I get frustrated when people deny evolution.
From my book Unholy Questions:
It is worth looking at evolution in light of what is necessary for humanity, or any living organism, to exist. First of all, there must be a cycle to life. We must reproduce. Any life form that simply existed as a finite number would have to be impervious to danger, immortal, in order to sustain their population. Organisms will die from natural causes, and as a result, they must reproduce in order to keep populations stable, or grow populations (in other words, to exist). Once we establish that reproduction is essential, we can then establish other necessary conditions required for existence. It is a simple formula. In order for a species to exist, and to continue existing, the organism(s) must survive to reproductive age, and must be able to effectively reproduce. For example, if humans could only reproduce over the age of one hundred, and we lived, on average, to seventy-five, then we would die out as a species. This is unarguable. Even Creationists cannot argue against this, given that it is logically coherent, and evident in every organism around us. Put simply:
1) Life must undergo reproduction, since finite numbers of organisms would die off in time.
2) Therefore, organisms must reach reproductive age to exist as a species.
3) Upon reaching said age, organisms must reproduce effectively to survive as a species.
Now, taking this into account, we also know, incontrovertibly, that organisms, on conception, join the male genome and female genome of their parents together to make the new genome of the newly conceived organism. This itself can be a source of evolution, combining new variations of genes, particularly if the two parents have a wide variation in their genomes.
In another source of evolution, when cells reproduce, the DNA in them (the coding mechanism) is copied (replicated). Sometimes, these replications are faulty. A part can be lost, added or swapped. In 99% of cases, though, this is corrected by cellular DNA checking mechanisms. In 1% of cases, the change stays. This change can be split into roughly three characteristics. The change can produce a trait or physical change that is problematic for survival or reproduction (points 2 and 3 above). The changes can also be neutral, or beneficial to these needs. If, for example, an organism mutated a weakness whereby it could not cope with cold temperatures anymore, and reproduced so that this trait was prevalent across the species, and there was a very cold winter that year, then the species (or members with that trait) could die out as a result of that mutation. If, on the other hand, the mutation created a mechanism that was beneficial to coping with the cold, and an ice-age came about, then that organism and its offspring would be more likely to survive (exist) through that time. Mutations are happening all the time, and organisms change, and react to their environment (or don’t) so that they survive (or don’t). This is a very simplistic view of evolution, and it is far more complex, with additional mechanisms and areas into which I will not delve. Suffice it to say, it seems to me to be a rather self-evident and simple process whereby very simple organisms gradually, over billions of years, have morphed into more complex and more varied species. Et voilà, homo sapiens sapiens arrives, via a common ancestor that we share with other primates (no we are not evolved from the apes on earth now, as is often cited, but we are all evolved from a common ancestor, for which there is much proof[1]).
[1] The oft cited Creationist mantra that we have evolved from monkeys / chimpanzees etc. makes me very angry. It is incorrect and espoused by utter dolts.
In : Science