2nd Quarter Learning Log Highlights

The Future is Wild

This documentary, which was aired in Discovery Channel, showed the possible state of the Earth 5 million years to 200 million years from now.

If I were going to judge the film based on the ideas it wanted to convey, or the information it wanted to reach its viewers, then I would say that it was good. Not really appealing but the idea was clear and understandable enough—that after more than a hundred years, when humans cease to exist or leave the Earth, animals would evolve in ways beyond our imagination.

Basically, what it was trying to say is that when organisms are exposed to environmental pressures, the only ones that would survive are those that evolved (and we should remember that it was not their decision to change. It was the environment, which dictated the way they would change).

Visually, the movie did not appeal to me. The graphics were clean but poorly done, and for some reason, I even doubted if the people talking in the documentary were scientists at all. I only convinced myself that maybe they are because if not, then Discovery Channel would lose its credibility.

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The idea of evolving animals still intrigues me, not because mating between different species is bizarre (we all know that this is not new), but because I still cannot imagine how different traits from different animals would be acquired by a single organism. I mean, would it be possible that a product of mating between different species would not be sterile anymore, and could multiply? Because we all know that today, this kind of mating would result to sterile organisms.

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Mitochondrial Eve and Y-chromosome Adam

I thought Adam and Eve only existed in the Bible, but guess what, the scientific community has its own version of mankind’s parents.

Mitochondrial Eve

- It was believed that humans had a common ancestor—a mother. To test the idea, scientists had to find a way to trace the phylogeny of humans. Tracing it thru chromosomes would be very difficult because chromosomes are prone to recombination, except haplotypes, which are stretches of chromosomes immune to genetic recombination. They resorted to tracing our lineage thru the DNA from women’s mitochondria, because these are the same mitochondria that we have inherited from our mothers, and our grandmothers, so forth and so on. Therefore, using the mitochondrial DNA, scientists are sure that the DNA went thru the least changes possible.

Y-chromosome Adam

- If mitochondrial DNA were gathered from women, Y-chromosome was gathered from men. Scientists chose the Y-chromosome because this was unique to the males, and of all the chromosomes in the body, they were sure that this went thru the least changes possible that could affect their tests.

Where did the idea of a mitochondrial Eve, and Y-chromosome Adam come from, anyway? Well, theories about the beginning of the human race may have started this, being the Out of Africa Theory, and the Multiregional Origin Theory.

These two theories had opposing ideas. The Out of Africa Theory states that humans started to evolve in Africa, and the first members of Homo sapiens was found there. From Africa, they crossed land bridges and seas to reach different parts of the world, and from there, started a new race. The Multiregional Origin Theory, on the other hand, states that Homo erectus from Africa crossed the seas, and the land bridges. When they reached different areas of the world, it was then that they evolved to become Homo sapiens due to environmental pressures.