The study of plants is called botany or
plant biology. Biologists 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.
Plants are divided into two major groups:
the nonvascular (Bryophytes and Thallophytes) and the vascular plants (Tracheophytes).
They are divided by their characteristics which are listed below.
THALLOPHYTES (algae, diatoms, kelp, seaweed)
small to medium (one cell--microns to meters in
aquatic (marine or fresh water)
found in cold to warm water, upper 200 meters of
BRYOPHYTES (liverworts, hornworts, mosses, and "whiskferns")
small in size
live in the arctic and antarctic, mainly found living in the tropical and
temperate areas of the world
need shade and moisture to survive
not well adapted to land conditions, have such small anchoring structures
that their plant body size must remain small in order to stay clinging to
TRACHEOPHYTES (horsetails, ferns, conifers, and
large in size compared to Bryophytes
live where extreme cold and heat does not exist
need direct sunlight to survive
all have a long root system
all produce seeds
Plants which produce seeds are the plants
which dominate the land today. Aquatic plants do not produce seeds. The first
seed plants appeared during the Devonian period (approximately 350 million
years ago) and were known as the seed ferns. Biologists believe that the seed
ferns are the ancestors of the seed plants living today. The two most abundant
plant groups of the Tracheophytes are the gymnosperms and angiosperms.
Gymnosperms produce naked seeds and angiosperms produce seeds within flowers,
fruits, or vegetables. Students should look at the worksheet and try to
determine whether the plants are thallophytes, bryophytes or tracheophytes.
- Students need to examine the different
types of plants and then classify them into Tracheophytes, Thallophytes, or
Bryophytes The answers to the worksheet are the following: -
Tracheophytes (1,3,4,6,9,10); Thallophytes (2,8) ; Bryophytes (5,7)
- If you have internet access have the
students look up different plants and have them group them into the 3 groups.
The PLANTS Database provides standardized information about
plants, and it focuses primarily on plants of the USA and its territories,
including checklists, distributional data, references and other plant