1. Diversity of Plants

2. Features of plants Photosynthetic with Chlorophylls a and b and carotene accessory pigment cellulose cell walls carbohydrate storage as starch in chloroplast Chloroplast structure organised into grana mechanisms to protect the zygote

3. Evolution of plants Evolution is driven by the need to absorb, transport and retain water, and the need to reduce the requirement of water for fertilisation.

4. Groups of plants The non-seed, non- vascular plants Mosses, Liverworts and Hornworts The non-seed vascular plants Whisk ferns, Club mosses, Horsetails, Ferns Gymnosperms Angiosperms

5. Mosses, Liverworts and Hornworts Important today both ecologically and economically peat-burning provides part of Ireland's energy requirements, and unlike fossil fuels, peat is a renewable resource when properly managed. In addition, peatlands are the habitat of commercial crops such as blueberries and cranberries. Important in horticulture for potting and as a soil additive First colonisers of bare land

6. Mosses, Liverworts and Hornworts No leaves No vascular tissues No true roots Poorly defined cuticle flagellated spores (sperm) Gametophyte dominant Sporophyte on gametophyte Hornworts have a long lived sporophyte Liverworts have a lobed thallus

7. Life cycle Spores produced by meiosis Fertilisation of egg gives Diploid sporophyte which then divides to produce a stalk and capsule Sperm Archegonium gives single egg cell by mitosis Antheridum gives sperm by mitosis Female gametophyte Male gametophyte Spore (n) Protonoma

8. Development of Moss from the protonoma Moss spore Early protonema Developing moss plant

9. Moss reproductive structures Antheridia give flagellated sperm Archegonia with egg cell

10. Non-seed, non-vascular plants and water Capillary uptake of water, sufficient only for a few centimetres, restricts the height of the plant. All parts of the plant must photosynthesise as no phloem to transport sugars - no subterranean roots. Abundant water needed for germination and growth of the protonema Need a film of water for the sperm to swim in for fertilisation

11. Seedless vascular plants All have phloem and xylem in the stem to transport sugars and water (tracheids only) All have underground stem (rhizome) All have essentially the same reproductive system with a dominant sporophyte Whisk Ferns Club mosses horsetails ferns

12. Whisk Ferns (Psilophytes) No true leaves, but expanded surfaces without vascular tissue (enations) - restricts the length of the enations.

13. Club mosses (Lycophyta) Microphylls (leaves with a single unbranched vascular bundle). Leaves may be long but not wide. Now rare, but in past times, tree-form club mosses more than 35 metres tall were abundant

14. Horsetails Microphylls (may be more than one parallel vascular bundle) means leaves may also be wider. Only one genus Equisetum survives today although in carboniferous times, they were abundant and tree-sized.

15. Ferns Megaphylls (leaves with branched vascular bundles). Leaves may be any size or shape.

16. Life cycle Spore bearing leaves (sporophylls) produce Spore-producing structures (sporangia) Spores produced by meiosis Sometimes two different sizes of spores, microspores and megaspores giving male and female prothalli, are produced from microsporangia and megasporangia. This may explain how seeds originated.

17. Life cycle of Whisk ferns, Club mosses, Horsetails and Ferns Mature plant is sporophyte 2N Spores produced by meiosis Spores germinate to give protonema N Protonema germinates into a heart shaped prothallus Antheridia develop on the prothallus Archegonia develop on the prothallus Sperm released Sporophylls

18. Water and non-seed vascular plants Phloem allows underground, non- photosynthetic parts which provide anchorage and take up water. Xylem allows the plant to grow to a great height. Plants need water for growth of the protonema/ prothallus. Need a film of water for the sperm to swim in for fertilisation

19. Gymnosperms

20. Heterospory - male and female spores are different Retention and protection of the female spores Pollination Seeds (born naked) Well developed roots 4 subgroups Conifers Cycads Gnetophyta –Gnetum –Welwitschia –Ephedra Gingkgophyta –Ginkgo biloba

21. Seeds may have evolved by a megaspore not being shed Mature plant is sporophyte 2N Megaspore not shed and germinates on the plant. Protonema germinates into a heart shaped prothallus Archegonia develop on the prothallus Sporophylls Megasporangium 2n gives a megaspore (n) Microsporangium gives microspores (pollen)

22. Reproduction in the gymnosperms = egg (n) Female gametophyte (n) = female prothallus = archegonium (n) nucellus (2n) = megasporangium Sporophyll (2n) Seed bearing scale leaf (lots of these make up a cone) Integuments (2N) Protective covering derived from parent (gives seed coat) Micropyle (opening to allow fertilisation) Ovule

23. Angiosperms Flowers Fruits (seeds not born naked) Endosperm Xylem vessels Split into two sub- groups Monocotyledons Dicotyledons

24. Differences between monocots and dicots

25. Monocotyledons

26. Families within the monocots Palms arums agaves, amaryllids, bromeliads (pineapple) yams grasses, sedges, cat- tails Irises lilies orchids gingers and bananas

27. Orders within the Dicotyledons Magnoliids (Primitive flowering plants) sunflowers, scrophs, potato Ericads (Blueberries, etc.) "Lower" Hamamelids (Sycamores, etc.) "Higher" Hamamelids (Oaks, Figs, Elm, etc.) Ranunculids Rosids (Roses, Legumes, etc.)

28. Reproduction Essentially the same as gymnosperms except that efficient vectored pollination. Growth of a long pollen tube to deliver the male gametes. Fertilisation occurs soon after Pollination Double fertilisation –normal fertilisation to give a zygote –fertilisation with 2 polar nuclei gives endosperm Developing zygote occurs within the enclosing sporophyte tissues - fruits