Paleontologists have long
thought that
Archaeopteryx fossils,
including this one discovered
in Germany, placed the
dinosaur at the base of the
bird evolutionary tree;
evidence suggests the beast
may have been a birdlike
dinosaur.
CREDIT: Humboldt Museum
für Naturkunde Berlin
Evolution Continued:
Evidence & Other
Concepts
http://1.bp.blogspot.com/-zkeALNoUN-A/T_Kt0nx-8I/AAAAAAAAAWo/udwwi2Zs5UI/s1600/Evolution__Biologia_UEPB_by_resenhista.jpg
On the
following
slides, the
orange
sections
identify the
main points;
Underlined
words =
vocabulary!
Hyperlinks are
in green.
 Today,
most of the evidence for evolution
is grouped into these main categories:
◦ Fossil Record
◦ Biogeography
◦ Homologies
Anatomy
Embryology
Molecular
◦ Observable Events
http://en.wikipedia.org/wiki/File:Equine_evolution.jpg
The Evidence of
Evolution
Use the information on the following slides to complete your “Matching
Notes” student sheet.
 Most
fossils are found in
layered sedimentary
rock
 Older fossils = lowest
layers
 Comparing fossils from
different layers shows:
◦ Life on Earth has
changed
◦ Increased biodiversity
Watch “Fossils
1 - FOSSIL RECORD
As Evidence for Evolution”
 Paleontology
– study of fossils
 Types of Fossils:
◦ Remains: EX bone, tooth, or shell
◦ Traces: EX burrow, footprint, or imprint
Dinosaur fossil searcher Ray
Stanford discovered a large
fossil of a Nodosaur just a few
feet from this spot.
Tracy A. Woodward / THE
WASHINGTON POST
Fossils Cont.
http://www.washingtonpost.com/rf/image_606w/20102019/WashingtonPost/2012/08/17/Local/Images/NASADino6_1345234800.jpg
 Biogeography:
the
geographic
distribution of
organisms
◦ organisms living
widely apart
(even different
continents), may
be similar
because they
share a common
“Biogeography As Evidence for Evolution”
ancestor
2 – Biogeography
Beaver
Muskrat
Beaver and
Muskrat
Coypu
Capybara
Coypu and
Capybara
Watch
3 - Homologies:
Anatomy
Watch “Anatomical Development and Homologies as Evidence for
Evolution”
structures: w/ similar
structure, but different function show an
evolutionary relationship
◦ EX limbs of vertebrates (turtle, alligator
vs. mammal)
http://4.bp.blogspot.com/0rVjJQ9_gsQ/TtoEjKxfZ1I/AAAAAAAAA2Y/5XV9AmEwOlE/
s1600/Pentadactyl.JPG
 Homologous
Anatomy Cont.

Vestigial structures: reduced in size, are
nonfunctioning remnants of similar structures
◦ Show an
in ancestral species
organism’s
evolutionary past
◦ Ancestral species
would have similar
structures that are
still functioning
 EX human
tailbone,
appendix, whale
femur/pelvis
http://www.kirksville.k12.mo.us/khs/teacher_web/alternative/whale-vestigialstructure.jpg
Anatomy Cont.
Can you spot the vestigial limbs?
(Photo Credit: Marc Mythos)
of different
species may appear
similar in early stages
of development
◦ Can show
developmental
relationships
http://www.evolutionnews.org/Mader_2010.jpg
 Embryos
4 - Homologies:
Developmental
(Embryology)
 Hox
genes: found
in animals,
determine the
pattern of the body
during
development
◦ Control
transcription
factors
◦ Can show genetic
relationships
4 - Homologies:
Developmental
(Homeobox/Hox Genes)
http://www.nobelprize.org/nobel_prizes/medicine/laureat
es/1993/illpres/protmol-aminoacid-v4.gif
 The
genetic code
[GCAT] is the same in all
organisms
◦ Triplets (or codons) of
DNA bases code for
specific amino acids to
build proteins
5 – Homologies:
Biochemistry
 Sequence
http://www.bio.miami.edu/dana/pix/hemoglobinc
omparison.jpg
of amino acids in a particular
protein is compared between organisms
 AA Sequencing is probably the strongest
evidence for relationships among
organisms
 Cladogram:
diagram that
shows the
evolutionary
relationship
among a group of
organisms.
Biochemistry Cont.
 Some
changes in species have been
observed and studied in recent times
P. & R. Grant’s Study of
Beak Size Shift in
Darwin’s Finches
H. Kettlewell’s Study of
Peppered Moth Color
Shifts
 Observable
events show that evolution is
an ongoing process
Observable Events
 Species:
a group of
organisms that breed with
one another and produce
fertile offspring
◦ Speciation: the
formation of a new
species as a result of
evolutionary change
caused by certain
isolating mechanisms
◦ Isolating Mechanism
Animation
Speciation
http://evolution.berkeley.edu/evosite/evo101/VBDefining
Speciation.shtml
 Two
populations
become
reproductively
isolated from
each other
◦ Members
cannot
interbreed so
the genetic
material
becomes too
different
Spotted owl subspecies living in
different geographic locations show
some genetic and morphological
differences.
Isolating Mechanism:
Reproductive Isolation
Photo Credit, Mike Eggett
 Two
populations are
capable of interbreeding,
but have differences in
courtship rituals, etc that
involve behavior.
◦ EX two different species of
cricket that would be
indistinguishable unless
you heard their mating
songs a noticeably
different pitch
◦ Video
Isolating Mechanism:
Behavioral Isolation
 Two
populations
are separated by
geographic
barriers
◦ EX rivers,
mountains, or
bodies of water
http://biology-forums.com/gallery/33_14_07_11_6_00_25.jpeg
Isolating Mechanism:
Geographic Isolation
 Two
species reproduce at different
Photo Credit, Christian Ziegler
times.
Populations may mate or
flower at different seasons
or different times of day.
Three tropical orchid species
of the
genus Dendrobium each
flower for a single day; the
flowers open at dawn and
wither by nightfall.
Britannica
Isolation Mechanism:
Temporal Isolation
 Do
a population’s genes (or gene pool)
change over time? Yes!
◦ % of an allele in a gene pool = allelic
frequency
◦ Genetic equilibrium: frequency of
alleles remains the same
 A population in equilibrium is NOT
evolving
 Influenced by
◦ Environment, mutations
◦ Genetic drift
◦ Video
Genetic Equilibrium
 Adaptive
http://media-1.web.britannica.com/eb-media/11/54911-004-B661673C.jpg
radiation: type of
divergent
evolution;
ancestral species
evolve into an
array of species
to fit diverse
habitats
◦ EX Galápagos
Finches
◦ Video
Types of Evolution:
Divergent Evolution
True or False?
The shark and the dolphin
are closely related?
http://matthewbonnan.files.wordpress.com/2012/06/convergent-evolution.jpg
evolution:
when unrelated species
occupy similar
environments, evolving
similar traits, but are
NOT closely related
◦ Convergent evolution
results in analogous
structures
◦ EX Bat wing vs.
butterfly wing
Types of Evolution:
Convergent Evolution
http://bio3vo.files.wordpress.com/2011/04/analogous-structures.jpg
 Convergent