Lecture 7: History of Life on Earth

What is the Oparin-Haldane Hypothesis?

Created the thought how life could be created to be exact “simple organic compounds could have formed inorganic compounds in earth atmosphere”

What is the 4 main stages of origin?

Synthesis of simple organic molecules, synthesis of macromolecules, formation of protocells, and origin of self replicating mechanisms

What is the Hadean Eon

Occurred in 4.6 - 4 BYA

What is the Archean Eon

Occurred in 4.0 - 2.5 BYA. The first evidence of life the stromatolites

What is the Proterozoic Eon

2.5 BYA - 542 MYA. atmospheric oxygen levels rise due to photosynthetic bacteria and the ride of soft bodied multicellular eukaryotic organisms

What is the endosymbiotic theory?

Describes how nuclear envelope in the membrane bound organelles form ancestral prokaryotic cell membrane inwards and that the mitochondria and chloroplast are derived from two different bacteria. The mitochondria came before the chloroplast

Who proposed the endosymbiotic theory?

Lynn Margulis

What is the phanerozoic eon?

Occurred 542 MYA - Present. Eon of visible animals

What are the three eras in the phanerozoic eon?

Paleozoic, Mesozoic, and Cenozoic

When did the Paleozoic Era occurred?

542 - 251 MYA

When did the Mesozoic Era occurred?

251 - 65.5 MYA

When did the Cenozoic Era occurred?

65.5 MYA - present

What occurred in the Cambrian Period?

The Cambrian explosion occurred which was the huge increase of diversity and disparity of animals

What occurred in the Ordovician period?

The origin of ostracoderms

What occurred in the Silvirian Period?

Rise of jawless freshwater fishes

What occurred in the Devonian Period?

The age of fish, origin of placoderms, and origin of bone fishes

What occurred in the Carboniferous Period?

Diversification of boney fish and formation of polar ice gaps/glaciers

What occurred in the Permian Period?

Mollusca diversity increased and formation of continents due to sea levels dropping

/What is the Permian/Triassic Mass Extinction?

One of the mass extinctions and eliminated almost everyone on earth due to increased volcanic activity and methane producing bacteria

What occurred in the Triassic Period?

Origin of dinosaurs and small animals

What occurred in the Jurassic Period?

The diversification of dinosaurs

What occurred in the Cretaceous Period?

The diversification of dinosaurs, the origin of flowering plants, and living insects appear

What is the Cretaceous/Paleogene Mass Extinction?

The second largest mass extinction, killed 80 percent of species, and could’ve been caused by an asteroid

What occurred in the Paleogene Period?

Mammal disparity increases and all surviving species diversify

What occurred in the Neogene Period?

Homins appear

What occurred in the Quaternary Period?

Humans appear

What is the order of the periods?

Cambrian → Ordovician → Silurian → Devonian → Carboniferous → Permian → Triassic → Jurassic → Cretaceous → Paleogene → Neogene → Quaternary

What is diversity?

number of different species

What is disparity?

number of body plans