PLANT DIVERSITY

Chapter 22

What Is a Plant Plants:

Multi-cellular Eukaryotic Have a cell wall made of cellulose Develop from multi-cellular embryos Use chlorophyll(green pigment) to

carry-out photosynthesis

Plant Evolution & Classification Early Plants

The origin of plants was most likely photosynthetic green algae.

Plant Kingdom The Plant Kingdom is divided into four main groups or

categories based on water conduction tissue, seeds, and flowers.

The four categories are Mosses & their relatives Ferns & their relatives Cone-bearing plants (smallest group) Flowering plants (largest group)

What Plants Need For Survival Sunlight

Plants use the energy of the sun to carry-out photosynthesis. Plants have developed features to help them in this process

(i.e. Broad flat leaves). Water & Minerals

Necessary materials for photosynthesis Plants have well developed root systems for maximum water

and mineral absorption and some plants have structures that minimize water loss.

Gas Exchange Plants require Oxygen & Carbon Dioxide to carry-out

photosynthesis which the obtain via the atmosphere. Movement of Water & Nutrients

Plants have specialized structures tissue that facilitates the movement of water and nutrients.

Plant Classifications Bryophytes (Mosses & their relatives)

Mosses: Most common, grow near water, can live in harsh conditions. Not vascular, no true roots instead they have rhizoids

Liverwarts: Named for their liver shape, found on the surface of moist soil, in their mature form they have gemma cups, they produce both sperm and egg cells.

Hornwarts: Named for their green horn shaped structure, found on the surface of moist soil

Plant Classification Life Cycle of Bryophytes

Plant Classification Seedless Vascular Plants (Ferns & their

relatives) Have vascular tissue (conducts water & nutrients

through the plant). Xylem-Carries water upward from roots to the rest of the

plant Phloem- Transports nutrients and carbohydrates Lignin- Enables the plant cell wall to be rigid

First group of plants to have true root systems, stems, and leaves. Roots- Underground organ that absorbs water and minerals Leaves- Photosynthetic organ that contains vascular tissue Veins- Vascular tissue made of xylem & phloem Stems- Support structure that connects roots and leaves,

carries water and nutrients between them.

Plant Classification Club Mosses: Resemble miniature pine trees,

sometimes called “ground pines” Was at one time a group of large trees

Horsetails: Resemble a horse’s tail, grows to about a meter in height Was at one time used to clean pots and pans

Ferns: More than 11,000 species, survived through much of earths evolutionary history, can survive with little light, mostly found in wet or seasonably wet climates. Rhizomes- Strong, creeping, underground stems. Fronds- Larger leaves of fern

Plant Classification

Club Moss

Horsetail

Fern

Plant Classification Seed Plants (Divided into two categories;

Gymnosperms & Angiosperms) Gymnosperms(Cone Bearing): Seed plant that

bears its seed directly on the surface of cones. Includes; Conifers such as pines and spruces as well

as cycads, ginkgoes, and gnetopphytes. Angiosperms(Flowering Plants): Seed plants

that bears its seed within layers of protective tissue. Includes; grasses, flowering trees and shrubs,

wildflowers

Plant Classification Gymnosperms (means naked seed)

Do not need water to reproduce Reproduce within the cones Transfer pollen via wind, insects, small animals Embryos held in seeds

The four main types of gymnosperms Gnetophytes: 70 known species of these plants

which has its reproductive structures are clustered into cones.

Plant Classification Gymnosperms

Cycads: Palm-like plant that reproduces using a large cone, most commonly found growing in tropical and subtropical regions.

Ginkgoes: Contains only one living species; Ginkgo biloba, which is the oldest seed plant species alive today, often planted in urban areas, resistant to air pollution, popular shade trees.

Plant Classification Gymnosperms

Conifers: The most common of the gymnosperms Includes; pines, spruces, cedars, redwoods Some can live for 400 yrs Some can grow 100m in length Evergreens (keep leaves)

Plant Classification Angiosperms (Flowering Plants)

Develop reproductive organs known as flowers Pollinated primarily by birds and bees The flowers contain ovaries which develops into fruit Animals often eat the fruit and disperse the seeds

through excretion ( this helps increase the range of their habitat)

Divided into two groups based on cotyledons: (seed leaf, first leaf or first pair of leaves produced by embryo of seed plant) Monocots: Single cotyledon Dicots: Two cotyledons

Monocots vs. Dicots

Woody & Herbaceous Plants A. Woody Plants include: tree, shrubs, and

vines B. Herbaceous Plants include: flowering plants

that have smooth or non-woody stems; dandelions, zinnias, petunias, and sunflowers.

Annuals: Complete life cycle in one growing season, garden plants and vegetables.

Biennials: Complete life cycle in two growing seasons, first year they grow roots & stems, second year they grow flowers.

Perennials: Live through many years, most have woody stems