Plant Diversity

1. Plant Diversity Chapter 22

2. 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

3. 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)

4. 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.

5. 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

6. Plant Classification • Life Cycle of Bryophytes

7. 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.

8. 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

9. Plant Classification Fern Club Moss Horsetail

10. 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

11. 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.

12. 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.

13. 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)

14. 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

15. Monocots vs. Dicots

16. 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