22.1 Introduction to Botany

1. 22.1 Introduction to Botany Essential Question What is Botany?

2. What is botany? • Botany is the study of plants. • Areas of botany: • Plant Anatomy and Physiology • Plant Taxonomy • Plant Geography • Plant Ecology • Plant Genetics • Plant Cell Biology • Economic Botany • Ethnobotany

11. Generalized Plant Life Cycle

20. Cont’d • Plants also grouped according to how they obtain water. • Vascular plants have tube-like structures that transport water from the roots to the leaves. • Nonvascular plants can only absorb water through their roots.

21. Nonvascular plants • Nonvascular plants or bryophytes are found in moist areas because they do not have long roots to absorb water. • They are usually less than 20 cm tall. • Three classes: • Mosses • Liverworts • Hornworts

22. Floweringplants Cone-bearingplants Ferns andtheir relatives Flowers; SeedsEnclosed in Fruit Mosses andtheir relatives Seeds Water-Conducting(Vascular) Tissue Green algaeancestor Figure 22–6  A Cladogram of Plant Groups Section 22-1 Go to Section:

23. Figure 22-7 The Diversity of Plants Section 22-1 Cone-bearing plants760 species Floweringplants235,000 species Ferns andtheir relatives11,000 species Mosses andtheir relatives15,600 species Go to Section:

24. Cont’d • Plants also grouped according to how they obtain water. • Vascular plants have tube-like structures that transport water from the roots to the leaves. • Nonvascular plants can only absorb water through their roots.

28. Vascular Plants • Two categories: • Gymnosperms – bear seeds in cones; pine trees • Angiosperms (Flowering) – largest category- bear seeds in flower

30. Angiosperms Commonly called flowering plants Two types: monocots – one seed leaf dicots – two seed leaves Fruit – ripened ovary of a flower Includes trees, grasses, and shrubs

31. First Plants • Oldest fossils (450 million years) show that earliest plants were similar to today’s mosses • Early plants depended on water for reproduction • Over time plants evolved adaptations that allowed them to reproduce without water and also to exist in a wide range of terrestrial environments.

32. Origins in water • First plants evolved from multicellular green algae. • These algae have the size, color, appearance of plants • Reproductive cycles of algae like plants • Cell wall and pigments of algae identical to plants

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