Patterns of Evolution

how did life arise

1. small organic molecules were synthesized (monomers of macro-molecules)

2. small molecules →macro-molecules

3. molecules packaged into protocells (membrane-containing droplets)

4. self-replicating molecules allow for inheritance

synthesis of organic compounds on early earth

The process by which simple organic molecules formed from inorganic substances under prebiotic conditions, leading to the formation of more complex molecules essential for life.

ex. h2o vapor, n2, co2, h2, h2s methane, ammonia

fossil record

used to reconstruct history;

1. sedimentary rock

2. mineralized

3. organic (naturally fossilized)

4. incomplete record - destroyed, not found, etc

strata

sedimentary rock layers

relative dating

uses order of rock strata to determine relative age of fossilsrad

radiometric dating

measures decay of radioactive isotopes present in layers where fossils are found

longest to shortest geologic time scale

eon → era → period → epoch

endosymbiont theory

the theory that explains the origin of eukaryotic cells from prokaryotic organisms, suggesting that certain organelles originated as free-living bacteria that were engulfed. (mitochondria and chloroplasts)

mass extinctions

diversity of life, major periods in earth’s history end with mass extinctions and new one begin with adaptive radiations

adaptive radiation

many new species arise from a single common ancestor

1. few organisms make way to new, distant areas (allopatric speciation)

2. environmental change → extinctions →open up new niches for survivors

evo - devo (evolutionary + developmental biology)

evolution of new forms results from changes in dna or regulation of developmental genes

heterochrony

evolutionary change in rate of developmental eventsh

homeotic genes

master regulatory genes determine location and organization of body parts ex. hox genes

evolutionary novelties

ex. eye developed independently in multiple animals