Chapter 20 : Plant Diversity

1. Chapter 20 : Plant Diversity

2. Land plants evolved from green algae. KEY CONCEPTPlant life began in the water and became adapted to land. • Plants and green algae have many common traits: • photosynthetic eukaryotes • have the same types of chlorophyll • use starch as a storage product • have cell walls with cellulose

3. Genetic analysis points to the common ancestor of all plants. • extinct green algae species in class Charophyceae • modern charophyceans common in lakes and ponds

4. Important plant characteristics likely originated in charophyceans. • multicellular body allowing for specialization of cells and tissues • cell division that allows for chemical communication between cells • reproduction involving sperm swimming to egg

6. Challenges of living on land have selected for certain plant adaptations. A cuticle allows plants to retain moisture. waxy, waterproof layer Plants have adaptations that allow them to live on land. • holds moisture in • Stomata are tiny holes in the cuticle. • can open and close • allow air to move in and out

7. A vascular system allows resources to move to different parts of the plant. water and mineral nutrients sugars • collection of specialized tissues • brings water and mineral nutrients up from roots • disperses sugars from the leaves • allows plants to grow higher off the ground

8. A seed is a storage device for a plant embryo. • seed coats protect embryos from drying wind and sunlight • embryo develops when environment is favorable

9. Pollen grains allow for reproduction without free-standing water. • pollen grains contain a cell that divides to form sperm • pollen can be carried by wind or animals to female structures

10. Plants have adaptations that prevent animals from eating them. • spines and thorns • defensive chemicals

11. Nonvascular plants grow close to the ground to absorb water and nutrients. Seedless plants rely on free-standing water for reproduction. Liverworts belong to phylum Hepatophyta. often grow on wet rocks or in greenhouses can be thallose or leafy Mosses and their relatives are seedless nonvascular plants. KEY CONCEPTPlants can be classified into nine phyla.

12. Hornworts belong to phylum Anthocerophyta. • found in tropical forests and along streams • flat, lobed body with little green “horns”

13. Mosses belong to phylum Bryophyta. • most common seedless nonvascular plants • sphagnum moss commonly used by humans as “peat”

15. A vascular system allows club mosses and ferns to grow higher off the ground. Both need free-standing water for reproduction. Club mosses belong to phylum Lycophyta. Club mosses and ferns are seedless vascular plants. • not true mosses • oldest living group of vascular plants

16. Ferns and their relatives belong to phylum Pterophyta. frond fiddlehead • whisk ferns and horsetails are close relatives of ferns • ferns have large leaves called fronds

17. Seed plants have several advantages over their seedless ancestors. can reproduce without free-standing water, via pollination Seed plants include cone-bearing plants and flowering plants. • pollination occurs when pollen meets female plantparts • seeds nourish and protect plant embryo • seeds allow plants to disperse to new places

18. Gymnosperms do not have seeds enclosed in fruit. • most gymnosperms are cone-bearing and evergreen. • the cone is reproductive structure of most gymnosperms. • pollen is producedin male cones. • eggs are produced in female cones. • seeds develop on scales of female cones.

19. most common gymnosperms alive today • includes pines, spruce, cedar, fir, and juniper • Conifers are gymnosperms in Phylum Coniferophyta.

20. Angiosperms have seeds enclosed in some type of fruit. • A flower is the reproductive structure of angiosperms. • A fruit is a mature ovary of a flower. • Angiosperms, or flowering plants, belong in Phylum Anthophyta.

21. Flowers allow for efficient pollination. animals feed on pollen or nectar pollen is spread from plant to plant in process Flowering plants have unique adaptations that allow them to dominate in today’s world.

22. Fruit allows for efficient seed dispersal. • a fruit is flower’s ripened ovary • Surrounds and protects seed(s) • Many forms, each function in seed dispersal

23. A cotyledon is an embryonic “seed leaf.” Monocots have a single seed leaf. leaf veins usually parallel flower parts usually in multiples of 3 bundles of vascular tissue scattered in stem Botanists classify flowering plants into two groups - monocots and dicots

24. Dicots have two seed leaves. • leaf veins usually netlike • flower parts usually in multiples of 4 or 5 • bundles of vascular tissue in rings in stem

25. Stem type can be woody or herbaceous. Wood is a fibrousmaterial made up ofdead cells. Wood has highconcentrations oflignin and cellulose. Woody stemsare stiff. Oak Flowering plants are also categorized by stem type and lifespan.

26. Herbaceous plants have no woody growth - only green stems and leaves Iris

27. There are three types of plant life spans. • Annuals mature from seed, flower, and die in one year. Wheat

28. Biennials take two years to compete life cycle. Foxglove

29. Perennials live more than two years. Big bluestem