How Life Began - Origins - PBS Nova

[mobbob2244]

i think the planet that hit earth is call thee

[sbergman27]

44:00 CO₂ keeps getting portrayed as "noxious" & O₂ as "good". In fact O₂ is a deadly poison to life forms not specially equipped to protect themselves from it, as we are. Cyanobacteria treat it as a nasty waste product. But O₂'s reactivity makes it a convenient reactant for generating energy. O₂-using organisms evolved sophisticated protections simultaneously with the ability to make use of it. Those protections are not perfect. And oxidative damage is still a problem for us today.

[sbergman27]

22:45 That crater in Arizona was is a natural wonder which should belong to the American People. However in 1903 a mining engineer, Daniel Barringer, staked a mining claim to it & received a patent (Yes, a patent.) on the crater. Today, the crater is owned by his family, & is a commercialized profit-circus similar to Royal Gorge in Colorado. I visited, but when I realized the situation, refused to pay admission & left. I'm happy & proud pay admission to a National Park. But not to Meteor Crater.

[JjjeeesssBbb]

Great show, very well put together. I'd rather watch these documentaries than ordinary TV

[dHotdogStand]

Neil sounds boring when narrating. I'd rather hear him lecturing. He's very lively during his lectures.

[BrunoHP89IT]

Watch out we are dealing with a MEME over here =)

[MrDBarch]

I often wonder if gender, which seems to be really interesting and universal in life, had anything to do with the creation of life itself. Were there male chemicals and female chemicals which eventually coalesced to form life itself?

[icculus574]

@MrDBarch Gender is not universal in life. There are scores of asexual animals -- although the majority of them are microscopic. Gender is a very advantageous trait though because it allows greater genetic variation(per generation) compared to asexual species.

There is a chemistry concept called 'chirality' in which there are two possible configurations for each amino acid known as 'left' and 'right' handed versions, but life exclusively uses the left-handed variation.

[sbergman27]

@icculus574 "Gender is not universal in life. There are scores of asexual animals"

And sexual reproduction is not necessarily limited to just 2 sexes. Some species have more. And some are switch-hitters.

[MrDBarch]

Life is the presence of growth. combine material elements such as carbon, hydrogen etc, with non material elements such as electricity and heat, atmospheric pressure and you end up with the recipe for life. how this recipe is combined is the million dollar question. asking the right question will surely render the correct answer! I think the secret is right in front of us, it's all about sex, and gender. most life comes in male and female and arises from a combination of genders..chemical sex?

[Thief8Bit]

I love this show. I may not agree 100% about the Origin of man with some people, but I recognize that science has helped us understand the process of our development.

[sbergman27]

@Thief8Bit "I may not agree 100% about the Origin of man"

In a world where cross-species comparisons of genomes is quite routine, & personal genome analysis is affordable even to middle class individuals, the constraints for "disagreeing" with the trail clearly documented in the data are tight indeed. Pretty much limited to the <1% of genes which differ between the human/chimp common ancestor. We've come a *long* way from depending upon fossils. A good presentation is here:

/watch?v=uEP7Z55Z6nM

[Thief8Bit]

@sbergman27 Dude, you could have saved yourself a lot of finger strain by just saying "I agree/disagree" or "That's a valid/invalid point", because you lost me at genome analysis. That's difficult to admit, having an IQ like I have.

[sbergman27]

@Thief8Bit Sorry. It's YT's 500 char limit.

Individual gene sequences can be tracked along the branches of the evolutionary tree. Even sequences of Junk DNA. So chains can be uncovered documenting the relationships of species (current & extinct) along individual branches of the tree. Our Genus, Homo, is firmly attached to the rest of the tree, & our closest relative is the Chimpanze, with whom we share 98+% of our genes. This leaves very little room for disagreement regarding the origin of man.