Thursday, April 9, 2015

Outstanding problems in the history of life

Gregor Mendel
In a previous article I wrote about the origin of life and related problems. That is only the first of the outstanding issues regarding evolution. There are many more, for we are far from having an explanation for everything that happened during the history of life.
The theory of evolution through natural selection was first proposed by Darwin and refined by his followers when new discovered biological phenomena solved some of the problems posed since the beginning of the theory:
1.      The laws of heredity (Mendel, 1865).
2.      Mutations (Hugo de Vries, 1900).
3.      The laws of genetics (Thomas Hunt Morgan, early twentieth century).
4.      The synthetic theory of evolution (Simpson, Dobzhansky and others, around 1930)
5.      The transmission of inheritance through DNA (Oswald Avery, 1944).
6.      The structure of DNA and the deciphering of the genetic code (Watson, Crick, Rosalind Franklin and others).
7.      The neutral theory of evolution (Motoo Kimura, 1968).
8.      Punctuated equilibrium (Stephen Jay Gould, 1972).
9.      Epigenetics (early twenty first century).
Rosalind Franklin
Currently the theory of evolution can be considered well established. However, it is far from explaining everything. There are still many mysteries. I will mention only a few:
·         How was the genetic code invented? Could it have been different?
·         How did photosynthesis appear?
·         How did cellular organelles enter in symbiosis with eukaryotic cells?
·         How did sexual reproduction arise?
·         Is the concept of species dependent on sex?
·         How is intra-genomic conflict resolved?
·         How and why did multi-cellular organisms arise?
·         How did the spatiotemporal development of multi-cellular beings come to appear?
·         Why are there so many examples of symbiosis?
·         What gave rise to insect societies?
I'll address these issues in subsequent articles, not necessarily all of them or in the same order.

Manuel Alfonseca

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