i don't understand evolution?

Question

there are some things i don't understand about evolution.

one, how do complex systems, such as vision, evolve? like, isn't the visual system composed of a plethora of moving parts like rods and cones and lenses? if the visual system doesn't work without so many different parts working together, then how would the ability to collect and interpret visual stimuli ever get off the ground?

two. if a creature develops a beneficial genetic mutation, why doesn't it require a mate with the same mutation to reproduce this trait? what determines whether a mutation becomes a dominant trait?

keith h. one, i'm not religious. two, thanks for answering "how did vision evolve" with "it EVOLVED". saying it louder helps it to make sense.

seriously, people who espouse evolution without understanding how it works are just as dogmatic as creationists.

Answer 1

Thinking about it logically, vision would have to start out simple, just a few photosensitive cells which help a simple creature discern light from dark. Evolution has had billions of years to refine simple systems into complex ones, by the accumulation of many improvements and modifications. It is a morphological process.

To address your second question, any mutation which radically improves the survivability of an organism either becomes a dominant trait or it is lost.

Evolution is not perfect. Sometimes desirable traits are lost. For example, humans and a few other species have lost the ability to make vitamin C in the liver. Four enzymes are required in the process. We have the first three, but the gene to make the fourth enzyme is defective. The only reason that genetic defect we all have is not fatal is because we get enough vitamin C in our diets, most of the time. However, put goats and humans on a vitamin C restricted diet, and only the humans will get scurvy.

Answer 2

Yea you're right. There's no way a complex system such as vision could have evolved biologically.

It must have been God.

Seriously though. Vision EVOLVED from a basic system to a better one. It's not magic. It took (is taking) time to get better.

For your second question, what if the creatures that didn't take on this mutation died off because it was inadequately equipped to compete with the mutated species for survival. This would lead to the evolved creatures to mate while the others died off.

Google Darwin.

EDIT (Response) : I understand evolution perfectly thanks which is why I didn't really feel the need to explain it to people that pull blinders over their eyes. What isn't there to understand? Jesus.

Here is a theory from Zoologist Dan-Erik Nilsson on how the eye might have evolved.

When evolution skeptics want to attack Darwin's theory, they often point to the human eye. How could something so complex, they argue, have developed through random mutations and natural selection, even over millions of years?

If evolution occurs through gradations, the critics say, how could it have created the separate parts of the eye -- the lens, the retina, the pupil, and so forth -- since none of these structures by themselves would make vision possible? In other words, what good is five percent of an eye?

Darwin acknowledged from the start that the eye would be a difficult case for his new theory to explain. Difficult, but not impossible. Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive pigmented spot on the skin, could have gone through changes and complexities to form the human eye, with its many parts and astounding abilities.

Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.

Biologists use the range of less complex light sensitive structures that exist in living species today to hypothesize the various evolutionary stages eyes may have gone through.

Here's how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.

Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.

In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientists' hypotheses about how complex eyes like ours could evolve. The first animals with anything resembling an eye lived about 550 million years ago. And, according to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.

So now you can read it and be like, I don't get it.

I also liked how you posed your question, "I don't understand evolution?" as if you are confused about your inability to grasp the concept. Don't worry, we are all questioning what you are having such difficulty understanding.

Answer 3

>if the visual system doesn't work without so many different parts working together<
What's to say a simpler system doesn't work - that you have to have a complex system? In fact, there are lots of examples in living animals where simple optical sensors get increasingly complex. At the simplest level an "eye" is a cell on the end of a nerve that produces an impulse to turn toward light - like the surface of the sea. Take a "mutation" that results in multiple cells, then a million years later take one that has some cells more sensitive to color, then more cells in a package that has special functions scattered across it, like the eye of a fly.
Hey, you just defined why we see dominant traits. If a trait was not a dominant one, it couldn't express itself (maybe). So dominant traits exist because without them evolution would have to work a lot harder.

Answer 4

Evolution takes place over enormous expanses of time. Complex systems evolve gradually.

The visual system has very few moving parts. Rods and cones are sensor cells that reside in the macular region of the eye. The lens moves only in the sense that it is stretched or permitted to relax by the muscles which are used to change to focal point. It is not useful to think of the evolution of a system as though it were an engineering project with a deadline.

Genetic mutations often exist for many generations before they are expressed as attributes that can improve the chances of survival for those that possess it in comparison with those who do not, and in that time it can be passed on to many members.

Of course, this is necessary only if the trait is genetically recessive--if it is dominant, it is expressed in any offspring to whom the gene is passed.

Answer 5

I think others have answered this question well, but I'd like to address the original poster's comment that "people who espouse evolution without understanding how it works are just as dogmatic as creationists". That's simply not true. Most complex systems around us--whether they're biological systems, or something more mundane and man-made, such as electronics, are well beyond the scope of most people's understanding. You may not know, for example, how your computer works (beyond a basic understanding of its components), but I think it's safe to say that you do understand and accept that there are clear, established, provable scientific principles for how and why it works. Creationism is faith, not science, no matter how much some people try to package it as "science" to make it more palatable. There is no way of understanding, let alone proving any basis for creationism--it's all about simply accepting it.

Answer 6

Maybe if we ask why there are such different degrees of vision capability we can get a better sense of how evolution works?

Why do eagles and falcons have great vision, while some species of moles don't even have eyes?

If vision was just vision, why wouldn't all creatures have the same ability?

Answer 7

well the number one thing to remember is time, evolution takes a very loooong time. the other aspect is that mutations happen simultaneuosly, like sunburn on a beach, it is hardly ever a mutually exclusive mutation.

dominace (strenght) is not the key to evolution,ability to adapt is, most people get that wrong.

Answer 8

You have to understand evolution involves at least as much belief without proof as any religion. Also, things like "logic" and "reason" have no place when discussing the evolution of one species to another. Also- If we came from apes, why do we have apes still?

Answer 9

transmitting other signals from the dark energy and using space
to signal the target which grows deeper into your heart with a
spell that is used with forces of lost souls.

Answer 10

AND GENSIS CLEARED IT ALL UP AND LEFT NO QUESTIONS??????????