In botany Botany, plant science, phytology, or plant biology is a branch of biology and is the scientific study of plant life and development. Botany covers a wide range of scientific disciplines that study plants, algae, and fungi including: structure, growth, reproduction, metabolism, development, diseases, chemical properties, and evolutionary, a leaf is an above-ground plant organ In biology and anatomy, an organ is a tissue that performs a specific function or group of functions within an organism specialized for photosynthesis Photosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of Bacteria, but not in Archaea. Photosynthetic organisms are called photoautotrophs, since it allows them to create their own food. In plants, algae and. For this purpose, a leaf is typically flat (laminar) and thin. There is continued debate about whether the flatness of leaves evolved Natural selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations. It is a key mechanism of evolution to expose the chloroplasts Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis to more light Light is electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye . In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not or to increase the absorption of carbon dioxide Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. CO2 is a trace gas being only 0.0383% of the atmosphere. In either case, the adaption was made at the expense of water loss. In the Devonian period The Devonian is a geologic period and system of the Paleozoic era spanning from 416 to 359.2 million years ago . It is named after Devon, England, where rocks from this period were first studied, when carbon dioxide concentration was at several times its present value, plants did not have leaves or flat stems. Many bryophytes Bryophytes are all embryophytes that are non-vascular: they have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. They neither have flowers nor produce seeds, reproducing via spores. The term bryophyte comes from Greek βρύον - bryon, "tree-moss, oyster-green" + φυτόν - fyton & have flat, photosynthetic organs, but these are not true leaves. Neither are the microphylls The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based. The traditional definition of microphylls and megaphylls will be employed in this article for simplicity; of lycophytes The Division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae. It is the oldest extant (living) vascular plant division at around 420 million years old,[citation needed] and includes some of the most "primitive" extant species. These species reproduce by shedding spores and have macroscopic alternation of generations,. The leaves of ferns, gymnosperms Gymnosperm is a group of spermatophyte seed-bearing plants with ovules on scales, which are usually arranged in cone-like structures, and angiosperms The flowering plants or angiosperms are the most diverse group of land plants. The flowering plants and the gymnosperms are the only extant groups of seed plants. The flowering plants are distinguished from other seed plants by a series of apomorphies, or derived characteristics are variously referred to as macrophyll The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based. The traditional definition of microphylls and megaphylls will be employed in this article for simplicity;, megaphylls, or euphylls.
Leaves are also the sites in most plants where transpiration Transpiration is the evaporation of water from the aerial parts of plants, especially leaves but also stems, flowers and roots. Leaf surfaces are dotted with openings called stoma that are bordered by guard cells. Collectively the structures are called stomata. Leaf transpiration occurs through stomata, and can be thought of as a necessary " and guttation Guttation is the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface take place. Leaves can store food Food is any substance, usually composed of carbohydrates, fats, proteins and water, that can be eaten or drunk by an animal, including humans, for nutrition or pleasure. Items considered food may be sourced from plants, animals or other categories such as fungus or fermented products like alcohol. Although many human cultures sought food items and water Water is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life, and are modified in some plants for other purposes. The comparable structures of ferns A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. The group is also referred to as Polypodiophyta, or Polypodiopsida when treated as a subdivision of tracheophyta . The term "pteridophyte" has traditionally been used to describe all seedless are correctly referred to as fronds A frond is a large leaf with many divisions to it, and the term is typically used for the leaves of palms, ferns or cycads. Furthermore, leaves are prominent in the human Humans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving. This mental capability, combined with an erect body carriage that frees the arms for manipulating objects, has allowed humans to diet In nutrition, the diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. Although humans are omnivores, each culture holds some food preferences and some food taboos. Individual dietary choices may be more or less healthy. Proper as leaf vegetables Leaf vegetables, also called potherbs, green vegetables, greens, or leafy greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Although they come from a very wide variety of plants, most share a great deal with other leaf vegetables in nutrition and cooking methods.
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Irish Times
HE MAY not have attracted quite as large a crowd as ageing rocker Ozzy Osbourne for his book signing in Dublin at the weekend, but Bertie Ahern still drew ...
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Big Leaf Maple This is a beautiful recreation of the majestic big leaf maple Leaves are life size and made of copper with a multi color copper finish The size and depth of the
The Muppet
Sun, 20 Sep 2009 05:37:01 GM
Random . Leaf. V.1. Kadri centering a line of Kessel and Kulemin might be pretty sweet coming out of next years camp. Sadly, some punter nicknames the line based on the first letters of their name and is promptly beat up at the bar. ...
