Shermer, Aliens and Convergent Evolution

A response to the idea, voiced by Michael Shermer, that if aliens existed, they would not resemble earth life. While I don't know (or think we ever will know) if alien life exists, I think that if it does, it's much more likely to resemble the flora and fauna of earth than Michael Shermer supposes.

Video I'm responding to can be found here: http://www.youtube.com/watch?v=JKAXrmkx12g

Category:

Science & Technology

Tags:

• Michael
• Shermer
• evolution
• biology
• physics
• life
• convergent
• science
• laws
• of
• nature
• convergence
• marsupial
• placental
• shark
• dolphins
• dorsal
• fins
• Australia
• ecological
• niche
• Darwin
• form
• morphology
• alien
• extraterrestrial
• speed
• light
• yt:stretch=16:9

[FlowCell]

Earth-like planets will produce earth-like animals, I agree, but what about planets that are similar to Earth to support life, but have different problems to overcome? I would guess that the less a planet is like Earth, the less its animals will look like ours.

[tumbleweedjoe]

@FlowCell Much evidence suggests that conditions for life are also extremely narrow and specific. See Peter Ward and Michael Denton on this. Basically, any planet that has life is likely to be earth-like.

[stuchly1]

@stuchly1 and was on this tiny piece of rock is the only way it can EVER happen?

[stuchly1]

@stuchly1 chance of different appearance. A multicellular colony on an alien planet would bear a far stronger resemblance to a multicellular colony on earth than lets say "dominant macrofauna" of those worlds, and even though the cells could have been similar on the outside, the duplication and all the stuff going on inside it could well work very differently to what we know, or it would be achieved differently, by an entirely different process not found on earth. How do you know that what is

[stuchly1]

@stuchly1 arboreal alien would have long limbs, that an aquatic alien would be streamlined, that an aerial alien would have wings, that a terrestrial alien could well have legs to support its weight... but the shape, number and ancestry of all these structures could well be nothing like anything on earth. I know you're not suggesting we'd find mammals out there, but as far as similarities would go, the differences would've overweighted them. Also, the more complex the lifeform, the greater the

[stuchly1]

@stuchly1 Silicon life is pretyy much plausible, as far as scientists think. Is this out of question just because there is carbon-based life on earth? and would you consider a silicon-based lifeform earth-like? and is it even possible for a silicon-based lifeform to come even remotely close to earth's life because of the fundamentally different chemistry? Your assumptions would only work for carbon-based life, and even then it would be like spinning a coin. Don't get me wrong, I agree that an

[stuchly1]

@stuchly1 have a completely different genetic heritage than earth's life, and this could might well lead to solutions that never took place on earth! Do you really think that even though there definitely are limits to how many times you can spin one thing around, but are you really so sure that even earth has exhausted all possibilities there are? also, with a planet slightly closer or farther from the star, there would be different conditions, which would lead to different adaptations.

[stuchly1]

@tumbleweedjoe hmmm... I think not enough is known to draw conclusions, other than that rocky planets with liquid water on their surface are the most likely to support life, but what would the life look like or what you consider earth-like... Some animals on earth converge with others, and some aliens would definitely converge with others, but would aliens converge with earth's animals? I guess they kinda would to some degree, but how high degree of resemblance would there be? The aliens would

[zepherighost]

to a degree u r certainly correct, arms are on many species precisely because they are convenient survival tools, it is that concenience that is important. but life may have other avenues on other worlds because of differences in gravity and ammonia life may be an alternative to water life

[gustjorodedheo]

I think that life would look relatively 'earth-like' given an earth-like planet, and a suitable amount of time to develop, and a carbon-based chemistry. Life would be quite different with silicon based chemistry, which might work for colder planets, like Saturn. As an example of silicon life: molecule structure and genetic code based on silicon, requires ammonia for metabolism instead of water, and methane instead of oxygen.

[rd1999]

great video, I have thought of this myself many times

[DyslexicGamer]

Will know one day.