Plearth Test 3 - Mass Extinctions, Cambrian Explosion, & Precambrian Geobiology

What are the 'Big Five' mass extinctions?

Cretaceous-Tertiary, Triassic-Jurassic, Permian-Triassic, Late Devonian, Ordovician-Silurian

What is radiometric dating?

Determining age of rocks using decay of radioactive isotopes

What is the Chicxulub impact crater?

Impact site of asteroid that caused K-T extinction

What is the Cretaceous-Tertiary (KT) Boundary?

Geological boundary marking end of Cretaceous period

What is iridium?

Element found in high concentrations in K-T boundary layer

What is shocked quartz?

Quartz with unique microscopic features from impact events

What are tektites?

Small glassy objects formed from impact events

What is a tsunami deposit?

Sediment layer deposited by a tsunami

What are foraminifera?

Single-celled organisms with shells used for biostratigraphy

What is a fern spike?

Increase in fern spores in rock layers after mass extinction events

What are the Deccan Traps?

Large volcanic province in India

δ13C data

Measure of carbon isotope ratios used to study past life existence

What is the Central Atlantic Magmatic Province (CAMP)?

Large volcanic province in eastern North America and North Africa

What are the Siberian Traps?

Large volcanic province in Russia

What are zircons?

Minerals used for radiometric dating and studying geological processes

What is the Permo-Triassic (PT) Boundary?

Geological boundary marking end of Permian period and start of Triassic period

What are fullerenes?

Molecules used to study past impact events

What is the Siljan Impact Crater?

Impact site in Sweden

What are the Viluy Traps?

Large volcanic province in Russia

What is Late-Ordovician Glaciation?

Global cooling event during the Late Ordovician period

What is δ18O data?

Measure of oxygen isotope ratios used to study past climate change

Who is Charles Walcott?

Paleontologist who discovered Burgess Shale

What is the Burgess Shale?

Fossil deposit in Canada with exceptional preservation

What is Wiwaxia?

An extinct marine animal with a hard exoskeleton

What is Sanctacaris?

An extinct marine animal with a soft body and spiny limbs

What is Pikaia?

An extinct marine animal with a notochord, possibly a chordate ancestor

What is Hallucigenia?

An extinct marine animal with spines and tentacles

What is Dinomischus?

An extinct marine animal with a hard exoskeleton and feeding appendages

What is Marella?

An extinct marine animal with a hard exoskeleton and large eyes

What is Anomalocaris?

An extinct marine predator with a segmented body and large appendages

What are stromatolites?

Rock-like structures formed by ancient microbial communities

What is the Cambrian Explosion?

Rapid diversification of life during the Cambrian period

What is the 'empty barrel' hypothesis?

Hypothesis that the Cambrian Explosion was due to a lack of fossil evidence from earlier periods

What are HOX genes?

Genes that control the development of body plans in animals

What is the predation and arms race hypothesis?

Hypothesis that the Cambrian Explosion was driven by the evolution of predator-prey relationships

What is the age of the Earth?

4.5 bya

When did the first atmosphere form?

4.4 bya

When did the first surface water form?

4.3 bya

When did the origin of life occur?

4.3-3.8 bya

What is the Last Universal Common Ancestor?

4-3.5 bya

When did the evolution of photosynthesis occur?

4-3.5 bya

When were the oldest known fossils found?

3.5 bya

When did the first Great Oxidation Event occur?

2.4-2 bya

What is gravitational accretion?

Formation of Earth by gravity

What is the Giant Impact Hypothesis?

Moon formed from impact

Why is the Moon formation important?

Stabilizes Earth's rotation

What is volcanic outgassing?

Release of gases from volcanoes

What is the composition of the first atmosphere?

H2O, CO2, N2, CH4

What are Banded Iron Formations (BIFs)?

Layers of iron-rich rock

What is the Circumstellar Habitable Zone?

Distance from star for liquid water

What are the sources of the first surface water?

Comets, asteroids, degassing

What is Chirality and Homochirality?

Molecules with handedness

What is the Miller-Urey Experiment?

Simulated early Earth conditions

What are the stages of the origin of life?

Abiotic synthesis, self-replication, metabolism

What are the possible locations for the origin of life?

Hydrothermal vents, tidal pools, clay

What is the possible role of rocks/minerals in the origin of life?

Catalysts, templates, energy sources

What are Cyanobacteria?

Photosynthetic bacteria

What is the cause and result of the first Great Oxidation Event?

Photosynthesis, oxygenation, ozone layer