Give reason with example :Gographical and reproductive isolation of organisms gradually leads to speciation.
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The mom of one species never gives birth to offspring of a different speciesAn individual never changes from one species to another.A “species” is really just what you call a lineage during a particular time range.
So, how WOULD you get a new species?
The way it works, is that the DNA of the mom and dad need to match well enough to make offspring…and, over time, there are small differences.
So, taller parents tend to have taller kids,
If the kids reproduce, their genes are passed on, and the lineage doesn’t go extinct.
If the genes are NOT passed on, the lineage goes extinct.
So, lets say being tall increases the odds of passing on genes…so, the population starts to include more tall offspring. They live in a jungle and climb trees to catch smaller prey/evade leapards.
Lets say that being TOO tall means passing on fewer genes…that makes the population level off around a height that “works”…as they don’t break the branches, etc.
Now, lets say that the tall ones are passing on more genes because it makes it harder to be killed by the local population of leapards, and, because of the darn leapards, some had migrated out of the jungle to the shore line.
Being at the shore, there were no leapards, and, lots of fish, so they start eating fish…and genes that are associated with getting more fish are being passed on more.
So, one group of that species is passing on genes associated with fighting off leapards and climbing trees, and the others of that group are passing on genes for catching fish and swimming.
There can also be mutations, etc, that produce discrepancies between populations, and so forth.
Over time, the genes of one group get different enough from the others, that the rungs on their DNA ladders don’t match up well enough for offspring to result successfully.
At that point, we typically consider the group to have split off into two species…the jungle one and the shore one, etc.
If the two groups kept in contact, so both were constantly interbreeding, the genes would not drift, as the re-mixes would keep combining the DNA sequences in a matched arrangement…so the isolation, either geographical or behavioral, is what allows the DNA to drift towards what is working, separately, in different directions.
So, how WOULD you get a new species?
The way it works, is that the DNA of the mom and dad need to match well enough to make offspring…and, over time, there are small differences.
So, taller parents tend to have taller kids,
If the kids reproduce, their genes are passed on, and the lineage doesn’t go extinct.
If the genes are NOT passed on, the lineage goes extinct.
So, lets say being tall increases the odds of passing on genes…so, the population starts to include more tall offspring. They live in a jungle and climb trees to catch smaller prey/evade leapards.
Lets say that being TOO tall means passing on fewer genes…that makes the population level off around a height that “works”…as they don’t break the branches, etc.
Now, lets say that the tall ones are passing on more genes because it makes it harder to be killed by the local population of leapards, and, because of the darn leapards, some had migrated out of the jungle to the shore line.
Being at the shore, there were no leapards, and, lots of fish, so they start eating fish…and genes that are associated with getting more fish are being passed on more.
So, one group of that species is passing on genes associated with fighting off leapards and climbing trees, and the others of that group are passing on genes for catching fish and swimming.
There can also be mutations, etc, that produce discrepancies between populations, and so forth.
Over time, the genes of one group get different enough from the others, that the rungs on their DNA ladders don’t match up well enough for offspring to result successfully.
At that point, we typically consider the group to have split off into two species…the jungle one and the shore one, etc.
If the two groups kept in contact, so both were constantly interbreeding, the genes would not drift, as the re-mixes would keep combining the DNA sequences in a matched arrangement…so the isolation, either geographical or behavioral, is what allows the DNA to drift towards what is working, separately, in different directions.
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