Late_Cretaceous

Asking questions like "where was the first individuals to have such-and-such?", is equivalent to asking "who was the first person on earth to learn to read and right?" or "on what day was the first loaf of bread ever baked?" or "when is the moment that a baby becomes aware of its own existance?" or "where does tropical turn to temperate?"

The art of writing, and the ability of people to read developed bit by bit over a few generations. Nobody just magically was able to read.

Something like bread was developed over generations of people doing different things with wheat, water and fire. The recipie for baked leven bread did not just appear one day in.

A newborn baby is not fully aware of its own existance. Yet a 10 year old child is. So where did self awarness in the individual come to be. Did you just wake up one day at the age of 2 and realize that you existed. Selfawareness takes several steps.

If you start driving from the Florida Keys up the east coast, you begin in a tropical environment, by the time you get to New Jersey, you are in a temperate environment. Is there an exact demarcation between these two climates?

Most things in the world do not have exact, specific beginins and ends. When do you cease to be young, and start to be old? Yet somehow we are inclined to believe that all things have a precise starting point like July 4, 1776. But those kind of things are the exception, not the rule.

Stephen Jay Gould wrote an excellent essay (it can be found in Dinosaur in a Haystack) about the actual development of the game of baseball. Baseball evolved from games played in England and Colonial America. The modern form is an amalgamation of different styles of the game. However, there are romantic "creation stories" about how the first game of baseball was played on a certain day iin a certain field - and none of them prove to be true. Somehow it is just comforting to people to be able to point to a location and date and say "this is where the first game of baseball occured"> I guess it is just more romantic and heroic that way.

SanDiegoAtheist

You're making a fundamental misconception about what a 'species' is here. A species changes over time - the entire population as a group, not individuals. What we, as humans, are today is genetically almost certain to be significantly different from what a homo sapiens from 100,000 years ago. It might even be far enough that we could no longer interbreed.

Consider the horse and the donkey. Two seperate 'species', yet they are close enough together evolutionarily speaking, that they can still produce offspring together - however, far enough apart, that that offspring is no longer genetically viable enough to produce it's own offspring.

A million years or so ago (maybe even sooner, I'm just making a guess here), the horse and the donkey WERE one species - for some reason (most likely geographic seperation), the donkey population became seperated from the horse population and evolved seperately over that timespan to what they are now, while the other branch became what we now call horses. This happened as a group, as mutations accumulated in the population, and natural selection and genetic drift operated to change the genetics of the population as a whole. The differences have accumulated to the point where they are seperate species, but not far enough that they are completely genetically incompatible.

Individuals of course, do play a key part in evolution - individuals are the ones where specific mutations pop up. However, it is a mistake to think that evolution involves mutations which change that individual so significantly that it can't interbreed with the rest of that species. This, it seems, is a frequent misconception that the Creationists have - that one species essentially gives birth to another species distinct from it's parents. This IS an evolutionary impossibility. Any mutation which changes the individual to the degree which it can't interbreed with others of that same species is, as far as evolution goes, a fatal mutation - as that individual can't pass their genes on.

Instead, evolution works by small steps - single and small groups of mutations (like transpositions and such) which CAN be bred into the population as a whole. Thus, the species would change slowly over time, becoming different from it's ancestors - yet, you wouldn't be able to point to a specific spot on a timeline and say 'here is the division between the two species'. Evolution - even when we refer to things like punctuated equilibrium - involves, as far as individual generations go, very gradual change, as successful or neutral mutations from individuals gradually spread through the rest of the population, slowly changeing the genotype along with them.

Cheers,

The San Diego Atheist

lpetrich

Eric H
I am not interested in how the second generation of anything exists, I am only concerned about the first generation of any four legged creature.

Except that it would be a fish that had its fins modified into legs, something like Ichthyostega or Acanthostega -- real-life "Darwin Fish". These would not be legs that came out of nowhere.

Notice your own arms and legs -- notice that they have a finlike pattern of bones, but with the proximal (close-in) bones being greatly elongated.

Evolution often works like this. Giraffes, despite their long necks, have the usual mammalian number of neck vertebrae, that is 7. But 7 long vertebrae.

And that "first four-legged creature" would have been able to interbreed with fish with more finlike sidelimbs, and their offspring would have been able to interbreed with each other. It's no more a paradox than (say) the emergence of pesticide-resistant strains of insects. Which mosquitoes would the first DDT-resistant mosquito have bred with?

While you are talking about fine-tuning fins, the body of the fish remains fish like. Too many other features have to change to go from a successful sea creature to a successful land creature.

True, but an poorly-adapted land creature can still be a functional one. Consider walking catfish or mudpuppies. These fish may not be well-adapted to living on land, yet they can nevertheless walk on land.

And once one starts walking on land, other dry-land adaptations can follow.

Can a shark evolve into a tiger? Can a whale evolve into an elephant? Can tigers evolve into horses, can rats evolve into dogs, and can spiders evolve into birds?

Although such possibilities are interesting to speculate about, that's asking the wrong question about how evolution has worked -- the question to ask is what kind of shared ancestors could they have had.

Eric H

Quote Monkeybot
it means a certain trait becomes more common in a population. Individuals don't evolve, populations do.
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But does this mean that there has to be one individual male or female in a population that starts a change?

From what I understand it requires a population of about two hundred to start a species, correct me if this number is wildly out.

If this is the case then somehow the evolutionary process has to make around two hundred creatures independently with similar traits that could mate and start a species lets say the rat species. That also means eight hundred legs all working in a forward direction, with working hip joints, knee joints and all the toe joints.

And at the same sort of time it has to also make around two hundred of each; of a thousand other species, some of these would be many times the size of an elephant.

I can look at skeletons of animals, with fins or legs and see the similarity, and I can only perceive that a vast amount of detail has to work in a correct way for success to happen.

Peace

Eric

Eric H

Quote Coragyps
It was such a gradual "becoming" that you or I could never see it happen - a hundred years, after all, will fit into a million years 10,000 times.
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I have some understanding of what you are saying, and in five billion years five years will divide a billion times, I do not believe mathematically that a billion generations is enough to get from single cell to a working elephant size life model, through a constant evolutionary process.

Being fair when you are talking about evolution of single cells, and multi cells in the early stages of life in a young Earth it may only take hours or days to multiply. So evolution may have a thousand billion generation to evolve life to be what we see today.

This may be enough if every evolutionary process was a success; and an improvement on the last generation.

However if a thousand billion generation is needed to go from single cell life to arrive at what we see today, we must take death before mating into account.

If death of a large percentage of a species happened; then surely the whole species would die over a period of time. How many times would this happen over a period of a thousand billion generations of evolutionary processes? Would it be once in a hundred generations, once in a thousand generations, once in a million generations?

I believe that life on Earth would still be some form of simple bacteria, if death of a species occurred even once every million generations, because this means it could happen a million times.


peace

Eric

Eric H

Quote Scigirl
Point mutations (one base turning into another base) have played an important role in evolution. But our DNA can do other complex things like allow retroviruses to cut huge chunks out and transport them to other places, or duplicate parts of itself allowing for a gene to branch out its functions.
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I have been round natural history museums and seen the similarity in design between skeletons of diverse sea and land creatures.

It is the sheer amount of separate parts in a skeleton that have to work together that makes me feel mathematically that the odds of this happening are too remote if there is no design, or the G word.

Look at the motions of a lean racehorse in slow motion and see how many parts of the body are moving at the same time. How many separate instruction would there have to be to set this in motion. I only say Race horse as an example because you can see the movement of the bones through its hide.

Look at the movement required to move two legs forward, then look at the opposing movement of the whole body when the other two legs move forward.

I can look at any mechanical man made object, and I fail to see this same amount of controlled movement in anything man made.

Mathematically I cannot see evolution on it’s own producing this level of complexity even in twenty billion years.

Peace

Eric

Principia

What mathematics?
Eric H, I don't understand how evolution developing these creatures over millions of years is any more difficult to believe than the observed fact that all of these features can arise from a single cell. What does your mathematics tell you about the odds of a single cell assembling all these moving parts of a lean racehorse in the right places?

Yet... You should try looking at the blueprints for a modern microchip, or perhaps for the shuttle though. Pretty sophisticated stuff.

Asha'man

Yea, an individual change happens as a mutation in a single individual. However, that individual isn’t part of a new species yet, he is just a little different than the rest of the population. As that population continues to exist, that mutation is spread by sexual reproduction, until some portion of the population all has that trait. As this is happening, other mutations from other individuals are also spreading throughout the population.

Some traits, or combination of traits, are advantageous for the individuals that have them. Natural selection slowly weeds out anyone without those traits, and soon the population consists only of individuals with the new traits.

At any point in time in this process, there is a large population that can interbreed. There is no sudden change, no species just popping out of thin air. But the earlier population may appear significantly different than their descendants, and we may draw a line and call it a new species. That line is entirely artificial, however, because the reality is a gradual change.

If a population is ever split by a breeding boundary, the slow accumulation of new traits in one group won’t migrate into the other group. When that happens, different sets of changes accumulate in each group, and a single species can split into two (or more).

Does this help, Eric?

lpetrich

And features do NOT have to be "complete" in order to be useful. Walking catfish are poorly adapted for living on land, yet they can walk from pond to pond.

Asha'man

Since you like horses, look at the difference between a pony, a thoroughbred, and a Clydesdale. These are not natural breeds, they were all produced by man in the last few thousand years. How did man do it? Clearly, we didn’t use advanced genetic engineering. We did the exact same thing that a pack of wolves or a couple of saber-toothed tigers would have done: we made sure that certain horses didn’t breed. Only the fastest ones were allowed to breed, and soon they were all faster. Only the largest ones were allowed to breed, and soon they were all larger. Look how far this process can take a horse in only a few thousand years! Now look at the differences between dogs, like a toy Poodle and a St. Bernard!

So, you have worked out the math yourself? What numbers did you use? Where are your equations?

This appears to be nothing more than proof by disbelief and ignorance. The good news is that ignorance can be cured, and this is a good place to do it.

The question to ask is how often do mutations happen? How many of them are fatal, how many are neutral, and how many are (or eventually will be) favorable? How many new traits exist simultaneously in a population? And how many mutations are required to achieve a specific amount of change or complexity? (For example, how many genetic differences are required to separate a pony from a thoroughbred?)

When you can answer all those questions, then run the math and see what the answers look like.

If you need a hand, scigirl or Rufus can probably point out where to locate real numbers, as opposed to pulling them out of a skeptical hat.