Chp 21-22 Flashcards
How do Plants Affect other Organisms?
Plants play a crucial Ecological Role; Provide Humans with necessities and luxuries.
What Are The Key Features of Plants?
Plants have multicellular, Dependent Embryos; Plants have Alternating Multicellular Haploid and Diploid Generations
What is the Evolutionary Origin of Plants?
The Ancestors of Plants were aquatic.
How do Plants adapted to Life on Land?
Plant bodies resist gravity and drying; Plant Embryos are protected, and some plats have sex Cells that disperse without water.
What are the Major groups of Plants?
Nonvascular Plants Lack conducting structures; Vascular plants have conducting cells that also provide support; The seedless vascular plants include the Club Mosses, Horsetails, and Ferns;
The Seed Plants are Aided by two important adaptations: Pollen and seeds; Gymnosperms are nonflowering Seed Plants and Angiosperms are Flowering Seed Plants; Recently evolved plants have smaller gametophytes.
What is photosynthesis ?
The process by which plants use energy from sunlight to convert water and carbon dioxide to sugar. The color comes from the presence of the pigment chlorophyll in many plant tissues.
What distinguishes plants from other organisms?
Their multicellular Embryos.
What distinguishes plants from algae?
Multicellular, dependent embryos that are not found among photosynthetic protists.
Describe Alteration of Generations
A life cycle, typical of plants , in which a diploid sporophyte (spore -reproducing) generation alternates with a haploid gametophyte (gamete-producing) generations. In organisms with this, separate diploid and haploid generations alternate with one another. (Diploid has two sets of chromosomes; a haploid one)
What is a Sporophyte
In the diploid Generations, the body consists of diploid cells (sporophytes) In plats the multicellular embryos described are part of the diploid sporophyte generation) The multicellular diploid stage in the life cycle of a plant; produces haploid, asexual spores through meiosis.
What is Gametophytes
The multicellular haploid stage in the life cycle of a plant. Certain cells of sporophytes undergo meiosis to produce haploid reproductive cells called spores and they develop into gametophytes.
Alternation of Generations in plants : Plant life cycle
A Diploid sporophyte generation produces haploid spores through meiotic cell division -> the spores then develop into a haploid gametophyte generation that produces haploid gametes by mitotic cell division -> the fusion of these gametes results in a diploid zygote that develops into the sporophyte plant.
How do plants help the ecosystem?
Capture energy that other organisms use, help maintain atmosphere with oxygen gas as a by-product of photosynthesis; Plants build soil when they die its stems, leaves, and roots become food for fungi, prokaryotes and other decomposers. Making soil more fertile. Keep Earth Moist.
How do plants provide us with Necessities and Luxuries?
Nothing for humans would’ve been possible without plants. Plants provide shelter, fuel and medicine. Wood is fuel. Coal is composed of remains of ancient plants that have been transformed by geological process; Drugs such as aspirin, heart medicine, cancer treatments Taxol and vinblastine, the malaria drug quinine, the painkillers codeine and Morphine, and more.
What is the evolutionary origin of plants?
Ancestors are photosynthetic protists similar to the modern algae known as stoneworts. They are plants closest to living relatives; DNA comparisons show evolutionary relationship; Green algae and plants use the same type of chlorophyll and accessory pigments in photosynthesis.
Ancestors were aquatic
Modern stoneworts , the protists that gave rise to plants lacked roots, stems, leaves and complex reproductive structures such as flowers or cones, features that appeared only later in the evolutionary history of plants. ; Life in water had many advantages; Water a body is bathed in a nutrient-rich solution, and supported by buoyancy and not likely to dry out. Life in water facilitates reproduction, because gametes (sex cells) and zygotes (fertilized sex cells) can be carried by water currents or propelled by flagella.
How did the plants adapted to live on the mainland?
Structures that support the body and conserve water, conducting cells that transport water and nutrients to all parts of the plant, and processes that disperse gametes and zygotes by methods that are independent of water.
How do they resist gravity and drying?
Roots or root-like structures that anchor the plant and absorb water and nutrients from the soil; A waxy cuticle (fatty coating no the surfaces of aboveground epidermal cells of many land plants) that covers the surface of leaves and stems and limits the evaporation of water ;
- Porse called Stomata (sing, stoma) in the leaves and stems that open to allow gas exchange but close when water is scarce, reducing the amount of water lost to evaporation.
- Later in the transition to terrestrial life:
- Conducting cells that transport water and minerals upward from the roots and that move photosynthetic products from the leaves to the rest of the plant body.- The stiffening substance lignin, which is a rigid polymer that impregnates the conducting cells and supports the plant body, helping the plant expose maximum surface are to sunlight.
Plant embryos are protected how?
Seed plants: characterized by specially well-protected and provisioned embryos and waterless dispersal of sex cells. Key adaptation of these plants are seeds, pollen, and , in the flowering plants, flower and fruits.
Major Groups of Plants
- Non vascular (bryophytes) require a moist environment to reproduce and thus straddle the boundary between aquatic and terrestrial life (like amphibians of the animal kingdom)
- Vascular (Tracheophytes) drier habitats colonizer
How do Non vascular plants conduct nutrients.
- THey retain some characteristics of algae. Lack true roots, leaves and stems.
- Posses Rhizoids (rootlike anchoring structures)
- Do not have structures for conducting water and nutrients so rely on poorly developed conducting tissues.
- Body size is limited. Also limited by the absence of any stiffening agent in their bodies. (less than an inch tall).
What is the evolutionary tree like in Plants?
Liveworts -> Mosses -> Ferns -> Gymnosperms and Angiosperms
Non vascular plants
Hornworts, liveworts, and mosses. Named for their shapes. Features - Haploid spores are carried by wind, early embryonic development occurs within the archegonium of a gametophyte.
Vascular Plants
Ferns, conifers, and flowering plants: Water and nutrient transport structures: All have different features.
