GRADE: Seventh

CONTENT STANDARDS: Life Science

CONTENT TOPIC: Diversity and Adaptations of Organisms

CONCEPT: Plants are classified according to various structures.

CONTENT OBJECTIVE: 7H2.00 To understand the broad taxonomic division of the plant kingdom

INSTRUCTIONAL OBJECTIVES: The learner will:

2.01 recognize the characteristics of plants as opposite to other life forms.
2.02 explain how plant are classified.
2.03 define and recognize the simplest plants - algae.
2.04 compare and contrast the liverworts and mosses.
2.05 examine the development of a vascular system in the ferns.
2.06 name and distinguish between the two groups of seed plants - gymnosperms and angiosperms.
2.07 examine the characteristics of gymnosperms.
2.08 list and observe the characteristics of angiosperms.
2.09 suggest ways that man uses the different types of plants.
2.10 use a key and plant specimens to classify the plants.

I. General plant characteristics
II. Simple plants
A. Algae
B. Moss & liverworts
III. Vascular plants
A. Ferns
B. Gymnosperms
C. Angiosperms

TN COMPONENT OF SCIENCE: Process Of Science

TN GOAL:

To enable students to demonstrate the process of science by posing questions and investigating phenomena through language, methods and instruments of science

1.5 EXPLAINING - Phenomena and related information are made understandable through discussion that culminates in a higher level of learning

1.5c Information should be related to prior knowledge.

BENCHMARK: Prior knowledge provides a foundation for new learning experiences.

TIME REQUIRED:

Three to four days of instruction and observation

Slide of Spirogyra, light microscope, moss plant, dissecting microscope or hand lens, fern leaf with spores, pine cone, large flower.

Chlorophyll, cone, deciduous, diffusion, fertilize, osmosis, photosynthesis, sessile, spirogyra, and spores

We will be learning about and examining the different categories of plant life found on earth today. You have been living around and with these types of plants all of your life. Many of these plants can be found around your home or in your home. All animals depend on these plants for food and oxygen. We will see in our study of the different plant types, how they have evolved from very simple plants into the most complex types we have on earth.

Plants are different from animals because they can make their own food. The process is called photosynthesis and involves the plant's chlorophyll and sunlight. Plants are also different in that most are sessile, they do not move about like animals.

There are two main groups of plants, non-vascular and vascular. Non-vascular plants lack true roots, stems and leaves. They must depend on osmosis and diffusion to move materials in and out of their structures. Due to the pull of gravity, these non-vascular plants do not grow tall. Vascular plants have advanced enough to develop true roots, stems and leaves. These plants have weed-developed tubes that will transport materials up and down their structures. Therefore, these plants can and do grow tall.

The simple plants that are non-vascular are algae, moss and liverworts. The different types of algae are given credit for many things man enjoys - the greatest contribution being the huge amount of oxygen that algae contribute to our environment through photosynthesis. One of the best types of algae to observe under the microscope is the spirogyra. (Perform laboratory activity and point out the large, winding chloroplast.)

Mosses and liverworts are also non-vascular plants. They have no true roots, stems or leaves so diffusion and osmosis move materials through these very "low to the ground" plants. They have structures that look like these plant parts but are not true vascular structures. (Look at moss under a microscope.)

The first class of vascular plants involves plants known as ferns. These plants have true roots, leaves and stems. This situation allows ferns to grow tall because they can transport materials up and down the plants. These plants, class Flicinae, were once the dominant plants on earth and were found in vast "fern forests". Ferns do not reproduce with seeds as do the higher plants but they reproduce with spores. These spores are located on the underside of fronds, the fern's leaf. (Have this under magnification or observation.) The ferns are not nearly as plentiful as a natural plant today. Due to vast changes in the earth's atmosphere, natural ferns are found mainly in the tropical climates or in dense forests.

There are two groups of seed plants on earth, the gymnosperms and the angiosperms.

Gymnosperms are the plants that are known as evergreens. They keep their leaves or "needles" all year. They are also known as conifers. The seeds of the gymnosperms are produced in a cone. The seeds are released from the cone when mature. This is why the seeds are referred to as "naked seeds". They are not protected once they are released from the cone. Some of the more common plants in this group are pines, cypress, firs and boxwoods.

The most advanced plants on earth are the angiosperms. These are the flowering plants that produce seeds in a fruit. The angiosperms are deciduous because they lose their leaves each fall. The reproductive structure for angiosperms is the flower. Once the eggs inside the flower are fertilized the seeds develop. A fleshy fruit develops around the seeds to act as a protector for the seeds. This fruit can also aid the seeds in dispersal away from the parent plant.

We have spent several days studying and observing the different groups of plants found on earth today. We now know how plants are classified and, more important, why our world is so dependent on plant life.

1. We have studied diffusion and osmosis in a previous chapter. Who can recall what these two movements involve? (response)

2. How is the transport system in vascular plants similar to the human circulatory system? (Move liquids)

(The following activities can be used to enhance the lesson:

1. Exhibit a fern frond under microscope - face down to show spores on underside of frond.

2. Have students collect and bring pine cones - look for seeds or places where seeds were in the cones.

3. Obtain flowers from local sources (florist, grocery, nursery...) to observe under microscope. Also, cut open types of fruits to show the seed or seeds in the fruit or vegetables.)

chlorophyll - green pigment used in photosynthesis

cone - structure containing seeds

deciduous - plants that shed leaves in the fall

diffusion - movement of materials from high to low concentration - a natural movement

fertilize - egg & sperm

osmosis - water moving through a membrane

photosynthesis - process where plants make food

sessile - non-moving, stays in one place

spirogyra - type of green algae

spores - reproductive cells of ferns

This is the time this file has been accessed since 04/02/98.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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