2 Kingdom Protista: Algae & Protozoa BOT 101Kingdom Protista: Algae & ProtozoaOrganisms in this Kingdom don’t fit clearly into what we call plant, animal, or fungi.Most diverse eukaryotic Kingdom (>60,000 species).We are interested in this Kingdom because of the Chlorophytes & Charophyceans - green algae.
3 BOT 101The line between Kingdom Protista and Kingdom Plantae is still being discussed……Fig 29.4
13 2. Alternation of Generations BOT 1012. Alternation of Generations
14 2 multicellular life stages: Sporophyte: Diploid BOT 1012 multicellular life stages:Sporophyte:DiploidDivides by meiosis to form sporesSpores – haploid cells that can grow into a new, multicellular, haploid organism (the gametophyte) without fusing to another cell.Gametophyte:HaploidDivides by mitosis to form the gametes (egg and sperm)Egg & sperm fuse to form the diploid zygote, which divides by mitosis to form the sporophyte
15 3. Spores produced in sporangia BOT 1013. Spores produced in sporangiaSporangia =diploid cells within the sporangia divide by meiosis to form the haploid spores
19 5. Multicelluar, dependent embryos BOT 1015. Multicelluar, dependent embryosZygote divides by mitosis to become the sporophyte.
20 BOT 101Other examples of adaptations to life on land: (not all plants have the following):Cuticle –Secondary compounds –Roots –Shoots - stems and leaves to make food.Stomata – openings in the leaf surface to allow gas exchange for photosynthesis and to regulate water loss.
21 BOT 101More Adaptations4. .5. A vascular system that transports food & water from roots to shoots and vice versa.
24 Nonvascular Land Plants: Bryophytes BOT 101Nonvascular Land Plants: BryophytesEarliest land plants3 Phyla:Hepatophyta –Anthocerophyta –Bryophyta -.Peat moss (sphagnum): doesn’t decay rapidly, stores 400 bil tons of carbonGametophyte is the dominant generation:
37 Forests of the Carboniferous period (290-360 mil years ago): BOT 101Forests of the Carboniferous period ( mil years ago):Heat + pressure + time ----> coalPulled lots of CO2 out of atmosphere, cooling the earth & forming glaciersLarger species died out when climate became drier
38 Terrestrial Adaptations of Seed Plants BOT 101Terrestrial Adaptations of Seed PlantsSeeds replace spores as main means of dispersal.Why?Gametophytes became reduced and retained within reproductive tissue of the sporophyteHeterospory –Zygote develops into an embryo packaged with a food supply within a protective seed coat.Pollen & Pollination - freed plants from the requirement of water for fertilization.
39 1. Seeds replace spores as main means of dispersal. BOT 1011. Seeds replace spores as main means of dispersal.old way (ferns & mosses) =new way: the sporophyte RETAINS its spores within the sporangia & the tiny gametophyte develops within the spore.ovule =after fertilization, the ovule becomes the seedseed = sporophyte embryo + food supply (mature ovule tissues)
40 2. Reduction of the gametophyte: BOT 1012. Reduction of the gametophyte:Similar to Fig 30.2
41 3. Separate male & female gametophytes BOT 1013. Separate male & female gametophytesOld way: sporangia spores bisexual gametophyte (antheridia sperm, archegonia -> eggs)New way:Microsporangia microspores male gametophyte sperm
42 4. Ovules and seed production BOT 1014. Ovules and seed productionOvule =After fertilization, embryo develops, ovule becomes a seed
44 BOT 1015. Pollen & PollinationMicrosporangia microspores male gametophyte spermPollen =Pollination =Pollen tube brings sperm to egg within the ovule
45 Two types of seed plants: 1. Gymnosperms BOT 101Two types of seed plants:1. GymnospermsEvolved first“naked seed” –2. AngiospermsEvolved from gymnosperms
46 Gymnosperms Four phyla: Ginkophyta – Cycadophyta – Gnetophyta – BOT 101GymnospermsFour phyla:Ginkophyta –Cycadophyta –Gnetophyta –Coniferophyta –Dominate forests of the N. hemisphereMost are evergreenNeedle-shaped leaves to reduce water loss during drought
56 Notice the triploid stage! BOT 101Notice the triploid stage!Each pollen grain (male gametophyte) produces two spermSperm travel down the pollen tube & into the ovule.Double fertilization –Ovule matures into the seed – contains sporophyte embryo & endosperm (food).Ovary (female sporangium tissues) matures into the fruit.
59 The parts of a flower are typically attached to the: pedicel – the stalk of a single flower. It attaches the flower to the plant.Flower parts occur in 4 sections:1. Sepals –2. Petals – a typically colored or white, delicate structure. Petals function to attract pollinators.
60 3. Each male flower part is called a stamen. The stamen is composed of:1. Filament –2. Anther – a collection of pollen sacs that sits on top of the filament.
61 Each female part is called a pistil. Pistil = the female reproductive organ, consisting of:1. Stigma –2. Style –3. Ovary – the base of the pistil, contains the ovules. (Mature ovules are seeds and mature ovary is the fruit)
62 The Angiosperm Life Cycle Male gametophyte =Female gametophyte = embryo sac, develops in the ovule of the ovary. Produces egg
63 Development of Male Gametophyte (Pollen) Anther is composed of pollen sacs (sporangium).Each microspore divides by mitosis to make 2 cells:Generative cell –Tube cell – will make pollen tubeThe 2 cells enclosed in thick wall => pollen grain
64 Development of the Female Gametophyte (Embryo Sac) Ovule = female sporangiumOnly one megaspore survives and divides by mitosis 3 times to make 8 haploid nuclei.
69 MaturationEndosperm begins to divide to form structure that provides nutrients to developing embryoOvule is now a seed – dehydrates & becomes dormant (low metabolism, no growth).Ovary tissues divide & mature into fruit
71 Flowers are diverse……. Complete flower = Incomplete flower = lacks one of the above parts
72 Raceme = single flowers on pedicels along the rachis Inflorescence types:Inflorescence = the entire flowering part of a plantSpike =Raceme = single flowers on pedicels along the rachisPanicle = a much-branched inflorescenceSolitary flowerMany more!!