Evolution and Classification of Plants: From Algae to Angiosperms

1. Kingdom: Plantae

2. General Characteristics • Multicellular, Photoautotrophic, Eukaryotic • Chloroplasts contain chlorophyll a and b, and carotenoids • Cell wall made of cellulose, Starch is the food storage compound • Adaptations to life on land include waxy cuticle and stomata to allow for exchange of gases through cuticle

3. Multicellular Algae to Plants • Plants began the movement onto land about 425 million years ago • Evolutionary history involves increasing adaptations to changing terrestrial conditions

4. Adaptations for Life on Land

5. Vascular Tissue • Xylem – transports water and minerals up from root (Xylem is dead at functional maturity) • Phloem – transports sugars (food) throughout plant

6. Four major periods in Plant Evolution • Origin of plants from green algae • Adaptation of vascular tissue (tissue which allows transport of materials throughout plant) • Origin of seeds (embryos enclosed with food in coating) • Emergence of flowering plants (bear seeds in protective coating)

7. Evolutionary trends • The reduction of the haploid generation with increasing dominance of the diploid generation • Adaptations to terrestrial life

8. Classification

9. Bryophyta (mosses) • No vascular tissue • Gametophyte generation is dominant • Sperm must swim to egg • Plants must live in moist environments

10. Bryophyta (mosses) • Gametophyte is the dominant (photosynthetic) generation, Sporophyte is brown capsule and stalk

11. Reproduction and Life Cycle • Life cycle involves Alternation of Generations between haploidgametophyte and diploidsporophyte • Moss Animation

12. Liverwort, Hornwort and Moss

13. Phylum Tracheophyta

14. Vascular System – 3 areas • Roots - Tubes gathered in center, anchor plant, absorb moisture and nutrients • Leaves – Major site of photosynthesis, stomata, veins of vascular tissue • Stems – Contains vascular tissue for transport, xylem and phloem

15. Tracheophyta -Seedless Vascular Plants • Psilophyta – whisk ferns

16. Tracheophyta – Seedless Vascular Plants • Sphenophyta - horsetails

17. Tracheophyta – Seedless Vascular Plants • Lycophyta – Club Moss

18. Tracheophyta -Seedless Vascular Plants • Pterophyta - Ferns • Produce spores • Able to live in drier environments than the Bryophytes, but sperm still must swim to egg

19. Fern Life Cycle • Life cycle of a fern

20. Spermopsida – Seeded Plants • Gymnosperms (naked seeds) • Angiosperms (covered seeds)

21. Gymnosperms – Seeded Plants Cone-bearing plants that produce seeds in cones Seeds are not contained in fruits – seed has thin protective coating that is part of seed itself

22. Coniferophyta – cone bearers

23. Cycadophyta - cycads

24. Ginkgophyta – Ginkgo biloba

25. Angiosperms -Seeded Plants • II.Angiosperm (“covered seeds”) Anthophyta – Flowering plants with protected seeds Fruit is ripened in ovary of flower that helps disperse seeds

26. Angiosperms, cont. • Monocots vs. Dicots

27. Monocot

28. Dicot

29. Plants exhibit indeterminate growth

30. Primary growth is at tips of root and shoot

31. Secondary growth increases a plant’s girth