Cosmology and our View of the World
When, where, and how did life start- How did it evolve?
Lead: Seth Goodnight
Summary by Lorraine Wilson
When, where, and how did life start?
Seth’s presentation revolved around the following questions, in this order:
-Is life inevitable?
-Is there life as we don’t know it?
-How did life begin?
-How did life evolve?
-How can we know?
-Do we have to die?
Conditions for Life
Seth began with the necessary conditions for life, such as, heavy elements, a planet, etc. He quotes the reading from “Cosmic Heritage”, “life requires chaos”, which suggests that life starts after extreme conditions like an asteroid strike. Professor Moebius questioned this claim, that life requires chaos, expressing, life comes in where it’s more reasonable for life to exist, but these events are creating the necessary conditions. The idea of life coming from chaos is incongruent. The word chaos suggests confusion, yet if these conditions are necessary to life, they are purposeful and without any type of disorder.
Seth added that we would be unable to know whether life had existed before an event like a huge asteroid impact. The impact of the asteroid could effectively wipe the planet of all fossils, and traces of life previously on earth. This would mean that there would be no trace of life having existed before this event and we would be unable to tell. Professor Moebius added that life could have started and ended on this planet 7 times over.
Discussion progressed to the question whether life was inevitable. To introduce this concept, the Urey Miller experiment was explained. The experiment simulated the conditions believed to be on earth when life first formed. It was undertaken under the hypothesis that primitive earth favored chemical reactions that create complex organic compounds. 20 different amino acids were produced in the experiment. Reference was made to finding of amino acids in space within interstellar clouds. This matter is coming to Earth all the time.
This lead to the question, were a planet to have the same conditions for life, would life inevitably arise? Later, it was discussed how contact with life on other planets could be one of the few ways we could come closer to solving the mystery of the conditions for life. Yet, this would really mean just gaining more evidence to support a claim. Seeing similarities between other examples of life would give us more insight and allow us to compare and contrast, but so long as there is a concept of life as we know it, there is a possibility of life as we don’t know it.
Then the second question: what if the conditions we know, or have determined for life, are not the only possible conditions? Beginning with research into the creation of artificial life forms, we discussed experiments that could give insight into the conditions that led to the origin of life.
Seth brought up the discovery of hydrothermal vents, debunking the idea that sunlight is a necessary condition for life, as life was found growing in underwater volcanos. This discovery means that places like Titan or Europa could have life in their oceans, heated by Jupiter’s gravitational pull. Talking about this discovery also gave a better perspective for students how the conditions for life are revised.
RNA, DNA, and Mutations
From fossils, we are able to determine chronological accounts of organic life’s history on Earth. For example, diversification in evolution between members of a species can be traced back using fossil evidence. The fossil records have put into perspective how little time humans have inhabited Earth compared with the planet’s existence:
It was questioned whether cells could have been simpler at the beginning of life on earth and evolved to be more complex. Professor Davis brought up an argument held by those for “intelligent design” that cells are irreducibly complex and therefore unable to function without being so complex, meaning they can’t have evolved to be that way. Another student, Michael mentioned that, being so complex, someone had to have put cells into existence.
On the level of chemistry, crystals (or the patterns in atomic structure) in clay have been found to self-replicate, tying into the idea that life requires replication. Within the patterns, mutations can occur and evolution takes place. These mutations were described as errors, and Professor Davis suggested a different wording for the connotation it held. He expanded, if you’re going to create something that evolves you would need to give it the capability to have variants. Seth debated that with replication there’s an intent to build off of what works. If there is too much variation the organism becomes something different.
Prof. Davis questioned whether something instructs variation or it just naturally occurs. Professor deVries compared this to Newton’s Laws, how they describe the movement of the planets, but do not direct it. He went on to point out that the individual nature of an organism also has a hand in determining the process of replication. The history of an organism can also determine its replication. As a crystal only replicates like a crystal, any organism will replicate in its own way. This was refuted as replication being a tendency rather than a property. A student added that variation is just as natural as a perfect copy. The necessity of a hereditary trait was brought up. It was agreed that the hereditary trait is a pre-requisite to variation. There must be some variation, even in a case of almost 100% replication. Variation is what allows for natural selection to take place.
In light of replication, the paradox of sex was later touched upon. The paradox of sex is the matter of evolution being short sighted; traits that only benefit future generations rarely evolve. So while sex is beneficial in the long run, it is less beneficial in the short term because only half of one’s genetic material is being passed on. The red queen hypothesis proposes that sex gives two sources of immunity to disease. Yet, having two gene pools has its own drawbacks, for example, in the case of sickle cell anemia. Sickle cell anemia is a hereditary condition where the hemoglobin distorts cells into a ridged crescent shape. The sickle cell blood cells can become easily stuck in small blood vessels and cause blocking of oxygen. Also a genetic response to malaria, a disease, which infects actin to reshape the red blood cells so they do not return to the spleen where the abnormal blood cells would be destroyed. The sickle cell is able to prevent “actin mining”, as it is called and the cells are destroyed in the spleen.
A student questioned whether the necessity of variation implied intelligent design. Seth disagreed with, “necessity means needing something to get from A to B.”
Theory, Creation, & Discovery
Three paths were proposed to track down the origin of life.
Professor deVries challenged the third path, suggesting that it would tie in with number 2, i.e. that inevitability would need to be shown to people, such as the Urey Miller experiment. Seth drew a parallel between the question and the simulation of star formation and evolution. Professor Möbius went on to explain how initially astronomers only had an inference from one, namely our own planetary system. But since about 20 years they have found exoplanets observationally, in ever increasing numbers.
As the discussion evolved it was proposed that finding aliens would only lead to more questions. Likewise lab creation would show that life can come from design, but not speak to natural creation. However, creating life would give us the tools to test the parameters necessary for life. For example, are there multiple roots to creating life? This ultimately looped back to the road block of “life as we know it.”
Next Steps in Life
Due to a lively discussion on the concept of swamp man in a previous class, Seth compared the swamp man example to putting the genomes of animals into different species in order to combat extinction. The swamp man was the idea of a creature that looks exactly like you and had all your memories rising out of a swamp. Would the swamp man be you? Would it be identical to you? The question whether the animal was identical to others of its species, or was lacking some key traits like in the case of swamp man, was raised. The class seemed to come to the conclusion that it would be the same species of animal as it is able to replicate with others of the same species. The ethics of bringing back extinct species was also touched upon.
Finally, Seth raised the question, do we have to die? The topic began with how the body breaks down, and a solution to this decay could mean eternal youth. Progress in health and medicine has increased the maximum age for a person dramatically. Yet, if we were to never die, it would follow that reproduction would be put to a halt and the evolution of our species with it.
Another way to eternal life could be the transfer of one’s consciousness into a robot. Machines can be fixed and virtually able to last forever. Professor deVries disagreed, you can’t redo the brain-- what if that wears out? Someone else brought up the influence of hormones from the pituitary gland on the brain and how the body specifically can greatly influence thought. Putting one’s consciousness in a robot may also detach the brain from the senses which make up our memory and unique experiences.
• Is genetic engineering happening on other planets? We may not be the first civilization to try it.
• Are we capable of creating new life at all?
• What would the creation of synthetic life mean?
• Can we live forever? Should we?