Download Origin of the Solar System

EVOLUTION POPULATIONS, SPECIATION AND ADAPTIVE RADIATION
Population – a group of interbreeding organisms
Gene pool – the sum of all of the genetic components
in a population
Speciation – the origin of new species
Species – a collection of populations within which there
is free flow of genes
EVOLUTION POPULATIONS, SPECIATION AND ADAPTIVE RADIATION
Geographic barriers (Allopatric speciation)
Kaibab
Squirrel (left)
Aberts
Squirrel (right)
EVOLUTION POPULATIONS, SPECIATION AND ADAPTIVE RADIATION
Adaptive radiation
Hawaiian honeycreepers
EVOLUTION POPULATIONS, SPECIATION AND ADAPTIVE RADIATION
Adaptive radiation also occurs at other taxonomic levels
Adaptive radiation of mammals at beginning of
Cenozoic Era
Evolution above the species level is macroevolution
THE FOSSIL RECORD
Phyletic gradualism
Phyletic gradualism is the gradual progressive change
by means of an almost infinite number of small,
subtle steps
THE FOSSIL RECORD
Phyletic gradualism
THE FOSSIL RECORD
Punctuated equilibrium
Punctuated equilibrium is sudden changes interrupting
long periods of little change
Periods of little change are called stasis
Most change occurs over a short period of time
THE FOSSIL RECORD
Punctuated equilibrium
THE FOSSIL RECORD
Punctuated equilibrium
Punctuated equilibrium suggests that evolution occurs
in isolated areas around the limits of a populations
geographic range
Groups in these areas are peripheral isolates and
rapid speciation may occur here
Also known as allopatric speciation
When the new species expands into its original territory,
it is seen as a sudden appearance
THE FOSSIL RECORD
Allopatric speciation
THE FOSSIL RECORD
Allopatric speciation
THE FOSSIL RECORD
Allopatric speciation
THE FOSSIL RECORD
Phylogeny
Phylogeny is the sequence of organisms placed in
evolutionary order
THE FOSSIL RECORD
Phylogeny
Diagrams are used to illustrate ancestor-descendent
relationships.
Phylogenetic Tree
THE FOSSIL RECORD
Phylogeny
Branches on the diagram are called clades
THE FOSSIL RECORD
Phylogeny
Cladograms are diagrams drawn to show ancestordescendent relationships based on characteristics
shared by organisms
Do not include information on time or geologic ranges
THE FOSSIL RECORD
Phylogeny - Cladogram
THE FOSSIL RECORD
Sequential Evolution
THE FOSSIL RECORD
Homology
Homology is the similarity of body parts in regards to
origin, history and structure, without reference
to function
Homologous organs and bone configurations have a
common origin and ancestry
THE FOSSIL RECORD
Homology
THE FOSSIL RECORD
Fossils and Stratigraphy
Principle of Fossil or Faunal Succession
William Smith
Used for
Age
Correlation
THE FOSSIL RECORD
Fossils and Stratigraphy
The geologic range of an organism is the interval
between its first and last occurrence.
THE FOSSIL RECORD
Paleontologic Correlation
Cosmopolitan species are found almost everywhere;
they are not restricted to a single geographic
location in their environment.
Endemic species are confined to a restricted area
in the environment in which they live.
Cosmopolitan species are most useful in correlation
because they have a geographically widespread distribution.
Fossils found only in limited environments (endemics) are
not as useful in matching up rock layers that are far apart.
THE FOSSIL RECORD
Paleontologic Correlation
Appearances and disappearances of fossils may
indicate:
Evolution or Extinction
Changing environmental conditions that
cause organisms to migrate into or
out of an area
THE FOSSIL RECORD
Index Fossils
Index fossils or guide fossils are useful in identifying
time-rock units and in correlation.
They are:
oabundant
owidely distributed (cosmopolitan)
oorganisms with short geologic ranges
(rapid evolution rates)
THE FOSSIL RECORD
Biostratigraphic Zones
Biozone = a body of rock that is identified only on the
basis of the fossils it contains. They are the basic
unit for biostratigraphic classification and
correlation (much as the formation is the
fundamental unit for lithostratigraphy).
THE FOSSIL RECORD
Biostratigraphic Zones
Range Zone = the part of the stratigraphic column
containing the total geologic range of a species or
other taxon
THE FOSSIL RECORD
Biostratigraphic Zones
Assemblage Zone = the part of the stratigraphic
column containing an assemblage or set of several
associated fossils that coexist
THE FOSSIL RECORD
Biostratigraphic Zones
Concurrent Range Zone = the rock where the ranges
of two (or more) taxa overlap