Mankind Forcing Evolutionary Changes In Animals

[MA-Caver]

Super-Predators: Humans Force Rapid Evolution of Animals



Robert Roy Britt
Editorial Director
LiveScience.com robert Roy Britt
editorial Director
livescience.com – Mon Jan 12, 5:17 pm ET
http://news.yahoo.com/s/livescience...atorshumansforcerapidevolutionofanimalsActing as super-predators, humans are forcing changes to body size and reproductive abilities in some species 300 percent faster than would occur naturally, a new study finds.
Hunting and fishing by individual sportsmen as well as large-scale commercial fishing are also outpacing other human influences, such as pollution, in effects on the animal kingdom. The changes are dramatic and may put the survival of some species in question.
In a review of 34 studies that tracked 29 species across 40 different geographic systems, harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they first reproduce is on average 25 percent earlier.
"Harvested organisms are the fastest-changing organisms of their kind in the wild, likely because we take such high proportions of a population and target the largest," said lead researcher Chris Darimont of the University of California, Santa Cruz. "It's an ideal recipe for rapid trait change."
Darimont told LiveScience that while he considers the changes to be evolutionary, some biologists consider them phenotypic and, without evidence of genetic shifts, would not call them evolution.
The study found dramatic change in several fish species and creatures as small as snails and as large as bighorn sheep and caribou.

It shouldn't be no surprise that humans are causing this change in the animal kingdom. As the dominate predator upon the planet it stands to reason that we are in effect changing our prey or I should say our prey is changing to adapt to our hunting techniques to survive.
The saddest thing is that it causing these animals to change before they're due for change on the evolutionary clock as it were. It's usually climate or environmental changes, and/or over population or isolation that causes these changes. But the greed and insatiable appetites of mankind is undoubtedly affecting these changes.

By harvesting vast numbers and targeting large, reproductively mature individuals, human predation is quickly reshaping wild populations, leaving smaller individuals to reproduce at ever-earlier ages, Darimont explained.
"The pace of changes we're seeing supercedes by a long shot what we've observed in natural systems, and even in systems that have been rapidly modified by humans in other ways," Darimont said. The study found the changes outpace by 50 percent those brought on by pollution and human introduction of alien species.
"As predators, humans are a dominant evolutionary force, he said.
Others agree the problem is serious. Columbia University biologist Don Melnick recently said trophy hunting is akin to selective breeding and is "highly likely to result in the end of a species."

related article:http://www.livescience.com/animals/top10-species-kiss-goodbye-1.html

Man also is guilty of driving a host of species to extinction before Nature determines it's natural selection. The Dodo, Passenger Pigeon, Steller Sea Cow, and others were prolific animals and useful in their own way to their respective environments.

Could it be that if the predation of these animals were slowed down in time that they'd still be here but different from their ancestors because of our presence. Our encroachment on their habitats and food supply?

I wonder about the Cetaceans which were nearly hunted down to extinction have evolved from their ancestors of say 300 years ago? Are they faster, smaller, more acute hearing (for engine propellers)? Hard to say. Shouldn't be surprising.

http://www.livescience.com/animals/090106-reverse-evolution.html

 

[Sukerkin]

There's little denying that we, as a species, are indeed a force of nature - and have been for quite some time.

Whether it's morally good or bad is a different question from the pragmatic outcomes of our influence. For me the most important is the need for us to draw back from the brink of hunting to extinction those creatures we like to eat. Species can bounce back quite quickly given the chance, thus ensuring we get to snack on them far into the future.

 

[sgtmac_46]

I never quite get the 'faster than would occur naturally' pronouncement.....as if humans are some artifical entity that exists outside of nature. This planet produced us, and our effects are as 'natural' as any other entity on the planet.

 

[CoryKS]

The saddest thing is that it causing these animals to change before they're due for change on the evolutionary clock as it were. It's usually climate or environmental changes, and/or over population or isolation that causes these changes. But the greed and insatiable appetites of mankind is undoubtedly affecting these changes.

Due for change? What is due for change? They change as needed by their surroundings, including us. We ARE members of the animal world, not some freaky invader from another planet.

JFC, any reason to criticize people for acting like... people.

 

[Sukerkin]

We ARE members of the animal world, not some freaky invader from another planet.

Given that 'our' natural body-clock does not match the rotational period of the Earth, that may not be as absolute as you might think .

 

[sgtmac_46]

Given that 'our' natural body-clock does not match the rotational period of the Earth, that may not be as absolute as you might think .

......okayyy......

 

[CoryKS]

Given that 'our' natural body-clock does not match the rotational period of the Earth, that may not be as absolute as you might think .

You don't get to use the foreign invader argument until you prove it's true. Otherwise, I get to argue that my invisible friend created everything in seven days.

 

[Andy Moynihan]

I have often read a certain bumper sticker on vehicles of individuals I can only assume must be overly environmentally conscious.

I do often wish they would follow their own advice.

It reads: "Save the planet--Kill yourself."

That would seem to cut down on our tax dollars being wasted on such studies as these I would think.

 

[Sukerkin]

Hmm ... erm ... I'm fresh out of proof on that particular avenue of speculation, Cory (tho' your invisible friend's best selling book does make reference to extra-terrestial cross-species mating, which might have some bearing on the matter ) .

 

[tellner]

sgt_mac: It's not that we're "outside of nature". It's that we change things very, very quickly because our cultural evolution is Lamarckian while biological evolution is Darwinian. That is, we pass on acquired cultural traits and knowledge very quickly. Biological evolution of the normal sort is by recombination, mutation and reproduction. That's much slower.

We are already causing the fifth Great Extinction. It's on the scale of the dinosaur killer. We've moved species all over the world. We're causing significant climate change. And geologists are beginning to agree that our age represents a new geological era. Aluminum, concrete, asphalt and so on are significant additions to the surface of the planet. The salinization of river valleys and other farmland is a significant event.

That's all in about eight thousand short years, nothing on planetary time scales.

If we were a regular predator species we would mostly kill the young, the old and the sick. The normal selection pressures would still favor the large and strong among birds and hooved mammals. But since we are very efficient at killing them off and doing it selectively we are causing a very rapid selection for small and weak.

Ain't evolution grand?

 

[tellner]

Sukerkin, there's been some work on the Circadian rhythm. I'm not up on the literature or qualified to have a real opinion. To the best of my understanding there's an emerging consensus. A slightly longer period allows us to adjust to changes in day length. There were other speculations, but again it's been a long time since I read the abstracts.

 

[sgtmac_46]

sgt_mac: It's not that we're "outside of nature". It's that we change things very, very quickly because our cultural evolution is Lamarckian while biological evolution is Darwinian. That is, we pass on acquired cultural traits and knowledge very quickly. Biological evolution of the normal sort is by recombination, mutation and reproduction. That's much slower.

We are already causing the fifth Great Extinction. It's on the scale of the dinosaur killer. We've moved species all over the world. We're causing significant climate change. And geologists are beginning to agree that our age represents a new geological era. Aluminum, concrete, asphalt and so on are significant additions to the surface of the planet. The salinization of river valleys and other farmland is a significant event.

That's all in about eight thousand short years, nothing on planetary time scales.

If we were a regular predator species we would mostly kill the young, the old and the sick. The normal selection pressures would still favor the large and strong among birds and hooved mammals. But since we are very efficient at killing them off and doing it selectively we are causing a very rapid selection for small and weak.

Ain't evolution grand?

Evolution is what it is.......we are a product of this planet, and our actions are a natural consequence of that.

 

[tellner]

No doubt. But since we have those overdeveloped brains we should have sense enough not to do stupid things. Wiping out more species than anything since the K-T Event, salinizing our most productive croplands, degrading our fresh water and top-grading the prey species are all stupid.

Massive population crashes and going extinct are also natural. I'd prefer that we not do those either.