The Problem with Christians

[TheRocketSurgeon]

We don't have either of those two classes. Why not say that the mammalian brain is "on the path" to the less developed brain? After all, it is a lot easier to lose genetic information and weaken the phenotype than it is to improve it. If the shark brain was on the path to the mammalian brain, then why has it not changed in so many millions of years? I don't think sharks experience selective pressure for intelligence.

Seriously, dude, work on your understanding of population genetcs. As you pointed out, if there's little selection pressure for intelligence in sharks (they seem to be doing fine as they are), then they're unlikely to develop higher intelligence. Even if a really smart shark emerges... what good does it do him? How does it add to his genetic fitness for reproduction.

What I meant by "on the path" is that, as various subspecies branched off from earlier forms, some of them developed higher-order brain systems that led to us. We and sharks share a Phylum, Chordata, in which our neural "trunk" (spine) developed a cluster at one end that became the brain. Thus, we come from the same path. In our case, higher intelligence in our ancestors was evolutionarily useful, so it was selected for. You made the same mistake with the shorter-necked giraffes, from which long-necked giraffes evolved. The Okapi, a really short-necked giraffe, went the other direction. From http://www.livescience.com/52903-transit...ssils.html:

They analyzed the neck bones of four S. major individuals, three giraffes (Giraffa camelopardalis) and three okapis (O. johnstoni). On average, giraffes had 6.5-foot-long (2 meters) necks. In comparison, the necks of S. major were about 3.2 feet (1 m) long, and the okapi necks extended about 1.9 feet (60 centimeters).

The findings surprised them: Not only was the length of the S. major neck between that of the giraffe neck and the okapi neck, but its shape and the angles between bones were also intermediate.

If the researchers were to paint an S. major neck, color-coding its giraffelike parts red and its okapilike parts white, the top of the neck would be covered with red and white dots, and the bottom of the neck would be pink, the researchers said.

giraffe, Samotherium major and okapi neckPin It An illustration of the giraffe, Samotherium major and okapi necks and skulls.

"In every way, it's intermediate," said study first author Melinda Danowitz

There's no direction to evolution. Things survive and reproduce as they can, and they tend to diverge whenever the sub-populations are no longer exchanging genes (such as moving into a new environment, or developing behavioral traits that prevent mating with the original group). That does not mean that the original group must die out, or will change.

Finally, I have no idea what you mean by the bits about the loss of genetic information. How many demonstrated cases of gaining new information (such as the nylonase gene) do you need to see before you grasp that it can and does happen? Which is easier is irrelevant.