29 NOV 2013 by ideonexus
The Origin of Life from Molecules
The account of the origin of life that I shall give is necessarily speculative;
by definition, nobody was around to see what happened. There are a
number of rival theories, but they all have certain features in common.
The simplified account I shall give is probably not too far from the truth.
We do not know what chemical raw materials were abundant on earth
before the coming of life, but among the plausible possibilities are water,
carbon dioxide, methane, and ammonia: all simple compounds ... 1 
notes
notesHighlights from Dawkin's description of how molecules evolved through natural selection to eventually form life.
29 NOV 2013 by ideonexus
Survival of the Stable
Darwin's 'survival of the fittest' is really a special case of a more general
law of survival of the stable. The universe is populated by stable things.
A stable thing is a collection of atoms that is permanent enough or
common enough to deserve a name. It may be a unique collection of
atoms, such as the Matterhorn, that lasts long enough to be worth
naming. Or it may be a class of entities, such as rain drops, that come
into existence at a sufficiently high rate to deserve a collective name,... 1 notes
notesOne of the characteristics of a successful species is stability.
04 JAN 2012 by ideonexus
Organic Chemists Merely Increase the Probability of Results
It is, I believe, justifiable to make the generalization that anything an organic chemist can synthesize can be made without him. All he does is increase the probability that given reactions will 'go.' So it is quite reasonable to assume that given sufficient time and proper conditions, nucleotides, amino acids, proteins, and nucleic acids will arise by reactions that, though less probable, are as inevitable as those by which the organic chemist fulfills his predictions. So why not self-dupli... 1 notes
notesIn nature, with enough time and proper conditions, the results would happen eventually without him, including self-duplicating molecular systems like viruses.
01 JAN 2012 by ideonexus
We Have Announced Our Presence to the Stars
There are those who predict a dire catastrophe if we broadcast our presence to
another star. The extraterrestrials will come and – eat us, or something equally
unpleasant. (Actually, if we are especially tasty, they need only sample one of us,
determine what sequence of our amino acids makes us appetizing, and then
reconstruct the relevant proteins on their own planet. The high freightage makes
us economically, if not gastronomically, unappetizing.) The message aboard Pioneer
10 was critici... 1 notes
notesJazz-band radio broadcasts are our first emissaries into space, now nearly 100 light years out.
21 SEP 2011 by ideonexus
1.5 Percent Gene Difference Translates to Thousands of Pr...
But recent work shows that our genetic resemblance to our evolutionary
cousins is not quite as close as we thought. Consider this. A
1.5 percent difference in protein sequence means that when we line up
the same protein (say, hemoglobin) of humans and chimps, on average
we’ll see a difference at just one out of every 100 amino acids. But
proteins are typically composed of several hundred amino acids. So a
1.5 percent difference in a protein 300 amino acids long translates into
about four di... 1 notes
notesThe analogy is made that if you change 1 percent of the words you change much more than 1 percent of the sentences, and the same applies to the genetic drift between humans and chimps.
29 JUN 2011 by ideonexus
Cross-Species Milk
Our notions of mother's milk come from what we see, and for most of us the milk we see is cow's milk, a brilliant white liquid. But milk from other species looks quite different—kangaroo milk, for example, is pink. But whatever the hue, breast milk is species-specific; that is, the composition is finely tuned to the particular growth and maturational needs and digestive system of the young of each species.^ ^ For example, cow's milk is higher in volatile fatty acids than human milk, and hum... 1 notes
notesA comparison of the milk produced by females of various species, its nutritional content, and what that tells us about their lifestyle.
09 JUN 2011 by ideonexus
The Uselessness of Nitrogen in the Atmosphere
My 165-pound body consists of about 110 pounds of oxygen, 30 pounds of carbon, 16 pounds of hydrogen, 6 pounds of nitrogen, and 3 pounds of everything else. Basic stuff, mostly, the stuff of water and air. You'd think we could get almost everything we need to build our bodies by taking deep breaths and gulps of water. But it's not quite that simple. Consider those 6 pounds of nitrogen in my body. Our cells build proteins by stringing together chemical units called amino acids, and every amino... 1 notes
notesRaymo describes how many pounds of each element there are in his body, and why, despite them mostly all existing in the air we breath, they are bound up in molecules so that we cannot access them.
