The History of Life

By: Devin Tooley, James Costian, Sarai Alonso

Beginnings of Life

Here's what we think happened:

  1. The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases
  2. The joining of these small molecules into macromolecules, such as proteins and nucleic acid
  3. The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings
  4. The origin of self-replicating molecules that eventually made inheritance possible

Early species that came out of this include Dinosaurs.

We believe this based on the experiment done by Miller-Urey, which showed that advanced organic compounds could be made from simpler things and electricity (lightning).


Macro-evolution is the broad pattern of evolution above the species level.

EX: terrestrial vertrbrates

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Earth's history has 2 eons: Archean and then Proterozoic. Fossils give us records of Earth's history, like Stromatolites, the earliest discovered. Based on stromatolites, it's reasonable to believe that unicellular organisms came way before multi-cellular ones. Stromatolites and the history of earth are shown below.

Endosymbiotic Theory

Mitochondria and chloroplasts were separate cells before they became part of cells. This is based on the fact that they are bounded by their own double-membrane, and they have transport systems and organelles with enzymes. They also replicate independently from the rest of cells.
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Plate tectonics

The earth has 4 layers - crust, mantle, outer core, and inner core. The convection in the mantle causes the tectonic plates to move, which changes affects crust, and it causes some weird rock formations. The phenomenon of tectonic plate shifts affecting continents is called continental shift.
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Adaptive Radiation

Evolution causes new species to form and each species has adaptations that allow them to perform specific roles in their environment.

A lot of species that came from adaptive radiation came because of mass extinctions that did not affect specific species - those species found a way to reproduce to make more species with the new, game-changing adaptations.

Developmental Genes

Developmental Genes affect rate, timing, and spatial patterns of developmental genes of changes in an organism's form as it develops into an adult. Hox genes affect the spatial arrangement of things.