test 3 origins of life plearth

Cretaceous-Tertiary (65 mya)

impact: chixalub in mexico, evidence of tusnami deposists, iridium, shocked quarts, spherules (cooled molten), hydrocarbons
volcanism: deccan traps in india, phase 2 is biggest effect (of 3), fern spikes (show extinction)

fern spikes

evidence of an extinction, can survive many condidtions, first to repopulate after extinction

Triassic-Jurassic (200 mya)

CAMP volcanism (central atlantice magmatic province)

End Permian (248 mya)

the WORST, 96% dead
volcanism: siberian traps, black shale
allotrope
impact: fullerenes

black shale

evidence of anoxia in ocean, the ocean in end perimian couldn't break down organic material

fullerenes

cages of carbon where gas gets trapped in them
in End Perm Helium 3 was high rather than natural 4, evidence of astroid bringing H3

Late Devonian (358 mya)

simple things go extincit
impact: siljan impact, datign contriversial
volcanism: viluy traps, 2 pulses, 1st pulse is FF boundary, 2nd pulse matches w extinction pulse

Ordivician-Silurian (443 mya)

caused by glaciation
volcanism: caused by volcanic aerosols
impact: caused by impact aerosols
delta O18 increase, drop of C13

Iridium

levels rarely found in the earth crust, strange high level from KT boundary (Cretaceous), sign of extraterrestrial event

Radiometric dating

calculates how old geological materials are

tektites (spherules)

glasses formed by the impact of meteorites or comets

tsunami deposit

water rips up frock on sea and deposits it

foraminifera

ocean plankton, when die shells become part of rock

δ13C

proxy for max extinction, negative excursion means extinction, plants take c12, so drop means loss of plants

δ18O

proxy for glaciation, increase of O18 in foraminifera means climatic cooling referencing glaciation

Charles Wallcott

discovered burgess shale, tried to classify burgess specimens into existing phyla

Burgess Shale

FILL IN BLANK ANSWER, saw weird organisms, soft tissure

Wiwaxia

Mollusca

Sanctacaris

Arthropoda

Pikaia

Chordata

Marella

Arthropoda

Dinomischus

Ctenophora

Hallucigenia

Ohychophora

Stromatolites

layered mud, cyanobacteria

Cambrian Explosion

appearance of most major animal phyla

Hypothesizied triggers

Oxegyn levels rise, HOX, predation and arms race, empty barrel

Oxygen levels rise

organisms need oxygen to grow large, pre cambrian did not rise bc photosythesis and organic decay balenced, in cambrian the ocean basin geometry changed, rifting continents and erosion from mountains buried organic carbon on seafloor, couldnt cycle, increased oxygen (2nd oxygen even is cambrian not first)

HOX genes

control when and where things develop

Predation and arms race

prey developing defenses against predators, and predators evolving to overcome those defenses

empty barrel

lots of land was available for grabs but then after the first rush, it was difficult to establish for yourself

Formation of Earth

4.6 bya

First Atmosphere

4.4 bya

First Surface Water

4.3 bya

Origin of Life

4.3-3.8 bya

LUCA

4-3.5 bya

Evolution of Photosynthesis

4-3.5 bya

Oldest Fossilis

3.5 bya

First Great Oxidation Event

2.4-2 bya

gravitaional accretion

gas particles and etc came together under gravity

Giant Impact hypothesis

moon formed by collision

moon formation

created magma ocean, vaporized part of earth mantel, made earth liveable

volcanic outgassing

the release of gases into the atmosphere during volcanic eruptions

first atmosphere

hydrogen and helium, by volcanic outgassing

BIFs

sedimentary layers of iron, evidence of early photosynthetic prokaryotes.

Circumstellar Habitable Zone

region around a star in which liquid H2O could exist on the surface of an Earth-like planet

Sources of first water

water-rich asteroids, comets, and potentially even water locked within Earth's rocks

Chirality

mirror, but not the same thing

Homochirality

uniformity of chirality (mirror, but not the same thing)

Miller-Urey

no oxygen, replicated how life came form no life

Cyanobacteria

first organisms to perform photosynthesis, releasing oxygen into the atmosphere and enabling the evolution of oxygen

First Great Oxidation event

introduced oxygen to atmosphere

Ozone layer

protect from UV