It doesn't matter wether you right or wrong ? just try to sum up your ideas , you can say it in one sentence , but it will be great if you are more generous with words !!
feel free to share your knowledge , some may find what you say more helpful than academic books !
natural selection, evolution's main mechanism (there are others- gene flow, genetic drift, sexual selection [itself a subtype of natural selection]), works like this:
from a few uncontroversial facts we derive natural selection.
-organisms reproduce more offspring than there are resources (food, mates, shelter, etc.) to support.
-organisms must compete for access to and control of the limited resources in order to survive.
-the characteristics of organisms of the same species vary within the species with some individuals being longer and larger or shorter and smaller; some having better eyesight or sense of smell; some being faster or having markings that afford it the ability to blend into its background or, conversely, stand out from its background and serve as a warning to would be predators. of course there are populations within the species that do and do not have certain characteristics.
-the characteristics of an organism that allow it to better compete and ultimately survive are coded in its genes and passed down to the next generation.
-in surviving, an organism is in a position to pass on its genetic code to subsequent generations, the same genetic code that increased its chances of survival and reproduction. this creates a survival differential in the species with the more successful population- the population with the characteristics that afford them the ability to better compete- reproducing more frequently than other populations within the species. before long you can see that the better competing population that reproduces more will make up the largest proportion of the population of the species or, indeed, come to out compete the other populations altogether such that the other populations go extinct. the species will then be said to have evolved.
here it is simplified and graphic:
you mentioned Dawkins' The Selfish Gene. Dawkins (but others before him had laid the groundwork or said much the same thing) said that we could easily explain many animal behaviors that were selfless and altruistic at the level of the individual by looking deeper, at the level of the gene. while the individual animal appeared to be doing something selfless it was a behavior that increased the gene's likelihood of survival and, as such, the gene could be said to be selfishly looking after its welfare by predisposing the individual to selfless behaviors.
so, for instance, in looking at cooperation we are forced to ask why an individual would waste energy cooperating when if it just concentrated on its own needs it could do just fine. and that we are forced to ask the question seems to be a violation of natural selection because it's an economical process that doesn't favor waste.
and the answer is that while cooperation seems funny at the level of the individual on natural selection, when we look at the gene level it makes perfect sense. cooperation increases the population's chances of survival and since genes exist in populations and not just in individuals genes can and do predispose individuals to behaviors that increase the reproductive fitness of the gene by increasing the likelihood that the population in which the gene occurs will survive.
the thing to be mindful of is that "selfish" is used totally metaphorically. there's no intent or motivation behind genes or behind natural selection. so, too, you should recognize that when i say "natural selection doesn't favor waste" i don't literally mean that natural selection favors anything in the sense that you or i favor something. it's just that words like these are helpful when explaining the dumb cold process.
Thank you so much Nelson for your detailed and easy-to-follow answer , I really appreciate that ...
Now the bees exmaple that Dawkins used makes sense , I took things literally and thereby couldn't grasp the meaning ... I am working on acquinting myself with the terminology of biolgy and hope that this will lead to a better understanding of such books !
thanks again for your time Nelson
I see what you mean Reg ; so many non-religious scientist on a video I watched on youtube say that if there is a ''god'' , it cannot be the same god of nowadays religions or all the previous religions...they went further (joking) and said that aliens helped by providing the right conditions for The Primordial Soup .
That actually has (at least) three totally different and plausible interpretations:
Evolution of our Universe?
Evolution of our Solar System?
Evolution of life on Earth?
Presumably you referring to the last, so I'll give it a shot (without using google or reading other responses!):
It starts with Abiogenesis, which is the study of how biological life started. Still a bit in it's infancy, there is good evidence of how the available molecules would arrange themselves to form the building blocks of life. Life as we know it is based on carbon, which is the most versatile (in forming chemical bonds) molecule and a natural building block. It would attract sugars and proteins, and eventually end up forming DNA. The DNA then attracted lipids to form a protective shell, thus forming the first proto-cells.
These carbon based cells needed carbon to replicate, which incidentally was quite common on the young earth due to volcaning activity. This process (via photysynthesis) released massive amounts of oxygen into the atmosphere, a molecule which has been shown to turbo-charge evolution of life. Cells which could "cooperate" with other cells had a higher probability of successful reproduction, and the march towards multi cellular life started.
After this initial phase, there is very much repetition over a theme. As DNA replicates, there are always some small mistakes (mutations), and (more importantly) certain offspring may have different combination of alleles switched on and off creating genetic drift. As conditions changed throughout the Earth's history, these first multicelluar globs evolved into basic oceanic lifeforms, from which subsequent life can trace its roots.
Certain traits proved to be better adapted to the environment and carriers of these traits would reprocreate more successfully than the average population. The less well adapted variants would eventually die out, and the highly adapted ones would continue to evolve, etc.
I can probably write a lot more, but I think that should probably contain enough schoolboy mistakes for any evolutionary science literate person to get a good laugh. :)
Mutations should not be considered “mistakes”. If cells are constantly dividing and replicating (passing on DNA) then mutations creep in. So if it happens once in a billion (that is a very small number on the genome level) a sequence in the DNA chain is altered. This may result in the mutation getting naturally selected or rejected depending on whether or not it is beneficial to the life (survival) of the organism. That decision is based upon the environment where the organism is living. It is really only this decision that is important as Evolution is only concerned with survival NOW in order to pass on its genetic code. Another way of looking at it is that Evolution has no long term goals.
One thing to bear in mind (sorry for repetition) and is a great one to hit the fundamentalists with is that Evoultion does not explain how life on Earth began. It has nothing to do with it. I have often heard them say “But the Theory of Evolution does not explain how life started”. No it does not is my reply because that is not what it is about. The fact that fire heats water does not explain why water freezes. It only seeks to explain how life evolved after it got started.
It can be a difficult idea to see clearly because it is based on changes made over time – usually a very long period of time. We generally cannot imagine what 100,000 years is like but life on Earth began over 500 million years ago. I have a few video on my page about evolution. I am not a Fronkey hunter for nothing you know !!!
Thanks for correcting me.
I think I grasp the fundamentals of the concept, but yet oh so much to learn about it before having even the right to hold any objection to it, if I ever would.
I actually saw the last video linked before and left a statement which should have been a question: Couldn't her claim be contradicted by punctuated equilibrium?
In the bare minimum terms, a genetic trait simply needs to arise, and it needs to be propagated. The mechanisms for both cases are numerous and varied.
disclosure: I'm simply using the worms as a hypothetical example because they're already on the table for conversation. I have no idea how these worms actually evolved or what factors were at play.
The trait for arsenic resistance in worms may have existed prior to arsenic contamination of their environment. It could have been a trait that had neutral impact on individuals carrying it, insufficiently negative impact to hinder survival, or was beneficial in some other way. The important thing is that individuals carrying the trait survive and propagate it, even if the trait itself is not immediately beneficial for survival.
Now introduce arsenic into the environment. The trait of arsenic resistance, even if only at a rudimentary stage of development suddenly becomes very relevant for survival. Those worms carrying it are far more likely to survive and propagate. Those worms not carrying it will not survive, no matter how fit they are by all other standards. Depending on how much genetic variation there was in the overall population and how many worms were killed off in the arsenic, you may see a considerably change in the allele frequencies in the population inside the affected areas. Some traits may disappear entirely from that population. If you compare worms in the affected area to worms outside the affected area, you'll see different sets of selection factors being applied to groups with possibly different allele frequencies and different levels of genetic diversity.
I don't know that much about worm reproduction or genetic variation, but a hundred and seventy years is probably over one hundred generations. That still seems like a remarkably short amount of time to diverge into a new species, but under those conditions, it seems somewhat plausible.