natural selection questions

I am well versed in darwinian evolution via natural selection and I find the theory lacking logic.
Here are a few questions for the Darwinians.

  1. If life began as basic single cell organisms what was the need to evolve to more complex life forms?

2)the “original life forms” were asexual-a very simple way to reproduce and continue to survive and therefore the “fittest”. Why then evolve into life forms dependant on a more complicated, and therefore “less fit”, male/female reproductive process?

3)If the process of natural selection inherently leads to survival of the fittest why did we humans “evolve” the ability to decide whether or not to survive,i.e suicide?

  1. The “need” to evolve and become more complex is not really a need at all. Evolving is what life does, it is always adapting to new environments. My answer to this boils down to be as simple as, “because it can.” Like Ian Malcolm says in jurassic park “life will find a way.”
  2. Life varies greatly, and many species have developed more effecient ways of doing all sorts of things. Humans, for example, breathe and eat out of the same pipe. Which inherently means people are going to choke and die while eating. This seems to be an inefficient way of consuming; dolfins, also mammals, have one repitory tube and another for consuming nutrients.This is just another example of the diversity of life.
    Also, Im not positive but I think that for more complex life to be able to prosper they would need the male female reproductive system.
  3. Humans have evolved to become the most intelligent creatures on the planet. That intellectual compacity does come with some psycological problems but they do not inhibit our species. Its not about individuals, its about the fate of the species.

I question how well versed you are in the theory of evolution if you are still using Spencer.

As I understand, an answer for this question does not yet exist; however, simply because the question has no answer has no bearing on the validity of the theory, in much the same way not knowing how gravity works has no bearing on the validity of the theory of gravity.

We know things gravitate towards each other, and we don’t know what causes it; similarly, life evolves into more complex life forms, and we don’t know what causes it.

There could also be advantages to doing so that we simply don’t realize. As Dylan pointed out as well, evolution is somewhat of a random mutation process (not to be confused with natural selection, which is NOT random). If an evolutionary change in a certain trait occurred, and it didn’t have a great enough disadvantage to deplete that trait from a species, then it wouldn’t really have any benefit in falling out.

We know how life got to the point it’s at now, but how will it change now that a species has the ability to reason, to choose, and to visualize the future? This is a question that is beyond the explanation of natural selection.

  1. There’s no such thing as ‘need’ in natural selection, it happened, the resulting offspring survived and flourished more than the simpler replicators.

  2. Because mixing two different sets of genes means that an organism is more likely to throw up some sort of beneficial variation. Greater variation is also a form of protection against sudden environment changes as it is inherently more adapatable.

  3. Has been adequately answered.

All of the responses are valid and worth considering. Thank you for keeping this a discussion and not turning it into a series of condecending attacks - which happens all to often on this site. Before i respond please allow me a few days to think over what everone has said. I believe the topic of evolution is of the utmost importance not worthy of knee jerk reactions-which I have a tendency to do.
“X” Perhaps I am not an evolutionary biologist like you, so I have no idea what,or who,“spencer” is. These were questions I came up with on my own and I believe they are valid. If you have valid answers I am all too willing to listen.

Sorry, it had been a long day, and I was feeling testy. My apologies.

Here is a quick bit on survival of the fittest. I think that people often take ‘survival of the fittest’ to mean ‘the strongest, fastest, smartest, ect.’ when that isn’t how natural selection operates at all. It is more about finding and filling a niche and being adaptable enough to weather any challenges that such a niche might bring with it. Which brings me to your questions:

  1. There is the old saying ‘many hands make light work’ and this concept holds true in biology as well. One of the reasons I react strongly to the term ‘survival of the fittest’ is because is places almost exclusive emphasis on the competative aspect of life and evolution when cooperation plays at least as important a role. It boils down to game theory, where cooperation is generally the most effective way to rack up more ‘points’. Now, again according to game theory, if everyone cooperates, then nobody wins or if someone is playing a different game the whole system falls apart. So, there has to be this balance between cooperation and competition as well as similar goals for either to occur. Multicellularity is just a more complex expression of this system.

  2. Sexual reproduction has a variety of advantages over asexual reproduction because it keeps genetic diversity very high and (because of that) allows natural selection to take place more efficiently. Bacteria are able to overcome this problem by simply reproducing so quickly that random mutation is more than able to provide all the genetic diversity they need (though, it should be noted that even bacteria have a ‘sexual’ element, small pieces of DNA that can be traded between bacteria quickly and efficiently called plasmids. Antibiotic resistence is something that is normally found on a plasmid, for example).

  3. Well, I think that question relies too heavily on teleology. You’d think over time things would get more ‘perfect’ but really they just better adapt to the environment they are in. Sometimes, that leads to trade-offs. For a long time, evolutionary biologists were puzzled over the lack of a tail in humans. After all, a tail is a pretty useful thing to have, so you’d expect neutral selection at the very least. But, a tail, takes a lot of oxygen to maintain. So does a brain of our size. So, it became a trade-off between having a tail or a bigger brain and it looks like the bigger brain in the more useful tool. Trade-offs like these can lead to things like suicide. If I were to speculate why suicide is present in humanity, I would say that humans are hyper-emotional creatures. This makes sense because emotions and empathy are essential to social existence and humans are an incredibly social species (the lone human is a pretty pathetic thing). But that same hyper-emotionalism that allows for good social interaction can also lead to depression and ultimately suicide.

Or I could point out that suicide is present in many forms of life, even the single-celled yeast that make your bread and beer can commit suicide. Normally, it is those who are genetically unfit in some way that take this option, but occasionally it just has to do with population dynamics. Oops, not enough food for everybody, so a bunch of us are gonna have to die! While I think that applying the logic of cells to the logic of the human mind is a bit of a stretch, but at the same time, I think that since this phenomenon is observed in non-human areas, it would seem to be a more fundamental part of biology that one might first think.

darwinism is somewhat lacking in the concepts of single generation adaptations, but it could be said that there was a form of stimulas warenting adaptation, food becoming scarce = need for more efficent digestive processes, competition from other orgenisms= need to be bigger and stronger than them.

a common concept being viral infection, there are studys on how some species of snails are asexual while others are sexual, they have often noted the presance on harmful bacterial agents amoungst those who are sexual, so it is assumed that in order to avoid complete destruction from a single strand of virus the snails began to reproduce sexually in order to mix and match to make them more resistant to the virus.

one of the interesting adaptations of humans is their ability to reason out concepts and determine solutions, though this trait is not inherantly human, combine that with our ability to communicate with eachother, our ability to alter out surroundings, and our ability to copy and use other animal cheracteristics, example being wearing armor to imitate a beetles shell or building weapons to immitate a predators fangs.

We are able to make living a simple matter, the trouble being that when our ability to reason has no useful function it can easily turn inwards and overcomplicate situations, this can often cause more trouble than its worth, an odd concept being that a number of people who concider suecide concider themselves worthless, this could be simply an overcomplication of natural selection.

plese bear in mind these are only possabilaties and not exacts or even my oppinion, it is simply one view on it.

Trevor and Carol

Xunzian…You’re an evolutionary biologist AND a philosopher? Are you familiar with R.C. Lewontin’s “Biology as Ideology”?

Microbiologist, actually. But since evolution exists at the crux of modern biology, I know a thing or two about it.

And, no, I am not familiar with it, but I am remedying that as I type.

This freakin’ website has caused me to order more books . . .

Do you use any confocal microscopes?

Not personally, but people in my lab have. Assuming that I can find a freakin’ antibody for the protein I am working on that doesn’t have an annoying amount of background, I would like to.

Neat stuff. The campus I’m on just got a new one. Multiple-photon microscopy produces some wonderfully clear images.

Pretty, pretty.

(Note: the ‘it’ in the second half of my previous message related to the book, not evolution. Upon re-reading, it was semantically unclear).[/img]

“dorky” random mutation and natural selection go hand in hand. natural selection keeps the beneficial mutations. The theory of gravity and evolution are not analogous-the former is an observable fact regardless if we understand it completely-while I’ve yet to observe a reptile become a mammal
“matt and X” I understand that mixing genes improves odds of survival but in the beginning there was no gene pool to mix up-nor any way to mix it up if there was one. This does not answer the question. Of course bacteria, like all living things, adapt but in the end its still bacteria. Adaption and evolution are not interchangeable terms. Suicide implies choice, I was unaware yeast had that ability.

Please re-read my questions.

Part of the problem here is something I’ve discussed in other threads, which has to do with how ‘species’ is defined. It really is a problem because the way it has been defined, a speciation event is pretty much impossible.

We have observed bacteria whose genomes have been so radically altered that if you were to sequence them, they no longer appear to be the same species as they once were. I mean, the sheer amount of diversity in any given Bacterial species is simply huge. If we were to apply that same definition of species to mammals, there would be two species of primates! Additionally, many dog breeds can no longer successfully breed with one another. Yet, this isn’t considered a speciation event because ‘a dog is a dog’. Furthermore, nothing better explains the genetic interrelatedness of life.

If you are taking an applied definition as an actual one, then absurdity naturally results I think this is one of the tougher concepts. People often mistake the label for the thing itself.

Species are defined in many different ways depending on the context. Although you do not define how you are defining species it seems to consist of genomic divergence.

I’ve never seen species defined like that to be honest.

As an evolutionary concept species is a group of individuals that form a reproductively isolated unit. Whether this population undergoes a large genomic change or not doesn’t really matter. It will still be one species if it does show large genomic change and maintains the connection as one reproductive connected unit of organisms.

Your confusion seems to stem from the fact that there are other definitions of species. There is the taxonomic definition of species. We label a distinct phenotype as a certain species. We then examine individuals and if they meet certain criteria of the phenotype that fits a specific species they are labeled as such. This isn’t an evolutionary definition. It is one of convenience. And it works very well for the its purpose.

You can now already see it coming that large genomic change with no form change or small genomic change with large form change do not prove or disprove evolution. They are merely examples of the mechanisms of evolution and development which allow for both. In taxonomy large change in form would often receive a label as a new species. However, it is not a measurement of something intrinsic in evolution. It is a human tool of nomenclature. For the actual process of evolution change or no change, change in form, or change in the genome is all irrelevant. They are all part of evolution.

A lot of what I’m talking about was discussed at this report. One of the snags was that a useful definition for bacteria and archaea ended up creating fairly absurd situations in Eukarya.

But what you’ve said re-affirms my point. When you start having multiple definitions for something, it isn’t because the thing that you are defining it a concrete thing but rather because it is a fluid concept. If I am talking about the ribosome, I am talking about something everybody pretty much agrees on.

We can argue over certain molecular details but there isn’t the degree of disconnect that there is with species. The point is just that it is a definition of convenience! But the utility of such a definition decreases dramatically if you take the gene itself to be the basic unit of selection as opposed to the species.

I’m not saying let’s ditch the concept of species, as a label it is still useful. But let’s not reify the concept either – it is a label, based on fairly arbitrary criteria.

You don’t seem to have read my post at all.

Species can be defined in many different ways and still you talk about THE concept of species.

There is none as I have made clear before. There are many.


I don’t see where you are disagreeing with my point.

We seem to be in total disagreement.

First of all you never define species although you hint at what it may be.

secondly the term species poses absolutely no problem for evolution, something you seem to contest in your post. Which is mainly due to the fact you do not define species and think that there is one definition of species. I on the other hand gave you two definitions. One which doesn’t always go well with evolution, the other being a evolutionary definition of species.

Hence I do not share your feelings.