Biology Week 13 - Plant Classification

Day 1 | Day 2 | Day 3 | Lab | Weekly Quiz | Quizstar

Plants Chlorophyll Nonvascular Moss Vascular Ferns Fronds Bryophyta Pterophyta Cereals Spices	Cone-forming Coniferophyta Fruit-forming Anthophyta Cotyledon Root Gametophyte Root crops Legumes Vegetables	Stem Leaf Gymnosperm Angiosperm Monocot Dicot Cultivar food crops Sporophyte Fruits Nuts Herbs

Members of the plant kingdom are green (they all contain chlorophyll) and most are rooted in soil. There are more than 250,000 species within the kingdom.

Check out these predator plants!

Even if you don't know many plants by sight, the one represented here is one you should recognize. Its three toothed leaves are a shiny green and its berries are white.

It sometimes grows on trees with a friend with 5 leaves.

Plant classification:

Land plants are divided into two groups (vascular and nonvascular) based on whether they have vascular tissues or not. Vascular tissues are specialized for conducting food and water within the plant. All nonvascular plants are placed in one division. There are nine divisions of vascular plants based on whether they form seeds or not. This class will be concerned with the following groups:

Division Bryophyta - nonvascular plants

• Class Musci - the mosses

Division Pterophyta - ferns, a group of seedless plants

Division Coniferophyta - cone-forming seed plants

Division Anthophyta - fruit-forming seed plants

• Class Monocotyledonae - plants with one seed leaf
• Class Dicotyledonae - plants with two seed leaves

Comparing vascular and nonvascular plants:

Nonvascular plants do not have vascular tissues, roots, stems, or leaves.
Nonvascular plants are much smaller than most vascular plants.
Vascular plants live in more types of environments than nonvascular plants.

There are more than 10,000 species of moss plants. Mosses don't receive as much attention as flowering plants, ferns, or conifers because most are small and inconspicuous. They have no vascular tissue or wood, nor do they have large leaves or showy cones or flowers. This does not mean that mosses are not important. Mosses play important roles in reducing erosion along streams, water and nutrient cycling in tropical forests, and insulating the arctic permafrost.

• Mosses have structures that anchor them and absorb water as well as structures that catch sunlight for photosynthesis, but they have no true roots or leaves.
• The sphagnum moss is known for its moisture holding capacity, absorbing up to 20 times its dry weight with water.

Mosses reproduce sexually by forming spores.
A single moss "plant" is a gametophyte. Sperm from one gametophyte fertilizes the egg of another, producting a zygote.	A stalk-like structure, called a Sporophyte, with a capsule at the top containing the spores grows from the zygote.
When released, the spores will grow into new gametophytes. All mosses show alteration of generations. View the moss lifecycle.

Ferns:

Ferns are vascular plants forming true roots, stems, and leaves. They reproduce sexually by forming spores, not seeds. There was a time when ferns were the dominant form of plant life on Earth. Today, their distribution is limited by the requirement of having drops of water at a certain time for reproduction.

Ferns range in size from just a few inches to 25 meters in height. Ferns can be recognized by the "feathery" appearance of their leaves. The leaves of a fern are known as fronds. Spores form in sacs called sporangia on the under side of the fronds. Many ferns form a horizontal stem (rhizome) instead of a vertical one.

View the fern lifecycle.

Day 1 Assignment - Plant Classification
This assignment must be turned in by the end of class today to receive credit.
Scoring criteria

1. What is the common name of the plant pictured at the top of this page? The species name gives you a hint.
2. What pigment makes plants green?
3. What division of plants does not have vascular tissue?
4. How are vascular tissues involved in determining plant size?
5. Why does moss only grow in moist, shaded environments?
6. Why are water droplets required for ferns to reproduce?

Day 2

A plant has net-veined leaves. Is it a monocot or dicot?

The seed-forming plants:

A seed is a fertilized ovule (part of the plant ovary). It is a multicellular structure containing an embryo plant and its food. Seeds can survive long periods of inactivity between their formation and activation. Today, seed plants are the most successful plants on Earth.

Seed plants are broken into two groups based on how their seeds are formed:

Gymnosperms: plants that produce "naked" seeds.
	Gymnosperm seeds are protected by a "cone". Pollen cones (male) produce pollen. Seed cones (female) produce the seed. There are about 700 species of gymnosperms.
Angiosperms: plants that produce seeds enclosed in a fruit.
Is this a Monocot or Dicot?	Class Monocotyledoneae: Monocots have one cotyledon, or "seed leaf". About 90,000 species are known. Class Dicotyledoneae: The embryo plant of a dicot has two seed leaves. About 185,000 species are known. View the flowering plant lifecycle.

Monocots and dicots are easily distinguished by their physical characteristics.

Day 2 Assignment - Plant Classification
This assignment must be turned in by the beginning of class tomorrow to receive credit.
Scoring criteria

1. What is a seed? Explain
2. Compare the differences between Gymosperms and Angiosperms.
3. What is the common & scientific name of the most common Gymnosperm in Arizona? Give a description.
4. List characteristics that describe monocts and dicots.
5. Is a pecan a monocot or a dicot? (give the reason for your answer)
6. Is a peanut a monocot or a dicot? (give the reason for your answer)
7. Is a corn plant an monocot or a dicot? (give the reason for your answer)
8. Is a queen palm a monocot or a dicot? (give the reason for your answer)
9. What protects the seeds of Angiosperms?
10. In which division do flowering plants belong?
11. What is the difference between a monoecious plant and a dioecious plant?

Day 3

What is the most widely grown food crop in the United States?

Food Crops:

The cultivation of plants for food probably began about 11,000 years ago with wheat, barley, lentils, and peas. Through the years, people have selected plants that produced the largest or tastiest fruits. However, through selection we have also changed many of the plants so much that they could not grow and survive without us. These plants are known as cultivars, a contraction of the terms cultivated and variety.

Agricultural food chains are quite different from natural food chains.

Agricultural Scientist

Of the more than 350,000 plant species, people use at least 10,000 for food. Over 90% of our food supply is provided by fewer than 20 plant species.

Day 3 Assignment - Plant Classification
This assignment must be turned in by the beginning of class tomorrow to receive credit.
Scoring criteria

1. In addition to producing the food and oxygen that we need to survive, plants have many other important uses. Choose a plant that is not used for food by humans and write a paragraph describing the plant and its special use.

2. This website has information about crops grown in all U.S. states. Use it to answer the following:
   1. What cereal grain is most commonly grown in Maricopa County, Arizona?
   2. How many farms in Maricopa County, Arizona grow grapefruit?
   3. What vegetable is planted in the greatest number of acres in Arizona?
   4. How many acres of cotton are planted in Arizona?
   5. How many pounds of peanuts are harvested in Arizona?
   6. Which state has more apple trees, Washington or California?
   7. Which state has more farms growing corn, Nebraska or Iowa?

3. Chocolate is a very special treat that comes from a plant. Summarize how the cacao plant becomes the treat we enjoy.

4. Aspirin is probably the world's most widely used medicine. The bark of the white willow, containing salicin, has been used to treat headaches since the time of the ancients Greeks. Today's aspirin is made of the synthetic chemical known as acetylsalicylic acid. What is the chemical formula for acetylsalicylic acid?

Research Links:

• Species Identification - Audubon Field Guides Online
• Taxonomy & Botant Links - The Internet Science Room
• Botany 201 - Texas A&M University
• The Families of Flowering Plants - Delta Database
• A Glossary of Terms for Vascular Plants - Australian National Botanic Gardens
• Selected Botanical WWW Sites - University of Florida
• Earth's oldest living inhabitant - the bristlecone pine
• Chemical search - Chemical Industry

Moss is a land plant and does not grow in water.

Plants with net-veined leaves are almost always dicots.

Wheat is the most widely grown food crop in the United States.