Life Cycle - Plants (4A)
Pre Lab 

   
OBJECTIVES:
  • Classifying plants.
  • Defining the characteristics of plants.

VOCABULARY:

  • classification
MATERIALS:
  • plant classification worksheet

Students use a worksheet to classify plants.



Aspen trees with flowers growing on the ground.

BACKGROUND:

The plant kingdom includes one celled organisms (diatoms) as well as complex organisms like angiosperms. Some plants and trees (tracheophytes) have vascular tissue or well-developed conducting tissue through which water and solutes are transported to various parts of the plant. Other plants are non-vascular (bryophytes) and do not possess internal transport systems. Most non-vascular plants live in water or in wet environments that facilitate the direct diffusion of water and nutrients. Vascular plants, however, live on land and possess special features adapted to this environment such as roots, stems and leaves. As in most classification systems, not all botanists agree on the same classification system or the same categories. In this program we are using the following simplified classification scheme:

Brown-green algae refers mainly to one-celled plants called diatoms. These form major component of the oceans and are important because they are at the bottom of the food chain and are responsible for some oil formation.

Brown-red algae
refers to the large plants of the sea, including kelp and seaweed. Plants in the marine environment do not need the elaborate vascular conducting system of land plants for transporting nutrients because the marine environment has all these nutrients available. Bryophyta, which include mosses and liverworts, are mainly inconspicuous plants growing in moist habitats. They are not fully adapted to life on land because they need water to reproduce. Bryophytes do not get very large.

Sphenophyta or horsetails are easily recognized by their jointed stems and rough, ribbed texture. Early settlers used horsetails to help clean pots and pans because of their rough texture. You find these plants in wet environments.

Ferns (filicopsids) are familiar vascular land plants that reproduce by using spores rather than seeds. Ferns prefer wet, moist climates.

Gymnosperms (which includes Ginkgoes) or conifers (pine-like trees) are mainly cone-bearing plants. There are only about 550 species of living conifers. They dominate the forest of the Northern Hemisphere, but are known in the tropics and Southern Hemisphere. The leaves of most conifers are needle-shaped and are all simple or have scales.

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

 PROCEDURE:

  1. Using the worksheet, students are to write down notes about each group of plants as you provide them with information. Instruct the students to write a sentence about each groupís characteristics and uses.
      
  2. If you want students to learn more about the different groups you may want them to view the web sites listed below. You may want to do a search on bryophytes and sphenopsids to see if any new sites would be useful to your students.

http://osu.orst.edu/instruct/for241/
Dichotomous key of conifers in the Pacific northwest. Well designed and easy to use.

http://www.hcs.ohio_state.edu/hort/plants.html
Ohio State list of about 1500 plants with images.

http://nature.snr.uvm.edu/www/mac/plant_id/
University of Vermont, School of Natural Resources. Site has both angiosperms and gymnosperms.

http://www.visuallink.net/fern/index.html
American Fern Society maintains this site and has basic biology to different species of ferns.

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