Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Kingdom Plantae Overview • Autotrophic Eukaryotes • First group of truly multi-cellular organisms – Allows for specialization and organization of structures! – Cells Tissues Organs Organ Systems • Organized into Divisions rather than phyla – 12 major divisions Evolution • Believed to have evolved from a freshwater green alga – Similarities: • contain chlorophyll a and b • store carbohydrates as starch • have cell walls of cellulose • Major evolutionary advancements include the development of: – – – – embryo protection vascular tissue seeds flowers Evolution – cont’d • Fig. 29.1 Reproduction - Terminology • Haploid (1N) – half chromosome count • Diploid (2N) – full chromosome count • Mitosis – generates identical cells • Meiosis – divides diploid cells to haploid cells • Spore – haploid cell – develops into a sexcell producing structure • Gamete – haploid “sex cell”, – will fuse with another gamete • Zygote – First cell formed after fusion (fertilization) – Diploid Characteristic Reproduction Alternation of Generations • ALL plants exhibit two multicellular stages in life cycle – Gametophyte • Haploid (1N) • Gamete producing stage (mitosis) – Gametes fuse 2N zygote sporophyte – Sporophyte • Diploid (2N) • Spore producing stage (meiosis) – Spores are 1N develop into gametophyte Alternation of generations cont’d • Fig. 29.2 Alternation of Generations cont’d • Different plants exhibit variations of the generalized life-cycle – Dominant phase changes • primitive plants = gametophyte dominant • advanced plants = sporophyte dominant – Only phase capable of forming vascular tissue Alternation of Generations cont’d Size of the gametophyte versus the sporophyte Fig. 29.3 Bryophytes - Overview • Non – Vascular Plants • Lack vascular tissue • specialized tissues or organs for transport of water and nutrients • Do not have true roots, stems, or leaves • Gametophyte is the dominant generation – Sporophyte is attached to the gametophyte and derives nourishment from it – Sperm must swim to egg for fertilization • Representative Organsims – Mosses, hornworts and liverworts Bryophytes cont’d • Turn and talk to your neighbour... – What impact would these characteristics have on the growth and development of these plants? Bryophytes – cont’d • Must live in a moist environment – Rely on diffusion and osmosis for nutrients • Limits the ability of the organism to grow to a large size – All plant parts must have direct access to nutrients and water Bryophytes – Structure • Simplified plant structure – No true organs. • Rhizoids – Root like filaments • Limited anchoring • Limited absorption Bryophytes – Structure • Stalk – Elongated cells – Helps with the osmosis of water between cells • Leaf-like appendages – Large flat structures • not a true leaf Liverwort, Marchantia • Fig. 29.4 Moss life cycle • Fig. 29.5 Bryophyte Reproduction • Asexually – fragmentation • Sexually - Sphagnum Moss • AKA - Peat Moss • Fuel source – Can be cut into 'bricks' and used for heating. – Newfoundland has large peat resources – Over millions of years peat is compressed and forms coal Sphagnum Moss • Has high absorption capabilities – Used in gardening, oil spills and diapers • Antiseptic properties – Very low pH – Used as wound dressing in WWI Vascular Plants Vascular Plants • Tracheophytes – Land dwelling plants – Have specialized structures for the transport of nutrients and water • Vascular Tissue! • Artificially divided into two major groups, – Seedless vascular plants – Seed plants – Official division is into many more groups. Division Pteridophyta • Seedless Vascular Plants – Representative Organisms - Ferns Pteridophytes • Pioneer Plants (with mosses) – Able to grow in adverse conditions • Bare rock, or limited soil • Highly acidic soil, after forest fires – Often first multi-cellular organisms to grow in an area • Help to create growing conditions for other plants Pteridophyte Structure • Fronds – Leafy portion • Rhizomes – Barely visible stem – Grows horizontal to surface • Roots • Fiddleheads – Early stage of new fronds Pteridophyte Asexual Reproduction • Fragmentation – Several clumps of fronds result from one plant – If the Rhizome connecting them is split, each clump will survive Pteridophyte Sexual Reproduction • Alternation of Generations • Spores produced under fronds in structures called sori Pteridophyte Sexual Reproduction • Gametophyte • Gametophyte with early development of sporophyte Fern life cycle • Fig. 29.11 Vascular Seed Plants Overview • Plants that reproduce using seeds • Evolutionary advantage – Seed contains a sporophyte embryo and stored food • Allows survival until conditions are favorable for germination Overview cont’d • Two main groups – Gymnosperms • gymno = naked; sperma = seed • ovule not completely enclosed by diploid tissue – seeds develop on the surface of the sporophyte – Angiosperms • angio = vessel, receptacle, container • ovule completely enclosed within diploid sporophyte tissue (ovary) which becomes a fruitseeds Gymnosperms – Representative Organisms • Conifers – Spruce, Cedar – Grow in all climate zones and on all continents except Antarctica. – Economically important • Pulp and paper • Gnetophytes – Ephedra is only species in N. America – Adapted to hot temperatures Gymnosperms – Representative Organisms • Gingkophytes – One surviving speciesGingko biloba, the maidenhair tree – Fleshy seeds give off foul odor – Resistant to pollutionoften used in ornamental plantings – Used in herbal remedies • Cycads – Resemble palms or ferns – Pollen or seed cones grow on top of long vertical stem – Plentiful in Mesozoic era at the time of dinosaurs Gymnosperms - Structure • Generally Evergreen – Don’t drop leaves each year • Leaves – Thin, needle-like – Have thick waxy outer coat • Roots – Shallow roots – Cover wide area Conifer- Reproduction • Conifers are dioecious – Generate both male and female cones • Exhibit heterospory – Two types of spores , which produce female (♀) and male (♂) gametophytes – Pollen grains = ♂ gametophyte – Pollination – deposition of pollen on a ♀ gametophyte – Pollen tube – sperm pass through pollen tube to reach ovule • No water required as it is in previous groups – ♀ gametophyte develops within ovule Pine life cycle • Fig. 29.12 Conifers- Adaptations • Adapted to cold, dry weather • Pollen cones and seed cones are adaptations to land • Needle-shaped leaves have small surface area-decreases water loss – Also have a thick cuticle and recessed stomata • Wood is used in construction and for making paper • Resins are used for production of chemicals