How are plants classified? Lesson 3

Vocabulary Gymnosperm: a seed plant that does not produce a flower. They include pines, firs, and other cone-bearing trees. Angiosperm: a seed plant that produces flowers. All angiosperms have seeds that are covered by some kind of fruit. Xylem: a series of tubes that move water and minerals up the stem. (From the plant roots to the leaves)

Gymnosperm, Angiosperm, Xylem

Vocabulary Phloem: moves sugars that are made in the plant’s leaves to other parts of the plant. Phloem tissue is a two-way transport route. It flows both up and down in a plant. Cambium: xylem and phloem cells are produced in the cambium, then move inward. Photosynthesis: the process of making food. Leaves need three raw materials: sunlight, water, and carbon dioxide from air.

Cambium, Phloem

Photosynthesis

Vocabulary Transpiration: the loss of water through a plant’s leaves. Picture on page 58. Cellular respiration: energy is released when the cells of organisms use oxygen to break down the sugars stored as starch.

Transpiration, Cellular respiration

How are plants classified? Nonvascular plants are small and survive without a transport system. (Moss) Vascular plants do not have size limitations. Trees can grow to heights of more than 200 feet. Vascular plants are divided into seed plants and seedless plants.

Nonvascular, Vascular

How are plants classified? Two main types of seed plants: gymnosperm (does not produce a flower), and angiosperm (does produce a flower).

What are roots? A root is part of the plant. Root hair is a threadlike projection from a plant root. Root hair absorbs moisture like a sponge. Root cap covers the tip of the root. It protects the root tip while it pushes into the ground. Epidermis is the skin of the root. Just like our epidermis is our skin.

What are roots? Cortex layer is located just under the epidermis. The cortex stores food and nutrients. The vascular system of the root is located in the center of the root. Just like our vascular system is in the center of our body. Aerial roots are roots that never touch the ground. Orchids have aerial roots.

What are roots? Fibrous roots are thin, branching roots. They do not grow deep, but they often cover a very wide area. (Marigold plants) Taproots have a single, main stalk-like root that plunge into the ground. (Poplar Tree) Prop roots usually grow at the bottom of a plant’s stem. They prop up and support the plant so it cannot be knocked over. (Corn plants and mangrove trees)

Fibrous roots, Taproots

Prop roots

What are stems? The plant’s stem has two functions. First, is a support structure. The stem of a tree must support the weight of the entire tree. Stems must be sturdy enough to support leaves, flowers, and branches. Stems come in two basic forms-soft stems and woody stems. Soft stems, green, and can bend. Woody stems are often covered with bark and do not contain chlorophyll.

Plant and Stem Allows sugar from the leaves of the tree to flow to the rest of the tree. Allows water and nutrients from the ground to flow to the rest of the tree.

What are leaves? Many leaves are flat and broad, which allows the leaf to collect the most sunlight possible. The top of the leaf is covered with a waxy cuticle, or waterproof layer that prevents moisture from evaporating. Leaves use stomata, a single pore which opens and closes to regulate the amount of water and air loss in the plant.

Plant leaf

What are leaves? As water evaporates from the leaves, more water is carried from the bottom of the plant to the top. Photosynthesis, the production of sugar and oxygen while absorbing carbon dioxide and water.

How are photosynthesis and respiration related? Cellular respiration: the process of using oxygen to break down the sugars stored as starch in the process. Cellular respiration occurs in the mitochondria of the cells.

Cellular respiration in plants