Evolution?

Question

Do we evolve over time, or instantly?

The eyes - one of the most complex peices of our bodies, how did we come to have them? Did we have 1/4 of an eye, then half, then a whole eye, or simply had two full eyes one day.

Birds, mammals, reptiles, all have eyes. Did we all come from the same species, and evolve into different groups? Since we all have relatively similar lungs, eyes, a brain, nervous system and skeletal structure?

Is evolution pre-written into genes? How did it get there?

Answers and views from all sides are fully welcomed.

Answer 1

It was once thought that eyes evolved at least seven seperate times in the animal kingdom. This is because the eyes of insects, arthropods, vertebrates, etc., seem so structurally different. Now, thanks to studies of molecular genetics, we know that eyes evolved only once. All of the diversity of eyes among species evolved from one common ancestor. The earliest eye was nothing more than a photosensitive cell. That was adaptive to animals such as flatworms, who need to detect light vs. dark in finding sources of food. The next adaption was photosentive cells in a depressed area (eye cup)--that would help to determine directionally of light. The next step in evolution is to have an eye cup deeper, with only a pinhole of light coming through--that has the effect of a crude lens. So you can see, step by step, with each step conferring adaptive advantage, how eyes can evolve.

Answer 2

All of these questions are answered ad-nauseum on science blogs, forums, websites, university websites, videos, even free online courses. In fact they are hard to avoid.

What I am worried about in your questioning is not even the questions its the inability to reason. Why on earth would you think half an eye would form on a random individual as the basis on which the occular system evolved. Thats absolutely bonkers.

We do all have relatively the same lungs...but if you take any species and the design of its respiration system and compare that repeatedly with other species that are either genetically similar or genetically different you'll see that those similarities wane the further away you get. Thats because as these species diverge they will keep the same base system but that system will deviate. No system, eyes, respiration, nervous systems are tied to anything but the environment, when it changes a species does one of two things...it adopts to the new environment, or it dies out completely.

The eye is interesting in that it evolved not once or twice but as far as we know on four separate occasions. That however should be of no surprise since eyes of all description are a response to the environment...and we do have light for at least half a day. Anything added to an environment will alter the response of any population of organisms in that environment... the population of barnacles for example multiples extremely fast on sunken ships...because the resources offered are far better than being stuck on a rock. Eventually all the resources offered to barnacles by sunken ships will be used if we gave it enough time and enough ships.

In another example a bacterium altered its ability to not only live on, but also consume man made nylon products. Now we've only had nylon in this world for a little over a century. So we can be pretty much sure that the ability to digest nylon is not something that bacteria tend to carry around as a fail safe 'just in case'...all that's needed is nylon, bacteria of any description, a slow removal of the regular resource that bacteria uses to reproduce.

There are animals that have a more rudimentary use of light that you could call 'eyes' some have eyes with no lens, others with very crude sense of light. They don't have more advance vision because there's no selective pressure to increase the efficacy of the ones they have.

Yes birds, reptiles, mammals all share a common ancestor.

Evolution is not a 'program' running in your genes... its a process, like gravity... your genes don't pull you towards the earth, gravity does... Evolution also works on other things, non living things. Its what is known as a complex adaptive system. That means its a non linear, non predetermined and complex feedback loop of action and reaction.

If you want to see how that works look up 'cellular automata' ...simple rules, complex output... all governed by CAS.

REF:

en.wikipedia.org/wiki/Complex_adaptive_system‎
http://www.youtube.com/watch?v=jS0zj_dYeBE
http://en.wikipedia.org/wiki/Elementary_cellular_automaton
http://en.wikipedia.org/wiki/Nylon-eating_bacteria
http://jb.asm.org/content/155/1/22.long

If you want to learn anything about evolution you must first remove it completely from attempts to be anthropomorphic about it...its a process, not a thinking agent.

The easiest way to do that...is to take out a pencil and grided paper... choose 1's and 0's randomly and put them into the top line of the grided page... then literally apply one of the cellular automata rules... you know yourself that a single rule should not be able to paint a picture on that paper that has complexity, form and geometry... and yet thats what will emerge before your eyes... its just a process.

Answer 3

to really answer your question would take a long time. Eye evolution is actually pretty well understood nowadays. Even unicellular organism have light sensitive parts. If you google scholar eye evolution you will find plenty of articles. Also look up pax genes, it is fascinating how the same genes are even involved in eye development in organisms which has as different eyes as insects and humans.
As usual wikipedia is also a good starting place for your research. Also read some standard biology textbooks about evolution. If you really want to understand it, it will take some time, because think you also first have to learn something about how evolution works.

Answer 4

The complexity of the eye is one of the most common things used by creationist as indicating evolution is impossible.

It has been shown scientifically many times to have developed from very basic cells on the skin that are sensitive to light. When this evidence is presented to creationists, they then turn to the immune system and ask, how could that have developed?

One of the things that makes evolution so hard to understand is our short human life span compared to the huge amount of time over which evolution has occured. A million years is a snapshot of time in evolution, but about 40,000 generations of humans.

An example of a lifeform that can evolve very quickly with respect to a human life is bacteria which we have developed an antibiotic to kill off. A person gets a bacterial infection and is treated with an antibiotic. 1000s of people are treated with the same antibiotic. Somewhere in these 1000s of people some of the trillions of bacteria don't die. Instead they reproduce a few billion more bacteria that are resistant to the antibiotic. This is evolution in action that we can see in our everyday life: people going to hospitals and picking up antibiotic resistant germs.

Answer 5

Here: I don't have time today to go into the mish-mosh of things you're asking - I'm presuming with legitimate interest. Simply read this article on the evolution of color vision for your answers.

http://www.talkorigins.org/faqs/vision.html

(And the bright chemistry student who answered above has it all backwards. It's not that we're wonderfully at the right distance from the sun or that chemicals magically combine in just the right order, that just the right wavelengths of light fall upon the earth, etc. -- it's that we've EVOLVED to use what was there! )

Answer 6

Not all eyes are the same. I've heard the first type of eyes started appearing in the cambrian period, about 700 million years ago, and it was a very simple structure. Even today we find a lot of creatures that have very simple eyes, and even eyes that are much better than ours, like in birds. It seems that there are a lot of simpler versions of a lot of things.... and think, our eyes last about 80 to 100 years, some creatures need eyes that will last for less than one year, some for just a couple of months... they get by with a lot less.

Answer 7

In response to dendronbat's answer: I found a few pens and pencils in a coffee mug on my table. I now use the pencils mostly for things like math assignments so I can erase. When I have to take notes, I pull out one of the pens. I found a few highlighters that I can use when studying.

So what I can infer from this is that the pencil obviously adapted to my math notebook. And because of their similar appearance, it is safe to say that the pencils and pens had a common ancestor. The pen found itself on foreign grounds while I was studying and by natural selection, came my highlighters.

But over a course of millions and millions of years, of course.

Answer 8

jklachia… You are correct, your pen, pencil and highlighter all have a common ancestor, the first writing instruments from when humans first started writing, Over the 1000's of years, through selecting the best tools to write with, pens evolved to take up specific roles in writing, pens because they are permanent and neat, pencils because they can be erased and highlighters because they do not mess up the writing below them.

Answer 9

We have three theories for evolution.

lamark's theory which is 'THEORY OF ACQUIRED CHARACTERS'advocated that the characters which we acquired in life are transffered to next generation.He gave the ex. of Girraf that their neck elongated due to lack of grass on earth so they strecth their neck and evolved in present shape.So according to Lamark 1/4 erye would have been converted into half then one and double.But his theory was critisised by August Wiseman who perform experiments on 21 mouse and cut their tail but no tailless mouse was obtain on 22generation.

Then we have Darwin Theory'Theory of natural selection' which tells that the population became constant in a same speices due to struggle for food,space and mate.Those who were the fittest survive and the unfit lost their existance.So according to him their were four creatures of different eyes and we 2eyed person survive.

Then we have the most popular theory neo darwanism who tells that change in environment led to variations which further led to evolution.

Ernest Haecal Gave the biogenetich law'Ontogony recapetulats philogony'It means that an embreyo repeats the race of history.

Their are enough proof to show that our components are derived from meteors.We have homologous organs which have same internal structure but different external appearance and functions like forelimbs of man,bat and dog and Analogous organs having different internal structure but same function like wings of bird and insect so this show that we have evolved from a common ancestors.

Answer 10

I am a chemistry major at one of the largest universities in the United States. The more I study science, the more I become convinced of what I already believed; that nature is too complex, too intricate to have come about by chance. How could the earth come into existence the perfect distance from the sun to sustain life by chance. How could something as complex as the eye come about by chance. I am convinced that God created the universe and everything in it out of nothing. Furthuremore, there is much evidence for this if someone looks with an open mind. I would suggest taking a look at the institution of creation research @ www.icr.org.