Earth Science || 1st Semester || Midterms

Geosphere

the solid part of the earth consisting of the crust and outer mantle

Atmosphere

A thin layer of gases surrounding Earth

Hydrosphere

All the water on earth

Biosphere

the part of Earth where life exists

Inner core

solid iron and nickel at the center of Earth

Outer core

molten iron and nickel that surrounds the inner core of Earth

Lower Mantle

-soft rocks

-less ductile

-gutenberg discontinuity

Upper Mantle

-solid rocks

-malleable

-mohorovicic discontinuitty

asthenosphere

"weak sphere" is the soft layer of the mantle on which the tectonic plates move

lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

oceanic crust

earths crust located under the ocean

continental crust

A solid, thin outermost layer of Earth

age of star

star must be at least 3 Ga to give life an ample time to evolve

Stable planetary habitable zone

"Goldilocks zone" shell-shaped region of space surrounding a star where the temperature is just right

High metallicity

presence of heavier elements (heavier than H & He)

Low stellary variation

fluctuation in the star's luminosity

Distance from a star

planet must be in a comfortable distance from a star

Terrestrial

planet must be large enough to retain the atmosphere and have a molten core

Orbital eccentricity

elliptical orbit

Axial tilt

the angle at which a planet's axis tilts (23.5 degrees)

Rotation

The spinning of Earth on its axis

Geochemistry

planet should have elements most vital to life

Pangea

term for the super continent which contained all the plates together

Troposphere

clouds

Stratosphere

ozone layer

Mesosphere

meteoroid

Thermosphere

aurora

ionosphere

highly ionized gas

exosphere

outermost layer fo the earth's atmosphere

ecosysytem

biotic and abiotic enviroment

Biomes

large ecosystems classified according to the vegetations

Aquatic biome

includes freshwater and marine biomes

Forest biome

tropical, temperate and boreal (taiga)

Grassland biome

dominance of grass

Desert biome

low rainfall

tundra biome

coldest biome

Grassland biome

dominance of grass

Biomes

radioactive decay

unstable atoms emit energetic particles and gamma rays that heat the surrounding rock

planetary differentiation

more dense materials of a planet sink to the center, while less dense materials stay on the surface.

Geologist

a scientist who studies the earth

Petrology

study of rocks

Stratigraphy

the study of rock layers and the sequence of events they reflect

Paleontology

the study of fossils

Igneous Rocks

rocks formed by the cooling of molten rock (either magma or lava)

Sedimentary Rocks

rock that forms when sediments such as muds, sands, or gravels are compressed by overlying sediments

Metamorphic Rocks

forms when other rocks are heated and squeezed together; requires heat and pressure

Relative Dating

places rocks in their chronological sequence or order of occurence without knowing their actual age

Principle of Original Horizontality

layers of sediment are generally deposited in a horizontal position

Principle of Superposition

states that in undisturbed rock layers, the oldest rocks are on the bottom and the rocks become progressively younger toward the top

Principle of cross cutting relationship

younger features cut across older features

Principle of inclusion

rock bodies are younger than inclusions within them

Unconformity

corresponds with a gap in sedimentation resulting from nondeposition or erosion

Angular unconformity

tilted rocks are overlain by flat-lying rocks

Disconformity

beds above and below are parallel

Nonconformity

Absolute Dating

places the actual ages of rocks

radiometric dating technique

process that gives numeric date when an event occured

Half Life

time for the nucleus of the atom of a redioactive element to decay

decay rate

described in terms of half life

isotopes

atoms that has the same number of protons and but different number of electrons

Carbon 14

used to measure the age of prehistory plants and animals

age

millions of years

epoch

tens of millions of years

period

one hundred million years

era

several hundred million years

eon

half a billion years or more

Precambrian

the oldest and longest span of geologic time

Hadean Eon

Earth's first eon with hellish conditions

Archean Eon

oldest fossil (apex chert and stromatolites)

Proterozoic Eon

fossil of a bacteria and b-g algae

Cambrian Period

marine shelled invertebrates

Ordovician Period

first vertebrates

Silurian Period

first land plants

Devonian Period

first amphibians and forest

Carboniferous Period

large nonflowering plants and amphibians

Permian Period

reptiles became dominant

Triassic Period

first dinosaur appeared

Jurassic Period

age of dinosaurs

Cretaceous Period

first mammals and extinction of dinosaurs

Paleocene Epoch

first primates evolved

Eocene Epoch

primitive horse branced out

Oligocene Epoch

apes, primates, and elephants became dominant

Miocene Epoch

grasses became abundant

Pliocene Epoch

flowering plants became abundant

Pleistocene Epoch

rise of man and mammals

Holocene Epoch

man and vegetation flourished (current era)

true form fossils

when the whole organism has been preserved

mold fossils

hollow impressions of a living thing in a rock

cast fossils

formed when a mold is filled in

Trace fossils (ichnofossils)

rocks that show certain animal activities

William Smith (1769-1839)

- different rock layers contain different fossils

- created first geological map

- these concepts of geology became known as uniformitarianism or actualism

principle of fossils

fossil organisms succeed each other in an order that is definite and determinable according to

index fossils

a fossil that is useful for dating and correlating the strata in which it is found.

Cosmology

study of the universe

Religious Cosmology

Many world religions have origin beliefs that explain the beginnings of the Universe and life

Biblical cosmology

God created the heavens and the earth

Mormon cosmology

there was a pre-existing or pre-mortal life

Hindu cosmology

sees the universe undergoing cycles of creation and destruction

Islamic cosmology

Allah created the universe