Lecture 14 Flashcards
Deep Time
The concept of geologic time, spanning billions of years, which includes the formation of Earth, the evolution of life, and the development of modern ecosystems.
Geological Time Scale
A system of chronological dating that divides Earth’s history into eons, eras, periods, epochs, and ages.
Cenozoic Epochs
The epochs most relevant to human evolution: Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene, and the proposed Anthropocene.
Cynodonts
Small, mammal-like reptiles that evolved into the first true mammals during the Mesozoic era.
K-Pg Extinction Event
The Cretaceous-Paleogene extinction event (66 Ma) that wiped out the dinosaurs, opening ecological niches for mammals, including primates.
Plate Tectonics
The theory that Earth’s lithosphere is divided into plates that move and interact, influencing climate, ecosystems, and the distribution of continents and oceans.
Continental Drift
The gradual movement of continents across Earth’s surface, driven by plate tectonics.
Paleocene-Eocene Thermal Maximum (PETM)
A period of rapid global warming around 56 million years ago, coinciding with the origin of crown primates.
Antarctic Circumpolar Current
An ocean current that formed around 30 Ma, isolating Antarctica and leading to greater global temperature differences.
East African Rift Valley
A prominent example of continental rifting, which created diverse habitats and played a key role in human evolution.
Milankovitch Cycles
Long-term changes in Earth’s orbit and tilt that drive climate fluctuations. Includes eccentricity, obliquity, and precession.
Eccentricity
Changes in the shape of Earth’s orbit around the Sun, occurring on a ~100,000-year cycle.
Obliquity
Changes in Earth’s axial tilt, varying between 22.2° and 24.5°, occurring on a ~41,000-year cycle.
Precession
The wobble in Earth’s rotational axis, occurring on a ~26,000-year cycle, affecting the relationship between Earth’s tilt and eccentricity.
Glaciation
The formation and movement of glaciers, which significantly impact global climate and sea levels.
Oxygen Isotopes
Used to track past climate changes. Oxygen-16 is lighter and more common in glacial ice, while Oxygen-18 is heavier and more common in ocean water during glacial periods.
Interglacial Periods
Warm periods between glacial periods when glaciers retreat and sea levels rise.
Glacial Periods
Cold periods when glaciers advance, trapping lighter oxygen isotopes and lowering sea levels.
Paleocene Primates
Early primates that evolved after the K-Pg extinction, including plesiadapiforms.
Crown Primates
The group of primates that includes all living primates and their common ancestor, originating during the PETM.
Crown Anthropoids
The group of primates that includes monkeys, apes, and humans, originating around 30 Ma.
Crown Hominoids
The group of primates that includes all apes (lesser apes, great apes, and humans), originating around 20 Ma.
Hominins
The group of primates on the human lineage, including Homo, Australopithecus, and others, originating around 5-7 Ma.
Messinian Salinity Crisis
A period around 5.96–5.33 Ma when the Mediterranean Sea nearly dried up, leading to significant climate and ecological changes.
Genus Homo
The genus to which modern humans belong, originating around 2.5 Ma during the onset of modern glaciation.
Faunal Interchange
The exchange of species between continents, such as when Africa collided with Eurasia around 20 Ma, leading to the migration of species between the two landmasses.
Uplift of Eastern African Highlands
The geological uplift that blocked humid Indian Ocean air, leading to drier conditions in Africa and the formation of savannas, which influenced human evolution.
Anthropocene
A proposed epoch marking significant human impact on Earth’s geology and ecosystems, beginning around the Industrial Revolution.
