What are leaves?

Unit Standards 5.L.4B.1 Analyze and Interpret data to explain how organisms obtain their energy and classify organisms as producers, consumers (including herbivore, carnivore, and omnivore), or decomposers (such as Fungi, Bacteria insects and molds). 5.L.4B.2 Develop and use models of food chains and food webs to describe the flow of energy in an ecosystem. 5.L.4B.3 Construct explanations for how organisms interact with each other in an ecosystem (including predators and prey, and parasites and hosts). 5.L.4B.4 Construct scientific arguments to explain how limiting factors (including food, water, space, and shelter) or newly introduced organisms can affect an ecosystem.

What are leaves? Inside the thin blade of the leaf are the structures that provide Earth with food, oxygen, and clear air. Leaves with only one blade are simple leaves. Leaves with two or more blades are compounds leaves.

What are leaves? The parts of a leaf work together to help keep the plant alive. The outer most part of the leaf is its epidermis. Cells of the epidermis secrete a waxy coating called a cuticle. This waxy covering helps prevent water from leaving the plant.

What are leaves? The leaf makes food in cells between the layers of the epidermis. These cells contain chloroplasts. The epidermis on the lower surface of a leaf contains many tiny pores called stomata (singular= stoma).

What are leaves? Stomata open and close to let gasses, such as carbon dioxide and oxygen, in and out. These openings also control the amount of water that leaves the plant. Guard cells surrounding the stomata regulate when stomata open and close.

What are leaves? The veins that run through the leaf blade bring water and minerals to the last stop on their journey from the roots.

What are leaves? When carbon dioxide enters through the stomata and sunlight is captured by the chlorophyll in the chloroplast, all the ingredients are in place to produce food.

What are leaves? Some leaves, such as spinach or lettuce, store food. Others are designed to protect the plant.

What are leaves? The spines on a cactus are actually the leaves. They do a good job of protecting the plant from being eaten, and their small size and pointed shape minimize water loss in the dry environment of a desert.

What are leaves? In some areas of the world where there are seasonal changes in changes in temperature, plants shut down their food-making factories at certain times of year. During the winter months, they live off the food they have stored.

What are leaves? Green chlorophyll disappears from the leaves. When this happens people can see the other colors, such as yellow and orange, that are usually masked by the green pigment.