Examples of speciation in the following topics:
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- Two patterns are currently observed in the rates of speciation: gradual speciation and punctuated equilibrium.
- In terms of how quickly speciation occurs, two patterns are currently observed: the gradual speciation model and the punctuated equilibrium model.
- In the gradual speciation model, species diverge gradually over time in small steps.
- The primary influencing factor on changes in speciation rate is environmental conditions.
- In (a) gradual speciation, species diverge at a slow, steady pace as traits change incrementally.
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- Speciation is an event in which a single species may branch to form two or more new species.
- Biologists have proposed mechanisms by which this could occur that fall into two broad categories: allopatric speciation and sympatric speciation.
- Sympatric speciation (sym- = "same"; -patric = "homeland") involves speciation occurring within a parent species remaining in one location.
- Biologists think of speciation events as the splitting of one ancestral species into two descendant species.
- Define speciation and discuss the ways in which it may occur
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- Sympatric speciation occurs when two individual populations diverge from an ancestral species without being separated geographically.
- The process of speciation within the same space is called sympatric speciation.
- A number of mechanisms for sympatric speciation have been proposed and studied.
- One form of sympatric speciation can begin with a serious chromosomal error during cell division.
- In this way, sympatric speciation can occur quickly by forming offspring with 4n: a tetraploid.
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- Allopatric speciation occurs when a single species becomes geographically separated; each group evolves new and distinctive traits.
- This is known as allopatric speciation.
- Scientists have documented numerous cases of allopatric speciation.
- These variances can lead to evolved differences in the owls, resulting in speciation.
- The owl is an example of allopatric speciation.
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- Speciation occurs over a span of evolutionary time.
- After speciation, two species may recombine or even continue interacting indefinitely.
- This term is used because the low success of the hybrids reinforces the original speciation.
- Over time, via a process called hybrid speciation, the hybrids themselves can become a separate species.
- After speciation has occurred, the two separate-but-closely-related species may continue to produce offspring in an area called the hybrid zone.
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- Two segments of DNA can have shared ancestry because of either a speciation event (orthologs) or a duplication event (paralogs).
- Homologous sequences are orthologous if they were separated by a speciation event: when a species diverges into two separate species, the copies of a single gene in the two resulting species are said to be orthologous.
- Paralogs can be split into in-paralogs (paralogous pairs that arose after a speciation event) and out-paralogs (paralogous pairs that arose before a speciation event).
- Between species out-paralogs are pairs of paralogs that exist between two organisms due to duplication before speciation.
- Within species out-paralogs are pairs of paralogs that exist in the same organism, but whose duplication event happened after speciation.
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- Biodiversity has been affected by five mass extinction periods, which greatly influenced speciation and extinction rates.
- The number of species on the planet, or in any geographical area, is the result of an equilibrium of two evolutionary processes that are ongoing: speciation and extinction.
- When speciation rates begin to outstrip extinction rates, the number of species will increase; likewise, the number of species will decrease when extinction rates begin to overtake speciation rates.
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- Sympatric speciation can begin with a chromosomal error during meiosis or the formation of a hybrid individual with too many chromosomes, such as polyploidy which can occur during whole-genome duplication.
- An example would be the recent speciation of allopolyploid Spartina — S. anglica; the polyploid plant is so successful that it is listed as an invasive species in many regions.
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- Reproductive isolation, through mechanical, behavioral, and physiological barriers, is an important component of speciation.
- Speciation can occur when two populations occupy different habitats.
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- Changes in the environment often create new niches (living spaces) that contribute to rapid speciation and increased diversity.
- Late in the Cenozoic, further extinctions followed by speciation occurred during ice ages that covered high latitudes with ice and then retreated, leaving new open spaces for colonization.