delboy

I guess we're all what we are due to previous evolution. But if you feel you're like your parents rather than other people I think it's more of a genetics and behavioural question than evolution. You got all your genes from them and they brought you up so there will be a lot of similarities. Surely evolution is a broader thing and makes us all roughly alike whereas being like our parents is due to things on a much shorter time scale. Genetics makes us the same, evolution changes us. Long time since I've seen that film!

I was thinking more about how you go from inevitable chemical reactions, to animals with competitive thoughts and feelings. In effect, how can a chemical develop an emotion.

I can understand that at the start of life (or before), RNA/DNA came into being and started to replicate. And those molecules that replicated more effectively soon became more common than those less so, and so opened the door to change by evolution. I think I can imagine the same process happening within the genes in cells - selection just blindly choosing one over the other. What I find difficult to imagine is how a living thing seems to have a desire to survive, compete and reproduce, and when and how this arose. Are there any ideas on this, or is it a bit like pondering the nature of consciousness?

The difficulty is, if a non scientific person says they think humans are superior, they don't really want to measure something, it's more of a gut feeling and overall view. But measuring by biomass and distribution seems a reasonable way, and humans fare pretty well by that combination. Krill beat us for biomass. And ironically, cows and sheep are highly successful by both measures, by virtue of being very tasty to humans and very controllable. A very unusual route to evolutionary success for a prey species. But I don't think many would see that as a measure of superiority. No other species can come close to the number of other species we can control, manipulate or destroy if we feel the need. Nor can they do much of what we have done. Does that make us superior. Or is the question wrong, can it not be answered in an overall way, only by some specific measurement.

Relative success as a species? Ability to manipulate other species for our own gain? To farm what we wish to eat or destroy what hinders us.

I'm not sure that a science/evolution based answer is the best one. I semi-seriously suggested that maybe Krill were superior to us because they had more biomass and vastly more individuals than us. I was ridiculed a bit of course. But I do find it difficult to get away from thinking, when you stand back and make an overall judgement, we are superior. But I also feel uncomfortable with that view - there does seem something wrong with it. I just think to be arrogant and not care about being arrogant normally comes back to bite you somehow. Memory is one standard of intelligence, and by that particular memory standard chimpanzees are more intelligent than us. Maybe the environmental aspect is why we shouldn't feel superior, because our intelligence is never going to give us complete control over nature to neutralise any impact we may have. But I'm never comfortable with the guilt trip message about our species. Partly because I believe any species who had reached our position would have done something similar. And partly because environmental damage comes mainly from the effect of the entire population but we all have to make decisions based on our own individual lives and what our genes tell us to do.

I recently heard someone say that they thought humans were obviously the most superior species. I found it difficult to argue against, but it didn't seem right to see it that way. I guess it's not a very scientific question because it's open to opinion. It also seemed a slightly arrogant way to view us, and one which could lead to abusing our position in the natural world. Any thoughts?

No you didn't accuse. Wallace was right to reject Lamark's theory of descent, whereas Darwin didn't do that. Don't want to diminish Darwin, just big up Wallace a bit

I've just started reading The Selfish Gene and notice that Dawkins himself attempts to take no credit. In the preface to the second edition he says that he is just taking technical ideas and popularising them, and in the preface to the first edition he lists those who's work are the basis for the book. But agreed, the popular perception is that it is his theory. I would have thought that I guess, until recently. A bit like the popular perception that just Darwin came up with the theory of natural selection.

Getting trapped in a park with them and being chased.

No misunderstanding I think. I realise we certainly didn't evolve from chimpanzees, but from another unidentified ancestor ape, the same as the chimpanzee's ancestor. But the above evidence must mean the common ancestor to all life was neither archaea nor bacteria as defined at the moment.

So did neither spring from within the other? If so there must be another as yet undefined group?

Not in relation to caucasian skin colour since that is better adapted to a northern (cooler) climate. Humans evolved to be very adaptable pretty early on - more so than the forest dependent apes. I think you would say that adaptability and a capability to live in a variety of habitats was a natural state for humans. We are a very different animal to a bonobo, and humans evolved to live in a completely different habitat to them.

The questions you have in mind are not really relevant to evolution surely - human technology (clothing, shelters, sunblock etc) renders them irrelevant. For a caucasian the most healthy amount of sunshine is a limited one, but this might be able to be managed in a hot country depending on lifestyle. Humans evolved in Africa, but lighter skin (and perhaps other adaptations to the cold) evolved further north so those humans were better adapted for more northern climates than to an African climate, but again modern human lifestyle makes it irrelevant. Only some humans left Africa of course, and only those that did had those slight adaptations to a more cold environment. I should live in a climate that you like the best, and just live healthy wherever you are!

I'm not thinking of divergence - one species leading to two - I'm thinking of one species evolving into one new species. This is a way for a new species to arise without reproductive isolation surely, which was the original question.

I'm not thinking of ring species. I'm thinking of a population with complete gene flow within the population.

But surely some reproductive isolation is only necessary to create two species from one. If a reproductive population is left for enough time the new individuals would not theoretically be able to reproduce with the original ones. Surely this must happen. So one new species has evolved from one original. Is this speciation or is there another name for it?

I would also answer 'no' to the reproductive isolation question. Intermediary individuals don't really exist because evolution is just a gradual process. As mentioned, species is an artificial concept, so an 'intermediary' is as much a species as any other. They do not die out but give rise to the next slightly different form - whether that be called a different species at any particular point in time is probably impossible to define, and rather artificial anyway.

This is what I suspected. It doesn't feel like it's extinction, particularly if you just think about the next species in the evolutionary line (plus the gradual and indefinable nature of becoming a new species). But taking as an example the common ancestor of birds - surely we have to consider that to be extinct. But we could also consider that it lives on in all extant birds. It seems to me that not all extinction is extinction, strictly speaking. Which is also very gradual and even more indefinable than the change from species to species.

It seems to me there are two types of extinction. One due to the population dying out, and one due to evolution into another species. One involves genetic extinction and the other is just evolution and is genetic success. Is there reason to make a distinction between the two? Maybe it's just an emotional thing, but the word extinction seems to imply failure in some way, but it could equally mean great success. I assume that with fossil species it can never be known which type of extinction occurred (unless it was clearly on an evolutionary line that is entirely extinct now).

For one species to become another a very large number of mutations would need to build up over many generations to create sufficient difference in the new population. Most mutations create very small differences (or no difference at all) and would never create a new species on their own. Mutations occur at cell division, so they would exist in the sperm and egg cells - meaning the new cells do not contain exactly the same information as the original cell they divided from. The mutation in either a sperm or an egg will be passed to the offspring regardless of any mutations in the other cell since the genetic material is combined when they come together to create the embryo.

I didn't mean to imply I thought it was wrong, it was only semi serious. It's just that human activities are normally considered unnatural, which is perhaps not really true. But the idea of self imposed evolution is an interesting one.

Unnatural Selection at work?

Evolution doesn't produce ideals, it's more about what's possible. If a giraffe can eek out a living with the advantages it has, then it is a success for the moment. There must be enough of an advantage of being able to eat the highest vegetation to outweigh any disadvantages. There are probably no other similar animals around for exactly the reasons you give. It's perhaps not ideal in many respects. Also - giraffes in Denmark need to evolve stronger migratory habits if they are to survive (not sure if this news has spread across the pond yet).

I see there are 5 species of Felis, but they all look reasonably similar to me.