Evolution and Diversity Flashcards
Microbes
often single celled organism from the three domains from life
-not always single celled
RNA world hypothesis
within the environmen some stable compartments with high concentrations of organic building blocks
-RNA bases paired with each other to go through and continue replicating RNA
-Some evolutionary forces kicked in such as improved replication, simple functions (stability, binding other molecules) and more complex functions (enzymes)
flow chart of RNA world hypothesis
evidence of RNA world hypothesis
-RNA can form intricate stable strcutres that can bind and carry out wide range of chemical reactions
-Protein are still made today using RNA components
-Many apparent relics from the RNA world (ribozymes and riboswitches, ribsosomes)
LUCA
-last universal common ancestor
-dont know what it was
-presumed features include DNA replication, transcription translation and cell division
-ATP served as energy itermediate,
-lipid bilayer membrane
-anaerobic metabolism using H2 as energy and CO2 as carbon
-limited number of genes in all modern organisms are all or presumably from LUCA
chemotroph
derive energy from releasing bond energy from chemical compounds
phototroph
-absorbs light and transforms it into chemical energy
what was the earth for the first 2 billion years
anoxic
what gave rise to ocygen in the atomosphere
-cyanobacteria producing oxygen as a waste product through oxygenic photosynthesis
what gave rise to aerobic organisms
-oxygen as a great electron acceptor
-efficient energy production using ocygen and made it more complex (beneficial)
endosymbiont theory
-eukarya lineage evolved from an arhea like ancestor that engulfed an aerobic respiring bacterium (phylum alphaproteobacteria)
-became an endosymbiont and ultimately mitochondria for efficient energy production
-transferred many bacterial genes into host organism
-plants emerged as a second event, when photosynthetic bacterium (cyanobacterium) became basis for chloroplast
endosymbiont theory diagram
evidence of endosymbiotic theory
-dna replication, transciption and translation machinery of eukaryotes more similar to archea than bacteria
-mitochondria and chloroplasts have their own genomes, ribosomes and tRNA
-mitochondria and chloroplastsa machinery are bacterial
is earth mostly microbial
yes, for most of earths history is has been a microbial planet
-despite their small size, mirobes make up a significant amount of biomass on earth
communities of microbes
-microbes live in complex and competitive communities
-microbial interactions take all life forms
-communiities can evolve quickly and fierce battles over nutrients
-competition drives evolution and diversity
