I used to blindly believe in evolution because science and the academia just told me to. Recently, I've had my doubts about it. When I pose my doubts to people on the Internet, it is usually an uninformed atheist who shouts out irrelevant nonsense. Then I remembered there are actual evolutionary biologists. So, that at least, strengthens my faith in evolution. I don't think scientists would dedicate their lives to a field of study that in my quite ignorant understanding seems so hopelessly flawed that it can't possibly be true. I want to believe, but no one can answer my pretty straightforward questions. I usually post on yahoo answers, and people just link me to scientific journals which are very complicated and I suppose I am to be intimidated.

Anyway, I don't believe in Creationism either. I don't think of it as an either/or proposition. How I stand right now is that evolution is very important to study, because it will eventually lead to a parallel theory that will explain the origins of species.

I am in college right now, studying engineering. I have taken my last biology class, molecular biology (200 level). I can't take anymore because I am out of electives.

So, respectfully, I have a few questions. I don't mind if you do link me to complicated science journals (the people on yahoo link me to irrelevant journals) if they answer the questions.

1) reproduction. Okay I admit I have no understanding of the first organisms to move beyond asexual reproduction, so I am probably being embarrassingly ignorant right now.

Wouldn't natural selection immediately destroy any organism that tries to produce sexually instead of asexually? It seems its survival rate would plummet to a point of impossibility if an organism needed to find another organism to reproduce when its competition just reproduces asexually.

Also, isn't the development of reproductive organs impossible? wouldn't there need to be a random chance mutation in a male organ that just happened to randomly meet a female organ that by chance mutated a complementary organ?

2) organ development. How did the eyeball evolve? it seems like it would take thousands of mutations that have no survival benefit, until the mutations actually reach an endpoint, like sight (or differentiation between light and dark). But beyond that, what about all of our internal organs that work in coordination with each other, the circulatory system, respiration, nervous system. They would all have to develop a small step at a time in coordination with each other. I would think there would be so many necessary intermediate mutations with no survival benefit to make the development of a human improbable. I have heard that in about 10,000 years, natural selection will find out pinky toes unnecessary and we will evolve without them. Assuming the time-line of that wive's tale is true, it takes ten thousand years to lose a toe, has there been enough time on our planet to make all of these millions of mutations to create a man (considering the slow progression of evolving all of the internal organs in a complementary fashion)?

3) Back to eyeballs. Isn't the first predator that mutates eyeballs the all time winner with near nuclear capability? Aside from sight, there most be at least a handful of mutations that doesn't just tip the scales of the survival of the fittest, but completely blows the scale all the table? The predator that first gains sight would ravage every other species, and thereby decimate his own population eventually through a lack of food, after killing all the other prey and other predators?

Anyway, these are my most serious objections to evolution. I have a hard time seeing past these points. If it takes too much of your time to answer these questions, you can simply link me to the answers. I do google searches but you end up reading blogs by unscientific atheists spouting out the greatness of science.

In conclusion, I'm sure I am not the first person to come up with these objections. There has to be scientific answers out there somewhere?

EXTRA CREDIT::: Currently, what are the most challenging objections to evolution?

1) No, and no, though well done for admitting your ignorance. Sexual reproduction is a method for mixing genes, and is used by multicellular lifeforms because of their increased complexity and relatively long generation time compared to single-celled organisms. For example, we humans have a generation time of somewhere between 15-40 years, depending on the individual considered. One of the most common of our commensal flora is E. coli, which has a generation time of 20 min, under ideal conditions. Think about what that means for a moment: evolution is measured in mutation across multiple generations, so if you can get through more generations quickly, you can evolve faster in response to a changing environment. We humans, along with virtually every other animal, have adopted sexual reproduction in order to mitigate the disadvantage of our long generation time. It does this by mixing genes in a process called meiosis, which basically introduces genome-wide recombination mutations, shuffling the genes from each parent chromosome into a new combination. Contrary to what you believe, this process isn't detrimental, its absolutely CRITICAL to the continued survival of most multicellular life. The benefits of sexual reproduction are so huge, that even organisms which normally reproduce asexually (like E. coli) have mechanisms for gene swapping analagous to sex.

Your "evolution of genitals problem" is a new one on me. The arrangement of genitals is a highly varied matter throughout life. Female birds, for example, have a structure called a cloaca and the males don't have a penis as such. Many fish and other marine life simply excrete their sex cells straight out into the water, in a kind of spray-and-pray approach. Lizards have things called hemipenis. Such diversity of methods strongly implies that sex is valuable enough, and universally applicable enough, to be widely adapted by many different species. That there are so many ways found to have sex by so many different animals (and plants, and just about everything else, for that matter) means that the method is almost immaterial, as long as it works.

This link is to a short article with lots of links in it to more detailed stuff

2)The question of eye evolution has been done to death elsewhere. See here:

3)You are missunderstanding the process here. Eyes didn't "blink" into existence (haha) in one species overnight. Predator-prey relationships are extremely close, and long before actual vision was evolved, the ancestors of your hypothetical predator and their prey were competing with on another to survive; one by eating the other, the other by escaping. Changes in one species in this kind of relationship immediately puts tremendous, directly applied evolutionary pressure on the other to respond. You can think of it as an arms race. If, as in your example, the predator developed a primitive light sensing strategy which enhanced hunting, the new selection pressure on the prey population would favour those individuals with effective counter measures, such as darkened pigments or maybe a behaviour to hide from light.

Consider the first (hypothetical) organism to develop a light sensitive organ. It certainly didn't do so in isolation, and, like most organisms on the planet today, it would have had relatives kicking around with it. The concept of "contingent evolutionary trajectory" tells us that evolutionary innovations occur non-randomly, even though the raw material (mutation) is basically random.

This is roughly analogous to the development of ideas in human society, including the original thesis of evolution theory; such an idea could not have been accepted before certain facts had been discovered, such as geological age and the fossil record. Once those facts were established and other conditions were correct, the same thought occurred to at least two people within a few years of one another (Darwin and Wallace). Similarly for lightbulbs, the steam engine and even really basic things like spears. In evolution, the context for a particular innovation is all of the previous evolution which has gone before it (ie the genomes carried by a population), plus the environment; in other words, any step in evolution is contingent on all of the steps before it as well as the environmental pressures the population is facing. This means that at any given time the likelihood of a particular beneficial innovation is determined by the twin restrictions of 1)those mutations which are allowed (ie not fatal) and 2)those which provide benefit, making the outcome non-random, also known as Naturally Selected. So, many different populations can independently come up with very similar solutions to the same problem at the same time. This concept was demonstrated in the lab:

http://en.wikipedia.org/wiki/E._coli_lo … experiment

Thus, your assumption about the dominance of the first-sighted is not correct. In fact, light sensitivity has evolved indepedently several times, indicating that a)vision is very useful, even if it's only a simple eye spot, and that b)the chances of the innovation occuring are likely enough for mutliple kingdoms and diverse phylums to arrive at effective solutions based on wildly different genetic and environmental contexts.

Last edited by John Steemson (5th Aug 2013 03:14:36)

Since you asked about eye evolution (my speciality!) I thought I'd link to a very nice paper written for college and high school-level students by two of my colleagues.  It explains both the molecular and morphological basis of eye evolution:

http://link.springer.com/article/10.100 … ltext.html

There is a paper by Dacks and Roger in Journal of Molecular evolution that discusses why sex is evolutionarily favourable :

http://link.springer.com/content/pdf/10 … 013156.pdf

They also cite many other papers, so you should be able to follow up on the areas that you find most interesting (I’m assuming you have access to journals if you’re at college).

Some key points that might help you are:

Sexual reproduction evolved before multicellular life forms did - single-celled eukaryotic organisms had been reproducing sexually for more than 100million years before the first multicellular organisms evolved.

These organisms were facultatively sexual – this means that they could reproduce asexually and sexually.

It seems likely that the common eukaryotic ancestor of all living eukaryotes was facultatively sexual and that some modern eukaryotes lost the ability to reproduce sexually (eg some amoeba), some lost the ability to reproduce asexually (eg humans) and many retain the ability to do both (eg most single-celled eukaryotes, many plants, algae and insects and even some reptiles).

It is worth noting that the modern single-celled eukaryotes reproduce asexually most of the time but will then switch to sexual reproduction under stress conditions.  So you were right when you mentioned that reproducing asexually normally helps to outcompete your rivals, but reproducing sexually seems to be beneficial when conditions are sub-optimal.