Theory Of Adaptation

[Murray]

Upon discussing creation with my dad ( masters in environmental science and health physics) I started to become very fascinated by this. My father, although more of a Agnostic-Christian type I suppose, believes evolution has been disproved, and his reasoning revolves heavily around adaptation. Adaptation from observational evidence makes a ton of sense and in my mind is fact, and this also helps to disprove adaptation in my mind.

Atheist argue that we evolved from apes correct? Then from apes we went to homo austrialius, but the monkeys did not all "
evolve into it", then into homo erectus then Neanderthal then homo sapiens. Now homo austrialius, homo erectus, and Neanderthals all disappeared, weird huh how monkeys still exist then. Evolve means to improve, and wouldn’t homo austrialius be an improvement to apes so thus they would all evolve, like all homo austrialius became homo erectus because erectus was an improvement.

But the big problem with all of this is that is their is 0 evidence linking us to homo austrialius, erectus or Neanderthals, so it seems possible that some fringe apes might have adapted into these but died out due to the law of natural selection because they were not fit. This clearly can be seen in Neanderthals which lacked the ability to run.

This was the bulk of our conversation and I was hoping you kind fellas could give me some feedback and post your views about it.

Note: I appoligize if I got the names wrong, or put them out of order, 12 o clock at night ya know.

[kmr]

I can see what you are saying, that if Australopithecus afarensis was better adapted to its environment than the other creatures of the day then it should have branched off and formed another species that survived to this day?

I personally do not believe in evolution, but the rebuttal to this would be that the adaption of bipedalism did not make the creature better, it just increased its chances of thriving in that environment. If the environment changes and suddenly you have Neanderthals and Homo erecti that have branched off from each other, then competition will drive one or the other to destroy the opponents. This would happen for the other hominids, and the best evolved would prevail. Even though there are no other hominids alive today, chimps and gorillas are (according to evolution) examples of other primates that branched off from the same ancestor as us. We didn't "evolve from apes" (according to evolution), but apes and humans branched off from the same ancestor. So, if you want to get into detail, it's not that monkeys "still exist", but they evolved into their current form from a previous form that at one time we shared with them. Our current state isn't the guaranteed "progress" of evolution, it is one of many forms that at one time increased chance for survival. Therefore, the common gorilla has also adapted to be "better" than its predecessor, we have just been the ones with the most suited adaptions.

I think the biggest problems with evolution include how incomplete the fossil record is. Have you ever looked up the Australopithecine Lucy? Look at how much is missing:



Then, we take those little bits and piece them together:

Then, we "fill in the blanks":

And finally, scientists give us a realistic look at what it looked like:

Miracle missing link, right there.

[kmr]

Sorry, you are probably gonna need to open the images separately...

[Murray]

But if austrailus (W/e) was branched from apes, It would have been superior due to the larger and better brain function which would mean all apes SHOULD have adapted into it. Kind of like how austrialus all branched into erctus because erctus was superior.

Another quick question, why did they all die out if they did not evolve, While I understand why in nearderthals, I do not understand why The others did unless all others were stemmed off austrailius and all australius adapted.

[Seraph]

Few small thoughts,

When something evolves it doesn't necessarily get better, its just a random mutation. If the mutation still allows it to survive in it's environment, it survives and passes on its genes. If not it is killed off by natural selection. But it doesn't have to necessarily be an improvement, it's just a change. Typically though over a long period of time there is an improvment since more mutations are present later and species no longer "improved" enough to survive go extinct. Thus theres no promise that just because a theoretical improvement exists for a species that it will evolve into it.

Also not all of a species will evolve into a new species. There is a branching effect where some of the species in a certain environment undergo the mutation while others of that species in a different environment either will not undergo a mutation, or will have a completely different mutation.

[Murray]

so these could have been failed mutations from apes?

[kmr]

The chances of a mutation that doesn't either have no effect or a "negative" effect are so remote that it almost never happens. When it does, the result usually doesn't even increase those chances of survival very much if at all. But eventually, one in a million of the creatures will "evolve" in to something with different adaptions that have a significant change. The rest of the ape species didn't evolve into Australopithecus because the chances of doing so were so remote, it can only happen once, even even then it shouldn't have happened at all. Then again, if gorillas were sentient instead of humans, they might ask why none of their ancestors were around any more, just these chimps and men! The chance of evolving into specifically gorillas is just as small, but according to Darwin, variation is always present withing a population and a species, so they will all evolve into some random thing. But there is no "proper" rate or result of evolution.

[Seraph]

"Failed" mutations and "No longer useful" traits are extremely common. This is partly evidenced by the fact that 99.9% of all species that have ever existed went extinct a long time ago.

[Murray]

So then why did all australius get the same exact mutation to form erctus.

[kmr]

What do you mean? It didn't get the same exact mutation... Homo erectus is clearly far different than Australopithecus. It isn't that the more of one mutation you get, the taller and bigger-brained you are, it's something called polygenetic inheritance. Several alleles contribute to the brain size and stature of an individual, and often more than one type of gene can change the intelligence or size of a certain creature. Random mutations, for example, will from the offspring of Australopithecus form four individuals: one that has a smaller brain and doesn't walk upright, one with silent mutations that didn't change the creature at all, one with a more adapted form of upright walking and one with better walking and a bigger brain. Now, these mutations were random, and only one of the four individuals had the traits that "lead" to humans, but those specific, random, and however unlikely traits allowed that one creature to outlive and out-reproduce its counterparts. Thus, the others that had different mutations, died out because they weren't as well suited to survive.

[zoegirl]

But if austrailus (W/e) was branched from apes, It would have been superior due to the larger and better brain function which would mean all apes SHOULD have adapted into it. Kind of like how austrialus all branched into erctus because erctus was superior.

Another quick question, why did they all die out if they did not evolve, While I understand why in nearderthals, I do not understand why The others did unless all others were stemmed off austrailius and all australius adapted.

No, it would depend upon whether ALL of the population was in that environment.

For example, say the environment changed enough so that there were two types of conditions. So in a population of animals, it would be conceivable that some of the animals retained the original phenotypes because they fit the original condition whereas another section of the population would fit the new environmental conditions. Given that scenario, you can have some common ancestor evolve into two separate populations.

[The Protector]

Forgive me if this is a dumb question, as I don't know a ton about evolutionary theory. What leads scientists to believe that australopithecus and the others are ancestors of modern humans? I mean, what in the evidence suggests that these extinct species were not from a completely different evolutionary line? after all, evolutionary convergence suggests that, where a particular trait or set of traits is more adaptive, different evolutionary lines may both evolve in similar directions. Correct? Hence the Tasmanian tiger looks a lot like a dog or coyote, and a red panda resembles a raccoon/fox/bear. So what leads scientists to believe that australopithecus was a human ancestor as opposed to, say, an extinct species with whom humans share a common ancestor, as with other primates?

[kmr]

I'm not exactly sure how, but there is some "method" for determining that.... I know that they have isolated several types of Homo erectus, some of which branched off from the line "leading" to humans and died off...

[SnowDrops]

Forgive me if this is a dumb question, as I don't know a ton about evolutionary theory. What leads scientists to believe that australopithecus and the others are ancestors of modern humans? I mean, what in the evidence suggests that these extinct species were not from a completely different evolutionary line? after all, evolutionary convergence suggests that, where a particular trait or set of traits is more adaptive, different evolutionary lines may both evolve in similar directions. Correct? Hence the Tasmanian tiger looks a lot like a dog or coyote, and a red panda resembles a raccoon/fox/bear. So what leads scientists to believe that australopithecus was a human ancestor as opposed to, say, an extinct species with whom humans share a common ancestor, as with other primates?

That's a good question. I think when it comes to evolution a lot of details are just assumed to be right, because the theory would work the best that way.

[PaulSacramento]

Forgive me if this is a dumb question, as I don't know a ton about evolutionary theory. What leads scientists to believe that australopithecus and the others are ancestors of modern humans? I mean, what in the evidence suggests that these extinct species were not from a completely different evolutionary line? after all, evolutionary convergence suggests that, where a particular trait or set of traits is more adaptive, different evolutionary lines may both evolve in similar directions. Correct? Hence the Tasmanian tiger looks a lot like a dog or coyote, and a red panda resembles a raccoon/fox/bear. So what leads scientists to believe that australopithecus was a human ancestor as opposed to, say, an extinct species with whom humans share a common ancestor, as with other primates?

There are a few books on the matter and I am sure most of them can answer your questions.
Since you are religious:
Creation or Evolution: Do We Have to Choose? Denis Alexander (Author)
I Love Jesus & I Accept Evolution Denis O. Lamoureux (Author)
Only a Theory: Evolution and the Battle for America's Soul Kenneth R. Miller (Author)