Unit 2 Interactions Among Living Things Chapter 5 – Energy and Ecosystems What do you think I eat? Unit 2 Interactions Among Living Things

How Plants Use Plant Structures Roots have two jobs – they anchor plants and they take in water and nutrients from the soil. Some roots like carrots also store food. Stems support the plant and enable its leaves to reach the sunlight. They contain tubes (xylem - that carry water and nutrients to the leaves or phloem – that carry sugar to all parts of the plants. Leaves make food for the plant. The outer layer (epidermis) keeps the leaf from drying out. The lower epidermis has many small openings called stomata. Stomata take in carbon dioxide when they are open during the day. They close at night so water does not leave the plant through transpiration.

Transpiration TRANSPIRATION is like PERSPIRATION – plants lose water through pores called stomata. You lose water by sweating, especially through pores in your underarms.

How Do Plants Produce Food? What job do plants have? Why do they need carbon dioxide? Why are plants important to humans? Plants convert solar energy into chemical energy in a process called PHOTOSYNTHESIS. The basic process converts six molecules of water and six molecules of carbon dioxide into one molecule of glucose (sugar) and six molecules of oxygen. The plant needs Chlorophyll to assist with the chemical reaction by absorbing sunlight. The sugar is stored by the plant in the leaves or roots. Some of the sugar is changed into starch. Humans (and other animals) eat plants.

Scientists define ecosystems as any group of organisms interacting with each other and with their physical environment. The Earth ecosystem is called the biosphere. Organisms within an ecosystem compete with each other for food, energy, and space. They interact with the nonliving parts of the ecosystem. Some examples of this interaction are: taking minerals from the soil, consuming water and oxygen, cutting down trees to plant crops, and anchoring topsoil so erosion does not take place. ECOSYSTEMS

Energy Transfer An ECOSYSTEM includes all the organisms in an area and the environment in which they live. Energy transfers as one organism eats another. decomposers Lesson 2

It All Starts with Plants WITHOUT SUNLIGHT, EVERY LIVING THING ON EARTH WOULD DIE. Plants are called PRODUCERS because they make their own food – during photosynthesis. If it wasn’t for plants, animals would not survive. Animals are CONSUMERS because they eat plants – or - they eat other animals that have eaten plants. When you eat a salad, you take in the energy stored in the lettuce leaves and carrot roots. If you eat strawberries, you get the energy that was stored in the fruit and seeds.

An HERBIVORE is an animal that eats plants or other producers An HERBIVORE is an animal that eats plants or other producers. They are also called first-level consumers. The Food Chain 2

An animal that eats mainly other animals is a CARNIVORE An animal that eats mainly other animals is a CARNIVORE. They get their energy by eating other animals. Food energy is transferred from the animal being eaten to the one doing the eating. Carnivores are also called second-level consumers. Some eat plants and animals – and are called OMNIVORES. The Food Chain 3

A DETRIVORE begins the process of breaking down a dead organism by breaking it into smaller pieces. A DECOMPOSER is a consumer that gets its food energy by breaking down the remains of dead organisms. Examples are earthworms, fungi, protists, and bacteria. As decomposers work their waste products mix with soil and become nutrients. THIS ALLOWS PLANTS TO TAKE IN THOSE NUTRIENTS AND THEY GROW!!! The Food Chain 4

FUN FACT Each time you move UP a step on the pyramid the amount of energy moved up is approximately 1/10 the amount on the step below it. Some second level consumers barely get any energy from what they eat!

Prairie Food Web

Pond Food Web

Rainforest Food Web

Northwestern North American Food Web

The Nitrogen Cycle Decomposers release nitrogen into the soil. A plant takes this form of nitrogen in as a nutrient as it takes water into its roots. The plant uses the nitrogen to grow strong. Animals eat the plant. Animals eventually die and the nitrogen is returned to the soil after the decomposers do their job.