| Electric Fish In Africa Could Be Example Of Evolution In Action |
| Saturday, May 27, 2006 |
 I love it when the science papers and news are all filled with evidence and examples of Evolution. This one is especially interesting.
Although these fish look alike and have the same DNA genetic makeup, they have very different electrical signals and will only mate with fish that produce the same signals. Cornell researchers believe that these different electrical signals are the fishes' first step in diverging into separate species.
When he (Arnegard) joined Hopkins' lab, the team was about to publish descriptions of two separate species. But when Arnegard decided to take a genetic look at these particular fish, he couldn't find any differences in their DNA sequences.
"These fish have different signals and different appearances, so we were surprised to find no detectable variation in the genetic markers we studied," Arnegard said.
Because all of the 20 or so species of mormyrid have distinct electric signals, Arnegard believes the different impulses of the fish he studies might be their first step in diverging into different species.
"This might be a snapshot of evolution," Arnegard said.
Understanding how animals become different species, a process known as speciation, is a major concern in understanding evolution. Arnegard's fish may allow researchers to test if a specific type of speciation is possible.
One common type of speciation is geographically dependent. Animals diverge into separate species because they become physically isolated from each other. Eventually, genes within each group mutate so that the groups can no longer be considered to be of the same species.
Another type of speciation, which many scientists have found harder to imagine, involves animals that live in the same geographic location but, for some reason, begin to mate selectively and form distinct groups and, ultimately, separate species. This so-called sympatric speciation is more controversial because there have been few accepted examples of it to date.
"Many scientists claim it's not feasible," Arnegard said. "But it could be a detection problem because speciation occurs over so many generations." These Gabon fishes' impulses, however, can change very quickly in comparison. So Arnegard suspects that the different shapes of the electric impulses from these mormyrids might be a first step in sympatric speciation.
Science daily |
posted by Roya @ 12:45 AM   |
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| 1 Comments: |
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Nice post!
I find science utterly fascinating. I loved my college courses in biology, anthropology and the philosophy of evolution. The Theory of Evolution, in particular, is endlessly intriguing.
From where did we come?
From what did we evolve?
Through what means did this evolution take place?
I was always a bit pissed off when I saw my anthropology classmates snoozing during a fascinating lecture. Their loss, I guess.
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Nice post!
I find science utterly fascinating. I loved my college courses in biology, anthropology and the philosophy of evolution. The Theory of Evolution, in particular, is endlessly intriguing.
From where did we come?
From what did we evolve?
Through what means did this evolution take place?
I was always a bit pissed off when I saw my anthropology classmates snoozing during a fascinating lecture. Their loss, I guess.