Small-Brained Fish Make More Babies

Guppies with experimentally shrunken brains produced more offspring than guppies bred for larger noggins, confirming a long suspected tradeoff of bigger brains.

By | July 12, 2012

Rchampagne" > A guppieWikimedia commons, Rchampagne

Since the 19th century, researchers have noticed that animals with large brains had survival advantages in complex environments, but also appeared to have fewer offspring. To test whether the two observations were causally linked, researchers from Uppsala University in Sweden bred guppies and selected for those that either had small brains or large ones. They tested the abilities of the fish on learning tests and found that, not surprisingly, the larger-brained fish did better.

But there was also a downside of the big brains: the fish produced fewer offspring. Small-brained fish produced an average of seven offspring, while large-brained fish had an average of six, the researchers reported at the Evolution Ottawa meeting on Tuesday (July 10).

"This is a real experimental result," David Reznick, an evolutionary biologist at the University of California who was not involved in the study, told ScienceNOW. "The earlier results were just correlations."

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July 12, 2012

Apparently holds for Homo Sapien(s), too

Avatar of: susannrautenberg


Posts: 1

July 12, 2012

Kann es sein, dass hier eine größere Anzahl die geringere Intelligenz bezüglich des Populationserhalts (vorübergehend/teilweise) kompensiert? Wäre evtl. vergleichbar mit R- und K-Strategen, nur auf anderer Basis.

Avatar of: Dov


Posts: 1457

July 13, 2012

I grow variouis fruits.
The brainless fruit plant grows a tremendous number of fruits, of which a very small fraction survives to maturity, of which a very very small fraction becomes naturally a fruit bearing plant...

Dov Henis (comments from 22nd century)

Avatar of: dovhenis


Posts: 97

July 14, 2012

On Brain And Natural Selection
July 14, 2012
On Brain And Natural SelectionA.…“exper... manipulate brain size, you get cleverer fishâ€쳌.“Experimentally manipulateâ€쳌 is Pavlov. Pavlov experimentally manipulated dogs’ genes. Manipulating creatures is manipulating their genes by manipulating their culture, which modifies their genes’ expressions since genetics is the progeny of culture.Genes themselves are oganisms, life’s primal organisms, evolved from modified RNA nucleotides in a cultural-natural selection-reaction to energetic circumstances. THIS IS DARWINIAN EVOLUTION. NATURAL SELECTION IS UBIQUITOUS TO ALL MASS FORMATS. LIFE IS JUST ANOTHER MASS FORMAT.B.I grow various fruits. Fruit trees are brainless, mindless, of low intelligence i.e. low capacity to learn from experience.A fruit tree sprouts, starts producing, a great number of fruits, of which only a small fraction complete their growth, of which in nature only few if any at all evolve into a fruit tree to reproduce the fruit-tree genes. This is the genes reproduction mode of the mindless creatures…Look around you at other creatures including humans and draw your own conclusion…Dov Henis (comments from 22nd century)

July 23, 2012

Agreed about the comment below that it applies to Homo Sapiens too  :)  

Therefore the majority of the future generations will always be more dumb

Avatar of: Padraig Hogan

Padraig Hogan

Posts: 5

July 23, 2012

I find the word "dumb" to be offensive and pejorative. There is nothing wrong with people who are less intelligent. The world is headed in a bad direction today because of people with more brains than sense. 

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