Natural Selection

survival - those that live have the babies and their genetic profile is perpetuated. Those that die don't have offspring and therefore their genetic profile become extinct.

Well, there is a major difference between natural selection and "unnatural selection", as I call it. What you are talking about with selective breeding is what I call unnatural selection: An artificially imposed criteria for success. If you're trying to get a dog with blue stripes, a dog with blue stripes will be more likely to survive even though genetically it's most likely a dead end.

But I digress.

Natural selection/evolution works as follows: First you have the mutation, then the selection. Over the course of generations, you occasionally have mutations. These can be of a few types: fatal, semi-fatal, neutral or beneficial. Now, if the mutation is fatal or semi-fatal, then the creature in question will almost definitely not be able to reproduce and pass down this genetic flaw (except in humans, with our advanced medicine) so this mutation effectively destroys its own chance of making it into the gene pool. A neutral mutation would not make it any more or less likely for the creature to live or die, to breed or not breed, so it would effectively have no effect.

A beneficial mutation however, would improve its chances. So now you have a creature with a beneficial mutation. This could make its reaction time very slightly faster, or it breeds more quickly, or it has slightly better camoflage (keep in mind, mutations are ITERATIVE. This means they make very tiny adjustments to the creature, not big leaps). Now, if that creature does something better, theres a higher chance of it surviving and breeding. If it survives and breeds, its children inherit this advantage. If its children are successful too, then on it goes.

If repeated mutations make the resulting successful creature different enough, eventually you get a new creature, which goes down its own evolutionary path, separate from the creature it originally was generations ago.

And there you have it, evolution in a nutshell.

Everything from available food to climate will cause the changes we see in natural selection. Random mutations occur constantly and when those mutations are beneficial for life, the genetic code is more likely to be passed on to future generations.

A process in nature in which organisms possessing certain genotypic characteristics that make them better adjusted to an environment tend to survive, reproduce, increase in number or frequency, and therefore, are able to transmit and perpetuate their essential genotypic qualities to succeeding generations.

Natural Selection

Natural Selection

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not.

genetic drift is a change in evolution based on small mutations in genetic make up over generations

natural selection is survival of the fittest, where only the surviving species will reproduce and live on

natural selection is caused partly due to genetic drift, since the mutated species will adapt to their surroundings and therefore become the fittest species.

The phenotype of organisms determines the way they interact with one another and with their environment. The way organisms interact with one another and with their environment determines how well each organism is able to compete for resources and mates - what the chances are of that organism successfully raising fertile offspring, in other words. Such offspring will likely carry the genes that give them their parent's successful phenotype. So over the generations, the genes that produce such successful phenotypes will become more numerous in the population, causing a shift in the average of phenotypes towards this successful phenotype.

The result is adaptation and evolution, as improved traits should increase the population of the best species over time.

Each individual in a population behaves in a slightly different manner.

Natural selection is the preferential survival of individuals with useful traits. On the other hand, when some individuals survive, others don't, either because they are out competed for resources or because they are simply killed. This is extinction!

Natural selection is most closely related to Darwin's theory of evolution.

Are those individuals best adapted to their immediate environment.

How does natural selection affect undesirable traits?

d. the accumalation of minor adaptive traits, over time, leads to new species

they are adapted to survive

They are the ones that are best adapted to survive in there environment.

It has not reached carrying Capacity

If there is a genetic mutation in an individual strong enough to modify there chance of survival it opens the door for natural selection. If the effect is positive they are more likely to outlive their original species. If it is negative it decreases their chance of outliving their original species. Also known as survival of the fittest it favors positive trays by "eliminating" negative ones.

ADAPTATION- It is the change in the physical appearance and/or the physiological characteristics of an organism upon exposure to different conditions of environment generally the harsher ones ( such as temperature, radiations and the nutrient sources ) . Gradually the immune system of an organism gets acquainted to the new environment and hence it is said to be adapted.

VARIATION- The transmittance of the adaptation to off springs results in new family of a species known as variants . The phenomenon of the generation of a new variant of a species is known as variation .

ADAPTATION is the source of VARIATION.
For examples if you look at the various breeds of canines ( dogs) in the world, they vary though they belong to the same species , this is because of their adaptation to the different prevailing climatic conditions.

The transfer of adapted features such as longer furs (canines in cold climates) and the modified hooked beaks in birds is due to the transfer of adapted traits from the parents to off springs through the vehicles of heredity known as DNA .

The passing on of the adapted traits to the off springs i.e. variation over an observed period is called as the EVOLUTION of a new variety or EVOLUTION .

Lamarck's idea of how evolution works was through inheritance of acquired characteristics which stated that offspring get the modifications acquired by parents. Further, he believed in "use and disuse", which stated that using a part of the body will make it bigger and stronger, while disuse will make it smaller (such as appendix). Of course, these ideas were strongly rejected in favor of natural selection.

Bacteria is the answer

Yes it does. Without variance in the organisms genome, that gives variance to the phenotype, there would be nothing for natural selection to select from.

organism best adapted to their environment survive- apex

natural selection occurs when animals need it

Vestigial structures are the expressed genetic remnants indicatory of a species evolutionary past. In humans one such vestigial remnant is the coccyx, which were once part of tail structures in our primate ancestors.

No. Natural selection is the non-random survival of randomly varying replicators. The random variation part could be thought of as mutation and recombination that the non-randompart, natural selection, works with.