Evolution questions
First Prev
of 2
Next Last

Level 7

Since: Sep 07

Valley Village, CA

#21 Mar 1, 2013
derekj72 wrote:
The real issues I see are related to:
1. Origin of life itself
2. If the "spark of life" did happen via a lightning strike in the primordial soup or whatever, why wasn't it quickly snuffed? Maybe it wasn't a onetime event?
This isn't actually a subject that's part of evolutionary theory. This is abiogenesis.

Evolution requires that life exists and reproduces imperfectly. It's completely indifferent to where the life came from.

However, the "lightning strike/puddle of ooze" thing is very outdated.

As for why life wasn't snuffed out, for all we know new "life" starts hourly and gets snuffed out 99.99999% of the time. What's important is that one time it didn't.
3. It seems to me that evolution requires both time and a sufficiently large gene pool upon which to operate. When considering how small the breeding populations of homo habilis or homo erectus must have been, do any serious scientists consider this an open question?
You are making some erroneous assertions.
First H. Habilis and H. Erectus did not have small populations. Erectus inhabited Africa, Europe, Asia and several Pacific islands. Depending on how H. Flores shakes out, that may be evidence that Habilis had a similar range.

Second, evolution does require time but not a large gene pool. In fact, isolation yields "island evolution" which produces very rapid change in small populations because any successful mutation can spread quickly across the population.
5. The classic objection over the dependent structures of the eye still is troubling me. I have no doubt it was accomplished through evolution, but it is still difficult to understand the mechanisn over time.
This is extraordinarily well documented with several online videos displaying examples and animations.

I suggest you google it.
6. What do scientists have to say about certain species that apparently havent evolved at all over many millions of years such as the horseshoe crab?
While the horseshoe crab may not have changed morphologically over the years, that doesn't mean that it hasn't evolved.

Disease resistance, reproductive rates, ability to digest various materials, social instincts, etc. All these things can evolve without leaving much of a trace in the fossils.

However, when a species hits upon a successful form that exploits a resource for which it doesn't have much competition, there's not much incentive to change.

Horseshoe crabs remain the same because they found a niche and own it.
7. What is the latest consensus on punctuated evolution? Why does evolution seem to take a break over eons? Is the answer probably related to the relative rarity in the fossill record so we only get very rare snapshots in time?
Evolution occurs more rapidly in times of stress, such as global climate change, because there is more pressure on resources.

Additionally, the fossil record gives us only glimpses at certain times and places. As such, events like rapid replacement where an invasive species drives out a similar existing species, seem like rapid evolution when they aren't.
8. Do scientists generally believe evolution is gradual over time or goes in fits and stops?
Both.
9. Why does religion exist? Does it perhaps confer a societal, cooperative benefit that can outcompete others without it? It sure appears to be a universal aspect of extant cultures.
Its easy to kill enemies of you can convince your side gods wants it.
10. Why does it appear that certain moral truths are "written on the hearts of men" such as being against murder, the incest taboo, the westermark effect, and many others?
Societies which don't have taboos against murder, incest or even theft tend to not survive very long.

Since we are codependent as a species, we've selected for cooperation.

Level 7

Since: Sep 07

Valley Village, CA

#22 Mar 1, 2013
derekj72 wrote:
On topic of population size of early hominids, I assumed it was small due to evidence such as the following:
1. Lack of discoveries outside of east Africa
Lots of discoveries outside of Africa. More in Africa, but that maybe more due to the preservation.
2. Genetic evidence such as "mitochondrial eve"
mEve predates this stuff. Yes, all homonid groups spread out from Africa initially, but that's not evidence that they didn't have sufficient populations after spreading out.
3. Skepticism that large populations could have been supported without advanced farming techniques, where we would very likely have seen evidence of.
There are plenty of human groups today that don't have agriculture.

Besides "large populations" means the total number of individuals, not clusters of individuals. You can have a wide ranging homonid living in small hunter gatherer bands all across Asia.

They won't have the density we have today, obviously, but there were plenty of them.
Is there anyone in the field that doubts all early hominids were hunter gatherers?
No. Agriculture is a late arrival, we'd killed off all our cousins long before we figured out how to plant crops.

“Nihil curo de ista tua stulta ”

Since: May 08

Orlando

#23 Mar 1, 2013
Nuggin wrote:
<quoted text>
This isn't actually a subject that's part of evolutionary theory. This is abiogenesis.
Nice. Well posted. Cudos!
Gillette

Fairfield, IA

#24 Mar 1, 2013
Punctuated equilibrium depends in large part on the vagaries of the environment, as I understand it. For example, an asteroid strike that destroys much of the earth and most of the large animals (dinosaurs, etc.) would seem to send the evolution of smaller mammals into rocket mode.

Level 1

Since: Feb 13

San Francisco, CA

#25 Mar 1, 2013
Can you be certain that only one would ultimately survive? Suppose life started by some external spark arranging some organic chemical molecules into a self replicating scheme (yes grossly simplified). What's to say this didn't happen a lot, and more than one would ultimately survive? Is this widely accepted among respected scientists? I'm just struggling to see why it MUST be that only one survived. Or do you mean that one FORM (that is a carbon-based form that we see today) survived.

I very vaguely remember in a college chemistry class at Minnesota my professor remarking that there really is no reason that given its location on the periodic table, a silicon-based life form couldn't exist, but obviously doesn't.

More Googling to do
Subduction Zone wrote:
2. Abiogenesis is thought to be a one time event because even early life consumed things. Once life starts it will consume the sources of life. It is a one at a time type of event. The very very first life may have died out and it may have happened more than once. Only one would ultimately survive.

Level 7

Since: Sep 07

Valley Village, CA

#26 Mar 1, 2013
derekj72 wrote:
Can you be certain that only one would ultimately survive? Suppose life started by some external spark arranging some organic chemical molecules into a self replicating scheme (yes grossly simplified). What's to say this didn't happen a lot, and more than one would ultimately survive? Is this widely accepted among respected scientists? I'm just struggling to see why it MUST be that only one survived. Or do you mean that one FORM (that is a carbon-based form that we see today) survived.
I very vaguely remember in a college chemistry class at Minnesota my professor remarking that there really is no reason that given its location on the periodic table, a silicon-based life form couldn't exist, but obviously doesn't.
More Googling to do
<quoted text>
While it's possible that there could be non-carbon based life, we have yet to find any anywhere.

All life on Earth is based on the same basic chemical make-up. It's possible that life started up multiple times. However, what's even more likely is that whatever life got started first would eat the new life long before that new life adapted well enough to compete.

Imagine new life were to spontaneously appear today in the ocean, how long do you think it would be before some bacteria comes along and absorbs it.

Level 1

Since: Feb 13

Richmond, CA

#27 Mar 1, 2013
My googling on this issue informed me about the chirality issue at the molecular level of life, which suggests if not a singular life forming event, than at least the same exact mechanism multiple times. But the single historical event has more intuitive appeal to me, if only because it was so improbable.
Nuggin wrote:
<quoted text>
While it's possible that there could be non-carbon based life, we have yet to find any anywhere.
All life on Earth is based on the same basic chemical make-up. It's possible that life started up multiple times. However, what's even more likely is that whatever life got started first would eat the new life long before that new life adapted well enough to compete.
Imagine new life were to spontaneously appear today in the ocean, how long do you think it would be before some bacteria comes along and absorbs it.

Level 1

Since: Feb 13

Richmond, CA

#28 Mar 1, 2013
Have evolutionists considered an explanation for why, with very rare exception, animals have bilateral external morphologicalsymmetry but a combination of bilateral and asymmetry in internal structures, especially for the digestive system as far as humans go.

I have often wondered this and tried to construct arguments as to which evolutionary pressures may have influenced this.

Two exceptions in humans that I am uncertain are interesting or not would be the spiral hair on our crowns as well as in males one testicle usually hanging noticeably lower than the other. There must be others, but these two are the most obvious to me.

Level 7

Since: Sep 07

Valley Village, CA

#29 Mar 2, 2013
derekj72 wrote:
Have evolutionists considered an explanation for why, with very rare exception, animals have bilateral external morphologicalsymmetry but a combination of bilateral and asymmetry in internal structures, especially for the digestive system as far as humans go.
I have often wondered this and tried to construct arguments as to which evolutionary pressures may have influenced this.
Two exceptions in humans that I am uncertain are interesting or not would be the spiral hair on our crowns as well as in males one testicle usually hanging noticeably lower than the other. There must be others, but these two are the most obvious to me.
Well, a singular organ digestive system is likely due to the fact that we are basically complicated donuts with a single hole at the top and bottom through which you can pass objects like food.

In order to have a dual digestive track, we'd need a second tube.

Dual eyes is an adaption to be able to see more stuff. There are lots of examples in non-mammals where the number of placement of eyes differs radically.

However, since evolution tends to adjust existing designs, once you lock in to something like "eyes on the head", it becomes rather difficult to evolve your way into a different option.

As for minor morphological differences to one side or another, I have no idea. It could be a simple as orientation of the fetus as it is developing in the womb. Other examples are handed-ness, often people have one leg that is slightly longer, etc.

Tell me when this thread is updated:

Subscribe Now Add to my Tracker
First Prev
of 2
Next Last

Add your comments below

Characters left: 4000

Please note by submitting this form you acknowledge that you have read the Terms of Service and the comment you are posting is in compliance with such terms. Be polite. Inappropriate posts may be removed by the moderator. Send us your feedback.

Evolution Debate Discussions

Title Updated Last By Comments
News "Science vs. Religion: What Scientists Really T... (Jan '12) 3 min thetruth 27,258
News Evolution vs. Creation (Jul '11) 4 min syamsu 186,683
News Atheism, for Good Reason, Fears Questions (Jun '09) 43 min emperorjohn 5,920
News Should evolution be taught in high school? (Feb '08) 1 hr One way or another 179,245
News It's the Darwin crowd that lacks the facts in e... (Mar '09) 8 hr DanFromSmithville 148,284
Are Asians/whites more evolved? (Sep '07) 14 hr Critical Eye 1,735
Poll How Do You View The New Millerite Adventist Inv... (Apr '15) Feb 1 Critical Eye 10
More from around the web