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The most poisonous animal, Contentious ethanol debate, Sleeping seeing fish

Update:  What is the most poisonous creature in the world?  We may have found it:  a small beetle.  A reader alerts me to these new developments.   Ryan, Phoenix, Arizona

The small (0.2-inch (5 mm) long) beetle may give the poison to poison-dart frogs. Photo courtesy of John Dumbacher, copyright, used with permission.

The most poisonous creature — a tiny poison-dart frog (Phyllobates terribilis) of Colombian jungles — may obtain its poison by eating a small beetle from the family, Melyridae.  We know the frog doesn't make its own poison but rather gets it by eating something toxic.  We didn't know what it eats to extract the poison until recently.  It's a convoluted story, and not yet entirely told, since Colombia restricts fieldwork, preventing further research there. 

So, we've sneaked up on the answer from far-away New Guinea.  Ornithologist John Dumbacher, now with the California Academy of Sciences, worked with John Daly, world expert on poison-dart frog chemistry, to discover a New Guinea bird with the same poison as the frog.  The scientists found high concentrations of the toxin in a small, brightly colored beetle.  They analyzed the bird's stomach contents, and found the bird had eaten similar poisonous beetles.  Moreover, the beetle family Melyridae is "cosmopolitan." Its relatives in Colombian rain forests could be the "source of the batrachotoxins found in the highly toxic Phyllobates frogs of that region," write Dumbacher, Daly and others in the Proceedings of the National Academy of Science.

"Our group is still working with Dr. Dumbacher on the mystery of batrachotoxin in beetles, frogs and birds," emails John Daly. 

We shall keep you posted...

Further Reading:

Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds, Proceedings of the National Academy of Science, November 2004

Most poisonous creature could by a mystery insect by April Holladay, WonderQuest

Comment

Readers' Comments:

• the article referred to a frog that cannot produce poison on its own but must consume another creature with poison to become toxic as the most poisonous creature on the planet, is in my mind somewhat arguable. While mankind doesn't exude any poison from its flesh, it is certainly arguable that it is an extremely toxic animal based on the destructive nature of the technologies it(mankind) has created. We, mankind as a whole has done more to poison the water, air and land than any other creature. I therefore postulate that mankind is the most poisonous animal there is. That is at least until we learn to change our ways. the article referred to a frog that cannot produce poison on its own but must consume another creature with poison to become toxic as the most poisonous creature on the planet, is in my mind somewhat arguable. While mankind doesn't exude any poison from its flesh, it is certainly arguable that it is an extremely toxic animal based on the destructive nature of the technologies it(mankind) has created. We, mankind as a whole has done more to poison the water, air and land than any other creature. I therefore postulate that mankind is the most poisonous animal there is. That is at least until we learn to change our ways. Freddie  Tottenham Ontario, canada

Q: I have read that ethanol-mixed gasoline is not as efficient as regular gas and will not run some small engines. How much of this is true?  Rick, Branson, Missouri

Q: I just read a political cartoon saying it takes more energy to make a gallon of corn ethanol than you get by burning it.  Is that really true?  Lanney, Sandia Park, New Mexico

Corn is the largest US crop; 99 % is fertilized. Photo courtesy of the USDA.

A: That's true:  ethanol-mixed gasoline is not as efficient as regular gas.  In fact, a gallon of E-85 (fuel containing 85% ethanol, 15% gasoline) has an energy content of 80,000 Btu — compared with about 118,000 Btu for a gallon of gas. 

E-10 Unleaded, however, "... is perfectly acceptable in lawn mowers, snowmobiles, ATVs and other small engines that run on ordinary unleaded gasoline," says the National Corn Growers Association.  "Virtually every small engine manufacturer, including Briggs & Stratton, Honda, Toro/Lawnboy, Kohler and Snapper, approves the use of E-10 Unleaded in its equipment." 

The second question is more complicated.  Corn ethanol seems to cost more energy to make than the energy ethanol contains — but the answer depends on who you talk to.  See the table below. 

Corn growers, the ethanol industry and the US Department of Agriculture (USDA) deny the inefficiency charge. 

We show that corn ethanol is "energy efficient" as indicated by an energy input to output ratio of 0.75, says the USDA in an in-house report, not peer reviewed. 

However, David Pimentel, professor of ecology and agriculture at Cornell University, disagrees.  He has said over the past twenty-five years (since his initial 1980 study for the U.S. Secretary of Energy, reviewed by 26 top scientists and unanimously approved):  "There is no energy benefit to using plant biomass for liquid fuel."  In his latest study (researched with Tad W. Patzek), Pimentel reports an energy input to output ratio of 1.29.

"In terms of renewable fuels, ethanol is the worst solution," agrees Tad Patzek, professor of civil and environmental engineering at the University of California, Berkeley. "It has the highest energy cost with the least benefit."

Pimentel and Patzek recently analyzed the energy input and yield ratios of producing ethanol from corn and other plants.  The results of their study (published in the peer-reviewed Natural Resources Research) has kicked off debate again.  (From here on, I'll refer to Pimentel and Patzek's study by the shorthand:  P&P.)

Everyone agrees on the amount of energy that corn ethanol contains.  The fireworks ignite determining how much energy it takes to make the stuff.  By "make" I mean such ingredients as pesticides for controlling corn-eating insects, fertilizer for growing the corn, running farm machinery, irrigating, grinding and transporting the crop and fermenting and distilling the corn ethanol (which, by the way, is corn liquor).  Some of these estimates vary by at least 2 to 1 between the P&P researchers and the USDA. 

The only way to sneak up on the 'truth' is to examine assumptions of the debaters.  But it's tedious, dreary business.  Enough to make you wish, perhaps, you'd never asked the question.  Here's the link to my discussion of the assumptions for whoever wants to peruse them, and the complete table, containing all the input-energy line items.  (The complete table is interesting.)

Thus, the table shows:

• P&P say it takes 21% more energy to make a gallon of ethanol than you get burning it. 
• The USDA claims the opposite:  25% to 40%  less energy. 

Pimentel and Patzek's assumptions make more sense to me than do the USDA's.  Therefore, I tend to agree with their conclusions:  it costs more energy to make a gallon of ethanol that you get burning it.  But, there you have it:  you decide.

Speaking to the larger picture, Pimentel points out that ethanol production and use "contribute to air, water and soil pollution and global warming.  Its production requires "large fossil energy input", and, therefore, contributes to "oil and natural gas imports and U.S. deficits." 

Besides, ethanol production cannot free us from using oil, even if we converted every grain of corn that we now produce to ethanol.  Currently, the U.S. produces 4.5 billion gallons of ethanol per year, which is only 1% of the total U.S. petroleum fuel used per year.  It takes 18% of the US corn production to produce this much ethanol.  If 100% of the US corn were used, it would replace only 6% of petroleum fuel the US currently uses. 

"Will this make the US oil independent?"  questions Pimentel.

Admittedly, it makes sense to reduce our dependence on oil for political reasons, if no other.  Also, we deplete fossil fuels at a vastly greater pace than nature replaces them.  One day, we will run out.

To convert from using fossil fuels, Pimentel favors producing electrical energy instead from photovoltaic cells (solar energy) and wind power, as well as burning biomass to heat buildings, and converting hydrogen to fuel.  Patzek seconds these ideas, but believes solar-cell technology is still "too immature" for use in large power stations.  He votes for nuclear power plants as the lesser evil, when compared with coal-fired plants.

Further Reading:

Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower by David Pimentel and Tad W. Patzek, Natural Resources Research, March 2005
http://www.springerlink.com/(0pcpvv55v5xymx451hbjiezs)/app/home/contribution.asp?referrer=parent&backto=issue,6,6;journal,5,49;linkingpublicationresults,1:105547,1

Producing ethanol from corn is not worth the energy (Pimentel, Patzek) by Susan S. Lang, Cornell University News Service

The net energy value of corn ethanol: is it positive or negative?, MathPro Inc., a paper, based on studies for the California Energy Commission, the Arizona Department of Environmental Quality, the US Environmental Protection Agency, the American Petroleum Institute, and several oil companies.

The energy balance of corn ethanol: an update by Hosein Shapouri, James A. Duffield and Michael Wang, the US Department of Agriculture

Comparison of fuel energy content, US Department of Energy

Ethanol and your vehicle, National Corn Growers Association

Ethanol, Wikipedia

Monthly Bonus Question with Readers' Answers:

Q:  Can fish still see when they are sleeping since they don't have eyelids? First-grade classroom in Southern California

A:  When fish sleep, they just "blank their minds, and do what we might call daydreaming" but they still are "alert for danger" while sleeping, says NOAA's National Marine Fisheries Service.  So, in a sense, they see while they sleep. 

Also, it's true most fish don't have eyelids, except for sharks, which do but, strangely enough, don't use them, at least the outer ones.  "Sharks don't blink," says the San Diego Natural Museum.  Their eyes have eyelids (upper, lower and inner) but the outer ones don't close; some sharks close the inner ones to protect their eyes when biting prey.  

A couple of European sea bass, which, like most fish, have no eyelids. Photo courtesy of Georges Jansoone and Wikipedia

Biologist David Graham was perhaps the first to observe sleeping fish responding to a flash of bright light, and, therefore, see.  Graham was working at the Portobello Marine Laboratory in the 1930s, when he saw a large Spotty (Notolabrus celidotus) asleep standing on its tail.  "For upwards of an hour," he relates, "I watched him one night, and he never moved until I switched on the electric light.  What happened?  The Spotty almost flung himself into a horizontal position, and swam rapidly around the tank as though alarmed at being 'caught napping'."

Readers' Answers:

•   As I understand it, fish don't sleep the same way we do. Instead, they have periods of low activity, including low brain activity.
     I'm guessing that 'seeing' is actually done with the brain rather than the eyes. The eyes just gather information. So, if the brain isn't in a state conducive to seeing (asleep, for instance), then it simply won't process signals from the eyes. Therefore, I don't think the fish sees much while asleep.
     But I imagine that, even if fish don't see all that much when they are relaxing, or fish-sleeping, they might  see just a little bit. I say this because if I were a fish, high on my wish list would be the ability to spot predators and react appropriately even while kicking back. I think fish are pretty paranoid about being eaten — even while asleep! Perhaps this is why they don't have eyelids in the first place.
  Paul
  Melbourne, Victoria, Australia

 
• They can see, otherwise they would be easy prey.
  Eli Auster
  Columbus, New Jersey

 

Further Reading:

Do fish sleep?  NOAA's National Marine Fisheries Service

Shark school FAQ, San Diego Natural Museum

Do fish sleep?  University of Otago, Dunedin, New Zealand

A Treasury of New Zealand Fishes by David Graham

(Answered August 1, 2006)

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