Evolution Blog

Class blog for BIO E Evolution and Systematics

Friday, December 01, 2006

Project 0, from Carrie, Part II

So what really is evolution? Based on the some dictionaries, evolution is

…the gradual process by which the present diversity of plant and animal life arose from the earliest and most primitive organisms, which is believed to have been continuing for the past 3000 million years.”

...the doctrines according to which higher forms of life have gradually arisen out of lower."

"...the development of a species, organism, or organ from its original or primitive state to its present or specialized state; phylogeny or ontogeny.” (http://www.talkorigins.org/faqs/evolution-definition.html )

These definitions can be considered as a source of debate especially for the non-believers of the theory.

A very good definition of evolution is stated by a most respected evolutionary biologist,

"…In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions."

- Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986

The word evolution has received so many bad comments and persecutions from different groups especially the religious ones, especially towards the person who bring this theory into existence, Charles Darwin. But in one article it says that this dreaded “E” word was avoided by Darwin himself.

…The name Darwin is considered by most people as synonymous with evolution, but in the Origin of Species the word "evolution" does not appear! Back in 1859 the word "evolution" had a very different meaning than what comes to mind today. Charles Darwin did not avoid using the word because he did not want to offend and incite the religious majority of his day. Rather, Darwin refers to the mechanism behind biological speciation as "descent with modification." He avoided using the word "evolution" because it did not convey the precise meaning he wanted. Ironically, the original definition of evolution implies a process more in keeping with Divine creation – that is, destiny or predetermination, if you will! (Stephen Jay Gould in his most recent essay, Natural History, February 2000)

Ironically, the original definition and view of evolution conforms to those religionist or particularly Creationist (well maybe in one sense I can consider myself as such), that is, evolution is the also the outcome of a predetermined events and not altogether the product of random mutation and selection. Although due to the extreme definitions of Modern Biologists and Geneticists, evolution has become very negative to these conservative people. They forgot to take into consideration predetermination. They rely more on the randomness of evolution not taking into consideration that there should be the interaction of random (selection) and predetermined. Therefore evolution is not completely random by itself but is forced in predictable directions by limitations imposed by other factors. These restrictions could be the environment where they live in.

The air, land and water impose limitations. Organisms try to have different strategies to be able to travel through these media. In water, large organisms develop a body form suitable for swimming, fins, flippers, adaptive body to the crushing forces of water at depth, and sensory location of objects and food in low levels of light. Animals who are on land and develop limbs for walking may have returned to the ocean and develop these structures like whales and dolphins of the mammals. Among birds are the penguins.

An animal whose locomotion is through air places has even more constraints on body form and appendage shape. They have become adapted for gliding or powered flight through their wings and have had to develop appendages that conform to aerodynamic laws. Their bodies had to reduce weight, such as hollow bones in birds. They also develop feathers as a form of insulation or maybe as a camouflage. Among mammals there are the bats, which evolved very early. Insects had to evolve wings and appendages which could propel them in controlled flight.

On land is not any different. Insects, because of their exoskeletons, small size, and segmented bodies, evolved more than two pairs of legs and they cannot evolve into super giants like we see in Hollywood. But animals with endoskeletons evolved only two pairs of legs. Land animals with six legs would require 50% more energy (ATP) than would animals with four legs (muscles eat up ATP). Thus, land animals with endoskeletons and two pairs of legs are evolutionarily favored.

The predator-prey relationship also imposes limitation that will lead to evolution. There are fossil remains of giant millipedes maybe because there was no predator for these slow-moving prey but the time came that predator exists and made them extinct and could not evolve again from their tiny cousins.

So, where God will come into the picture of evolution? Another article states;

…"For too long the Theory of Evolution has been taught as fact and as an undeniable truth. Scientists and educators have taught with fervor and passion that all life originated on Earth. Obviously there is some evidence that species change to adapt to the situation around them. But it is a giant leap of faith to assume we all came from some primeval ooze and gradually developed into complex life forms. I have had the luxury of seeing the complexity of just one cell. It is doubtful that life happened by chance. The logical conclusion is that there was a Creator. I receive many letters from scientists who claim to be experts in the field of genetics, who admit they are afraid to speak up. They are frankly afraid of losing their jobs, if they verbalize their own findings that the Theory of Evolution is in error." (THEORY OF EVOLUTION MINDSHIFT, Filer's Files #06 -- 2000, MUFON Skywatch Investigations, George A. Filer, Director, Mutual UFO Network Eastern February 12, 2000, Majorstar@aol.com (609) 654-0020 Web Site at www.filersfiles.com. -- Chuck Warren Webmaster.)

These are two contrasting views. So, is evolution really true or not? It is true because of evidences laid before us but it is not an absolute fact in a sense that it does not apply to all situations. There are always exceptions to the rule. Evolution is provisional. It is not absolute. Evolution does happen but still there is a Creator that predetermines everything. It is like the argument if God is preeminent why didn’t He anticipate that sin that will be committed by Adam or Eve. Why did He permit it to happen? Well we are endowed with a free-will which God cannot control or else He will not be a just God. But even though He knows man will fall He made a provision which is salvation through His Son Jesus Christ.

This is how I see evolution and this is what I want to discover in this course. I don’t know what really evolution is in a much broader sense but I want to expand my view. This desire is for me to be convinced of the theory much more than I am now and to be very clear with this as I teach the lesson to my students. This desire is also for my students, so I can be a teacher who is not only theoretically sharing to them the knowledge but letting them see and judge for themselves what evolution is and what is the connection of this in their lives.

I also am expecting to learn from this course how to effectively teach the topic. As of now I am giving injustice to this branch of Biology because as I said I am not an advocate of it especially if you will just base it on textbooks. As of now I do not include this topic in our course syllabus maybe because my coordinator told me not to do so because she said this topic is already tackled in Social Studies. Well they maybe tackling the part of the evolution of Homo sapiens from Homo erectus or from Java man but not the scientific part of it, which I know is my responsibility to teach as a Biology teacher. So after this course I know I am more convinced and more apt to teach this topic. I may include this as an introduction to Taxonomy which is the part I can say I really do justice in teaching.


Post a Comment

Links to this post:

Create a Link

<< Home