Introduction to Plants

1. Introduction to Plants Chapter 22 Honors Biology

2. Plants • Kingdom Plantae • Multicellular Eukaryotes • Cell walls made of cellulose • Make energy via photosynthesis using the green pigments found in chlorophyll located inside the chloroplast

3. What do plants need to survive? • Sunlight – energy from sunlight to carry out photosynthesis to make glucose • Water and Minerals – water to carry out photosynthesis and minerals to grow • Gas Exchange – need oxygen for cellular respiration and carbon dioxide for photosynthesis. Gas exchange occurs through stomata • Movement of Water and Nutrients – plants take up water and minerals via roots but make food in leaves. Simple plants use diffusion while complex plants use specialized tissues

4. What do plants need to survive? -What plants need video clip

5. Early Plants • For most of earth’s history, plants did not exist. Life was in oceans, lakes and streams. The ozone layer did not exist and the atmosphere was infested with harmful UV radiation. Photosynthetic organisms added oxygen to the atmosphere, and thus and ozone layer. When plants appeared, life changed dramatically. New ecosystems emerged and matter formed soil. • The first plants emerged from green algae; multicellular photosynthetic plantlike protists (kingdom protista)

6. Early Plants • What was the greatest “challenge” to plants as they began to live on the land??? Acquiring, transporting and conserving water

7. Kingdom Plantae

8. Bryophytes • Nonvascular plants (meaning they do not contain vascular tissues – specialized tissues for water and mineral transport) • Includes mosses, liverworts and hornworts • Can only obtain water by osmosis a few centimeters above ground so they are low growing plants • Produce sperm that swim through the water to reach the eggs of other individuals, must live in moist/wet environments • Lack true roots, stems and leaves; instead have rhizoids to anchor them to ground

9. Bryophytes

10. Seedless Vascular Plants • Contain vascular tissues – specialized tissues used to conduct water and nutrients throughout the plant, even against the flow of gravity • Xylem – transport system that carries water from roots to every part of the plant. Contain cells called tracheids, cell walls are hollow and thick to resist pressure • Phloem – transport system that carries nutrients and carbohydrates produced from photosynthesis from the leaves throughout the plant • Seedless vascular plants include ferns , club mosses and horsetails • Contain true roots, stems and leaves

11. Seedless Vascular Plants

12. Seed Plants • The ability to produce seeds and develop vascular tissues has allowed plants to thrive in almost any condition all over the world and become the most dominant group of photosynthetic organisms on land • Divided into two groups 1. Gymnosperms – bear seeds in cones • includes conifers (pines and spruces), cycads (ginkgoes) 2. Angiosperms – aka flowering plants, bear seeds within a layer of protective tissue that protects the seed • includes grasses, flowering trees and shrubs, wildflowers and cultivated species of flowers • Adaptations that have allowed seed plants to reproduce without water include: flowers or cones, transfer of sperm via pollination and the protection of the embryos in seeds

13. Pollen and Seeds • Pollen – the male gametophyte (sperm) • Pollination – the transfer of pollen • Seed – embryo of plant encased in a protective covering and surrounded by a food supply • Embryo - organism in its early stage of development. After fertilization (sperm meets egg) the embryo forms • Seed Coat – surrounds and protects the embryo from drying out

14. Angiosperms – Flowering Plants • Flowering plants have dominated earth’s plant life due to adaptations that aid in their reproduction involving fruits and flowers • Flowers, the reproductive organs of angiosperms, help attract animals which transport pollen. This is much more efficient than wind pollination seen in gymnosperms • Flowers contain ovaries, which surround and protect the seed. The ovary gives the angiosperm its name, enclosed seed. • After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal. The fruit is essentially a wall of tissue surrounding the seed

15. Angiosperms – Flowering Plants-ways to classify

16. Angiosperms – Flowering Plants-ways to classify Woody vs Herbaceous Annual vs Biennial vs Perennial • Woody – Produce wood as they grow trees, shrubs and vines • Herbaceous – Smooth and non-woody dandelions, petunias and sunflowers

17. Gymnosperms

18. Angiosperms