BIO 265 Lecture 12

Oparin Haldane hypothesis

Life arose gradually from inorganic molecules, with 'building blocks' like amino acids forming first and then combining to make complex polymers.

Miller-Urey experiment

Provided the first evidence that organic molecules needed for life could be formed from inorganic components.

RNA world hypothesis

States that the first life was self-replicating RNA.

Strata

Sedimentary layers; can be distinguished using distinctive fossil taxa.

Radiometric dating

A method of dating ancient rock layers by measuring decay of certain radioactive elements.

Endosymbiosis theory

Some of the organelles found in eukaryotic cells (e.g., mitochondria) were once free-living prokaryotic microbes.

Cambrian explosion

A relatively short evolutionary event, beginning around 542 million years ago in the Cambrian period, during which most major animal phyla appeared, as indicated by the fossil record.

Diapsids

Vertebrates with 2 temporal fenestrae (e.g., dinosaurs, birds, lizards, crocodilians).

Synapsids

Vertebrates with a single temporal fenestra (e.g., mammals).

Refugia

Areas with isolated populations that were formerly broadly distributed.

The six major evolutionary transitions

1) Separate replicators (genes) and formation of cell membranes → genome within cell; 2) Separate unicells → symbiotic unicells; 3) Asexual unicells → sexual unicells; 4) Unicells → multicellular organism; 5) Multicellular organisms → eusocial societies; 6) Separate species → interspecies mutualistic associations.