Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Seeing the Serpent [Human Evolution]
University of California, Davis ^ | 19 July 2006 | Staff (press release)

Posted on 07/20/2006 6:58:11 AM PDT by PatrickHenry

The ability to spot venomous snakes may have played a major role in the evolution of monkeys, apes and humans, according to a new hypothesis by Lynne Isbell, professor of anthropology at UC Davis. The work is published in the July issue of the Journal of Human Evolution.

Primates have good vision, enlarged brains, and grasping hands and feet, and use their vision to guide reaching and grasping. Scientists have thought that these characteristics evolved together as early primates used their hands and eyes to grab insects and other small prey, or to handle and examine fruit and other foods.

Isbell suggests instead that primates developed good close-up eyesight to avoid a dangerous predator -- the snake.

"A snake is the only predator you really need to see close up. If it's a long way away it's not dangerous," Isbell said.

Neurological studies by others show that the structure of the brain's visual system does not actually fit with the idea that vision evolved along with reaching and grasping, Isbell said. But the visual system does seem to be well connected to the "fear module," brain structures involved in vigilance, fear and learning.

Fossils and DNA evidence show that snakes were likely the first serious predators of modern mammals, which evolved about 100 million years ago. Fossils of snakes with mouths big enough to eat those mammals appear at about the same time. Other animals that could have eaten our ancestors, such as big cats, and hawks and eagles, evolved much later.

Venomous snakes evolved about 60 million years ago, raising the stakes and forcing primates to get better at detecting them.

"There's an evolutionary arms race between the predators and prey. Primates get better at spotting and avoiding snakes, so the snakes get better at concealment, or more venomous, and the primates respond," Isbell said.

Some primate groups less threatened by snakes show fewer signs of evolutionary pressure to evolve better vision. For example, the lemurs of Madagascar do not have any venomous snakes in their environment, and in evolutionary terms "have stayed where they are," Isbell said. In South America, monkeys arrived millions of years before venomous snakes, and show less specialization in their visual system compared with Old World monkeys and apes, which all have good vision, including color.

Having evolved for one purpose, a good eye for color, detail and movement later became useful for other purposes, such as social interactions in groups.

Isbell is currently working on a book about primate origins, including her snake hypothesis.


TOPICS: Culture/Society; Philosophy
KEYWORDS: atheistsrus; crevolist; dumbtopic; enoughalready; fetish; getsomesleep; giveitarest; godsgravesglyphs; junk; ntsa; onetrickpony; pavlovian; takeavacation
Navigation: use the links below to view more comments.
first 1-2021-4041-6061-80 ... 161-167 next last
Bold and underlinling added by me. Everybody be nice.
1 posted on 07/20/2006 6:58:12 AM PDT by PatrickHenry
[ Post Reply | Private Reply | View Replies]

To: VadeRetro; Junior; longshadow; RadioAstronomer; Doctor Stochastic; js1138; Shryke; RightWhale; ...
Evolution Ping

The List-O-Links
A conservative, pro-evolution science list, now with over 380 names.
See the list's explanation, then FReepmail to be added or dropped.
To assist beginners: But it's "just a theory", Evo-Troll's Toolkit,
and How to argue against a scientific theory.

2 posted on 07/20/2006 6:59:38 AM PDT by PatrickHenry (The Enlightenment gave us individual rights, free enterprise, and the theory of evolution.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry
whatever dude
3 posted on 07/20/2006 6:59:40 AM PDT by keithtoo (The GOP is fortunate that the Dim's are even more spineless and disorganized.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry

"We have nothing to fear but fear itself.....and snakes."


4 posted on 07/20/2006 6:59:41 AM PDT by Doctor Stochastic (Vegetabilisch = chaotisch ist der Charakter der Modernen. - Friedrich Schlegel)
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry

Typical evolutionary mumbo-jumbo. They try to use evolution to explain how primates use their eyes and limbs, to conceal the fact that evolution can't explain how they got eyes and limbs in the first place.


5 posted on 07/20/2006 7:01:21 AM PDT by happyathome
[ Post Reply | Private Reply | To 1 | View Replies]

To: All
Help for new visitors to the evolution debate
Another service of Darwin Central, the conspiracy that cares.

If you're interested in learning about evolution, visit The List-O-Links.
If you'd like to understand the concept of speciation, visit Micro-evolution, Macro-evolution, and Speciation.
If you're serious about debating this issue, see How to argue against a scientific theory.
If you're permanently stuck on stupid, but determined to post anyway, use the Evolution Troll's Toolkit.

6 posted on 07/20/2006 7:03:22 AM PDT by PatrickHenry (The Enlightenment gave us individual rights, free enterprise, and the theory of evolution.)
[ Post Reply | Private Reply | To 5 | View Replies]

To: PatrickHenry
Somewhere, I've read that chimps show an inherent, unlearned fear of snakes. Fits in, if so.
7 posted on 07/20/2006 7:05:39 AM PDT by VadeRetro (Faster than a speeding building; able to leap tall bullets at a single bound!)
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry
"There's an evolutionary arms race between the predators and prey. Primates get better at spotting and avoiding snakes, so the snakes get better at concealment, or more venomous, and the primates respond," Isbell said.

The perfect analogy of Hezbollah, the snake who hides among the Lebanese people to do their savage work……………

8 posted on 07/20/2006 7:06:12 AM PDT by yoe
[ Post Reply | Private Reply | To 1 | View Replies]

To: Doctor Stochastic
"We have nothing to fear but fear itself.....and snakes."

And spiders. They creep me out. Has anybody done a DNA analysis of spiders? Spiders are just so... alien.

9 posted on 07/20/2006 7:07:03 AM PDT by wyattearp (Study! Study! Study! Or BONK, BONK, on the head!)
[ Post Reply | Private Reply | To 4 | View Replies]

To: happyathome
Well, now I have the insider's scoop on science.
10 posted on 07/20/2006 7:07:40 AM PDT by VadeRetro (Faster than a speeding building; able to leap tall bullets at a single bound!)
[ Post Reply | Private Reply | To 5 | View Replies]

To: PatrickHenry

This doesn't look good for the Irish.


11 posted on 07/20/2006 7:08:04 AM PDT by Hoplite
[ Post Reply | Private Reply | To 1 | View Replies]

To: PatrickHenry
For example, the lemurs of Madagascar do not have any venomous snakes in their environment, and in evolutionary terms "have stayed where they are,"

Or, following the theme of this brilliant research, maybe the lemurs evolved such great eyes that the snakes just gave up on the arms race and decided to leave Madagascar altogether. Have you seen the size of those lemur-eyes? Those are "star-wars" eyes, the SDI's of evolution. They need to pay this lady a lot of public loot for this amazing discovery.

12 posted on 07/20/2006 7:11:00 AM PDT by Migraine (...diversity is great (until it happens to you)...)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Hoplite

LOL!


13 posted on 07/20/2006 7:11:22 AM PDT by null and void (It's a crazy world. Someone ought to sell tickets.)
[ Post Reply | Private Reply | To 11 | View Replies]

To: VadeRetro

Evolution is a hypothesis - it is neither proven fact nor universally accepted science. Its flaws and holes have been repeatedly pointed out. Rather than address those flaws and holes, proponents of the hypothesis lump their critics in the category of "uneducated fanatics" and go back to spinning fantastic elaborations of the theory.


14 posted on 07/20/2006 7:12:29 AM PDT by happyathome
[ Post Reply | Private Reply | To 10 | View Replies]

To: happyathome
[E]volution can't explain how they got eyes and limbs in the first place.

What do you mean when you say "evolution?"

15 posted on 07/20/2006 7:12:53 AM PDT by Condorman (Prefer infinitely the company of those seeking the truth to those who believe they have found it.)
[ Post Reply | Private Reply | To 5 | View Replies]

To: PatrickHenry
"I Hate Snakes!"


16 posted on 07/20/2006 7:13:29 AM PDT by Vaquero ("An armed society is a polite society" Robert A. Heinlein(the moon is a harsh mistress))
[ Post Reply | Private Reply | To 1 | View Replies]

To: Doctor Stochastic

On airplanes!


17 posted on 07/20/2006 7:13:40 AM PDT by 7thson (I've got a seat at the big conference table! I'm gonna paint my logo on it!)
[ Post Reply | Private Reply | To 4 | View Replies]

To: happyathome

"Typical evolutionary mumbo-jumbo. They try to use evolution to explain how primates use their eyes and limbs, to conceal the fact that evolution can't explain how they got eyes and limbs in the first place.

"

I see. Well, I'm convinced by your explanation, fer shure.

NOTICE: MineralMan is now a confirmed YEC creationist. Yessir, that's the ticket....


18 posted on 07/20/2006 7:17:09 AM PDT by MineralMan (non-evangelical atheist)
[ Post Reply | Private Reply | To 5 | View Replies]

To: happyathome
Evolutionists addressing supposed flaws and holes in evolution.

Evidence for the theory of evolution.

19 posted on 07/20/2006 7:18:38 AM PDT by hail to the chief (Use your conservatism liberally)
[ Post Reply | Private Reply | To 14 | View Replies]

To: PatrickHenry

Pfft. I'll believe it when a Pikachu evolves wings.


20 posted on 07/20/2006 7:22:11 AM PDT by hail to the chief (Use your conservatism liberally)
[ Post Reply | Private Reply | To 1 | View Replies]


Navigation: use the links below to view more comments.
first 1-2021-4041-6061-80 ... 161-167 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson