Mechanism of Evolution: Part II
But how can so much be down to chance, when all living creatures are so perfectly adadpted to thier enviornment.
The answer is provided by second key point:Selection.
Each indivisual is subjected to a process of natural selection.As we have learned, each indivisual is somewhat different to its fellows, and there is extensive variation within a species. Enviornmental influences have an effect on living creatures. These so-called selection factors include: predators, parasites, animals of same species. toxins, changes in habitat, or the climate.
Selection is a process that each indivisual is subjected to. Every creature has a unique mix of traits and characteristics. This helps them, to survive in their enviornment, or not, as the case may be.
Anyone with an unsuitable mix will be selected from the enviornment. Those with the right mix survive, and can pass on their enhanced traits and characteristics.This is why diversity is so important. This is why creatures make so much effort to produce offspring that are so different as possible. They increase the liklihood that at atleast one of their offspring passes nature's selection process. They maximize their chances of survival.
A good example of this can be seen in a group of finches living on a remote island. They are some of the most famous animals in the world of science, and are known as darwin finches, after their discoverer, Charles Darwin, and this is the story of those finches. A few hundred years ago, a small group of finches was blown onto the galapagos islands in the middle of the Pacific, probably by a big storm. The finches found themselves in an enviornment that was coompletely new to them, a real finch paradise: an abundance of food and no predators. They reproduced rapidly and numerously. The islands were soon heaving with finches. This meant that food supplies became increasingly scarce. The finch paradise was threatned with famine, and finch friends became competitors. This when selction intervened.Their individuality and small differences, in this case their slightly different beaks, meant that some of the birds were able to avoid competing with their fellow finches. The beaks of some of the finches were more suitable for digging for worms. Other finches were able to use their beaks better for cracking seeds. The finches consequently sort out ecological niches. In these niches, they were safe from excessive competition. They soon began to mate primarily with other finches that used the same niche. Over the course of many Generation, these characteristics were enhanced, enabling the finches to exploit their niches successfully. The differences between the worm-diggers and the seed- crackers became so large that they were no longer able to mate with on another. Different species emerged as a result. Today there are 14 different species of finch living on Galapagos Islands, all of which are descended from the same group of stranded finches.
This is how new species are created by evolution: through the interaction of unique indivisuals, the excess production of offspring, recombination and mutation in heredity, and finally through Selection.
It tells us where the variety of life comes from, and why living creatures are so perfectly adapted to their habitats. But it also effects us personally. Every person is the result of 3.5 billion years of evolution and that includes you. Your ancestors fought and adapted in order to survive. This survival was an extremely uncertain thing.
If we consider the fact that 99% of all the species that have ever lived are extinct, then you can consier yourself part of a success story. The dinosaurs have dissapeared, but you are alive reading this blog, because you're incredibly special, just like all the other creatures that exist today: irreproducible and unique in the universe.
Thankyou, Wait for the Last part of the evolution series.
Continued:
The answer is provided by second key point:Selection.
Each indivisual is subjected to a process of natural selection.As we have learned, each indivisual is somewhat different to its fellows, and there is extensive variation within a species. Enviornmental influences have an effect on living creatures. These so-called selection factors include: predators, parasites, animals of same species. toxins, changes in habitat, or the climate.
Selection is a process that each indivisual is subjected to. Every creature has a unique mix of traits and characteristics. This helps them, to survive in their enviornment, or not, as the case may be.
Anyone with an unsuitable mix will be selected from the enviornment. Those with the right mix survive, and can pass on their enhanced traits and characteristics.This is why diversity is so important. This is why creatures make so much effort to produce offspring that are so different as possible. They increase the liklihood that at atleast one of their offspring passes nature's selection process. They maximize their chances of survival.
A good example of this can be seen in a group of finches living on a remote island. They are some of the most famous animals in the world of science, and are known as darwin finches, after their discoverer, Charles Darwin, and this is the story of those finches. A few hundred years ago, a small group of finches was blown onto the galapagos islands in the middle of the Pacific, probably by a big storm. The finches found themselves in an enviornment that was coompletely new to them, a real finch paradise: an abundance of food and no predators. They reproduced rapidly and numerously. The islands were soon heaving with finches. This meant that food supplies became increasingly scarce. The finch paradise was threatned with famine, and finch friends became competitors. This when selction intervened.Their individuality and small differences, in this case their slightly different beaks, meant that some of the birds were able to avoid competing with their fellow finches. The beaks of some of the finches were more suitable for digging for worms. Other finches were able to use their beaks better for cracking seeds. The finches consequently sort out ecological niches. In these niches, they were safe from excessive competition. They soon began to mate primarily with other finches that used the same niche. Over the course of many Generation, these characteristics were enhanced, enabling the finches to exploit their niches successfully. The differences between the worm-diggers and the seed- crackers became so large that they were no longer able to mate with on another. Different species emerged as a result. Today there are 14 different species of finch living on Galapagos Islands, all of which are descended from the same group of stranded finches.
This is how new species are created by evolution: through the interaction of unique indivisuals, the excess production of offspring, recombination and mutation in heredity, and finally through Selection.
Why is this so important?
It tells us where the variety of life comes from, and why living creatures are so perfectly adapted to their habitats. But it also effects us personally. Every person is the result of 3.5 billion years of evolution and that includes you. Your ancestors fought and adapted in order to survive. This survival was an extremely uncertain thing.
If we consider the fact that 99% of all the species that have ever lived are extinct, then you can consier yourself part of a success story. The dinosaurs have dissapeared, but you are alive reading this blog, because you're incredibly special, just like all the other creatures that exist today: irreproducible and unique in the universe.
Thankyou, Wait for the Last part of the evolution series.
Example explained very well..
ReplyDeleteExample explained very well..
ReplyDeleteThank you Ms Ishu, You can follow my blog to be updated.
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