Biochemical Evolution

Ibarra JonatanhOuředničková Veronika

Faculty of chemistry, Brno University of Technology

Vocabulary

EN CZ EN CZAcquire Získat Enabling Umožnující

Pass on Předat Response Odezva

Traits Vlastnosti Requiring Požadující

Diversity Rozmanitost Allow Dovolit

Vast Obrovský Remarkably Pozoruhodně

Rate Poměr Ancestor Předek

Increasingly Zvýšeně Paths Cesty

Biological Evolution

The process by which populations of organisms acquire and pass on novel traits from generation to generation. Its action over large stretches of time explains the origin of new species and ultimately the vast diversity of the biological world.

Biochemical Evolution

Chemosynthesis: hypothesis to explain how life might possibly have developed from non-life.

Three stages:

1st Stage of Evolution

The initial generation of some of key molecules of life (nucleic acids, proteins, carbohydrates, lipids) by non-biological processes.

The prebiotic world. Urey-Miller experiment

1st Stage of Evolution The Earth´s early atmosphere

was probably highly reduced, rich in CH4, NH3, H2O, H2 + large amounts of solar radiation and lightning. Urey-Miller experiment (1950).

Prebiotic „lake“ – cold (under 0°C; clays); polymer synthesis rate must be higher than their hydrolysis (slow at low temperature).

2nd Stage of Evolution

The transition from prebiotic chemistry to replicating systems; with the passage of time, these systems became increasingly sophisticated, enabling the formation of living cells; membrane formation.

Formation of replicating molecules, variation and selective pressure = beginning of evolution.

2nd Stage of Evolution

RNA – an early replicating molecule; some RNA molecules possess catalytic activity, this was transferred to proteins

RNA directed the synthesis of proteins and still does in modern organisms through the development of a genetic code.

RNA lost its role as the gene to the chemically similar but more stable DNA

Evolution of membranes (hydrophobic barriers) – first unicellular organisms.

3rd Stage of Evolution

The biological evolution; energy-conversion processes (photosynthesis) and pathways for synthesizing the components of biopolymers from simpler molecules; evolution of unicellular organisms; colonies; differentiation and formation of multicellular organisms; response to environmental changes

3rd Stage of Evolution

The final transition was the evolution of sensing and signaling mechanisms that enabled a cell to respond to changes in its environment; cell-cell communication allowed the development of more-complex organisms.

Evolutionary tree – “the tree of life”

Organisms are remarkably uniform at the molecular level.

Uniformity life have come into existence only once (Darwin).

Evolutionary tree – “the tree of life”

This uniformity reveals that all organisms on Earth have arisen from a common ancestor (bacteria are no direct ancestors of higher organisms)

Evolutionary paths from a common ancestor to modern organisms can be developed and analyzed on the basis of biochemical information

Thank you for your attention