The Evidence Behind Human Evolution: Probability & Chance

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Discussion Overview

The discussion centers on the origins of life and human evolution, exploring whether these phenomena are the result of random processes or guided by other mechanisms. Participants examine concepts related to abiogenesis, evolutionary theory, and the implications of randomness in these processes.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question whether the formation of life is a result of random grouping of atoms and molecules, suggesting that this is a complex process rather than a single event.
  • There is a distinction made between abiogenesis and evolution, with some participants emphasizing that evolution involves more than just random mutations, as environmental factors play a significant role.
  • One participant proposes that life may arise from "autocatalytic sets," where molecules catalyze their own formation, suggesting a non-random aspect to the emergence of life.
  • Another participant argues that while mutations are random, the directionality of evolution is influenced by natural selection, which favors traits that enhance reproductive success in changing environments.
  • Concerns are raised about the assumptions underlying the estimation of the universe's age and the implications for understanding evolution and abiogenesis.
  • Some participants express skepticism about the probability of human evolution occurring through random mutations, while others argue that with the knowledge of our lineage, the outcome seems inevitable.
  • There is mention of the alkaline thermal vent model as a plausible explanation for abiogenesis, highlighting the complexity of developing a mechanism for the origin of life.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of life’s origins or the role of randomness in evolution. Multiple competing views are presented, with ongoing debate about the validity of different models and interpretations.

Contextual Notes

Limitations include the reliance on various assumptions regarding the age of the universe and the processes of abiogenesis and evolution. The discussion reflects a range of perspectives without resolving the complexities involved.

I_am_learning
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We know the exact age of Universe and the earth.
We know when life began on earth.
Is the formation of life a result of random grouping of atoms and molecules?
Is evolution the outcome of random mutations?
If so, is the chances of such series of random mutations resulting in formation of human beings, consistent with probability theories that it might be possible in some 4.5 billion years.
My motto is "I doubt that although Human Evolution may be outcome of random events and hence a happening of chance, we could appreciate it for a rare outcome."
But since I know almost nothing on this subject, feel free to teach me the basics.
 
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I_am_learning said:
We know the exact age of Universe and the earth.
We know when life began on earth.
Is the formation of life a result of random grouping of atoms and molecules?
Is evolution the outcome of random mutations?
If so, is the chances of such series of random mutations resulting in formation of human beings, consistent with probability theories that it might be possible in some 4.5 billion years.
My motto is "I doubt that although Human Evolution may be outcome of random events and hence a happening of chance, we could appreciate it for a rare outcome."
But since I know almost nothing on this subject, feel free to teach me the basics.
First, you've confused evolution with abiogenesis.

http://en.wikipedia.org/wiki/Abiogenesis

Then read the FAQ on evolution.

https://www.physicsforums.com/showthread.php?t=543950

Please start making an effort to at least search for basic information on the internet and reading FAQs that we have gone to the trouble of posting.
 
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I_am_learning said:
We know the exact age of Universe and the earth.
We know when life began on earth.
Is the formation of life a result of random grouping of atoms and molecules?
Is evolution the outcome of random mutations?
If so, is the chances of such series of random mutations resulting in formation of human beings, consistent with probability theories that it might be possible in some 4.5 billion years.
My motto is "I doubt that although Human Evolution may be outcome of random events and hence a happening of chance, we could appreciate it for a rare outcome."
But since I know almost nothing on this subject, feel free to teach me the basics.

We don't know the exact age of the universe and earth. We have a pretty decent idea about Earth. The Universe relies on the assumption that we can exactly reverse the current rate of the expansion of the universe to a tiny point and call that the beginning; I'm not sure how valid that assumption is, but you might ask the cosmology subforum what they think.

The chances are near zero, of course, with no a priori knowledge. But the chances are exactly one with our posteriori knowledge.

Whether we should appreciate it or not is not really a scientific question, but many scientists think we should. One of my favorite examples is Carl Sagan who always raved about us being made of the rarest material in the universe and that we are made from star stuff.

As for abiogenesis, there is a wonderful video that's been posted here before that explains how easy it would be fore life to come about in early Earth conditions.

If you want to get right to the technical details, go to ~2:42 or click here:
http://www.youtube.com/watch?v=U6QYDdgP9eg&feature=player_detailpage#t=172s

for the whole viewing (which includes dispelling creation myths) enjoy the full video here:
 
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I_am_learning said:
We know the exact age of Universe and the earth.
We know when life began on earth.
Within a few hundred million years we have an idea but that's not "exact". Also the formation of Earth and life were not single events but long processes.
I_am_learning said:
Is the formation of life a result of random grouping of atoms and molecules?
See the good answers others have given above
I_am_learning said:
Is evolution the outcome of random mutations?
No mutations are a small part of evolution. Whilst mutations are random they have non-random effects determined by the environment.
I_am_learning said:
If so, is the chances of such series of random mutations resulting in formation of human beings, consistent with probability theories that it might be possible in some 4.5 billion years.
It's not so much a question of probability as a journey across a fitness landscape.
I_am_learning said:
My motto is "I doubt that although Human Evolution may be outcome of random events and hence a happening of chance, we could appreciate it for a rare outcome."
But since I know almost nothing on this subject, feel free to teach me the basics.
Human beings could not have arisen at any other time. We are the product of our lineage and could no more have arisen at another time than you could have been born to your ancestors.

For the basics read and watch the resources linked above, our evolution intro also has links at the bottom to further resources.
 
I_am_learning said:
Is the formation of life a result of random grouping of atoms and molecules?

Stuart Kauffman in "At Home in the Universe" proposes that life is a result of "autocatalytic sets" in which the molecules in the set speed up the very reactions by which they themselves are created: A makes B, B makes C, C makes A again. He suggests it is these autocatalytic sets which are at the heart of life. The book is non-technical (basically) and you might find it interesting.
 
Mutation is, according to our best understanding, entirely random. Other ways in which genetic diversity arise such as methylation, gene transfer, and sexual shuffling, are also largely random.

The observed directionality of biological evolution is attributable to natural selection.
Whereby those variations that produce optimal phenotypes for reproductive success in the prevailing environment are favored.

It must be remembered that environments themselves are also in a state of dynamic flux. This provides an explanation for the phenomenon of "punctuated" evolution. Sometimes biological evolution has to wait for the environment to "catch up", if you will excuse the metaphor.
For example, the emergence of large multicellular organisms was unable to occur until after atmospheric oxygen levels became sufficiently high.

Turning to the quite separate issue of abiogenesis, one of the most intractable of the many problems with trying to derive a mechanism is that of the development of the cell.
While lipid vesicles can quite easily be generated in the lab (and I have used the fatty coacervate jacket model in some of my own early writings) they do not meet the requirement for two way selective interaction with the surrounding medium that is required for a cell to survive, let alone the quintessential proton pump.
The most plausible proposition I have come across so far is the alkaline thermal vent model.
This is discussed in the very fine book "Life Ascending" by Nick Lane which is available in most public libraries.
 
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