Friday, March 8, 2013

CH4: Making tracks through animal space

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Evolution of Organs

     Every human part is complicated. Take human eyes for example. It is less plausible to develop an eye from something radically different in one step. It is more plausible that we develop our eyes though millions of changes.

    From this argument, it is reasonable to assume that, at the beginning, we don’t have an eye. But better eyesight  helps us a little more in surviving. We gradually develop our eyes. Our eyesight become sharper though generation.  Up to some point, we can see sharper images and differentiate a tiger from a cat.
Despite the use of eyes as an example, the above fact is true for every organ such as ears, wings, venom glands. All organs evolve slowly. For example, 1% of hearing is better than no hearing at all, and 2% of hearing is better than 1% of hearing. The chance of survival increases continuously as each organ improves, no matter how small the change is. 

Evolution Pathway

     Evolution consists of small changes. An animal gradually changes over time, and may become another animal which totally differs from the original animal.  If we line up all animals from the original species to the final species, we will get the “evolution pathway” for this final species.  
Since the animal space is so vast, it is most likely that a process of evolving to a particular animal in the space is unique. It’s not that there is no way for two different species to evolve and end up having the same traits. It’s just that the probability of being so is vanishingly small. 

     However, it is possible to develop the same proficiency from different origin. This occurs when such the proficiency increases the chance of survival.  For example, both bats and dolphin live in optical navigation is of little use. Therefore, they both have developed an echo-location ability. 

Is There Any Designer?

     Consider a certain species for the moment. It’s tempting to  believe that someone has designed them so nicely such that such the species work so well. But if we consider the evolution pathway, we are going to see imperfection somewhere on the pathway. Sometimes, the imperfection is so bad, and you’d think the designer shouldn’t have designed it like this. But since biological objects are not like machinery, there are no designer. It’s normal to see imperfection. Over time, the object will evolve towards having better odd for surviving. In the end, we shall see a “good design”.

Life Cycle and Prime Number

     Some species live in a very specific life cycle. For example, it may have a life span of 7 years. Every generation borns, hunts, and dies in a periodic manner.  

     What does it has to do with prime number? First of all, a prime number is the number divisible only by ‘1’ and by itself. It does not have common divisor with other number. The claim is that a life form whose life span is a  prime number can avoid being hunted. 

     Consider a species whose life span is 14 years. The species would be hunted at birth by two generations of hunters whose lifespan is 7 years. To avoid this, the preys adapt their life not to be a multiple of hunters’ life span. Since there are so many hunters, the only way to have the life span not to be multiple of that of all hunters is to have prime-number of life span. 
"Evolution is irreversible"--Dollo’s Law
Book or Audiobooks?

Personally, I prefer audiobooks. It's fun, and I can listen when I'm doing something else. It also makes other activities (e.g., jogging) a lot more fun. For more detail about audiobooks, please read [this post].

There is one more reason that may encourage you to go for the audiobook version. You can get it now for FREE. Audible offers you a free trial for 14 days. Even if you get the book and cancel the subscription right away (so that you don't have to pay), you can keep the book. And, don't worry if you lost the audiobook file. Just log into You can keep downloading the over and over again.
About the summary: It takes time to finish up a book. And, when you do, sometimes, you want to review what you learn from the book. If you do not make  notes as you read, you might have to go through the book once again. This can be time-consuming when you are dealing with a book. But you can still flip through the book and locate what you are looking for.

However, when the material is an audiobook, it is extremely hard to locate a specific part of content. Most likely you will have to listen to the entire audiobook once again.

This book summary will help solve the pain of having to go through the book all over again.

I am leaving out the details of the books. Most books have interesting examples and case studies, not included here. Reading the original book would be much more entertaining and enlightening. If you like the summary, you may want to get the original from the source below.

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