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Kingdom Plantae. The plant kingdom is in the domain Eukarya and in the supergroup Archaeplastida. Common Ancestor. The closest living relative of plants are in the green algae are charophytes At one time they had a common ancestor. Traits Common to Green Algae and First Land Plants.
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The plant kingdom is in the domain Eukarya and in the supergroup Archaeplastida
Common Ancestor • The closest living relative of plants are in the green algae are charophytes • At one time they had a common ancestor
Traits Common to Green Algae and First Land Plants • Same rose-shaped cellulose synthesizing complexes • Both have peroxisome enzymes for photorespiration • Same cell wall formation • Flagellated sperm • Apical meristem to increase in length and produce specialized tissue • Both contain plasmodesmata or pores • Cellular/chloroplast DNA similarities
Terrestrial Advantages • More light (water reduces light reaching plants • More CO2available for photosynthesis • More minerals found in land • Few predators
Disadvantages • Less support (water gives more support than air) • Preventing desiccation (drying out) • Need for water (metabolic processes) • Reproductive barriers - bringing gametes together and preventing them from drying out
Land plants evolved new emergent propertiesto adapt to life on land
Four Derived Traits of Terrestrial Plants • Exhibit alternation of generations producing an embryo that is for some time dependent upon the female gametophyte. • Plants produce spores coated with “sporopollenin” to prevent dehydration and waxy cuticles for other plant parts.
Four Derived Traits of Terrestrial Plants • Multicellular gametangia to produce eggs and sperm. • Apical meristem- Area found on the tips of shoots and roots and other locations that specialize in the process of mitosis.
Alternation of Generations • Parental generation is diploid (2n) with two sets of chromosomes and called the sporophyte generation • Sporophyte form sporangia that will have cells inside that undergo meiosis to produce haploid spores (1n) one set of chromosomes • Spores may be of different sizes-megaspores and microspores
Alternation of Generations • Spores becomes the gametophyte generation • Megaspore produces a gametophyte via mitosis that contains an archegonium that produces an egg • Microspore produces a gametophyte that contain an antheridium that produces sperm • Gametophyte and sporophyte generation look nothing alike
Through evolution, the sporophyte generation has become more conspicuous than the gametophyte generation
Protected Spore Plantsproduce spores coated with “sporopollenin” a polymer to prevent dehydration in multicellular compartments
Fossilized spores. Unlike the spores of most living plants, which are single grains, these spores found in Oman are in groups of four (left; one hidden) and two (right). Fossilized sporophyte tissue. The spores were embedded in tissue that appears to be from plants.
Multicellular Gametangia Produces Eggs and Sperm Gametangia protects gametes from desiccation
Apical Meristem found on the tips of shoots and roots specialize in the process of mitosis (growth).
In the course of evolution of land plants, major events occurred to include development of vascular tissue, stems, leaves, roots, seeds and flowers. • There are major groupings include bryophytes, seedless vascular plants, and the plants that produce seeds and flowers.
Bryophytes Mosses, Liverworts, & Hornworts • Nonvascular land plants • Have structures that resemble leaves and roots (rhizoids) • Gametophyte dominant generation • Seedless • Form spore capsules (sporophyte) • Sperm swims to eggs through water droplets
Mosses • Grow in moist areas • Leaf-like structures & rhizoids • Archegonia (eggs) & antheridia (sperm) at top of gametophyte • Sporophyte makes spore capsule on a stalk
Polytrichum commune, hairy cap moss Sporophyte Gametophyte
Liverworts Flattened body (thallus) with lobed like shape Form cup-like structure for reproduction Gametophyte generation dominant
Hornworts have a leafy gametophyte like moss and the sporophyte generation grows out of and is dependent on the gametophyte.
LycophytesClub moss, Spike moss, Quillwort • Have vascular tissue (conductive) • Xylem-moves water and minerals upward and is strengthened with lignin in cell walls • Phloem moves water and organic nutrients both up and down. • Leaves (microphylls with single strand of vascular tissue) and roots evolved as extensions from the stem • Sporophyte dominant • Microphylls contain sporangia at the top of the plant in a strobili
Club moss with vascular tissue. Microphylls containing sporangia at the top of the plant.
Spike Moss Quillwort
PterophytesFern, Horsetails, Whisk ferns • Megaphylls or true leaves with branched vascular bundles • Increased photosynthesis • Ferns have underground horizontal stem (rhizome) and leaves (frond) that push up from the soil. • The gametophyte generation is reduced • Sporophyte dominant
Whisk Fern • Lack megaphylls (leaves) and roots • Made of only branching stems • Have underground, horizontal rhizome
Horsetails • One genus • Underground rhizome produces aerial stems with whorls of side branches • Cell walls with silica
Seed Plants • Produce seeds in the sporophyte generation • Seed consist of a seed coat, food, and sporophyte embryo • Spores produced by the sporophyte generation are retained in the plant and are not released into the environment
Seed Plants • All seed plants produce two different types of spores (heterospory) • Microspores make the male gametophyte (pollen) • Megaspores make the female gametophyte inside a structure called the ovule
Seed Plants • The female gametophyte never leaves the sporophyte • The ovule eventually becomes the seed once the egg of the female gametophyte is fertilized • The entire male gametophyte is used to deliver the sperm cells
Seed Plants • Seeds and pollen eliminates the necessity of water for reproduction • Both can be carried long distances and have a thick coats to resist drying out • Spread by wind, insects, animals, etc.
Two Types of Seed Plants • Gymnosperms and Angiosperms both reproduce by seeds • Gymnosperms make naked seeds protected in cones • Angiosperms make seeds surrounded by a mature ovule (fruit) • Angiosperms produce flowers to attract pollinators
Gymnosperms • Gymnosperms do not produce fruit or flowers • Conifers are the largest gymnosperm group with 575 species • Most do not shed their leaves in the fall • Includes pine tree, junipers, and sequoias • It takes 2 years to produce a seed
Other Gymnosperms • Phylum Cycadophyta-cycads have large cones and palmlike leaves • Phylum Ginkgophyta-only one species surviving. Deciduous fan leaves with fleshy seeds • Phylum Gnetophyta-species are found in tropics and desert
Flowering Plants • Phylum Anthophyta • A flower is a structure specialized for reproduction • Flower can have both male and female reproductive organs (Perfect flower) • Imperfect flowershave only male (staminate flowers) or only female (pistillate flowers)
Flower Types • If both male staminate and female pistillate flowers are on the same plant, it is monoceious • Corn is a monoecious plant • If male staminate and female pistillate flowers are on different plants, it is said to be dioecious • Persimmon and ash are dioecious
Perfect & Imperfect Flowers PERFECT COMPARISON
Parts of the Flower • Sepal-leaf like and protects the floral bud • Petals-Usually showy with colors to attract pollinators • Stamen-male reproductive organ consisting of stalk like filament with anther (pollen sac) • Pistil-female reproductive organ with sticky stigma at the top, stalk like style, and enlarged ovary (base) with ovules