The idea of evolution was not started by Darwin ... it actually goes back to the Greeks. What Darwin's theory of natural selection did was provide the *mechanism* by which evolution occurred.
It consists of three basic observations:
(1) Variation: All individuals within a species are NOT identical. They vary in many different ways ... some are shorter, some taller. Some are faster, some slower. Some are hairier, some less hairy. etc.
(2) Competition: More offspring are born than can possibly survive to propagate. If this were not true, then the world would be overwhelmed with overpopulation (of all species) within a few years. This means that some will survive to pass on their genes, others will not.
(3) Inheritance: Every individual passes characteristics on to its offspring. (Darwin did not know the mechanism for this inheritance ... what we now call "genetics", but it was clear that the offspring of a hairy individual, had a better chance of being hairy itself.)
Putting these three things together, we realize that any characteristic, that is part of normal variation, that produces a slight advantage, will tend to get passed on through inheritance into offspring. Therefore, advantageous characteristics will get passed on more within a species.
One important thing that a lot of people miss when you hear "survival of the fittest" ... it's not just survival ... it is SURVIVAL TO PROCREATE. I.e. it doesn't matter if you survive if you don't have offspring. E.g., a peacock's feathers don't help it survive, but it helps it to procreate (it attracts the ladies), and that is all that matters.
Again, the idea of *evolution* ... that organisms change over time ... is much bigger than the theory of natural selection. Darwin's theory merely provides the missing piece of information of HOW that change occurs.
2006-11-11 12:30:33
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answer #1
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answered by secretsauce 7
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1) "All evolutionary theory can only be about probability or improbability, since the process - in the majestic form advanced by Darwin - has not been, and cannot be observed, and therefore cannot be tested against the theory, or used to predict events." The process has been observed and is continuing to be observed. Human lifespan keeps increasing and humans are on average bigger and smarter. We're also observing species dieing out because of environmental changes, in time other species will take their place. 2) "It is amazing how many supporters of the theory of evolution by natural selection cannot see the difference between the micro-evolution of adaptation or alteration within species, and the far more ambitious developments of macro-evolution, in my opinion qualitatively different, which Darwinists believe in." Given some mass extinction wiped out the dinosaurs, smaller creatures took over and grew in size and continued to adapt to their environment. Large mammal fossiles are not found at the same time of dinosaurs. 3) "The fossil record is full of gaps and highly ambiguous. Species appear and disappear suddenly, which I should have thought would upset the Darwinist position quite badly, but somehow doesn't." Actually it supports the Darwinist position - the fossil records show how species appeared changed and died out, then other species grew to take their place. Eventually, man will most likely be wiped off of this planet, and something else will take his place. The ID position is simply that everything was created at once and nothing new has arisen over time. They refuse to explain the rise of the various species.
2016-05-22 06:07:32
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answer #2
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answered by Anonymous
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Ever wonder how the cheetah became the fastest animal on Earth? This came about through Natural Selection. Long ago, a gene mutation occurred in an early version of the cheetah, that resulted in legs that happened to be just a bit longer than the legs of all the other cheetahs. As a result, this cheetah could run a bit faster than the others. This became a slight advantage over the other cheetahs, as this particular one was able to run just a bit faster. He was the one who was able to run down and catch the gazelles. Other cheetahs in the population may have starved -- in part, because they were not fast enough to catch gazelles. So this means that the "special" cheetah survived, and was able to pass his superior genes on to the next generation. This process continued until the cheetah became the fastest animal on Earth!
2006-11-11 12:38:34
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answer #3
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answered by gregory_s19 3
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Natural selection is the theory that creatures with the best adaptations for survival will survive. This is with regards to environmental factors. After awhile, you will notice that those without the right adaptations tend to die off faster, and so the population gradually evolves so that most creatures will have the adaptation.
Imagine white moths which rest on white trunked trees in order to camouflage. Then imagine if all of a sudden something causes the trunks to progressively turn brown. After awhile you will notice that the darker toned moths will survive as the lighter toned ones cant adapt.
Eventually the moths will evolve to have darker tones.
2006-11-11 12:26:30
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answer #4
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answered by Mark T 3
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In any population of organisms there is a natural wide range of variation, and periodic mutations. Sometimes, some of these variations give an advantage to particular members of the population. If those members benefit in some way, and breed with each other producing offspring that also share the "beneficial feature", they eventually can form a "splinter group" that seperates from the main population. Over time, they can become different enough to become a seperate species.
2006-11-11 12:25:47
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answer #5
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answered by Anonymous
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Say you have an island, about twenty miles from any other island, where there is a species of bird, say finches. In any population of birds, there is going to be a variety of beak sizes and wing sizes, (like nose and ear size, and height variation in humans), suddenly there was a drought, lasting several years, and the main food source of the finches, say, sesame seed, was destroyed, and all they had to eat was wheat, which is harder to break and eat than sesame.
What characteristics would give one bird an advantage over another? Those with smaller beaks would have more difficulty cracking the wheat and feeding it to any baby birds, therefore they would have less live young. Those with largeer, stronger beaks would crack and eat more wheat and have more live young. Chances are, that their offspring would have, on average, larger, stronger beaks than those of small beaked finches. The stronger your beak, the more you eat, the more children you have.
So what other characteristics? Those with stronger, larger wings could try to find other food, but if they can't make to the other island, they die, those that make it to the other island, and if it has food, will have, on average, larger wings than those that didn't make it. They wil have more children, who, on average, will have larger wings.
These are simplified examples, it is more complex than this, but the basics are there.
Hope this helps.
2006-11-11 12:43:43
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answer #6
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answered by Labsci 7
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You're exactly right.
Maybe an example will help you.
First picture a couple of lions chasing a pack of giselles, trying to eat them.
Now, which of the giselles are going to be caught and eaten? The slowest ones.
The giselles that are faster will survive and mate; and their traits such as strong legs that help them run faster, will be passed down to their offspring.
In this case speed is the favoured characteristic of the giselle.
2006-11-11 12:28:49
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answer #7
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answered by Luken 5
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Natural selection - things with less favorable DNA will die because they are worse at surviving.
Darwin's theory of evolution - everything that exists has evolved from the simplest beginings of life.
Relation: Organisms that evolve are the organisms that survive in particular conditions. Organisms adapt to their surroundings and evolve over time in order to survive better. Organisms that don't adapt die, therefore getting rid of their faulty DNA and strengthening their species and helping them evolve.
2006-11-11 12:27:35
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answer #8
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answered by scurvybc 3
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you seem to get the idea
organisms which can survive have a greater chance of producing offspring who can survive who have a greater chance of producing offspring who can...etc, etc, etc
any offspring with disfavorable traits is not as likely to survive to breed. certain traits may be more favorable in one environments than in another, this is where you get divergence of a species and the idea of the niche comes in. certain pressures like overpopulation in an environment may make attributes for living in a different environment more favorable to some i.e. an overpopulated sea and a lifeless terrestrial environment etc.
2006-11-11 12:34:17
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answer #9
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answered by jezmek 2
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