2 Answers
Life probably started simple and acquired greater complexity over time. It probably tried to establish itself many times but only succeeded once. But once is enough.
Duplication is not the same as life. Complex chemicals are capable of duplication. Amino acids and protein are not alive, but they duplicate and are a requirement for replication.
Proto-life catalyzes and carries information required for its own existence.
Protocells constructed by complex chemicals evolving from reduced carbon-containing materials precede the formation of true prokaryotic cells.
Prokaryotic cells are older and simpler than eukaryotic cells.
The oldest rocks are about 3.8 bln years old; the oldest fossil prokaryotes are about 3.5 bln years old. The oldest eukaryotic fossils revealing complex cell structure are about 1.5 billion years old. There are no fossils of sophisticated organisms like bacteria from a similar period.
Emerging from a single eukaryotic cell, a single molecule of RNA is able to fold itself into intricate patterns, allowing it to display characteristics of both genotype and phenotype all by itself. DNA and protein, the information storage and the living activity of organic cells, use the RNA to adapt and replicate. An RNA-based organism produces a DNA-based organism.
Adenine, Cytosine, Thiamine and Guanine knit together along strands of amino acids in a string of double helixes that form DNA. As it replicates, it joins other strands of DNA to form genes.
Genes arrange themselves in a sequence called chromosomes. Chromosomes produce amino acids (proteins).
But what stops the fluid of this replication simply leaking away?
How about a wall? A jelly of carbohydrates and proteins encapsulates the chromosomes in a membrane and becomes a cell.
Cells communicate and co-operate. They form themselves into a collective behavior called complex creatures.
Complex creatures eat each other. To eat they must catch and process.
Successful creatures develop their own methods of evasion and predation. Successful methods are replicated by virtue of survival.
If a complex creature is to reproduce, all the component parts must be represented in a single transferable code.
A cell containing the code as carried by DNA, chromosomes and genes invades another cell produced by similar but separate complex creature containing similar but not the same DNA, chromosomes and genes. Both sets of DNA, chromosomes and genes connect in the correct sequence to begin the process of manufacturing the correct cells in the correct order to produce the completed progeny.
Where replication and reproduction are enabled, life is continuous. A single sperm and a single egg are all that it takes to get started.
Thus it is alive if it:-
procreates
shares a common ancestor
is a cell or a collection of cells
contains DNA.
The Magic Helix, the DNA of belief systems, is not alive but it may exist. If it does, it exists somewhere. In physcial DNA is a possibility. Where there is no life, there will be no Magic Helix.
If you've followed me thus far, hang on....But here are two possible choices.
Read on >http://www.magichelix.com/core/sequence/DNA.htm
11 years ago. Rating: 4 | |
DNA is a genetic blueprint applied to living organisms. I would not say that it's a living thing.