![Picture](/uploads/2/4/6/1/24615787/651507344.png?569)
Speciation:
The formation of new species, for example snowshoes hares compared to the usual hares
Allopatric isolation:
The formation of a new species as a result of evolutionary changes following a period of geographic isolation(photo on the left)
The photo on the left depicts two different species of fruit flies who in the first stage have had a period of geographic isolation, and then later on have joined and are reproducing
Sympatric isolation:
The evolution of populations within the same geographic area into separate species
The photo at the top of the page shows an example of sympatric evolution, with two different species of insects, one a mix of green and brown beetles, the other entirely brown. they have the same geographic area but separate into two species, whereas in allopatric isolation they reproduce together.
Reproductive isolating mechanisms:
Any behavioural, structural, or biochemical trait that prevents individuals of different species from reproducing successfully together
The formation of new species, for example snowshoes hares compared to the usual hares
Allopatric isolation:
The formation of a new species as a result of evolutionary changes following a period of geographic isolation(photo on the left)
The photo on the left depicts two different species of fruit flies who in the first stage have had a period of geographic isolation, and then later on have joined and are reproducing
Sympatric isolation:
The evolution of populations within the same geographic area into separate species
The photo at the top of the page shows an example of sympatric evolution, with two different species of insects, one a mix of green and brown beetles, the other entirely brown. they have the same geographic area but separate into two species, whereas in allopatric isolation they reproduce together.
Reproductive isolating mechanisms:
Any behavioural, structural, or biochemical trait that prevents individuals of different species from reproducing successfully together
Prezygotic mechanisms: Factors that prevent fertilization and zygote formation
2)Temporal Isolation: Different species breed at different times of the year. Example: Different species of flowers reproduce at different times of year. 3)Ecological Isolation: Very similar species may occupy different habitats within a region. Example: the mountain bluebird (Sialia currucoides) lives at high elevations, while the eastern bluebird (Sialia sialis) prefers lower elevations and does not encounter the mountain species. 4)Mechanical Isolation: Differences in morphological features may make two species incompatible. Example: Damselflies have an unique mating technique which is incompatible with any other species 5)Gametic Isolation: Male gametes may not be able to recognize and fertilize an egg of Postzygotic mechanisms: can prevent a fertilized egg from growing into a viable reproducing adult.
Zygotic Mortality: Mating and fertilization are possible, but genetic differences result in a zygote that is unable to develop properly. -Example; Only some Goat-Sheep embryos can survive. Hybrid inviability: A hybrid individual develops but either dies before birth or, if born alive, cannot survive to maturity. -Example; Tiger-Leopard babies die early. Hybrid infertility: Hybrid offspring remain healthy and viable but are sterile Example; Mules are sterile horse-donkeys and cannot give birth. |