Introduction to PLANT CLASSIFICATION

BellworkBellworkRoots, leaves, and stems are Roots, leaves, and stems are

very important parts of a very important parts of a plant. Pick one of those three plant. Pick one of those three parts, and describe in detail parts, and describe in detail how it helps the plant survive.how it helps the plant survive.

What is Taxonomy?What is Taxonomy?

Taxonomy is the system of Taxonomy is the system of classifying living classifying living

organisms. Today, you will organisms. Today, you will be learning about the be learning about the taxonomy of plantstaxonomy of plants

Plants Are in Their Own Classification Kingdom

Because…

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Plants are multi-cellular eukaryotes—that is, their cells contain membrane-bound

structures called organelles. Plants differ from other eukaryotes because they have

cell walls that are rigid, composed mainly of cellulose. The most important characteristic of plants is their ability to photosynthesize,

or make their own food.

Note the tiny green, spherical structures, called chloroplasts, near the edges of

the cell walls in this onion root.

Chloroplasts are essential to the

process of photosynthesis, in

which captured sunlight is combined

with water and carbon dioxide in

the presence of the chlorophyll molecule to produce oxygen

and sugars that can be used by animals.

Major Phyla

1. Mosses (Bryophyta)

2. Ferns (Filicinophyta)

3. Conifers (Coniferophyta/Gymnosperms)

4. Angiosperms (Flowering Dicots = 2 seeds parts)

5. Angiosperms (Flowering Monocot s= 1 seed part)

PLANT TAXONOMY

PLANT CLASSIFICATIONPLANT CLASSIFICATION

Plant classification is based on Plant classification is based on three main characteristics:three main characteristics:

Tissue StructureTissue Structure: vascular or non-: vascular or non-vascular.vascular.

Seed StructureSeed Structure: naked seeds, covered : naked seeds, covered seeds, and spores.seeds, and spores.

Main Body StructuresMain Body Structures: low to ground, : low to ground, high from ground, viney, branching, high from ground, viney, branching, herbs, rigid trunks, flowering or not, etc.herbs, rigid trunks, flowering or not, etc.

There are two main classification groups within the plant taxonomy.

Non-vascular plants lack true roots, stems and leaves. They absorb water directly from the base on which they grow or from the air. They must depend on osmosis and diffusion to move materials in and out of their cell structures. Due to the pull of gravity, these non-vascular plants do not grow tall because they have no way of transporting water and food a long distance.

Vascular plants have true roots, stems and leaves. These plants have well-developed tubes that transport food and water in and out of their cell structures. Therefore, these plants can grow tall. What are the names of the tubes that transport water and glucose throughout the plant?

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Xylem tubes carry water and phloem tubes carry the glucose.

Non-Vascular Bryophytes: mosses, liverworts and hornworts

Club Moss

Liverwort

Hornwort

Mosses prefer cool, moist, shady habitats. They grow on soil, rocks, and the bark of trees, and in bogs and shallow streams. Moss plants consist of small,

slender stalks and leaves. They reproduce by way of spores instead of seeds.

Algae are in the Protist classification. They have both plant and animal traits.

They are found both as prokaryotes and eukaryotes; some can photosynthesize; most have cell walls; and

some can move about on their own while others cannot. Algae lack the roots, leaves, and other structures typical

of true plants, so they are non-vascular.

Something Different: Algae

They are the most important photosynthesizing organism on

Earth. They capture more of the sun’s energy and produce more oxygen (a byproduct of

photosynthesis) than all plants combined.

The first green algae appeared more than 2 billion years ago in the fossil record—they are

believed to be the most immediate relatives of the

green land plants.

Vascular: trees, bushes, flowering plants, vegetables, fruits, weeds, ferns

Ferns

Conifers

Vegetables

Flowering Plants

Cells of Vascular Plant Tissue

The first group of vascular plants involves plants known as ferns. Having true roots, leaves and stems allows

ferns to grow tall because they can easily transport water and food up and down the plant’s body structure.

Ferns were once the dominant plants on earth and were found in vast "fern forests". Ferns do not reproduce with

seeds as do other plants, but they reproduce with spores. The spores are located on the underside of the fern’s leaf,

also called a frond.

Spores

The second group of vascular plants are calledgymnosperms, also known as evergreens or conifers. These plants keep their leaves/needles anywhere from

1-18 years. Examples would be pine trees, spruce, cedar, fir, etc.

The term gymnosperm is derived from two Greek words: gymnos, meaning naked, and sperma, meaning seed. The seeds of

gymnosperms are produced in a cone and are released from the cone when mature. They are referred to as "naked seeds“ because they are not protected by a covering once they are released from

the cone.

The third group of vascular plants are the most complex. They are the angiosperms. These are the flowering

plants that produce seeds in a fruit. The angiosperms are deciduous, which means they lose their leaves each fall.

The Latin term, “angi,” means

enclosed” and the Greek “sperma,”

means seed.

The term “angiosperm” means a seed contained in a vessel, and refers to flowering plants, in which seeds mature

within a fruit.

Angiosperms

Angiosperm Seeds Come in Two Types:

Monocots & Dicots

Dicots have two parts/cotyledons to their seed, or two

halves.

A monocot seed has only one part/cotyledon to it. Monocots are

commonly found in plants that include the iris, lily, corn, orchid,

grass and palm.

Differences Between

Monocots & Dicots

Monocot plants are distinguished from dicots because they have

flower parts in threes; one cotyledon (seed leaf); leaf veins

that are usually parallel; vascular tissue in scattered bundles in the

stem; and no true secondary growth.