Can anyone explain the finer points of evolution?

I understand "broad-brush" descriptions of evolution such as "survival of the fittest" and "the selfish gene", but can anyone explain the finer points? It seems to me that serious environmental problems are required to "wipe out" "the unfit", and perhaps selection of a mate by one or both partners could have something to do with species evolution. Am I right? And/or are there other mechanisms in play?Can anyone explain the finer points of evolution?A few key points:



* Don't ever forget that evolution just means *change*. It does not have to mean "change into a new species" ... even minor change is evolution ... and a lot of minor change produces major change.



* "Survival of the fittest" is a very loose description of natural selection ... but be careful. The point is not just *survival* of the fittest, but *reproduction* of the fittest. Sometimes the guy who doesn't live as long can reproduce *more* ... e.g. with the male praying mantis, or black widow, mating means certain death.



* That answers your question about mating. The male peacock's tail may be a *detriment* to survival (it certainly makes him easy pickings for predators), but if it provides an advantage to *reproduction* (because females pick the guy with the hottest tail package) then he wins. That's called 'sexual selection.'



* Serious environmental problems are NOT necessary to "wipe out" the "unfit". All that matters is that they do not compete as well with the "more fit" ... and gradually, generation after generation, they get weeded out.



* The term "fit" or "unfit" is always *relative to environment*. A change in environment, or moving into a new environment, can change what is "fit" or "unfit".



* Don't ever forget that natural selection is about competition between members of the *same species* ... not about competition *between species*. That's why there are no "super-antelopes." To survive, an antelope doesn't have to be able to outrun a lion ... it only has to outrun the other antelopes.



* There are *two* main mechanisms for evolution ... selection (usually called natural selection, but sexual selection and artificial selection also fall under this category) ... and genetic drift. Genetic drift is where genes become more or less frequent in the population by just random matings, not because there is any advantage or disadvantage. For example, recessive alleles may have no effect at all on the carrier in most cases, but they can spread slowly into the population until carriers start mating and produce offspring with a double dose ... and they are affected. This is how even harmful alleles can survive in a population for hundreds of generations ... or potentially advantageous alleles can go unnoticed for centuries, and then suddenly burst forth as carriers start mating and the advantaged offspring outcompete everyone else.



* It is important to understand *branching* ... why a species will split into two species (called speciation). In a nutshell,

evolution + isolation + time = speciation

I.e. if a population is separated into two reproductively isolated populations, then with enough time, the two populations will accumulate enough evolutionary change that they lose the ability to interbreed ... they have become two species. Once this happens, they are *forever* separate branches of evolution and will continue to get more and more different.



* The *pace* of evolution is an interesting part of research and debate. The concept of Punctuated Equilibrium holds that life can go through long periods of relatively minor, almost unnoticeable change ('equilibrium') interrupted ('punctuated') by periods of rapid evolution and production of new species, or even new *types* of species.Can anyone explain the finer points of evolution?
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Can anyone explain the finer points of evolution?It doesn't require huge catastrophes to happen. A small example can be the color of animals in the wild. Let take a snake for instance with 2 colors brown and white. Also, we have two enviroments a beach and a forest. The white snake will survive better on the beach than the brown snake because it will be disguised better and not get eaten. On the other side the brown snake will survive better in the forest because the white snake would be eaten. This means that the genes for the white snake gets passed on in the beach habitat but the brown snakes genes get passed on in the forest. This is evolution at work.



Also selection of a mate does have to do with evolution. An animal with a darker color may get chosen as a mate because it is more fit to survive as seen by its darker color which is evidence if eat well.



There are many mechanisms at play for evolution. Mutations drive the whole thing. A big concept is populations evolve not individuals.Can anyone explain the finer points of evolution?
I think you pretty much have it nailed.



'Characteristics' and Mutations that lead to the death of a species get deselected. Those that see the species prosper get selected.



At its most base. Men like women who have large boobs and nice asses (child bearing hips) because men are 'programmed' to be attracted to women who will be able to bear children. Those men attracted to other womens shapes are rare because they died out generations ago.



The reverse is true. Women like men with big muscles and big d*cks. As they are likely to be able to produce children and protect the family. Again those women who prefer the opposite, are rare.Can anyone explain the finer points of evolution?Fitness is a relative thing, in any generation of any species some individuals will have higher fitness than others - in general these will be the ones who go on to have offspring and then pass their genes on. Individuals with lower fitness may have reduced survival or just reduced reproduction, either way they don't contribute to the next generation. For example, the survival rate to the age of 1 year is very low in many animals, only the fittest make it even to this stage.



There are other processes at work - there is always an element of randomness in the system, an individual with high fitness might end up dying from an injury for example. In very small populations, less fit individuals are more likely to breed than in large ones and a process called genetic drift becomes dominant over selection. This is a process which is rather random.



Mate selection, called sexual selection, is different from but mirrors natural selection. Females (usually) choose on the basis of physical characters which should related to the male's fitness - for example better male peacocks grow better tails and the females choose these.