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C O U R S E L E C T U R E Speculations on How Life Emerged on Earth Notes taken on January 3, 2017 by Edward Tanguay |
how could all of this complex life have emerged from far more simple chemicals
a lot of room for speculation
what we have is speculation based on some empirical evidence
current hypotheses for the emergence of life
it happened a long time ago
1. panspermia hypothesis
it might have arrived from outside the earth
2. spontaneous generation
it might have happened here on the planet
agrobacterium tumefaciens
infect plants with cancer
e.g. the bacterium is regulating the tree, instead of the tree doing what it wants to do for itself, it serves the bacterium
the genetic material of the bacterium can change what a tree does
therefore the genetics must be very similar, otherwise this would not work
it points to similar biochemistry
points to a common ancestor
the building blocks of a banana are similar to that of humans
if you try to eat a rock, you can't digest it
tracing a common ancestor
points to a common ancestor about 3.5 billion years ago
tiny bacterial sitting on rocks
between DNA and proteins
like the Swiss Army knife of the body
stands for Ribonucleic acid, which is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes.
RNA and DNA are nucleic acids, and, along with proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life
RNA differs from DNA in three ways
RNA is single-stranded instead of double-stranded
RNA contains ribose, DNA contains deoxyribose
the complementary base to adenine in DNA is thymine, whereas in RNA, it is uracil
you find these three conditions in liquid water and clay