Transcript Fossils As Evidence for Evolution

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
 Summary
color is
orange; vocabulary is
underlined.
 Hyperlinks are in
green; they will take
to you videos and
animations.
Unit #12
Evolution Continued
http://1.bp.blogspot.com/-zkeALNoUN-A/T_Kt0nx-8I/AAAAAAAAAWo/udwwi2Zs5UI/s1600/Evolution__Biologia_UEPB_by_resenhista.jpg
 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
1 - FOSSIL RECORD
Textbook Reference pg. 399-400
Watch “Fossils 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 ancestor
2 – Biogeography
Watch “Biogeography As Evidence for Evolution”
Beaver
Muskrat
Beaver and
Muskrat
Coypu
Capybara
Coypu and
Capybara
3 - Homologies: Anatomy
Watch “Anatomical Development and Homologies as Evidence for Evolution”
Textbook Reference pg. 400-402
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 structures: w/
Anatomy Cont.

Vestigial structures: reduced in size, are nonfunctioning remnants of
similar structures in ancestral species
◦ Show an 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)
Textbook Reference pg. 402
 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
Textbook Reference pg. 402-403
 Sequence
of amino acids in a particular protein is compared
between organisms
 AA Sequencing is probably the strongest evidence for
relationships among organisms
http://www.bio.miami.edu/dana/pix/hemoglobinc
omparison.jpg
Biochemistry Cont.

Cladogram: diagram that
shows the evolutionary
relationship among a group
of organisms.
 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
 Observable
H. Kettlewell’s Study of Peppered
Moth Color Shifts
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
Textbook Reference pg. 409
http://evolution.berkeley.edu/evosite/evo101/VBDefining
Speciation.shtml
 Two
populations become
reproductively isolated from
each other
◦ Members cannot
interbreed because of
genetic material is too
different
Spotted owl subspecies living in different geographic
locations show some genetic and morphological differences.
Isolating Mechanism: Reproductive
Isolation
Textbook Reference pg. 410
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
Isolating Mechanism: Behavioral
Isolation
 Two
populations are
separated by geographic
barriers
◦ EX rivers, mountains,
or bodies of water
Isolating Mechanism: Geographic
Isolation
http://biology-forums.com/gallery/33_14_07_11_6_00_25.jpeg
 Two
species reproduce at different times.
Photo Credit, Christian Ziegler
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
Genetic Equilibrium
 Adaptive
radiation: type
of divergent evolution;
ancestral species evolve
into an array of species to
fit diverse habitats
◦ EX Galápagos Finches
http://media-1.web.britannica.com/eb-media/11/54911-004-B661673C.jpg
Types of Evolution:
Divergent Evolution
Textbook Reference pg. 412-13
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