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Epibiont
An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An epibiont is, by definition, harmless to its host. In this sense, the interaction between the two organisms can be considered neutralistic or commensalistic; as opposed to being, for example, parasitic, in which case one organism benefits at the expense of the other, or mutualistic, in which both organisms obtain some explicit benefit from their coexistence. Examples of common epibionts are barnacles, remoras, and algae, many of which live on the surfaces of larger marine organisms such as whales, sharks, sea turtles, and mangrove trees. Although there is no direct effect of the epibiont to the host, there are often indirect effects resulting from this interaction and change in the surface of the host. This has been found to be especially i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epiphyte
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phorophytes. Epiphytes take part in nutrient cycles and add to both the diversity and biomass of the ecosystem in which they occur, like any other organism. They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively. An organism that grows on another organism that is not a plant may be called an epibiont. Epiphytes are usually found in the temperate zone (e.g., many mosses, liverworts, lichens, and algae) or in the tropics (e.g., many ferns, cacti, orchids, and bromeliads). Epiphyte species make good houseplants due to their minimal wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epiphytes
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phorophytes. Epiphytes take part in nutrient cycles and add to both the diversity and biomass of the ecosystem in which they occur, like any other organism. They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively. An organism that grows on another organism that is not a plant may be called an epibiont. Epiphytes are usually found in the temperate zone (e.g., many mosses, liverworts, lichens, and algae) or in the tropics (e.g., many ferns, cacti, orchids, and bromeliads). Epiphyte species make good houseplants due to their minimal wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale). Odontocetes include the Monodontidae (beluga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epiphytic Bacteria
Epiphytic bacteria are bacteria which live non-parasitically on the surface of a plant on various organs such as the leaves, roots, flowers, buds, seeds and fruit. In current studies it has been determined that epiphytic bacteria generally don't harm the plant, but promote the formation of ice crystals. Some produce an auxin hormone which promotes plant growth and plays a role in the life cycle of the bacteria. Different bacteria prefer different plants and different plant organs depending on the organ's nutritional content, and depending on the bacteria's colonization system which is controlled by the host plant. Bacteria which live on leaves are referred to as phyllobacteria, and bacteria which live on the root system are referred to as rhizabacteria. They adhere to the plant surface forms as 1-cluster 2- individual bacterial cell 3- biofilm . The age of the organ also affects the epiphytic bacteria population and characteristics and has a role in the inhibition of phytopathoge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within", σύν ''syn'' "together" and βίωσις ''biosis'' "living".) Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects. There are two types of symbiont transmissions. In horizontal transmission, each new generation acquires free living symbionts from the environment. An example is the nitrogen-fixing bacteria in certain plant roots. Vertical transmission takes place when the symbiont is transferred directly from parent to offspring. It is also possible for both to be involved in a mixed-mode transmission, where symbionts are transferred vertically for some generation bef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoochory
In Spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living ( biotic) vectors such as birds. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the dispersal mechanism and this has important implications for the demographic and genetic structure of plant populations, as well as migration patterns and species interactions. There are five main modes of seed dispersal: gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus. These modes are typically inferred based on adaptations, such as wings or fleshy fruit. However, this simplified view may ignor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epilith
Lithophytes are plants that grow in or on rocks. They can be classified as either epilithic (or epipetric) or endolithic; epilithic lithophytes grow on the surfaces of rocks, while endolithic lithophytes grow in the crevices of rocks (and are also referred to as chasmophytes). Lithophytes can also be classified as being either obligate or facultative. Obligate lithophytes grow solely on rocks, while facultative lithophytes will grow partially on a rock and on another substrate simultaneously. Nutrients Lithophytes that grow on land feed off nutrients from rain water and nearby decaying plants, including their own dead tissue. It is easier for Chasmophytes to acquire nutrients because they grow in fissures in rocks where soil or organic matter has accumulated. For most Lithophytes, nitrogen is only available through interactions with the atmosphere. The most readily available form of nitrogen in the atmosphere is the gaseous state of ammonia (NH3). Lithophytes consume atmospheric a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption (skin)
Skin absorption is a route by which substances can enter the body through the skin. Along with inhalation, ingestion and injection, dermal absorption is a route of exposure for toxic substances and route of administration for medication. Absorption of substances through the skin depends on a number of factors, the most important of which are concentration, duration of contact, solubility of medication, and physical condition of the skin and part of the body exposed. Skin (percutaneous, dermal) absorption is the transport of chemicals from the outer surface of the skin both into the skin and into circulation. Skin absorption relates to the degree of exposure to and possible effect of a substance which may enter the body through the skin. Human skin comes into contact with many agents intentionally and unintentionally. Skin absorption can occur from occupational, environmental, or consumer skin exposure to chemicals, cosmetics, or pharmaceutical products. Some chemicals can be absorbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Ecosystem
An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic (slow moving water, including pools, ponds, and lakes); lotic (faster moving water, for example streams and rivers); and wetlands (areas where the soil is saturated or inundated for at least part of the time). Types Marine ecosystems Marine coastal ecosystem Marine surface ecosystem Freshwater ecosystems Lentic ecosystem (lakes) Lotic ecosystem (rivers) Wetlands Functions Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife. Aquatic ecosystems are also used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Life
Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. Marine organisms, mostly microorganisms, produce oxygen and sequester carbon. Marine life in part shape and protect shorelines, and some marine organisms even help create new land (e.g. coral building reefs). Most life forms evolved initially in marine habitats. By volume, oceans provide about 90% of the living space on the planet. The earliest vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians, which spend portions of their lives in water and portions on land. One group of amphibians evolved into reptiles and mammals and a few subsets of each returned to the ocean as sea snakes, sea turtles, seals, manatees, and whales. Plant forms such as kelp and other algae grow in the wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
