Re: Christmas 'hypocrites"

Dutch wrote:

Evolution is a theory designed to explain the diversity of life.

I don't think that the theory of evolution was "designed" per se for that reason. It was originally formulated to explain the distinct characteristics of animals which lived in isolation from other species. They developed in particular ways because specific characterstics were more successful under the local conditions, favoring the survival of certain individuals over others.


Darwin extended this idea, by saying that over huge amounts of time, these processes can add up to huge changes. It was his suggestion that the entire diversity of life on Earth could be explained by these slow processes, in the same way the topography of mountains and valleys could be explained by the long accumulation of slow processes, that turned biology on its head.


What about evolution is "convenient"?

It satisfies the human tendency to want things to be all tied up in neat packages with a bow on top.


That's what the religious explanations did. Evolution had an uphill battle to fight, and was certainly not convenient at the time it was growing. It succeeded because it is backed by mountains of empirical evidence.


These are different times. In those days we wanted to believe that God created the universe, now we want to believe that science can explain everything. Science is the new Sacred Cow.


Science is not trying to find God. Science starts with an observation, and any observation that cannot fit in with current theory destroys the theory. Religion is based on faith in things that cannot be supported empirically, ever. There is a big, important difference.

Evolution CAN explain the diversity of life, it can explain speciation.

Not to me it can't. Evolution can explain why birds on a island where long beaks are advantageous evolve into long-beaked birds, it doesn't explain how an amoeba transforms into an ape.


Well, an ameoba does not transform into an ape. Nor does an ape transform into a human. Primates share a common ancestor; they do not arise from one becoming the next.

Eukaryotes are descended from archae, a certain type of bacteria known to live in extreme locations. It's probable that cells living near each other in a situation like this started to form symbiotic relationships, and eventually became linked irrevocably. Once you have these simple organisms evolution just takes over. You are talking about processes that took billions of years; the most complex forms of life like mammals only showed up in the most recent history of life on Earth. These things happen slowly, but over time, lots of time, the changes add up.


It just does, because of the laws of the universe, and the special properties of oxygen, carbon, nitrogen, and hydrogen (along with some other important atoms).

That doesn't explain anything, what "special properties"?


Carbon has the ability to bond with up to four different partners, including itself, and form double and triple bonds as well. It is extraordinarly versatile and indispensable to life as we know it. Oxygen has the ability to make water, an extremely special molecule also required for life. The ionic attractions between water molecules and its ability to ionize to different pH levels is also utterly critical; oxygen also is involved in myriad redox reactions involved in storing energy and releasing it. Those four atoms I named together make up 99% or so of the mass of living things.

Once the initial conditions are set, it MUST happen.

Why?


Physics.



What is driving it?

Natural selection, generally.

I'm not talking about evolution per se. I mean what is driving the process of life manifesting period.


I don't understand the difference. It starts with spontaneously forming biomolecules, which have been shown to arise in a lab under strongly reducing conditions, which almost certainly were present somewhere in the nubile Earth. From there, the process of evolution takes over. What do you mean by "life manifesting"?

This really has little to do with atheism.

Sure it does, it goes hand in hand with it. Before evolution, science was stuck for an answer to the question of life itself. Now that we have a theory to explain how species adapt to their environments we have decided that everything "spiritual" is pure superstition. I think that we make a big mistake in doing that. Evolution does not explain everything, science can't explain everything.


That's true, but evolution does not rule out the possibility of God. Many evolutionist are religious. You are only clouding the issue of trying to understand evolution by introducing this second argument. One idea at a time.

The evidence for it is everywhere, especially at the genetic
and molecular level.

Give me a good reference to read on it.


I'll see what I can do but I am incredibly busy this week. The moral of the story is, at the molecular and DNA level, there is much more similarity in life on Earth than you might expect. More than Darwin could ever have known. The simplest ways to show this (not that there really is one for the layman) is to consider the biochemical pathways that are present in all living cells, like glycolysis. Nearly all living cells gain energy in the same way, using homologous enzymes to do the same jobs. We are not nearly as different as you might think.

At the DNA level, you can actually trace how far apart organisms are in evolution by looking at how similar certain genes are. Genetic mutations happen at a fairly regular rate. But for any given gene, there will be certain "parts" of it that are absolutely essential for its function. These parts can be found to be "conserved"; that is, be exactly the same for all organisms expressing the gene.

I'm trying to think of an example that works well for someone with no biology background, but it's hard.

Let's talk briefly about histones. Histones are proteins that associate with DNA. If all the DNA in your body was extended, from end to end, it would stretch to the sun and back many times. Your body needs an efficient way to wrap all that DNA up, and histones are the proteins that do this. There are several types. Histone H4 is the most conserved, showing barely ANY varience from organism to organims. For example, pea H4 differs from cow H4 is only 2 amino acids out of 102, the others are all exactly the same! Even the two that have changed over time have exchanged one amino acid for a similar one. The reason "conserved" regions in genes happen, is because any change or mutation that happened in this gene over time caused the organism to die. It was not passed on. When scientists begin trying to find out how a protein works, they look at these conserved regions first, as the critical functions must be encoded here.

Imagine that, from pea all the way to cow, the thing didn't change at all! Other histones are not so conserved, H1 varies hugely among organisms, for example. These changes happen over time because the mutations were tolerated; the protein still worked. By counting up how many of these changes have happened, we can estimate in time when two species diverged.

For speciation to occur, species must be genetically isolated from each other. Over time, enough of these changes add up that they are no longer the same species and they cannot interbreed. Then the changes really take off. Note that this isolation does not have to be geographic. There are many behavior changes, like mating rituals, or feeding and mating times, that can have the same effect. It is not a simple process, and indeed it's far more complicated than Darwin imagined. But there is mountains of evidence under the microscope and in sequenced genomes that he never had access to.

This is going to have to do for now. Too much to do today!


.

Relevant Pages

  • Re: Paper: A critique of directionality theory
    ... Directionality theory suggests that demographic entropy, ... equilibrium species and decrease in opportunistic species. ... been applied to explain the evolution of body size and of senescence. ... is the appropriate tool in the study of life history evolution. ...
    (sci.bio.evolution)
  • Re: The correct definition.
    ... "The processes that allows life to continue despite the ... What reason is there for what is recorded to be a lie? ... process stops the progress of evolution which claims it needs lots ... new species centered on the groups remaining after the extinction ...
    (talk.origins)
  • Chez Watt: Re: New falsifiable proposal/prediction of design
    ... > organisms from one population of a species to another does not result ... >> Is evolution something that has been proved on a case to case basis? ... >> divergent explanation to the ToE: ... > even though they are not useful in the living organisms. ...
    (talk.origins)
  • Re: Insights Ive gained from my Bio class so far
    ... about problems with evolution, the examples they give of problem organisms ... percentage of the life on earth. ... the selection processes that caused their evolution in the first place. ...
    (talk.origins)
  • Re: Insights Ive gained from my Bio class so far
    ... about problems with evolution, the examples they give of problem organisms ... percentage of the life on earth. ... the selection processes that caused their evolution in the first place. ...
    (talk.origins)
Loading