Earth Science Unit 7 Test

Half-life

The amount of time it takes for half of the chemicals in a rock to decay, or turn into another chemical

Relative dating

Puts geological events in chronological order without requiring that a specific numerical age to be assigned to each event

Uniformitarianism

States that geologic process occurring today have been occurring since the Earth was formed

Catastrophism

The theory that the Earth has largely been shaped by sudden, short-lived, violent events, possible world-wide in scope

Superposition

The principal that in an undisturbed rock sequence , the oldest rocks are at the bottom and each consecutive layer is younger than the one beneath it.

Unconformities

The surface of the Earth is constantly changing changing due to weathering and erosion

Angular unconformities

When younger flat rock layers were deposited over older tilted eroded rock layers

Disconformities

When a layer of rock is missing even though the rock layers are horizontal

Nonconformities

Occur when metamorphic or igneous rock are uplifted and eroded. Sedimentary rocks are then deposited on top of this erosion surface.

Index fossils

index fossils are used in fossil correlations that must be widespread and short-lived

Absolute-age dating

Puts geological events in chronological order without requiring that a specific numerical age be assigned to each event

Radiometric dating

Multiple ways to determine age

Isotopes

They are atoms of the same element that differ in their number of neutrons. They have different masses, but their other properties do not differ from one isotope to another

Ice cores

Cylinders of ice that are drilled from glaciers or ice sheets, contain trapped air bubbles to give information about the past

Age of fish

Before the age of reptiles (Called the Paleozoic period)

Age of reptiles

Before the age of mammals (Called the Mesozoic period)

Age of mammals

Last age of developing animals (Called the Cenozoic period)

Carbon films

When an organism is subjected to heat and pressure only carbon is left behind

Molds and casts

When an organism gets in the way of the formation of sedimentary rock, a mold is formed. The organism slowly decays and minerals fill in the mold thy form a cast

Permineralized or petrified fossils

Minerals seep into tiny spaces in the hard parts of dead organisms, sometimes original material remains. This can included DNA. Minerals can completely replace hard parts of dead organisms.

Trace fossils

Tracks, trails, and burrows

Preserved remains

Organisms preserved in resin, frozen, ect.

Micro-evolution

Evolves over a short period of time, like the light moths into the dark moths and the finches

macro-evolution

Evolves over a long period of time. turns into a completely new species

Natural selection

Things naturally breed and have babies creating variations of a species

Artificial selection

Humans breed animals and make them have babies to create variations of a species

Cyanobacteria

Bacteria that obtains energy via photosynthesis, before about 2.4 billion years ago, Earths was a virtually oxygen-free environment. The appearance of cyanobacteria changed that.

Panspermia

Life on Earth originated from microorganisms or chemicals precursors of life present in outer space and able to initiate life on reaching a suitable environment

Evaporites

A natural salt or mineral deposit left after the evaporation of a body of water

What part of a trilobite is the Cephalon?

The top part (head)

What part of a trilobite is the Thorax?

The middle part (stomach)

What part of a trilobite is the Pygidium?

The bottom part (tail)

Describe the conditions necessary for fossil formation

Plant and animal remains rarely fossilize, they need

• Rapid and permanent burial- protecting the specimen from biological or environmental disturbance

• Oxygen deprivation

• The absence of excessive heat or compression

Put these in order based on length of time: Era, Epoch, Period, Eon

Eon, Era, Period, Epoch

What is the widely accepted age of the Earth?

4.4 billion years

What evidence do we have for the age of the Earth?

• Meteorites

• Dated meteorites

• Dated moon rocks

• Seems to confirm the age of the Earth

What were the three main heat sources for early Earth?

• Gravitational contraction (movement of gas swirled around cause heat and pressure)

• Radioactivity (Isotopes have decayed, the radioactivity creates heat)

• Asteroid and meteorite (Asteroid collisions cause tremendous mounts of heat)

Discuss the early Earth, early atmosphere, and early ocean

• The atmosphere was virtually devoid of oxygen (no oxygen)

• There were no oceans, water was to hot

• The Earth had not distinct continents

Put these in order: Paleozoic, Cenozoic, Mesozoic

• Oldest to youngest- Paleozoic, Mesozoic, Cenozoic

• Youngest to oldest- Cenozoic, Mesozoic, Paleozoic

Be able to name a world view and describe how its different from the other two

Young Earth Creationism- believes fossils were created during the flood, deny uniforitarianism, believe life has not changed much over time, believe either Pangaea never existed or it broke apart during the flood, believe macro-evolution did not happen.

Match the era with the age of animal and put them in order

• Age of fish - Paleozoic

• Age of reptiles - Mesozoic

• Age of mammals - Cenozoic

Explain the bad science topic of conflicts of interest

Many companies will employ scientist to carry out and publish research - whilst this doesn’t necessarily invalidate the research, it should be analysed with this in mind, research can also be misinterpreted for personal or financial gain.