Tuesday, March 9, 2010

Macro v Micro Evolution

On page 32, Coyne says that creationists will admit that minor changes in size and shape might occur over time-a process called microevolution-but yet they reject the idea of macroevolution. What do you think is the reason that they will believe in one type of evolution, but not in the other? Theoretically, doesn't microevolution lead to macroevolution?


  1. Creationists believe in microevolution, “minor changes in size and shape [that] might occur over time” (32). Microevolution allows for the acceptance of both God as a creator and truth behind natural selection. A creationist would say that it is possible for a species to develop certain traits to help it survive in that environment. This was proved in Darwin’s study of the Galapagos finches. It was observed that the finches’ beaks would change shape according to the type of food available for the bird. However, change in the size of a beak would be considered a minor change, one that could happen without the alteration of an entire species. Macroevolution, on the other hand, is change from one species to another. Creationists would not accept this because they believe that God created every creature individually. Little evidence has been released proving a missing link between drastically different species (even in Why Evolution is True Coyne mentions the links found are cousins of what the actual link should be) so it is still extremely difficult to go against religious teachings to accept that one species could evolve into another: ie. Hippo to Whale.

  2. Microevolution is a term often applied to the process whereby a species (or a population) undergoes significant changes over time that aid that species in being able to survive and reproduce more efficiently. This term may also be extended to include the formation of new species, the process of speciation. The mechanism currently considered to play a
    major role in microevolution is natural selection, but may also involve other elements.
    Macroevolution refers generally to the formation of major groups of organisms from other groups that are distinctly different, such as the evolution of mammals from earlier non-mammalian tetrapods or the
    evolution of whales from terrestrial mammals. The mechanism for this process is generally considered to be the same as for microevolution, but carried on accumulatively over many millions of years, resulting in the ever-increasing diversity of life we see today. Creationists believe that when microevolution occurs, variations within a kind of animal or plant occurs. Sometimes these variations can lead to a new species, and in some cases, even a new genus. But the variations have limitations. That limitation is within the genetic information of the organism. In order for macroevolution to occur, new genetic information must arise in an organism. However, it takes a very long time for this new information to arise, and we don't see this in our lifetimes because this process takes at least several generations to occur. Since the evidence isn't empirical in multi-cellular forms, creationists have a difficult time believing that microevolution actually leads to macroevolution.


  3. I think one of the reasons that creationists are more accepting of microevolution in macroevolution is that microevolution is visibly seen in humans. In the 17th century, the average height for men and women was aproximately 3 inches shorter than the average heights of present day men and women. This is a simple and rudimentary, but visible example of microevolution that people are becoming taller, that changes are occuring in the human body. Because of the creationist belief that God created all of the species of animals on Earth, they are clearly not going to accept the idea that one species can evolve into a completely different one. That would go against the fundamental belief of creationism. They do however, believe in microevolution because they do understand that animals have to adapt to their environments in order to better survive. They do recognize that the Earth's environment is changing, and that all speices of animals will have to adapt to their new surroundings if they are going to be able to survive. However, they do not believe that these adaptations to be able to survive will lead to a new species. They feel that the organism may look different thant previous "versions" of the organism, but when it all comes down to it, it is still the same organism. Their belief in microevolution can also help them justify species going extinct. They can say that some species were not able to adapt to their environment, and therefore were not able to survive, even if they were created by God.



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