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Cenozoic Park: Cloning the Tasmanian Tiger
Mirk writes "The
Australian Museum
reports a breakthrough in their plans to clone the Tasmanian Tiger. The ``tiger'', actually a carnivorous marsupial, became extinct in 1936, when the last known
specimen died in captivity. Er, did I say ``extinct''?
Now it looks like what everyone thought was an extinction may be
``a 70-year hiccup'', to quote the press release. The museum's Evolutionary Biology Unit have successfully replicated individual Tasmanian Tiger genes using a process known as
PCR (Polymerase Chain Reaction)."
Couple of comments on the ever-so-brief-and-simple press release:
(1) No mention of the increasing research into why cloning large mammals if more difficult than thought. See recent New Scientist magazines for pop coverage.
(2) No mention of host animals. The Tiger can't be brought back whole and entire, something needs to act as a host - 90% close relative, 10% recovered DNA. Then work up.
(3) No mention of gene pools and viable population sizes. Pick one human - clone a breeding population from them. Fancy working with them? Didn't think so.
Still, interesting project!
All you really need to do is look at the track record of the introduction of foreign species into environments that had not evolved with them.
;) -- the introduction of the mongoose to fight the rat population in the sugar cane fields has had a negative impact on the native bird populations.
Take Hawaii (okay, share it with the rest of us
Or to quote my favorite Jeff Goldblum line:
"You were so busy trying to see if you could do it that you didn't stop to think about whether you should."
Old age and treachery almost always overcome youth and skill.
[sigh]
As another poster pointed out, the Tasmanian Tiger was in fact hunted to extinction (or possibly near-extinction, but recent sightings in the wild are unconfirmed) by humans -- there's no doubt about that. But that's not really the point. The real point is that whether or not an animal is "fit to survive in this world" is determined by one thing and one thing only, and that is, well, survival. If an animal goes extinct, for whatever reason, it is unfit. If it comes back, in any manner, it is by definition fit again. It's really that simple.
Many varieties of domesticated animals, from housecats to beef cattle, have been bred to be so different from their wild ancestors that the species would have significant trouble surviving without humans around to take care of them. Does this mean they're unfit? Of course not. It means they're perfectly fit for our current, human-dominated world.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
"Not every animal died because of evil humans, some died because they weren't fit to survive in this world."
Fitness to survive in the world has nothing to do with it. A meteor falls, and everything with a body mass greater than 100kg dies out. Were the larger animals less fit? A volcano erupts. A species dies. A flood wipes out a nesting ground. Chalk up another one. Human sailors bring in rats, goats and row plants, destroying practically all native flora and fauna of whole island chains.
Were any of these things destroyed because they were less fit? Of course not. If your building catches on fire, are the survivors more "fit" or are they simply lucky enough to be working on the first floor?
Despite the pitifully bad dialog of Jurassic Park, natural history does not represent some featureless plain on which species struggle against each other and the best win out. Catastrophes happen. Climates make sudden, radical shifts. Disease runs rampant. New vegetation suites are established. Chance is everywhere.
And chance is all it takes. Abandon any idea that the creatures you see around you are "better" than what came before. Different? Sure. Better? By what standards? They're here because of chance built on chance, built on chance. Feedback loops tend to enforce the status quo, keeping many species stable over millions of years (a feature generally absent for the last 12,000 years) but the best predator on Earth can't live if all the prey die and forest dwellers die when the forest goes bye.
The Thylacine happened to be a predator on an island where humans decided to raise sheep. It was fully "fit" in the environment before this point. Afterwards, it was "unfit" in the sense that it's hide was not bulletproof and it had an unfortunate predilection for traps.
Should we worry about the return of extinct species? At some point, yes, but not because some anthropomorphic "nature" selected them for extinction. We should worry because these creatures may be all too "fit" and have behaviors, breeding strategies, or feeding habits that are exceptionally successful in a modern setting.
Do you oppose the return of Grey Wolves to the Yellowstone Basin, or the reintroduction of Grizzlies to their historic range? Like the thylacine, these are creatures that have been absent from these territories for multiple generations. And the areas to which they are being "returned" have often experienced radical changes in the intervening years. Watching the ups and downs of these "reintroduction" projects should give us a good preview of the pitfalls to avoid when someone wants to put just a few Mastadons in Missouri.