Are there evolutionary reasons for reproduction?

You might want to read Nick Lanes book The Ten Greatest Inventions of Evolution as that covers sex. The first answer is that life possibly originated through the differential survival of replicating molucules and as evolution has no forsight its irrelevent if the resulting competition between replicating molecules and later cadres of replcating molecules has no purpose.The second aspect is that recombination during gamete production provides an oppurtunity for genes that reduce fitness to be removed and genes that enchance fitness be conserved. If an organism has several offspring then there is a good chance that in some of them the majority of beneficial genes will end up in one of them and a bunch of rubbish ones end up in another. The one with the good genes has a greater chance of reproducing whilst the one with the poor genes is less likely to reproduce. This is also an important mechanism for spreading beneficial genes through a population.Some organisms do breed asexually but tend not to do very well in the long run if they do not resort to sexual reproduction at some point or have some other means of altering their genetic material.Edited by Asking, : No reason given.

Evolution operates through the modification of existing genetic material, not the modification of genetic material which appears out out thin air. Therefore the condition that I exclude genetic material originating from pre-existing genetic material means that any answer I give has no bearing on evolution. As far as I know genetic material doesn't just appear out of nothing as the available evidence points to it being the product of pre-existing genetic material.Anyway the evidence for where the additional genetic material originates from.Gene duplication - http://171.66.122.45/content/9/7/629.full (Just one paper but there are countless more available if you search on google).The long and short of it is that the genes coding for Opsin have been duplicated and mutations alter the frequency of light they react to. This is actually a well researched subject and its been determined experimentally which specific mutations are required to alter the frequency of light they reach too. This is how we evolved tri-chromatic vision. Just google gene duplication as this will give more information about its relevence to other aspects of biology beyond sight. Evolution works through modification of what exists and gene duplication is a valuable source of genetic material to modify for another use.Polypoidy - (Polyploidy - Wikipedia)Most common in plants although there is a shrew which does this too and has an impressive number of chromosomes. Basically its the doubling up of the normal amount of genetic material in an individual organism which also has the side-effect of reproductively isolating it from its parent population and therefore leading to speciation. As I said unless they have some other means of altering their genetic material which is done via lateral gene transfer and mutations. Without this bacteria wouldn't be as resiliant as they are and doctors would have a much easier time stamping out bacterial infections.There are some animals that reproduce asexually but this is not an ideal method because 1) Benefitial mutations are restricted to a single lineage and cannot be rapidly distributed within a population, 2) Detrimental mutations can't be weeded out of a lineage as they can be with sexual reproduction, 3) as most mutations are either neutral or detrimental the net effect of asexual reproduction is a reduction in fitness. I first became aware of this after reading Nick Lanes book and have no looked into it again recenlty but here is a publication from 2007 looking into the origins of life at hydrothermal vents (On the origin of biochemistry at an alkaline hydrothermal vent - PMC). I believe that this was going to be tested experimental but after a quick look around I can't find anything stating explicitely some results from this (I'm no chemist so I may have missed something). When it comes to ambiogenesis though without being able to go back in time and see whats happened we'll never be able to say what exactly happened, only come up with scientific theories supported by experimental evidence as you rightfully expected.-------Returning to the original point have I answered the query as to what evolutionary reasons there are for sexual reproduction?Edited by Asking, : No reason given.Edited by Asking, : Bringing back to original question.Edited by Asking, : No reason given.Edited by Asking, : No reason given.Edited by Asking, : No reason given.Edited by Asking, : Alteration of original paragraphEdited by Asking, : Added quotationsEdited by Asking, : No reason given.Edited by Asking, : No reason given.Edited by Asking, : No reason given.Edited by Asking, : Clarifying somethingEdited by Asking, : No reason given.

"Wrong, or single celled organisms would have the information required to code for all of any organisms traits and physical features. Evolution requires adding of new information over time."Evolution does not require the adding of completely new genetic material over time. It works with existing material and through gene duplication and polypoidy it can provide additional material originating from existing genetic material to work on. If you want another example in addition to humans evolving tricolour vision via gene duplicaiton look up the information regarding the evolution of the component proteins of heamoglobin which relied upon gene duplcation."Although I'm sure this is a topic for another thread, I'm curious to know what information this is exactly...is there a thread for this?"Look up the stuff I've mentione above and don't expect to be spoonfed everything."This has no information on new information, only existing information. Furthurmore, it goes into great deal about cloning. I'm not sure if I mentioned this before, but similarity is also support for design. Since all cars have spark plugs, steering wheels, tires, seats, transmissions, doors, frames, etc., they too were designed. Genetic similarities in ape vision and human vision only shows that they are similar. Not that they are related."Its becoming apparant that you don't understand what I'm saying or are just ignoring it. Gene duplication creates more genetic material from existing genetic material upon which evolution can act. I have not said that gene duplication or polypoidy created new information, only that it provides more genetic material for evolution to operate that is sourced from existing material."I agree as well. However, asexual reproduction has it's advantages as well.1. Asexual organisms do not have to search for a mate, and this leads to greater population growth.2. Greater populations have greater chances of survival if there is any habitat change (be it preditorial, or environmental), and greater numbers also means out-completing organisms of similar nature for nutrients and water."Your first point is true but your second point is way of the mark. It doesn't matter if there are a million individuals in a population if they can't evolve quickly enough to keep up with changes in their environment."Read about this years ago. The logical mind refutes this instantly, since incomplete chemical structures travelling from land to the ocean floor sounds like a fairy tale. Even so, supposing this is even plausible, you still do not have DNA or mRNA to allow for reproduction. You also do not have more complex structures such as protiens (that are required for reproduction, orientation, and oxygen distribution). You do not have any usable information (such as DNA), that can be copied, that is stable, and that contains useful information."There is a much better account of this in Nick Lanes book on evolution and in his account its a combination of hydrothermal chemistry and self-replicating RNA. It doesn't require proteins when RNA can replicate itself. This is also supposed to be the begining of life (Life defined as something capable of multiplication, heredity and variation) and so why would we expect to have all the things in place that would have evolved later on?