisms depend on each other. Community: all the different organisms that make up an environment ▫Ex. a fish tank has coral, fish, plants Ecosystem: the combination of a community with the nonliving factors. ▫Ex. the fish tank also has water, oxygen, and light

Communities and Ecosystems The members of the community get the materials they need to survive from the ecosystem. Materials are constantly being recycled within an ecosystem. In our environment, oxygen is provided by green plants (via photosynthesis) Energy is not being recycled and comes from an alternative source, the sun.

Nutrition Every organism needs food to stay alive because food provides nutrients. ▫Used for growth, repair, and energy Plants make their food through photosynthesis ▫Use sunlight to change carbon dioxide into sugar Animals obtain nutrients by eating plants or eating other animals that eat plants. The sun is the original source of energy in all food.

Food Chains Plants make their own food. Herbivores (plant-eating organisms) get energy from plants. Carnivores (meat-eating organisms) get their energy from plants indirectly, by eating other animals that eat plants. Ex. a lion eats a zebra (prey) ▫The zebra gets nutrients from the grass ▫The lion gets nutrients from the zebras meat

Food Chains Producers: organisms that produce their own food ▫Ex. plants Consumers: animals that eat producers directly or indirectly ▫Ex. zebras When the lion dies, its body will decay Decomposers: break down the remains and waste of organisms ▫These nutrients can be used again by plants

Food Chains Food chain: the way nutrients get passed along from one organism to another ▫Example:  Grass produces food  Zebra eats the grass  Lion eats the zebra

Food Chains Decomposers include: fungi and some bacteria ▫These organisms cannot make their own food and depend on others for food The removal of one species can affect many other species. ▫What would happen if the zebras died out?

Food Webs Food web: when ecosystems contain a number of food chains that are interconnected If the balance is disturbed between producers, consumers, and decomposers, it can change the entire ecosystem

Food Pyramids Every organism uses some of the energy it consumes and stores the rest. The energy that is used is lost to the environment in the form of heat. Only the stored energy is available to the next consumer in the food chain. The result of this causes a decrease in energy available at each step in the food chain. As you move up the pyramid, it becomes less and less. The green plants (producers) are always at its base.

Food Pyramids

Symbiosis When organisms live together, they can interact in a number of ways. At least one organism always benefits. ▫The other organism may or may not benefit. Symbiosis: when two or more different organisms live in close association with another one. ▫One organism lives in or on another one

Symbiosis RelationshipDescription MutualismBoth organisms benefit from the relationship. CommensalismOne organism benefits while the other is not affected. ParasitismOne organism benefits while the other is harmed. Mutualism: crocodile with plover bird Commensalism: whales and barnacles Parasitism: dog with a tick

Upsetting the Balance of Nature Humans sometimes interfere with the balance of nature. ▫Example: Early settlers in the northeast killed off all of the wolves because they were eating the farm animals. But, the wolves were the only animal preying on the deer population and without the wolves the deer population skyrocketed. Many deer starved each year because their numbers were not kept in check by the wolves. Floods, forest fires, and other natural events can disturb the balance of nature.

Chapter 13: Organisms and the Environment Homework: Page 161, points