Speciation is a process in which organisms within a population evolve to become a new species over time. Charles Darwin believed that eventually a single species will split off into two different populations, becoming two new species. Some of the speciation modes are allopatric and sympatric, and polyploidy is a mechanism of speciation.
Allopatric Speciation
Allopatric speciation is a common mode of speciation in which a population of a single species becomes divided, geographically isolating part of that species from the other part. This can happen when a physical barrier, such as a desert or a city, divides the populations where one group of a species is on one side and the other group is on the other side, apart from one another. Allopatric speciation can also occur when populations of a species drift apart or disperse. When allopatric speciation occurs, variations and unique characteristics can flourish within a population, but be entirely different from other species populations found elsewhere. These variations occur as a form of adaptation and survival in response to their environment. (PBS, 2001) Geographically separated environments create genetic differences among the two separated species, allowing for evolution into two distinct species. Darwin’s finches of the Galapagos Islands are a prime example of allopatric speciation; as the various populations of finches are separated by the ocean, and therefore had limited gene migration. “Because they are isolated, the birds don’t breed with one another and have therefore developed into unique species with unique characteristics.” (National Geographic Society, 2017). Over time, the finch populations evolved into specific species as each group developed a unique beak adapted to their diet and environment. Beak size varies among these finches, ranging from thin long beaks for eating cactuses, to medium beaks for insects, and large beaks for eating seeds and nuts. Sympatric Speciation. Sympatric speciation is a new species evolved from a single ancestral species which is inhabiting the same geographic area. Sympatric speciation is somewhat rare, appears to be spontaneous and rapid. These species live in the same region but they are different in how they adapt to their environment. Sympatric speciation can occur by several mechanisms. Some members of a species may invest in a new niche while others do not, meaning that the self-separate. Another mechanism is polyploidy, but more on that later. For example, a fly lays its eggs in a hawthorn fruit, causing it to rot and fall off the tree, the maggots then dig into the ground then emerge months later as adult flies. …show more content…
Some flies lay their eggs in a relative of the hawthorn that was introduced in the 19th century, an apple. Now there are two groups of that species, one that lays eggs in hawthorns and one that lays eggs in apples. They are believed to be undergoing the process of sympatric speciation. (National Geographic Society, 2017)
Sympatric speciation can also occur when natural selection drives a species population to extremes, known as disruptive selection (Coyne, 2007). Another form of disruptive selection in regards to sympatric speciation can occur in mate discrimination. Which is when one sex prefers different types of the opposite sex, such as female insects preferring different types of male insects (Coyne, 2007). Polyploidy. Polyploidy is a mutation during meiosis where a species gamete cells inherits more or less than two complete sets of chromosomes. If either of the mutated gametes passes
Allopatric Speciation
Allopatric speciation is a common mode of speciation in which a population of a single species becomes divided, geographically isolating part of that species from the other part. This can happen when a physical barrier, such as a desert or a city, divides the populations where one group of a species is on one side and the other group is on the other side, apart from one another. Allopatric speciation can also occur when populations of a species drift apart or disperse. When allopatric speciation occurs, variations and unique characteristics can flourish within a population, but be entirely different from other species populations found elsewhere. These variations occur as a form of adaptation and survival in response to their environment. (PBS, 2001) Geographically separated environments create genetic differences among the two separated species, allowing for evolution into two distinct species. Darwin’s finches of the Galapagos Islands are a prime example of allopatric speciation; as the various populations of finches are separated by the ocean, and therefore had limited gene migration. “Because they are isolated, the birds don’t breed with one another and have therefore developed into unique species with unique characteristics.” (National Geographic Society, 2017). Over time, the finch populations evolved into specific species as each group developed a unique beak adapted to their diet and environment. Beak size varies among these finches, ranging from thin long beaks for eating cactuses, to medium beaks for insects, and large beaks for eating seeds and nuts. Sympatric Speciation. Sympatric speciation is a new species evolved from a single ancestral species which is inhabiting the same geographic area. Sympatric speciation is somewhat rare, appears to be spontaneous and rapid. These species live in the same region but they are different in how they adapt to their environment. Sympatric speciation can occur by several mechanisms. Some members of a species may invest in a new niche while others do not, meaning that the self-separate. Another mechanism is polyploidy, but more on that later. For example, a fly lays its eggs in a hawthorn fruit, causing it to rot and fall off the tree, the maggots then dig into the ground then emerge months later as adult flies. …show more content…
Some flies lay their eggs in a relative of the hawthorn that was introduced in the 19th century, an apple. Now there are two groups of that species, one that lays eggs in hawthorns and one that lays eggs in apples. They are believed to be undergoing the process of sympatric speciation. (National Geographic Society, 2017)
Sympatric speciation can also occur when natural selection drives a species population to extremes, known as disruptive selection (Coyne, 2007). Another form of disruptive selection in regards to sympatric speciation can occur in mate discrimination. Which is when one sex prefers different types of the opposite sex, such as female insects preferring different types of male insects (Coyne, 2007). Polyploidy. Polyploidy is a mutation during meiosis where a species gamete cells inherits more or less than two complete sets of chromosomes. If either of the mutated gametes passes