Plants

1. Plants Orchid • Characteristics • Plant evolution • Lower plants Hornwort

2. Characteristics of Kingdom • Photosynthetic autotrophs • Eukaryotic • Chemistry same as for green algae • Cell walls • Pigments • Multicellular • Tissues & organs • Embryos

3. Characteristics of Kingdom • Life cycle – alternation of generations Diploid sporophyte meiosis zygote spores fertilization gametes Haploid gametophyte

4. The Plant Life cycle • Asexual reproduction common • Sexual cycle involves alternation of two generations • Gametophyte – gametes, dependent on water (at first) • Sporophyte – spores, adapted to dry condition • Trend in evolution – reduction of the gametophyte (increased importance of sporophyte)

5. Plant spores • Produced by meiosis from sporophytes • Haploid reproductive (dispersive) cells • Grow into a gametophyte by mitosis • Covered by sporopollenin

6. Plant gametes • Produced by gametophytes by mitosis • Eggs & sperm • Fertilized egg (zygote) grows into sporophyte Fern egg & sperm

7. Plant Development • Embryos • Young sporophytes develop from zygotes • Protected and nurtured by parent

8. Plant Body • Root / Shoot • Meristems • growing points • root/shoot tips • (woody plants) – sideways to form wood • indeterminate growth

9. Evolved from Charophycean Green Algae • Mid Paleozoic • Strong similarities • Differences Chara A Coleochaete B Parka (Ordovician) From Berkeley Time Machine Coleochaete

11. Plant classification • Bryophytes – no seeds, no roots, no vascular • Mosses, liverworts, hornworts • Seedless, vascular plants – no seeds • Ferns, horsetails, club mosses, whisk ferns • Gymnosperms - seeds & cones • Conifers, cycads, ginkgo, gnetophytes • Flowering plants – seeds, flowers & fruits • Primitive, Monocots, Dicots

12. Non-vascular plants“Bryophytes” • Mosses, liverworts, hornworts • Gametophyte dominant • No roots – rhizoids • Often dependent on available moisture • Occupy ecological niches no other plants do • Represent first plants Moss Liverwort Hornwort

13. Phylum Bryophyta – Mosses • Leafy gametophytes • Sporophytes with complex teeth • Evolutionarily distinct group from other bryophytes

14. Moss Life Cycle • Sporophyte • Zygote • Embryo nurtured by gametophyte • Mature sporophyte with sporangium • Gametophyte • Spore • Protonema • Leafy gametophyte • Gametes eggs & sperm

15. Moss Life Cycle Male leafy gametophyte Female leafy gametophyte Protonema Sporophyte Gametophyte Spores

16. Sperm from antheridia Moss Life Cycle Leafy gametophytes Egg in archegonium

17. Moss Life Cycle Fertilization Meiosis to form spores within sporangium Young sporophyte Zygote Spore dispersal by wind Embryo

18. Sperm from antheridia Moss Life Cycle Egg in archegonium Gametophyte Fertilization “First thread” stage Sporophyte Meiosis Zygote Spores Embryo

19. Moss links • UBC Moss Class • Microscopy UK

20. Phylum Hepatophyta - Liverworts • Sporophyte simpler than mosses • Leafy • Thallose

21. Phylum Anthocerophyta - Hornworts • Sporophyte linear tube with meristem at base • Thalloid • Closest bryophyte to ancestor of other plants

22. Moss, Rhizomnium

23. Moss, Tortula, whole leaf

24. Sphagnum bog

25. Sphagnum = Peat Moss

26. Thallose liverwort Marchantia

27. Leafy liverwort Lophocolea

28. Hornwort, Anthoceros