How does Evolution really work?

Answer 1

Nature will "naturally select" the species most fit for survival in a given environment. For instance, in Anartica, a species need to be able to blend in with the extreme cold of the area. The species' unable to do so will be killed over time until extinct and there will only be the remaining species around. This is Natural Selection, as nature has selected particular species to survive.

Evolution is similar. It invovles nature killing particular members of a species group because of their attiributes not allowing them to survive in the environment. As an example, if our enviornment one day necessitated being tall to survive, short people would be killed off through natural processes and we as a species would "evolve" by becoming taller as a species. Since only tall people would survive thereafter, we would have taken a step forward in the evolutionary process.

Answer 2

Reverend Al, Please take your rants over to the religious section. This is Science, which you obviously don't understand. Even if you were presented with a transitional fossil, you would deny it's transitional. Take a look at the evolution of the horse from a four-toed forest dweller to the single-toed plains animal of today. Plenty of transitional evidence.

Evolution works in a combination of mutation and natural selection. Natural selection can breed for dominant traits within a species, but does not account for the progression from one species to another. Recessive traits will still occur in the gene pool, and may be brought forward due to environmental factors without changing the viability of the individual to breed within the species.

Mutation is an actual modification to the genome. These mutations occur due to transcription errors during reproduction, or actual damage to a pristine chromosome in a reproductive cell. Most mutations are either deadly or relatively innocuous. A very few may provide some reproductive advantage to the bearer.

There is a growing school of thought that mutation rates within a population may be tied to thealth of the magnetosphere. The Earth's magnetic field strengthens and weakens periodically. A weakening of the field can precede a pole reversal. During such a weakening, the surface is exposed to increased cosmic radiation, causing higher mutation rates to occur.

When a relatively small population is under stress, i.e. survival is uncertain, an advantageous mutation may confer a reproductive advantage to the bearer, which will lead to that individual's genes having a greater chance of being carried forward to the next generation. Natural selection does the filtering process. These advantages may allow the bearer to gather or process food more efficiently, withstand temperature extremes more easily, avoid predation more effectively, or compete for mates more successfully. The benefit may not benefit the bearer directly in any obvious way, but may in some way confer an advantage to the bearer's offspring to reach reproductive age themselves. If enough of these mutations occur while the population is small and under stress, the ability of that population to successfully breed with another similar population dwindles, and speciation occurs.

It is almost impossible for this process to work in a large population, because the benefits of having a reproductive advantage will be muted by sheer numbers. Picture if you will, dropping a drop of food dye in a test tube of water. The test tube water will change color. Drop the same drop of dye into a swimming pool, and nothing happens.

Mutations which occur in a large population will have very little chance of becoming dominant, and when an individual's genome becomes too far removed from the mainstream, it no longer can successfully reproduce. We call this infertility.

Mutations which occur in a small population which is not under stress will have no pressure to become dominant, and will often either lay dormant or be bred out of the population.

This is the foundation of the punctuated equilibrium model of evolution. Speciation takes place in small populations under survival stress. Genetic changes which confer a reproductive advantage breed true. When the stress is removed (climactic change, usually), the new population expands to fill it's ecological niche. If that niche is already inhabited, and the new species can outcompete the old, the new species takes over. Because of the relatively small populations in which this occurs, and the relatively rare incidence of fossilization, the probability of capturing such an event in the fossil record is extremely remote.

Answer 3

More strength in numbers. If a mutation develops that benefits a sepecies...the subject carrying the mutation will live long enough to reproduce as much as is possible for it's species. It's offspring, which inheret this mutation will again live long and produce as much offspring as possible. Thus the mutation gives advantage to a particular genetic line. Until eventually it dominates the species in totality and becomes charectaristic of all representatives therein.
Most mutations are negative. It's a very rare mutation that improves upon a species, but when it does, it allows for a longer life, and/or greater reproduction. Thus evolution proves itself.

Answer 4

The simplest answer is that it works through natural selection. Natural selection means that creatures that are more "fit" are more able to survive, and reproduce and pass on their genes to their children. The less "fit" are less able to survive and therefore less able to pass on their genes. Over time, the genes which make an organism more "fit" stay in the population, while the ones that make an organism less so get bred out.

There is quite a bit more information online, but beware of anything related to religion. Religion tends to have a hostile view toward science in general, and evolution in particular.

Answer 5

Natural selection is the basis of evolution if I'm not wrong ?

Bcos there is variation(naturally) in a population, there will be selection pressures on certain species.
Selection pressures causes certain species to be at a selective adv or disadv.
Those as seldctive adv will survive to reproduce and predominate,whereas those at selective disadv will not be selected for due to disadvantages traits.
Mutations are also causes of evolution. Mutations occur by chance in somatic or gamates cells. Muations can be caused by man- made factors such as radiation or X-ray. Only mutations in gamates will be passed on to future generations. Mutations can be missense or nonsense, and may or may not have effects or changes in the organism's phenotype. They may be masked, in a sense if they are recessive in an incomplete dominance interaction btwn alles. Mutations are generally disadvantageous to an organism and may cause them to become at a selective disadvantage.. and so on..(natural selection)

hope what I wrote wasnt fully rubbish! :P

Answer 6

To give a really simplified answer, everyone is just a little bit different. Those with more beneficial differences are better able to survive. They survive longer, are able to then reproduce with others that survived longer and that trait gets passed along.

For example: a giraffe. The longer neck enabled them to reach leaves higher on the trees that none of the other animals could reach. They didn't have to compete with all the other shorter animals and were able to get more food. The longer neck proved to be beneficial and as the longer necked "giraffes" bred, they next generation had even longer necks and so on until you get the giraffe we know and love today.

Humans: Apes discovered how to use simple tools - a rock to break open a nut or a pointy stick to hunt an animal. They started using their hands more for tools, which made them use their hands less for walking. That's how we straightened up to just two feet. They used their brains more, eventually tying a pointy rock to that stick to hunt bigger animals. We lost more of our animalistic senses, but developed our brain power.

Answer 7

Evolution is merely change in genetic frequency over time in a population. I think you mean natural selection, though. That is the selection of beneficial mutational variation, leading to the reproductive success of certain organisms, which then pass on that successful variation to progeny.

Answer 8

Most simply put:

Darwin's definition...descent with modification

Another def....gradual change over time

Its about species adapting to their environments...natural selection also plays a role in evolution

There are SO MANY websites! Just look it up

Answer 9

Darwins books "The ORGIN oF Species".
First Big Bang
than Trilobytes,
than ameboes,
than frogs,
than Dinosaurs,
Than Neanderthals,
Than Cro Mgnons,
Than Homo Sapiens,
Now: Still Evolving.

Answer 10

Its simple. If an animal or creature is placed in a different enviroment or surrounded by different species it will adjust and adapt to it over time.