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51 Cards in this Set

  • Front
  • Back
Distinguish Earth history from Earth dynamics.
Earth dynamics (or physical geology) and Earth history (or historical geology).
Explain the meaning of a scientific theory.
A scientific theory is a unifying idea that incorporates a number of provisionally accepted hypotheses.
Tantamount to fact
Plate tectonics theory
It states that the Earth’s outer shell (the lithosphere), which consists of the crust and upper mantle, is cracked and composed of pieces that float on a hot, deformable asthenosphere.

The pieces move in various directions, and may slowly spread apart, collide, or slip past one another.
Evolutionary theory
It is the process by which biological species give rise to other species by way of genetic changes.
Composition of the Earth’s Crust
Crust - The outermost layer of the Earth, defined by density, composition, and a seismic velocity difference from the underlying mantle.

Lithosphere - Outer, relatively rigid layer of the Earth, approximately 100 km thick, overlying the asthenosphere. It includes the entire crust plus the upper mantle.

Asthenosphere - Layer within the upper mantle and below the lithosphere where rocks are relatively ductile and easily deformed.
Explain what parts of the Earth system geologists study.
Earth system - The sum of the physical, chemical, and biological processes operating on and within the Earth.

The systems approach to studying the Earth is a way of breaking down large, complex problems into smaller components while remaining mindful of the connections between the components.

A change in one component in a system commonly has effects in other components and its systems.
Identify the major geologic processes operating on Earth.
1, tectonics, which involves the movement of lithospheric plates across the planet’s surface, and which is responsible for the recycling of rocks;

2, the action of water in various forms (liquid, ice, and water vapor), which plays a major role in weathering and erosion, and in the formation of rocks; and

3, biological processes, living organisms are source of profound
change on Earth surface, and their effects alter surface and subsurface areas, water systems, and the atmosphere.
The roles of water, carbon, and oxygen in Earth systems.
Sediments or derivative rocks may be exposed to weathering and erosion, and the elements may be released to continue cycling through
the Earth systems.

Water, carbon, oxygen, and other nutrients are cycled through atmospheric, biological, and geological systems.
Explain Hutton’s principle of uniformitarianism.
Uniformitarianism - The principle that processes acting upon the Earth today have also operated in the geologic past.

“the present is the key to the past.”
Describe Steno’s three principles of stratigraphy.
the science of layered rocks developed
from three principles first stated by Nichloas Steno
Describe Steno’s principle of Original Horizontality
Steno’s principle of original horizontality states that sedimentary
layers were deposited nearly horizontally and parallel to the
Earth’s surface.
Describe Steno’s principle of Lateral Continuity
Steno’s principle of original lateral continuity states that at the time of deposition, strata extended continuously in all directions until they terminated by thinning at the edge of a basin, ended abruptly at a barrier to sedimentation, or graded
laterally into a different sediment type.
Describe Steno’s principle of Superposition
Sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top.
a paradigm that attempted to explain the development of erosional surfaces and the extinction of species by violent, rapid, calamities, like giant floods.
Explain Lyell’s two principles of stratigraphy.
Principle of cross-cutting relationships – States that a rock unit, sediment body, or fault that cuts another geologic unit is younger than the unit that was cut.

Principle of included fragments - States that fragments of rock within a larger rock unit are older than the rock in which they
are enclosed.
Smith’s principle of biotic succession.
The principle that body fossils occur in strata in a definite, determinable order.This final major principle used to interpret the relative ages of strata
Basic Definitions
Fossils - any remains or traces of ancient organisms preserved in the rock

ROCKS - naturally occurring aggregates of minerals (basalt, granite)

Mineral – A mineral is a naturally occurring crystalline solid or a
synthetic, chemically identical equivalent.
Three basic types of rocks
Igneous - formed by cooling of the molten magma (basalt, granite)

Sedimentary - formed from sediments, which are materials deposited at the surface of the Earth by water, wind, ice, or organic activity (sandstone, shale, limestone)

Metamorphic - formed by alteration of other rocks within the Earth under conditions of high temperature and pressure (marble)
What are the factors that favor fossilization?
1) possession of “hard parts” that are hard to destroy (skeleton, shell, teeth, etc.)
2) rapid burial - as in shallow sea, lakes, tar pits (La Brea); so fossils can’t be eroded, broken, and scattered
3) lack of oxygen in the environment (so scavengers and bacteria can’t proliferate)
4) dry or very cold climate (so the action of bacteria is slowed down)
5) abundance of individuals (so odds are better that some are preserved)
Rock weathering
WEATHERING - physical disintegration and/or chemical decomposition of solid materials at the earth’s surface

Disintegrates physically (mechanical weathering)
Changes chemically (chemical weathering)
EROSION - removal of earth materials by water, wind, ice or gravity

SOIL - combination of weathered rock material, water, air, and organic matter; supports plant growth
CLASTIC (detridal) sedimentary rocks are formed from clasts (weathered solid fragments of preexisting rocks) that have been eroded, transported (by water, air, or ice), deposited, and lithified (compacted and cemented).
Examples: conglomerate, sandstone, mudstone, shale

weathering (mechanical or chemical)
erosion (removal of weathered material)
transportation (sediment carried by water, wind, ice)
deposition (settling out of fluid such as water or air)
lithification (compaction and cementation of sediment)
CHEMICAL sedimentary rocks are deposited by precipitation of minerals from solution.
Examples: rock salt, inorganic limestone (geyserite, travertine)

BIOCHEMICAL (organic) sedimentary rocks are formed by accumulation and consolidation of organic remains of animals and plants (shells, leaves, etc.).
Examples: biochemical limestone (chalk, skeletal), chert, coal
Elements, ions, and atomic bonds
The basic building blocks of minerals are atoms of chemical elements.
Atoms - the smallest individual particles showing all the distinctive properties of a chemical element. The nucleus is at the center of the atom. The nucleus
contains most of the mass of the atom, protons (positively charged particles) and neutrons (neutral particles).
Summarize the most important rock-forming minerals.
Silicate mineral – A silicate mineral has a silicate tetrahedron
(SiO4) as the basic chemical property. Silicates are the dominant
group in igneous, sedimentary, and metamorphic rocks.

Carbonate mineral – These minerals have calcium, magnesium, iron, or other ions attached to a carbonate ion (CO3-). They are important sedimentary rocks, and can form the metamorphic
rock marble.

Sulfate minerals – Sulfate minerals have calcium or other ions attached to a sulfate ion (SO4-2). Most rock-forming
sulfate minerals, such as gypsum and anhydrite, occur in sedimentary rocks.

Halide minerals – Halide minerals have positive ions such as sodium and potassium attached to negative ions such as chlorine and bromine. Most rock-forming halides occur
in sedimentary rocks.

Oxide minerals - Oxide minerals have metallic ions combined with oxygen. Oxides occur in igneous,
sedimentary, and metamorphic rocks.

Sulfide minerals - Sulfide minerals have metallic ions combined with sulfur. They occur in igneous,
sedimentary, and metamorphic rocks.
Metamorphic rocks form by the alteration of other rocks at high temperatures and pressures. Metamorphism causes chemical (mineralogical) and textural changes
in igneous, sedimentary, or other metamorphic rocks.
Determining the age of rocks
Two basic ways:
Relative dating (1800’s) tells which rock is younger or older than another. Does NOT tell the age of rocks in years

Absolute (numerical) dating (1900’s) tells the actual age of rocks in years. It is based on decay of radioactive elements in rocks
Methods of Relative Dating
Studying sequences of rocks and determining relative age based on basic principles (Superposition) and correlation

Using the Geologic Time Scale
Because of faults and unconformities, there is never a complete sequence of sedimentary rocks in any single area
So sequences from different areas need to be matched up (correlated) to reconstruct a complete sequence
Correlation: determining which rocks are the same age and matching them up
Best fossils for correlation are called:
Index Fossils:
1)They are distinctive (easy to recognize and distinguish from other fossils)
2) They make good fossils (robust and well-preserved, not too fragile)
3) They are geographically widespread (so you can use them for correlation
across continents)
4) They are abundant (easy to find)
5) They have short stratigraphic ranges. (“short-lived” as a species)
defined by stratigraphic interval between the earliest and latest appearance of a fossil.
Methods of absolute dating
Tree Ring Method:
Tree rings (dendrochronology) - uses annual growth bands on tree trunks to correlate & date events.
Can date events such as fires and droughts (as far back as 8000 years)
So even trees contradict the Creationist “young Earth hypothesis”
Methods of absolute dating
Radiometric dating:
Dating rocks and fossils based on radioactive decay of some elements in minerals
Most commonly used in geology -there are many methods
Atom consists of subatomic particles:
PROTONS - subatomic particles with a positive charge
NEUTRONS - subatomic particles with NO charge

Together they form NUCLEUS of an atom

Nucleus surrounded with complex orbital spaces containing electrons -
atomic number and mass number
ATOMIC NUMBER - the number of protons in the nucleus
MASS NUMBER - the number of protons plus the number of neutrons in the nucleus
atoms of the same element having different number of neutrons in the nucleus; they have the same atomic number but different mass number
Radioactive decay
During radioactive decay, an atom is changed to an atom of a different element (example: C-14 to N-14)
This means that the number of atoms of a radioactive element DECREASES with time at a certain rate of decay
This rate is fixed for each radioactive isotope and cannot be changed
How fast is the rate of radioactive decay?
It is different for different isotopes and best expressed in terms of HALF-LIFE

IN ONE HALF LIFE: one half of the radioactive atoms present will decay to the daughter element. In the next half life, one half of the remaining radioactive atoms will decay, and so on.
Geologic Time Scale
Geologic Time Scale

After one half-life, 50% of the parent remains,
and 50% of the atoms have become a daughter
product. After two half-lives, 25% (or half of the
50% amount) of the parent remains, and 75% of
the atoms have become a daughter product.
After three half-lives, 12.5% (or half of the 25%)
of the parent remains, and 87.5% of
the atoms have become a daughter product.
Further decay continues in the same way.
The essence of radiometric dating
1. We find rocks that contain radioactive isotopes (mostly igneous rocks)
2. We measure the amount of parent and daughter elements in them.
3. We count how many half lives have passed since minerals in rock formed.
4. We then calculate the age of the rock.
Linnaean Classification of Life on Earth
Understand how living things are classified.
Species are referred to using a two-part Latin name consisting
of a genus name followed by a species name. This is called
binominal nomenclature.

Binominal nomenclature - A technique of identifying organisms
using a two-part Latin name, a genus name followed by a species
name. The Latin names are set off from ordinary text using italics
or underlining.
Rules for biological names:
Name of genus is UNIQUE and CAPITALIZED
Name of species NOT CAPITALIZED
Names should be highlighted (bold or italic)
Names should be Latin or Latinized
You can’t name a species after yourself

Tyrannosaurus rex (T. rex)
Differentiate between a biological species
and a paleontological species.
Paleontological species concept - The concept that the limits of ancient species may be inferred from their preserved physical traits.

Biological species concept - The concept that members of a species can interbreed and produce fertile offspring and that members of a single species are distinguished from other species by reproductive isolation.
Explain the differences between prokaryotes and eukaryotes.
Prokaryote - (typically 1–10 μm) An organism that lacks a nucleated cell type and certain organelles.

Eukaryote - (typically 10–100 μm) An organism that has a nucleated cell type, more complex and incorporate heritable organelles.
Cellular organisms are usually organized into three domains and six kingdoms
The three domains are:

Eukarya (Eukaryotes),

Archaea (Archaebacteria - (Prokaryotes),), and

Bacteria (Eubacteria (Prokaryotes), (also sometimes
called Monera).

The six kingdoms are:
Protoctista, Fungi, Plantae, and Animalia.

(Eukaryotes (domain Eukarya).

Archaebacteria(domain Archaea)

Eubacteria, also sometimes called Monera (domain Bacteria)
methane-producing; halophilic, or salt-loving; and thermoacidophilic, or heat- and acid-loving prokaryotes

Archaebacteria metabolize by means of chemosynthesis,
which involves conversion of chemical energy into biologically
useful organic compounds. The ability of some archaebacteria
to withstand, grow, and reproduce in hot, oxygen-deficient
environments, including tectonically active areas, suggests
that they may have been the first organisms to evolve on Earth.

Chemosynthesis - Synthesis of organic molecules
using chemical energy released through oxidation
of inorganic compounds.
Bacteria (or eubacteria) are all the prokaryotes except
for those classified as archeans (archaebacteria). This
group is exceedingly diverse in structure and metabolism.

Eubacteria range from simple, solitary unicells to
more complex stalked, budding, and aggregated forms.

Eubacteria usually form organic compounds such as
sugars, starches, phosphorous compounds, and
proteins in one of two ways: through chemosynthesis
(similar to archaebacteria) or through
photosynthesis (similar to plants).

Chemosynthetic and photosynthetic nutrition are referred
to as autotrophy, which is the self-production of food and
derivation of energy from inorganic sources. Eubacterial
cycling of elements and compounds is essential for all life
forms on Earth.

Autotrophy - The process of “self-feeding” by
means of either harvesting light energy from
the Sun or from oxidation of inorganic
compounds to make organic molecules.

uses ATP
Symbiosis - A condition in which two or more dissimilar
organisms live together in close association.

Protoctists are eukaryotic microorganisms and their
descendants other than fungi, plants, and animals.

The best-known protoctists are algae, oomycotes (water molds,
slime molds, and slime nets), and protozoans (the protists such
as amoebas, ciliates, and diatoms).

Protoctists have a good fossil record dating to the
Proterozoic. Protoctists are unicellular
and multicellular eukaryotes.
Fungi are eukaryotic organisms that develop from chitinous
fungal spores (propagules), have chitinous cell walls,
and lack undulipodia at all stages of the life cycle.

Most fungi are multicellular. They all acquire
nutrients by digesting living or dead tissue through a
process known as absorptive heterotrophy. Fungal cells
can have more than one nucleus per cell.

Reproduction occurs asexually, through mitosis, or
sexually, in which meiosis produces haploid propagules.
Plants can be divided into two major groups:
nonvascular plants and vascular plants.

Nonvascular plants include mosses, liverworts, and hornworts.
Nonvascular lack the true stems, leaves, and roots
that characterize vascular plants.

Vascular plants include club mosses, psilophytes, horsetails,
ferns, gymnosperms (cycads, ginkgos, conifers, and
gnetophytes), and the angiosperms (flowering plants).
Animals can be divided in a couple different ways. One way is to
distinguish animals that lack backbones (the invertebrates) from
those that have backbones (the vertebrates).

Another way is to distinguish the animals that lack tissues
organized into organs (the parazoans) from those that have
tissues organized into organs and organ systems
(the metazoans).

Heterotrophy - A means of obtaining nutrients
by ingesting or breaking down organic matter.

Animals acquire nutrients through heterotrophy, and most
ingest food through an oral opening. Some animals are
parasitic and lack a digestive system. Rarely, animals
take in photosynthesizing symbionts that help them
acquire essential nutrients.

Animals normally have cells specialized for functions such
as respiration, digestion, and protection, and these cells
are grouped into tissues and organs.