The cross between two different homozygous lines produces an F1 hybrid that is heterozygous ; having two alleles, one contributed by each parent and typically one is dominant and the other recessive. Typically, the F1 generation is also phenotypically homogeneous, producing offspring that are all similar to each other. Population hybrids result from the crossing of plants or animals in one population with those of another population. These include interspecific hybrids or crosses between different breeds. In horticulture , the term stable hybrid is used to describe an annual plant that, if grown and bred in a small monoculture free of external pollen e.
Hybridization can occur in the zones where geographical subspecies overlap. For example, the butterfly Limenitis arthemis has two major subspecies in North America, L. The white admiral has a bright, white band on its wings, while the red-spotted purple has cooler blue-green shades. Hybridization occurs between a narrow area across New England, southern Ontario, and the Great Lakes, the "suture region". It is at these regions that the subspecies were formed.
From the point of view of genetics, several different kinds of hybrid can be distinguished. From the point of view of taxonomy , hybrids differ according to their parentage. Hybrids between different subspecies such as between the Bengal tiger and Siberian tiger are called intra-specific hybrids. When two distinct types of organisms breed with each other, the resulting hybrids typically have intermediate traits e.
Interspecific hybrids are bred by mating individuals from two species, normally from within the same genus. The offspring display traits and characteristics of both parents, but are often sterile , preventing gene flow between the species. For example, donkeys have 62 chromosomes , horses have 64 chromosomes, and mules or hinnies have 63 chromosomes.
Mules, hinnies, and other normally sterile interspecific hybrids cannot produce viable gametes, because differences in chromosome structure prevent appropriate pairing and segregation during meiosis , meiosis is disrupted, and viable sperm and eggs are not formed. However, fertility in female mules has been reported with a donkey as the father. A variety of mechanisms limit the success of hybridization, including the large genetic difference between most species. Barriers include morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo.
Some act before fertilization; others after it. In plants, some barriers to hybridization include blooming period differences, different pollinator vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and structural differences of the chromosomes. A few animal species are the result of hybridization.
The Lonicera fly is a natural hybrid. The American red wolf appears to be a hybrid of the gray wolf and the coyote ,  although its taxonomic status has been a subject of controversy. Plant Hybridization is more commonplace compared to animal hybridization. Many crop species are hybrids, including notably the polyploid wheats: Hybridization may be important in speciation in some plant groups. However, homoploid hybrid speciation not increasing the number of sets of chromosomes may be rare: Experimental studies suggest that hybridization offers a rapid route to speciation, a prediction confirmed by the fact that early generation hybrids and ancient hybrid species have matching genomes, meaning that once hybridization has occurred, the new genome can remain stable.
Many hybrid zones are known where the ranges of two species meet, and hybrids are continually produced in great numbers. These hybrid zones are useful as biological model systems for studying the mechanisms of speciation. Recently DNA analysis of a bear shot by a hunter in the North West Territories confirmed the existence of naturally-occurring and fertile grizzly—polar bear hybrids.
Hybrids are not as might be expected always intermediate between their parents as if there were blending inheritance , but are sometimes stronger than either parent variety, a phenomenon called heterosis, hybrid vigour, or heterozygote advantage. This is most common with plant hybrids. An economically important example is hybrid maize corn , which provides a considerable seed yield advantage over open pollinated varieties. Hybrid seed dominates the commercial maize seed market in the United States, Canada and many other major maize-producing countries.
In a hybrid, any trait that falls outside the range of parental variation and is thus not simply intermediate between its parents is considered heterotic. Positive heterosis produces more robust hybrids, they might be stronger or bigger; while the term negative heterosis refers to weaker or smaller hybrids. Similarly, the hybrids between the common pheasant Phasianus colchicus and domestic fowl Gallus gallus are larger than either of their parents, as are those produced between the common pheasant and hen golden pheasant Chrysolophus pictus.
Hybridization is greatly influenced by human impact on the environment,  through effects such as habitat fragmentation and species introductions. Humans have introduced species worldwide to environments for a long time, both intentionally for purposes such as biological control , and unintentionally, as with accidental escapes of individuals. Introductions can drastically affect populations, including through hybridization. There is a kind of continuum with three semi-distinct categories dealing with anthropogenic hybridization: Depending on where a population falls along this continuum, the management plans for that population will change.
Hybridization is currently an area of great discussion within wildlife management and habitat management. Global climate change is creating other changes such as difference in population distributions which are indirect causes for an increase in anthropogenic hybridization. Conservationists disagree on when is the proper time to give up on a population that is becoming a hybrid swarm, or to try and save the still existing pure individuals. Once a population becomes a complete mixture, the goal becomes to conserve those hybrids to avoid their loss.
Conservationists treat each case on its merits, depending on detecting hybrids within the population. It is nearly impossible to formulate a uniform hybridization policy, because hybridization can occur beneficially when it occurs "naturally", and when hybrid swarms are the only remaining evidence of prior species, they need to be conserved as well. Regionally developed ecotypes can be threatened with extinction when new alleles or genes are introduced that alter that ecotype. This is sometimes called genetic mixing.
These hybridization events can result from the introduction of non-native genotypes by humans or through habitat modification, bringing previously isolated species into contact.
Genetic mixing can be especially detrimental for rare species in isolated habitats, ultimately affecting the population to such a degree that none of the originally genetically distinct population remains. In agriculture and animal husbandry , the Green Revolution 's use of conventional hybridization increased yields by breeding " high-yielding varieties ".
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The replacement of locally indigenous breeds, compounded with unintentional cross-pollination and crossbreeding genetic mixing , has reduced the gene pools of various wild and indigenous breeds resulting in the loss of genetic diversity. Therefore, commercial plant geneticists strive to breed "widely adapted" cultivars to counteract this tendency. Familiar examples of equid hybrids are the mule, a cross between a female horse and a male donkey, and the hinny, a cross between a female donkey and a male horse. Pairs of complementary types like the mule and hinny are called reciprocal hybrids.
The clymene dolphin Stenella clymene is a hybrid of two Atlantic species, the spinner and striped dolphins.
Hybrid vehicle - Wikipedia
Among amphibians, Japanese giant salamanders and Chinese giant salamanders have created hybrids that threaten the survival of Japanese giant salamanders because of competition for similar resources in Japan. Among fish, a group of about fifty natural hybrids between Australian blacktip shark and the larger common blacktip shark was found by Australia's eastern coast in Among insects, so-called killer bees were accidentally created during an attempt to breed a strain of bees that would both produce more honey and be better adapted to tropical conditions.
It was done by crossing a European honey bee and an African bee. The Colias eurytheme and C. Plant species often hybridize more readily than animal species, and the resulting hybrids are fertile more often. Many plant species are the result of hybridization, combined with polyploidy , which duplicates the chromosomes.
Chromosome duplication allows orderly meiosis and so viable seed can be produced. Plant species that are genetically compatible may not hybridize in nature for various reasons, including geographical isolation, differences in flowering period, or differences in pollinators. Species that are brought together by humans in gardens may hybridize naturally, or hybridization can be facilitated by human efforts, such as altered flowering period or artificial pollination.
Hybrids are sometimes created by humans to produce improved plants that have some of the characteristics of each of the parent species. Much work is now being done with hybrids between crops and their wild relatives to improve disease-resistance or climate resilience for both agricultural and horticultural crops.
A sterile hybrid between Trillium cernuum and T. An ornamental lily hybrid known as Lilium 'Citronella' . Sterility in a non-polyploid hybrid is often a result of chromosome number; if parents are of differing chromosome pair number, the offspring will have an odd number of chromosomes, which leaves them unable to produce chromosomally-balanced gametes. Triploid bananas and watermelons are intentionally bred because they produce no seeds and are also parthenocarpic.
There is evidence of hybridisation between modern humans and other species of the genus Homo. In , a complete prehistorical skeleton found in Portugal , the Lapedo child , had features of both anatomically modern humans and Neanderthals. A 37, to 42,year-old human jawbone found in Romania's Oase cave contains traces of Neanderthal ancestry [a] from only four to six generations earlier. It is proposed that it was the offspring of a Neanderthal mother and a human father. From Wikipedia, the free encyclopedia. For other uses, see Hybrid. Hybrid speciation and Hybrid zone. Genetic mixing and Introgression.
List of plant hybrids. Archaic human admixture with modern humans. Retrieved 28 June Quantitative genetics and selection in plant breeding. The energy used to lift the containers can be partially regained when they are lowered. Hybrid systems are coming into use for trucks, buses and other heavy highway vehicles. Small fleet sizes and installation costs are compensated by fuel savings,. Kenworth Truck Company recently introduced the Kenworth T Class 6 that for city usage seems to be competitive.
The diesel engines run at a constant RPM for peak efficiency. In students at Minneapolis, Minnesota's Hennepin Vocational Technical Center, converted a Volkswagen Beetle to a petro-hydraulic hybrid with off-the shelf components. No lightweight materials were used. Ships with both mast-mounted sails and steam engines were an early form of hybrid vehicle. Another example is the diesel-electric submarine.
This runs on batteries when submerged and the batteries can be re-charged by the diesel engine when the craft is on the surface. Newer hybrid ship-propulsion schemes include large towing kites manufactured by companies such as SkySails. Towing kites can fly at heights several times higher than the tallest ship masts, capturing stronger and steadier winds. The fuel cell provides all power for the cruise phase of flight. During takeoff and climb, the flight segment that requires the most power, the system draws on lightweight lithium-ion batteries.
The demonstrator aircraft is a Dimona motor glider, built by Diamond Aircraft Industries of Austria, which also carried out structural modifications to the aircraft. With a wing span of Hybrid FanWings have been designed. A FanWing is created by two engines with the capability to autorotate and landing like a helicopter.
When the term hybrid vehicle is used, it most often refers to a Hybrid electric vehicle. A petroleum-electric hybrid most commonly uses internal combustion engines using a variety of fuels, generally gasoline or Diesel engines and electric motors to power the vehicle. The energy is stored in the fuel of the internal combustion engine and an electric battery set.
There are many types of petroleum-electric hybrid drivetrains , from Full hybrid to Mild hybrid , which offer varying advantages and disadvantages. Patton filed a patent application for a gasoline-electric hybrid rail-car propulsion system in early , and for a similar hybrid boat propulsion system in mid In , Henri Pieper developed the world's first petro-electric hybrid automobile. In , Ferdinand Porsche developed a series-hybrid using two motor-in-wheel-hub arrangements with an internal combustion generator set providing the electric power; Porsche's hybrid set two speed records.
His home-converted Opel GT was reported to return as much as 75 mpg with plans still sold to this original design, and the "Mother Earth News" modified version on their website. The plug-in-electric-vehicle PEV is becoming more and more common. It has the range needed in locations where there are wide gaps with no services. The batteries can be plugged into house mains electricity for charging, as well being charged while the engine is running.
Some battery electric vehicles BEVs can be recharged while the user drives. Such a vehicle establishes contact with an electrified rail, plate or overhead wires on the highway via an attached conducting wheel or other similar mechanism see Conduit current collection. The BEV's batteries are recharged by this process—on the highway—and can then be used normally on other roads until the battery is discharged. For example, some of the battery-electric locomotives used for maintenance trains on the London Underground are capable of this mode of operation.
Developing a BEV infrastructure would provide the advantage of virtually unrestricted highway range. Unfortunately, private use of the existing electrical system is almost universally prohibited. Besides, the technology for such electrical infrastructure is largely outdated and, outside some cities, not widely distributed see Conduit current collection , trams , electric rail , trolleys , third rail.
Updating the required electrical and infrastructure costs could perhaps be funded by toll revenue or by dedicated transportation taxes. In addition to vehicles that use two or more different devices for propulsion , some also consider vehicles that use distinct energy sources or input types " fuels " using the same engine to be hybrids, although to avoid confusion with hybrids as described above and to use correctly the terms, these are perhaps more correctly described as dual mode vehicles:.
Hydraulic hybrid and pneumatic hybrid vehicles use an engine to charge a pressure accumulator to drive the wheels via hydraulic liquid or pneumatic compressed air drive units. In most cases the engine is detached from the drivetrain, serving solely to charge the energy accumulator. The transmission is seamless. Regenerative braking can be used to recover some of the supplied drive energy back into the accumulator. A French company, MDI , has designed and has running models of a petro-air hybrid engine car.
The system does not use air motors to drive the vehicle, being directly driven by a hybrid engine. The engine uses a mixture of compressed air and gasoline injected into the cylinders. Petro-hydraulic configurations have been common in trains and heavy vehicles for decades. The auto industry recently focused on this hybrid configuration as it now shows promise for introduction into smaller vehicles. The charging engine runs at optimum speed and load for efficiency and longevity.
Although petro-hydraulic hybrid technology has been known for decades, and used in trains and very large construction vehicles, high costs of the equipment precluded the systems from lighter trucks and cars. In the modern sense an experiment proved the viability of small petro-hydraulic hybrid road vehicles in A group of students at Minneapolis, Minnesota's Hennepin Vocational Technical Center, converted a Volkswagen Beetle car to run as a petro-hydraulic hybrid using off-the shelf components. The accumulator vessel size dictates total energy storage capacity and may require more space than an electric battery set.
Any vehicle space consumed by a larger size of accumulator vessel may be offset by the need for a smaller sized charging engine, in HP and physical size. Research is underway in large corporations and small companies. Focus has now switched to smaller vehicles.
The system components were expensive which precluded installation in smaller trucks and cars. A drawback was that the power driving motors were not efficient enough at part load. The pump is highly efficient at all speed ranges and loads, giving feasibility to small applications of petro-hydraulic hybrids. The BMW i, gave double the mpg in city driving compared to the standard car. The design of petro-hydraulic hybrids using well sized accumulators allows downsizing an engine to average power usage, not peak power usage. Peak power is provided by the energy stored in the accumulator.
A smaller more efficient constant speed engine reduces weight and liberates space for a larger accumulator. It is restrictive and far from ideal to install petro-hydraulic mechanicals into existing bodies not designed for hydraulic setups. One research project's goal is to create a blank paper design new car, to maximize the packaging of petro-hydraulic hybrid components in the vehicle. All bulky hydraulic components are integrated into the chassis of the car.
One design has claimed to return mpg in tests by using a large hydraulic accumulator which is also the structural chassis of the car. The small hydraulic driving motors are incorporated within the wheel hubs driving the wheels and reversing to claw-back kinetic braking energy. The hub motors eliminates the need for friction brakes, mechanical transmissions, drive shafts and U joints, reducing costs and weight. Hydrostatic drive with no friction brakes are used in industrial vehicles. Energy created by shock absorbers and kinetic braking energy that normally would be wasted assists in charging the accumulator.
A small fossil fuelled piston engine sized for average power use charges the accumulator. The accumulator is sized at running the car for 15 minutes when fully charged. In January industry giant Chrysler announced a partnership with the US Environmental Protection Agency EPA to design and develop an experimental petro-hydraulic hybrid powertrain suitable for use in large passenger cars.
In an existing production minvan was adapted to the new hydraulic powertrain for assessment. The hydraulic and electronic components were supplied by Robert Bosch GmbH.
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Another form of hybrid vehicle are human power-electric vehicles. These include such vehicles as the Sinclair C5 , Twike , electric bicycles , and electric skateboards. In a parallel hybrid vehicle an electric motor and an internal combustion engine are coupled such that they can power the vehicle either individually or together.
Most commonly the internal combustion engine, the electric motor and gear box are coupled by automatically controlled clutches. For electric driving the clutch between the internal combustion engine is open while the clutch to the gear box is engaged. While in combustion mode the engine and motor run at the same speed. The first mass production parallel hybrid sold outside Japan was the 1st generation Honda Insight.
In a power-split hybrid electric drive train there are two motors: The power from these two motors can be shared to drive the wheels via a power split device, which is a simple planetary gear set. The combustion engine can act as a generator charging the batteries. On the open road, the primary power source is the internal combustion engine. When maximum power is required, for example to overtake, the traction electric motor is used to assist.
This increases the available power for a short period, giving the effect of having a larger engine than actually installed. In most applications, the combustion engine is switched off when the car is slow or stationary thereby reducing curbside emissions. A series- or serial-hybrid vehicle is driven by an electric motor, functioning as an electric vehicle while the battery pack energy supply is sufficient, with an engine tuned for running as a generator when the battery pack is insufficient.
There is typically no mechanical connection between the engine and the wheels, and the primary purpose of the range extender is to charge the battery. It operates as an electric vehicle until the battery charge is low, and then activates an engine-powered generator to maintain power, and is also available without the range extender.
The Fisker Karma was the first series-hybrid production vehicle. When describing cars, the battery of a series-hybrid is usually charged by being plugged in - but a series-hybrid may also allow for a battery to only act as a buffer and for regeneration purposes , and for the electric motor's power to be supplied constantly by a supporting engine. Series arrangements have been common in diesel-electric locomotives and ships. Ferdinand Porsche effectively invented this arrangement in speed-record-setting racing cars in the early 20th century, such as the Lohner-Porsche Mixte Hybrid.
Porsche named his arrangement "System Mixt" and it was a wheel hub motor design, where each of the two front wheels was powered by a separate motor. This arrangement was sometimes referred to as an electric transmission , as the electric generator and driving motor replaced a mechanical transmission. The vehicle could not move unless the internal combustion engine was running.
In Toyota released the first series-hybrid bus sold in Japan. Using supercapacitors they claim up to mpg in a series-hybrid arrangement. Another subtype of hybrid vehicles is the plug-in hybrid electric vehicle PHEV. The plug-in hybrid is usually a general fuel-electric parallel or serial hybrid with increased energy storage capacity, usually through a lithium-ion battery , which allows the vehicle to drive on all-electric mode a distance that depends on the battery size and its mechanical layout series or parallel.
It may be connected to mains electricity supply at the end of the journey to avoid charging using the on-board internal combustion engine. This concept is attractive to those seeking to minimize on-road emissions by avoiding — or at least minimizing — the use of ICE during daily driving. As with pure electric vehicles, the total emissions saving, for example in CO 2 terms, is dependent upon the energy source of the electricity generating company. Current tax systems in many European countries use mineral oil taxation as a major income source.
This is generally not the case for electricity, which is taxed uniformly for the domestic customer, however that person uses it. Some electricity suppliers also offer price benefits for off-peak night users, which may further increase the attractiveness of the plug-in option for commuters and urban motorists. A National Highway Traffic Safety Administration report examined hybrid electric vehicle accidents that involved pedestrians and cyclists and compared them to accidents involving internal combustion engine vehicles ICEV.
The findings showed that, in certain road situations, HEVs are more dangerous for those on foot or bicycle. For crashes involving cyclists or pedestrians, there was a higher incident rate for HEVs than ICEVs when a vehicle was turning a corner. But there was no statistically significant difference between the types of vehicles when they were driving straight.
Several automakers developed electric vehicle warning sounds designed to alert pedestrians to the presence of electric drive vehicles such as hybrid electric vehicle, plug-in hybrid electric vehicles and all-electric vehicles EVs travelling at low speeds. Their purpose is to make pedestrians, cyclists, the blind, and others aware of the vehicle's presence while operating in all-electric mode.
The hybrid vehicle typically achieves greater fuel economy and lower emissions than conventional internal combustion engine vehicles ICEVs , resulting in fewer emissions being generated. These savings are primarily achieved by three elements of a typical hybrid design:. Other techniques that are not necessarily 'hybrid' features, but that are frequently found on hybrid vehicles include:. These features make a hybrid vehicle particularly efficient for city traffic where there are frequent stops, coasting and idling periods.
In addition noise emissions are reduced, particularly at idling and low operating speeds, in comparison to conventional engine vehicles. For continuous high speed highway use these features are much less useful in reducing emissions. Hybrid vehicle emissions today are getting close to or even lower than the recommended level set by the EPA Environmental Protection Agency.
The recommended levels they suggest for a typical passenger vehicle should be equated to 5. The three most popular hybrid vehicles, Honda Civic , Honda Insight and Toyota Prius , set the standards even higher by producing 4. More fossil fuel is needed to build hybrid vehicles than conventional cars but reduced emissions when running the vehicle more than outweigh this.