PRESENTATION OUTLINE
Evolution aka descent with modification
Evolution consists of changes in the heritable traits of a population of organisms as successive generations replace one another. It is populations of organisms that evolve, not individual organisms.
The phylogenetic position of Methanopyrus kandleri has been difficult to determine because reconstructions of phylogenetic trees based on rRNA sequences have been unclear or inexact because a choice between alternatives has not been made.
Methanopyrus kandleri: an archaeal methanogen
The organism represents a separate lineage originating near the root of the archaeal tree. Although the 16S rRNA sequence of Mp. kandleri resembles euryarchaeal 16S rRNAs more than it does crenarchaeal, it shows more crenarchaeal signature features than any known euryarchaeal rRNA.
1.Certain aspects of M. kandleri biochemistry place this organism aside from other archaea. First, the membrane of M. kandleri consists of a terpenoid lipid, which is considered the most primitive lipid in the evolution of membranes and is the direct ancestor of phytanyl diethers found in the membranes of all other archaea.
2. Another unusual feature of M. kandleri is the high intracellular concentration of a trivalent anion, which has been reported to confer activity and stability at high temperatures on enzymes from this organism .Indeed, enzymes isolated from M. kandleri require high salt concentrations for stability and activity.
, Transcription and translation, provide a largely similar signal for archaeal phylogeny. In particular, our analyses support the appearance of methanogenesis after the divergence of the Thermococcales and a late emergence of aerobic respiration from within methanogenic ancestors. This discuss the possible link between the evolutionary acceleration of the transcription machinery in M. kandleri and several unique features of this archaeon, in particular the absence of a record factor.
Escherichia coli is not fixed. It continues to evolve, and even in the most carefully controlled experiments, evolution leaves behind a complicated history.
Bacteria have existed from very early in the history of life on Earth.
Normally E. coli do not use eat citrate when oxygen is present in the environment they are growing in. After 31,500 generations Lenski, scientist found one culture of E. coli was able to eat citrate when oxygen was present. This has been claimed to be proof that bacteria have evolved a new function and that useful information can be generated by naturalistic processes.
A difference in evolutionary history as the Archaea has evolved is the presence of lipids from 2.7 billion years ago from the start of their existence 3.5 billion years ago. Also Bacteria has evolved throughout their life. They have evolved as they have become resistant to antibiotics .
Also biologists think that it is possible that the last common of both Bacteria and Archaea was a thermophile, which raises the possibility that lower temperatures are "extreme environments" in Archaeal terms and organisms that live in cooler temperature appear later.