Exam 3 microbial evolution

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Relate changes in Earth's environment to evolution of life

"Environmental shifts (GOE

Prominent theories of life's origins

"RNA World

Shared characteristics of all living cells

"Genetic material (DNA/RNA)

How viruses influenced evolution

"Viruses drive gene transfer

Order domains of life by separation

"Bacteria first

Mutation & HGT create diversity

"Genetic changes across microenvironments produce vast metabolic and species diversity."

Endosymbiont theory

"Mitochondria/chloroplasts originated from engulfed bacteria; evidence includes double membranes

Genetic changes driving evolution

"Mutation

Features of a useful molecular clock

"Constant mutation rate; universally conserved genes."

Why 16S/18S rRNA are useful

"Highly conserved regions allow alignment; variable regions distinguish taxa."

How molecular phylogeny creates trees

"Sequence comparison → distance matrices → algorithms infer evolutionary relationships."

Why species concept fails for microbes

"Asexual reproduction and HGT blur lineage boundaries."

Alternatives to SSU rRNA analysis

"Whole genome sequencing

Great plate anomaly

"Most microbes don't grow on plates; highlights vast uncultured diversity."

How meta-omics helps study microbes

"Metagenomics

Establishing relationships for uncultured organisms

"Sequence-based phylogeny (16S/18S)

16S rRNA

"Ribosomal RNA gene used for bacterial phylogeny."

18S rRNA

"Ribosomal RNA gene used for eukaryotic phylogeny."

Banded Iron Formation

"Iron oxide layers formed during early oxygenation."

Black Queen Theory

"Gene loss leads to dependency on community functions."

Endosymbiosis

"Origin of organelles from engulfed microbes."

Evolutionary Selection

"Differential survival shaping traits."

Genetic Drift

"Random allele frequency changes."

Genome fingerprinting

"DNA pattern comparison for identification."

Great Oxidation Event

"Rise of atmospheric oxygen ~2.4 Ga."

Great Plate Anomaly

"Mismatch between observed microbes and cultured ones."

LUCA

"Last Universal Common Ancestor."

Metagenomics

"Sequencing all DNA in an environment."

Metatranscriptomics

"Sequencing all RNA transcripts."

Metabolomics

"Profiling metabolites in a system."

Molecular phylogeny

"Evolutionary relationships inferred from sequences."

Molecular Sequencing

"Determining nucleotide order."

Phenotypic phylogeny

"Classification based on observable traits."

Phylogenetic Tree

"Diagram showing evolutionary relationships."

Phylogenetic Species

"Species defined by evolutionary lineage."

Phylogeny

"Evolutionary history of organisms."

Polyphasic Systematics

"Combining phenotypic

rep-PCR

"Repetitive element PCR for strain typing."

Ribotyping

"rRNA gene pattern analysis."

RNA World

"Hypothesis that RNA preceded DNA and proteins."

SSU rRNA

"Small subunit rRNA used for phylogeny."

Subsurface Origin Hypothesis

"Life began in hydrothermal subsurface environments."

Whole genome sequence analysis

"Comparing entire genomes to determine relationships."