OBJECTIVES:
·         Comparing different plants.
·         Discovering requirements of plants.

VOCABULARY:
·         classification
·         plant

MATERIALS:
·         15 Angiosperms and Gymnosperms Worksheets
·         15 Bags (Angiosperms, Gymnosperms, and pollen)
·         Angiosperm leaves (broadleaf) (from trees with flat leaves)
·         Gymnosperm leaves (needle leaf) (from pine, spruce, etc)
·         What is a Tree?

BACKGROUND:

The study of plants is called botany or plant biology. Botanists believe that the plants that live on the land today are descendants of tiny green plants that lived about 350 million years ago in the ancient seas.  There are over 300,000 types of plants in several large groups. There are slightly different classification systems for plants, but most recognize two basic groups, the nonvascular plants, and the vascular plants. The vascular plants can either be herbaceous or woody. 

Herbaceous plants do not have specialized woody tissue for water transportation from the roots to the shoots.   Woody plants have conducting tissues called xylem and phloem tissues.  Xylem tissue transports water and phloem tissue transports food products. These tissues are absent in herbaceous vascular plants and  nonvascular plants. 

Nonvascular plants in the classification used in this curriculum include the Thallophytes (green algae,  brown-green algae, brown-red algae) and Bryophytes (mosses, and liverworts). Vascular plants or Tracheophytes include ferns (filicopsids), sphenopsids (horse tails), gymnosperms (needle leaves), and angiosperms (flowering plants).

Gymnosperms  (NEEDLE LEAF) (which include Ginkgoes) or conifers (just the pine-like trees) are mainly cone-bearing plants. There are only about 550 species of living conifers.

Gymnosperms produce unenclosed seeds located on the upper surface of scales, which are usually parts of cones. Most conifers are woody plants and are usually large with leaves that are usually evergreen needles or scales. Conifers are the most abundant gymnosperm today. Pines, spruce, fir, cedars, sequoias, redwoods, and yews are all conifers. Conifers cover large areas of North America, China, Europe, and Australia. The leaves of conifers are long and thin, and are often called needles. Even though the name evergreen is commonly used for these plants, it isn't accurate because needles don't remain on conifers forever.

Conifers have male and female reproductive structures called scales. Scales are grouped into larger structures called male and female cones. Male cones make male gametophytes called pollen. Female cones make female gametophytes called eggs. Later, the female cones hold seeds that develop on their scales. Each seed is covered by a seed coat, but the seed isn't protected by the cone. Since the seeds sit "naked," or on the outside of the scales, conifers are called naked seed plants, or gymnosperms ("gymno" means naked; sperm means seed).

Angiosperms (BROAD LEAF) (flowering plants) produce a seed cover for reproduction and are the most common small plants and trees. They are divided into groups monocots (grasses) and dicots (larger flowering plants).

Angiosperms produce specialized structures called flowers in which seeds develop. Angiosperms are the dominant members of the world's flora. Angiosperms are flowering and fruit producing plants. The angiosperms may be divided into the monocots and the dicots. Seeds and fruits may be variously modified, a factor that frequently assists in seed dispersal. Wind, animals, (including humans), and water are the most important agents of dispersal.

Angiosperms or flowering plants are the most dominant group of the vascular plant world. The term angiosperm was devised to describe one of the most definitive elements of flowering plants, namely the enclosure of the potential seeds within a hollow ovary. The angiosperms are considered to be advanced as compared with the gymnosperms and other tracheophytes (plants and trees). Flowering plants occur in a wide range of habitats including both salt and fresh water. The basic food supply of the world is derived from the seeds and fruits of angiosperms (rice, wheat, corn) and fibers, wood, drugs, and other products of great economic value.

The diagram below is just for instructors information and a visual difference between angiosperms and gymnosperms.

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PROCEDURE:

Note:  if there are samples in the classroom of tree rings, cones, or other tree parts, try and incorporate into lesson.

1.    Read “What is a tree?” to begin the discussion about plants.  The story just goes over gymnosperms and angiosperms.  So you might talk about the other plants mentioned above.
 

2.    Discuss with students the needs of plants which include water, air, soil, light, space, and moderate temperatures. You may want to make an overhead of the worksheet and discuss with children why or why not each is a plant. For each box ask students to answer the following questions in their mind before they answer yes or no. Does it move? (no); Does it make its own food? (yes); Can it live in the dark? (no); Does it need soil to grow big? (yes); Is it green? (yes)

 3.   Ask students how you can tell how old a tree is.  (Count the rings).  The light wood is the faster growth during spring and summer and the dark wood is the more dense wood during fall and winter when the tree is dormant or growing more slowly.  There are tree sections (tree “cookies”) in the lab that you can pass out and have the students count the rings.  Students can trade “cookies” to count and check.
 

4.    You may want to suggest that look at home to see if there are seeds or cones so they can classify into gymnosperms and angiosperms. 

5.    In the kit there is also some pollen.  Many children have heard about pollen as something people are allergic to, but most do not know that  pollen is produced by the male part of tree.   The yellow pollen in baggies are from pine trees.  They produce so much that if it rains when pollen is produced many puddles will have a yellow look because of all the pollen.

 6.    The female part of the plant will produce the seed.  In angiosperm the seed is protected, usually with fruit.  The gymnosperm will not have any protection and they come out of the cone.  

7. When the students identify each of the seeds, go over descriptive terms with each one.  This will help the children focus. Your kit has the following:
Gymnosperms:  Pondersosa  pine, Douglas fir, redwood, cedar rose
Angiosperms:  eucalyptus, alder, giant burr, liquid amber, pollen

 8.        Give students needle leaves and broad leaves that you have collected for them to sort.    Try to identify the trees before you use them so you can have the students identify. Make an art project of “Angiosperm” vs “Gymnosperm” as below.

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