JavaScript is required to use Bungie.net

OffTopic

Surf a Flood of random discussion.
Edited by Britton: 5/15/2015 3:03:32 AM
174

Evolution Explained

[b]EDIT[/b] So the first true warm blooded fish has been discovered. http://m.livescience.com/50839-first-warm-blooded-fish-found.html Pretty awesome. Pic above. Its called an Opah, or moonfish. [b]OP:[/b]Since the issue is always a lack of understanding, and its often requested to be explained when people point out anothers lack of understanding on it, I'll lay it all out for everyone. [b]Evolution[/b], put simply, is descent with modification. So let's break down the basics of how that happens. [b]DNA[/b] or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms that resides in our cells. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences. An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell. Its during this replication process that is constantly happening, that errors or mutations can occur. If an error occurs you now have a cell that is different from the original, due to mutation. [b]Mutations[/b] or copying errors cause the copied DNA to be different from the original. These mutations can be passed to the next generation of organisms when the gametes and zygotes contain the mutated DNA. Evolution occurs when you have a change in gene frequency within a population over time. What affects gene frequency? It is the [b]mechanisms of change.[/b] These mechanisms are [b]mutation, migration, genetic drift, and natural selection.[/b] Since I already went over how mutation occurs next comes [b]migration[/b] or how geographic location of populations can affect the overall gene frequency of a species. An example will be best here. You have 2 population of beetle species X. Population 1 typically has spots, population 2 typically does not. If these two populations migrate farther apart, you will see that difference become more defined due to isolation. If they migrate closer and intermingle, you'll see much more variation in the two populations. Migration, whether it be by the animals itself, or caused by other events, like plate tectonics (on a scale of millions of years) can allow or prevent the genetic divergence of populations of animals, resulting in a new species. [b]Genetic Drift[/b] is more random chance affecting organisms. Let's say in our beetle species X, population 1, lives in the lower forests, and population 2 live higher in the mountains. Well the mountain is a volcano, it erupts, and wipes all of population 2 out. All the little differences it had that were unique to it out of beetle species X, are now gone, resulting in the populations 2 genes to be gone from the future generations of beetle species X. Basically genetic drift accidental selection. And finally we come to [b]natural selection[/b]. Natural selection is the gradual process by which heritable biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. Or, put simply, it is the process of how the selecting factors in an environment; predators, food sources, climate, etc make certain inheritable traits more or less likely to be passed on to future generations. All of these mechanisms acting in conjunction cause evolution, and create new species. How do differentiate between species? A [b]species[/b], is often defined as the largest group of organisms capable of interbreeding and producing [u]fertile[/u] offspring. When one species becomes two, this is called speciation. This event creates all kinds of new opportunities for more evolution to occur. Its important to look at the timeline of life, not as a ladder of organisms getting "better", but as a tree, where the father up you go the newer the branches are, not necessarily better. Old branches can last a long time, like the [url=http://vertebrates.si.edu/fishes/coelacanth/indonesia_coelacanth_2.jpg]coelacanth[/url], and new branches can have relatively short life spans, like any of the many now recently extinct plants and animals. The tree just shows the lines of ancestry. Evolution does [b][u]not[/u][/b] address the origin of life. Evolution is how life forms have changed over time as a result of their environment and genetics. Claiming not having an answer for life's origins affects evolution is patently false. Yes, there are still questions being investigated in regards to evolution. For example: -Does evolution tend to proceed slowly and steadily or in quick jumps? - Why are some [url=http://www.evolution.berkeley.edu/evolibrary/search/imagedetail.php?id=260&topic_id=&keywords=]clades[/url] very diverse and some unusually sparse? Among other things regarding the specifics. All available evidence supports the central conclusions of evolutionary theory, that life on Earth has evolved and that species share common ancestors. Biologists are not arguing about these conclusions. But they are trying to learn more about how evolution happens, and that's not an easy job. It involves collecting data, proposing hypotheses, creating models, and evaluating other scientists' work. These are all activities that we can, and should, hold up to our checklist and ask the question: are they doing science? All sciences ask questions about the natural world, propose explanations in terms of natural processes, and evaluate these explanations using evidence from the natural world. Evolutionary biology is no exception. Darwin's basic conception of evolutionary change and diversification explains many observations in terms of natural processes and is supported by evidence from the natural world. This is a summary in my own words of how it works, so its entirely possible I forgot something. I've really tried to keep this as short, and simple as possible, and I welcome any questions and any issues you see.

Posting in language:

 

Play nice. Take a minute to review our Code of Conduct before submitting your post. Cancel Edit Create Fireteam Post

View Entire Topic
  • Edited by Master Chief: 5/21/2015 10:16:07 PM
    By Bruce Malone [quote]In the 1700's many scientists believed that life spontaneously generated from non-living matter (such as raw meat or sewage). In the 1800's, using careful experimentation, Louis Pasteur prove this concept wrong and verified that life only comes from previously existing life. Ironically, many scientists have once again return to believe that life came from nonlife... In spite of the fact that there is no experimental evidence to show how that could have happened. The reason this unsupported believe has returned is that science has been defined to eliminate the consideration of the only other alternative; the creation of life by an intelligent designer. Even the simplest living cell is an incredibly complex machine. It must be capable of detecting malfunctions, repairing itself, and making copies of itself. Man has never succeeded in building a machine capable of the same functions. Yet most scientists accept the belief that life arose from nonlife (in spite of the evidence clearly indicating that it did not and could not happen). This incredible belief is as absurd as finding a complex chemical manufacturing facility on Mars and assuming that it built itself. One classic experiment which is used to support the belief that life "built itself" is an experiment by Stanley Miller in 1953. In this experiment sparks were discharged into an apparatus which were circulating common gasses. These gases reacted to form various organic products which were collected and analyzed. Experiment succeeded in producing only a few of the 20 amino acids required by living cells. Yet the results have repeatedly been heralded as evidence that life could have arisen by itself. Furthermore, the dozens of major problems with this experiment as an explanation for the formation of life are seldom reported. For instance, are early atmosphere was assumed to have no oxygen because this would stop amino acid formation. However, with no oxygen, there would be no ozone shield. With no ozone shield, life would also be impossible. Furthermore, oxidize rocks throughout the geologic record indicate that oxygen has always been present. in addition to this, the same gases which can react to form amino acids undergo known reactions in the presence of sunlight which remove them from the atmosphere. The required gases would not have been around long enough for life to develop! In addition, a cold trap was used to keep the reaction products being destroyed as fast as they formed. The biggest problem is that the amino acids form in this experiment always a 50-50 mixture of stereotypes (L and D forms). Stereotypes are like a drawer full of right-hand and left-hand gloves, identical in every way except a mirror image of each other. Life only contains only L stereotypes of these randomly produced amino acids. Yet equal proportions of both types are always produced. How could the first cell have selected only L stereotypes from a random, equally reactive mixture? No anwser to this has ever been found. These are just a few of the problems with the fanciful idea that life generate itself. The leaking of these randomly produced amino acids into the required proteins is an even more overwhelming impossibility. No experiment has ever shown that matter has the ability to come alive. The best explanation for life is still that "life only comes from pre-existing life". As you search for the truth, perhaps you should consider the possibility that the source of all life... Is God. [/quote] [i]Taken from Bruce A. Malone's book, Search for the Truth[/i] ^^Explain that^^ Also, literally every "example" of evolution is just speciation. Name one actual example of evolution in today's world. My notifications don't work so I may take a while to respond.

    Posting in language:

     

    Play nice. Take a minute to review our Code of Conduct before submitting your post. Cancel Edit Create Fireteam Post

    11 Replies
    You are not allowed to view this content.
    ;
    preload icon
    preload icon
    preload icon