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Plants An Overview of Plants What are Plants? Trees ,flowers, vegetables, fruits, field crops like wheat, rice, corn Some plants are food sources for human. Without plants most life on earth is not possible. Plant Characteristics Plants range in size from Desert Paintbrush microscopic water ferns to giant sequoia trees(100m) They adapted to nearly Desert Sunflower every environment (frigid, ice bond polar regions and others grow in hot dry deserts. Desert Willow Plant Cells A plant cell has cell membrane, a nucleus, and other cellular structures. They have cell walls that makes them different than animal cells. Plant cells contain chlorophyll. It is found in chloroplast (Green). They have vacuole that stores pigment and regulates water. Origin and Evolution of Plants The ancestors were probably ancient green algae that lived in sea. Today, plants and green algae have the same types of chlorophyll and carotenoids that red, yellow, orange. Fossils are not good clue for plants. They usually decay before they become fossilize. Cooksonia a fissile of one of these plants. Exact origin of flowering plants is not known. Life on Land Earth has more sunlight and CO2 for Photosynthesis. Long time ago more plant adapted to land easily. Plants give off oxygen. This paved the way for organism that depends on Oxygen. Shallow pool provides water to green algae to survive. They make processes of photosynthesis. When it dries they dies. Water moves in and out. (Osmosis). Cuticle and Cellulose Stems ,leaves and flowers are covered by cuticle that is a waxy, protective layer secreted by cells onto surface of the plants. Cuticle slows loss of water. Cellulose is chemical compound that plants can make out of sugar. It forms tangled fibers in cell walls. These fibers provide structure and support. Reproduction Some water resistant spores helps plant reproduce successfully. Other plants adapted by producing water resistant seeds in cones or in flowers that developed into fruits. Classification of Plants. Vascular :have tube like structures that carry water and substances Nonvascular: Do not have tubelike structures. Scientist use Binomial Nomenclature. Quesrcus Alba (White Oak) SEEDLESS PLANTS Plants are made up of stems root leaves flowers. What else? Most plants grow from seeds. What plants do not grow from seeds. NONVASCULAR PLANTS. They are thick and only 2cm and 5 cm height. Most have stalks that look like stems and green, leaflike growths. (rhizoid) They absorb water and distributed to their cell membranes. They do not have flowers and reproduce by spores. Mosses, liverworts, hornworts. Mosses They have green, leaflike growths arranged around a central stalk. Their rhizoids are made of many cells. Stalks grow from moss parts. Spores are produced in the caps of these stalks. They are usually found in dump area and on tree trunks. Liverworts They are thought to be useful in treating diseases of liver. Wort means “herb” liverwort means “herb for liver” They are leaflike flattened bodies. Hornwort Most of them are less than 2.5 cm diameter and have flattened body. They have only one chloroplast in their each cell. Their spore producing structure is tiny horns of cattle. Nonvascular plants and The environment Mosses and liverwort can grow on long and dry periods , also grow in thin soil and in soils where the other plants do not grow. Their spores are carried out by wind. They start to grow easily. they are among the first plants to grow in new disturbed area. Organism that are the first to grow in new and disturbed areas are called PIONEER SPECIES. They build the soils therefore the other organism move in that area. Seedless Vascular plants Like ferns vascular seedless plant can grow big and thick because they can carry the water and minerals from soil to their leafs. Club Mosses Ground pines and Spike mosses are groups of plants that often are called club mosses. Spores are produced at the end of stem in structures like pinecones. They are endangered. Spike mosses resemble ground pines. Some of them adapted to desert condition. When water us scarce they curls and unfurl seem dead. When water becomes available the resurrection plants unfurls its green leaves and making food again. Horsetail The stem structure of horse tails is unique among the vascular plant. The stem is jointed and has a hollow center surrounded by a ring of vascular tissue. Spores are produced in conelike structure at the end of stems. The stems of horsetail contain silica a gritty substance found in sand. Horsetail has been used fro polishing objects, sharpening, tools, and scouring cooking utensil. Importance of Seedless Plants Dead plants are turned into coal ( took million years ) The same is process is happening on bogs which are poorly drained areas of land contain decaying plants. Overtime, slow decaying plants process without oxygen are compressed into substance called peat. Peat is used for energy source in Russia and Ireland. Seedless vascular plants are used for gardening and medicine, Their root can be used for food source too. SEED PLANTS What did you eat yesterday? Carrot, apple, watermelon, peanut butter? Most of plant you familiar with are seed plants that have leaves and stems roots. They have seed that contain embryo and food. They are classified into two groups A) Gymnosperms B) Angiosperms Leaves They do photosynthesis with leaves. Upper and lower surface layer covered with thin layer called Epidermis ( cuticle coats) Small opening are called STOMATA (it allows plant to take in take out water CO2 and oxygen) Each stomata surrounded by two guard cells Below the upper layer is called PALISADE LAYER ( it is rich for chlorophyll) What does it mean? (2pt ) Between palisade and lower epidermis is spongy layer. http://www.fw.vt.edu/dendro/forestbiology/photosy nthesis.swf Stems The trunk is really the stem. Materials move between root and leaves through the vascular tissue. Stems can be herbaceous( soft) or woody( hard, rigid) http://www.biology.ualberta.ca/facilities/multimedia/uploads/alberta/flower.swf Roots Water and other substances enter through tree from its roots. It has vascular tissue Roots anchors to soil to prevent plant being blown away. They can be found above – ground. Roots can store food. (carrots and beets) Plants use this stored food to grow. (Some store water) They perform absorbing oxygen such as plant which live in water) Vascular tissue Three tissues A) Xylem: hollow tubular cells that are stacked one on top the other to from a structure called vessel. It transports dissolved materials and supports plant. tracheids B) Phloem: Tubular that are stacked to form structure called tubes. They move food. C) Cambium: produces most of the new xylem and phloem cells. http://www.biotopics.co.uk/plants/pltrsu.html Gymnosperm The oldest trees. Bristlecone pine tree is 4900 years old. Gymnosperms are vascular plants that produce seeds that are not protected by fruit.( Naked seed) (They are needlelike green) They are classified A) conifers,( pines, firs, spruces, redwoods) B) cycads, C) ginkgoes, D) gnetophtes Conifers produce two types of cones ;Males and female. seeds develop on the female one. Angiosperm Angiosperm :A vascular plant that flowers and has fruit that contains one or more seeds. They grow everywhere. The fruits develops from a part or parts of one or more flowers Some plants flower are not recognized .they are nor colored. ( Ash flower) Some flower parts develop into fruit. Most fruits contain seed like apple. All fruits are nor juicy. The fruit of vanilla orchid. http://www.wisc-online.com/objects/index_tj.asp?objid=BIO1305 Monocots and Dicots A cotyledon is part of seed ,used fro food storage. mono mean one di mean two. Many important foods come from monocots including corn rice wheat and barley. Lilies and orchids too. Dicots also produce familiar foods such as peanuts green beans, peas. apples., and oranges. maple, oak, elm Life cycle of Angiospems Annuals complete life cycle in one growing season Biennials live for two seasons; flowers form in second season Perennials grow and produce seeds year after year Figure 30.3 Winged seed of a Fruit adaptations that enhance seed White Pine (Pinus strobus) dispersal: Red berries (left), dandelion (right) Dandelion seed dispersal Importance of seed plants THEY ARE EVERYTHING IN OUR LIFE •The most economically important plants on earth are the angiosperms. They form the basis of diets for most animals. grains barley, wheat, legumes, peas, lentils. •They are used to produce waxy substance resin that are used in soap, paint, varnish, and some medicines.
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