Origin Of Multicellular Life Essay

Origin Of Multicellular Life Essay-76
The evolution of a membrane surrounding the genetic material provided two huge advantages: the products of the genetic material could be kept close by and the internal environment of this proto-cell could be different than the external environment.Cell membranes must have been so advantageous that these encased replicators quickly out-competed "naked" replicators.Researchers who also contributed to this work include Alan Kuo, Uffe Hellsten, Jarrod Chapman, Astrid Terry, Jasmyn Pangilinan, Asaf Salamov, Harris Shapiro, Erika Lindquist, Susan Lucas, Igor V Grigoriev, Harris Shapiro and Daniel S. Miller at the University of Maryland, Baltimore, Ichiro Nishii at the Nara Women's University in Nara-shi, Japan, Lillian K.

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Experiments suggest that organic molecules could have been synthesized in the atmosphere of early Earth and rained down into the oceans.

RNA and DNA molecules — the genetic material for all life — are just long chains of simple nucleotides.

Replicating molecules evolved and began to undergo natural selection.

All living things reproduce, copying their genetic material and passing it on to their offspring.

-like ancestor within the last 200 million years, making the two living organisms an appealing model to study the evolutionary changes that brought about multicellularity and cellular differentiation.

To gather data for the comparative genomic analysis, the researchers sequenced the 138 million base pair and the sequence divergence between the two is comparable to that between human and chicken.Self-replication opened the door for natural selection.Once a self-replicating molecule formed, some variants of these early replicators would have done a better job of copying themselves than others, producing more "offspring." These super-replicators would have become more common — that is, until one of them was accidentally built in a way that allowed it to be a super-super-replicator — and then, that variant would take over.Through this process of continuous natural selection, small changes in replicating molecules eventually accumulated until a stable, efficient replicating system evolved.Replicating molecules became enclosed within a cell membrane.One of the most pivotal steps in evolution -- the transition from unicellular to multicellular organisms -- may not have required as much retooling as commonly believed, scientists have found.A comparison of the genomes of the multicellular algae Volvox carteri and its closest unicellular relative Chlamydomonas reinhardtii revealed that multicellular organisms may have been able to build their more complex molecular machinery largely from the same list of parts that was already available to their unicellular ancestors.Thus, the ability to copy the molecules that encode genetic information is a key step in the origin of life — without it, life could not exist.This ability probably first evolved in the form of an RNA self-replicator — an RNA molecule that could copy itself. Living things (even ancient organisms like bacteria) are enormously complex.However, all this complexity did not leap fully-formed from the primordial soup.


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