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relative dating
placing geologic events in a sequential order as
determined from their position in the geologic record
Absolute dating
provides specific dates for rock units or events expressed
in years before the present
Principle of Uniformitarianism
"The present is the key to the past"
Used to determine how and when rock
units and geologic structures were formed
Principle of superposition
subsequent floods produce new layers of sediments that are deposited (superposed) over previous deposits. When lithified, they become sedimentary rock.
Principle of original horizontality
Sedimentary particles settle from water under the influence of gravity and sediment is deposited in horizontal layers.
Principle of lateral continuity
sediment extends laterally in all directions until it thins and pinches out or terminates against the edge of the depositional basin
Principle of cross-cutting relationships
an igneous intrusion or a fault must be younger than the rocks that it intrudes or displaces
Principle of inclusions
inclusions, or fragments of one rock within a layer of another, are older than the rock itself
Principle of fossil succession
the fossils at the bottom of a sequence of strata are older than those at the top of the sequence
Unconformities
surfaces that represent times of nondeposition, erosion, or both
Hiatus
the interval of geologic time not represented by strata
Disconformity
a surface of erosion or Nondeposition separating younger from older rocks, both of which are parallel with one another
Angular Unconformity
the strata below the unconformable surface generally dip more steeply than those above,
Nonconformity
an erosional surface cut into metamorphic or igneous rocks covered by sedimentary rocks
Radioactive decay
the process whereby an unstable atomic
nucleus is spontaneously transformed into an atomic nucleus of a different elements.
Absolute Age Dating
Most of the isotopes of the 92 naturally occurring elements are stable
Alpha Particle Emission
lose a He nucleus (2p + 2n)
Beta Particle Emission
lose an e-
Electron Capture
gain an e-
Evolution
Explains change of life, not how life originated
Chromosomes:
double-stranded molecules of
deoxyribonucleic acid (DNA)
are found in all cells
Sex cells:
produced for reproduction by cell
division (meiosis)
- Contain only one chromosome of
each pair
Mutations
changes in the chromosome or
gene and are inheritable if they take place in a
sex cell
What brings about variation?
- Chemicals
- UV radiation
- X-rays
- Extreme temperature changes
- Spontaneous
Speciation:
The rise of a new species from an ancestral
one or a Change in the genetic makeup of
population
Species:
population of similar individuals that can
interbreed and produce fertile offspring
Allopatric speciation
New species arise when some individuals
are geographically isolated
Divergent evolution
Ancestor gives rise to diverse descendants each adapted to different lifestyles
Convergent evolution
Similar adaptations arise in
distantly related groups
Parallel evolution
Similar adaptations arise in closely related groups
Clade
Group of organisms sharing features derived from a common ancestor
Cladogram
Depicts relationships amongst members of a clade
Cladistics
Biological analysis, Primitive characteristics, and Derived characteristics or evolutionary novelties
Sexual selection
is a special type of natural selection in which males compete for mates or females select mates based on such traits.
A species is ____ isolated from other species.
Reproductively
Background extinction refers to ____.
the continual extinction of species
Features that serve the same purpose on very dissimilar organisms are called ____.
Analogous
In modern evolutionary theory, _____ evolve.
populations
Linnaean classification ____.
does not reflect evolutionary relationships in all cases
Linnaeus devised his classification scheme to provide a ____.
means to categorize organisms with like characteristics
Sexual reproduction and _____ account for most variation in populations.
Mutations
Structures that are superficially dissimilar but have the same structure in terms of bones, muscles, nerves, and blood vessels are best described as ____.
homologous
Ultraviolet radiation, X-rays, and extreme temperatures are all _____.
Mutagens
What is the order of the expanded Linnaean classification scheme?
Kingdom, Phylum, Class, Order, Family Genus, Species
What is the study of life as revealed by fossils?
paleontology
What term describes populations that have similar individuals that can interbreed and produce fertile offspring?
species
Which term best indicates changes such as the origin of new species?
Macroevolution
Who proposed the modern biological classification scheme?
Carolus Linnaeus
With the Linnaean classification scheme, as one moves down the hierarchy, the categories become more ___
Exclusive
_____evolution is the development of similar characteristics in distantly related organisms.
convergent
Cell division that results in cells containing only one chromosome from each pair is referred to as
Meiosis
The process in which changes occur in genes passed from one generation to another is called
genetic inheritance or heredity.
