EarthScience "Geological Time Scale"

Book-based.

Organisms that existed for a short period of time, then went extinct.

Index Fossils

3 criteria of an index fossil

-easily recognizable
-geographically widespread
-lived for only a short time

It shows the sequence of events that happened in the past up to the recent time.

Geological Time Scale

The wide scope of geologic time in the history of the Earth is separated into

Eons > Eras > Periods > Epochs

-First three eons
-Moon's formation
-The first evidence of life
-The filling of ocean basis

Precambrian

-“Rockless eon”
-During this time, the Earth was molten
-Earth’s continental and oceanic crusts began to solidify

Hadean Eon

-Single-celled organisms such as blue green algae, archeans, and bacteria, first appeared.
- Free oxygen

Archean Eon

-First continents appeared in this eon.
- Fossils of bacteria, archaea, and eukaryotic cells were found in this eon
Marked by the appearance of multicellular organisms and their mass extinction.

Proterozoic Eon

Continents merged into a single land mass called

Rodinia

-The first life forms with parts, such as shells, scales, and bones and teeth, appeared during this eon

Phanerozoic Eon

-Ancient Life
-Pangaea was formed

Paleozoic Era

-Aka "Age of Trilobites"
-Emergence of invertebrates
-First chordates appeared
-First vertebrate appeared
-Weird array of animals

Cambrian Period

-Many volcanoes and mountains formed
- The first corals, primitive fishes, seaweed, and fungi also appeared
- Ended in a huge extinction due to glaciation.

Ordovician Period

-The first jawed fishes and arthropods
-The first vascular plants with water-conducting tissue
-Brachiopods, crinoids, and corals were also abundant.
-

Silurian Period

- AKA “Age of Fishes”
- Fishes and terrestrial plants became abundant and diverse.

Devonian Period

- The Appalachian Mountains of North America were formed.
- Ice covered large areas of the Earth, and swamps covered the lowlands.
- First-winged insects appeared

Mississippian Period

First reptiles, ferns, mayflies, and cockroaches appeared.

Pennsylvanian Period

Mississippian and Pennsylvanian are subperiods of the

Carboniferous

- AKA “Age of Amphibians”
- Amphibians, reptiles, and gymnosperms dominated in this period.
- Phytoplankton and plants supplied oxygen to the Earth’s atmosphere which was close to the present level.
- Ended with the largest mass extinction recorded on Earth.

- Permian Period

An era of
-"middle animals"
-Age of Reptiles

Mesozoic Era

The first dinosaurs, mammals, and crocodyliforms appeared.

Triassic Period

- Many dinosaurs the Earth.
- The first birds, such as the Archeopteryx, appeared.
- The first flowering plants also evolved at this time.

Jurassic Period

-minor extinction occurred about 82 million years ago by an asteroid impact or volcanic activity, and ended with the large extinction of dinosaurs.
-earliest known butterflies appeared as well as snakes, ants, and bees

Cretaceous Period

-Most recent of the three major subdivisions of the Phanerozoic eon.
-Sometimes called the Age of Mammals, Flowering Plants, and Insects.

Cenozoic Era

This began with the mass extinction event at the Cretaceous-Paleogene

Paleogene Period

Marked with the low concentration of carbon isotope C13 in comparison with the more common carbon isotope C12.

Eocene epoch

-First primates begin to appear
-Ancestors of elephants appear
-the mammals slowly took over every niche in the Earth.

Paleocene epoch

-came from the greek words oligos meaning "few" and kainos "new", which refer to the sparse extant forms of the molluscs during this epoch

Oligocene epoch

it is divided into two epochs: Miocene and Plioence

Neogene Period

Characterized by a warmer climate than the Oligocene epoch.

Miocene epoch

Marked by the cooler and more arid climate compared to the Miocene epoch.

Pliocene epoch

Divided into two epochs: Pleistocene and Holocene.

Quaternary Period

Characterized by global cooling
– Ice Age.
- Many species of living things today were already existing.
- Many large animals like mammoths went extinct.
-Homo sapiens spread out worldwide

Pleistocene epoch

-Earth at present.
-Characterized by a warm period.

Holocene epoch

“Age of Man”

Anthropocene

What eon, era, period, and epoch, are we in?

EON: PHANEROZOIC
ERA: CENOZOIC
PERIOD: QUARTERNARY
EPOCH: HOLOCENE