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Colonie High AP Biology DeMarco/Goldberg
Chapter 24/25
Evidence of Evolution
Geological, Anatomical,
Chemical, Molecular
Dodo bird
Evidence Supporting Evolution Artificial selection
human-caused evolution
Fossil record
transition species
Anatomical record
homologous & vestigial structures
embryology & development
Molecular record
protein & DNA sequence
Artificial Selection
Artificial breeding can use variations in
populations to create vastly different
“breeds” & “varieties”
“descendants”
of the wolf
“descendants”
of wild mustard
Natural Selection in Action
Insecticide &
drug resistance
insecticide didn‟t
kill all individuals
resistant survivors
reproduce
resistance is
inherited
insecticide
becomes less &
less effective
Fossil Record
Layers of sedimentary rock contain fossils
new layers cover older ones, creating a record over time
fossils within layers show that a succession of organisms have populated Earth throughout a long period of time
Charles Lyell (1797-1875) studied the Temple of Scrapis (Sicily)
built on land & used until 200 AD
high tide now above temple floor
erosion in columns well above high tide
Meaning:
In less than 2000 years, temple
sunk well below sea level, and then
was raised up again — natural
processes and immense periods of
time could produce great changes.
“the present is the key to the past”
Geologist give us time for evolution…
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Colonie High AP Biology DeMarco/Goldberg
Fossil Record
A record showing us that today‟s
organisms descended from ancestral
species
Evolutionary Change In Horses
Millions of years ago
50
100
150
200
250
300
350
400
450
500
550
60 55 50 45 40 35 30 25 20 15 10 5 0
Equus
Hyracotherium Mesohippus
Merychippus
Nannippus
Bo
dy
siz
e (
kg
)
Evolution of Birds
Smithsonian Museum,
Washington, DC
Archaeopteryx
lived about 150 mya
links reptiles & birds ?
?
?
?
Land Mammal
Vestigial Organs Hind leg bones on whale fossils
Anatomical Record
Homologous structures
similarities in characteristics resulting
from common ancestry
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Colonie High AP Biology DeMarco/Goldberg
Homologous Structures
Similar structure
Similar development
Different functions
Evidence of close
evolutionary relationship
recent common ancestor
Homologous Structures
Forelimbs of human, cats, whales, & bats
share same skeletal structures
similar structure
similar embryological development
different functions
evidence of common ancestor
branched off from
common 4-limbed
ancestor
2006 Fossil Discovery of Early Tetrapod
“missing link” from sea to land animals
Analogous Structures
Separate evolution of structures
similar functions
similar external form
different internal structure &
development
different origin
no evolutionary relationship
Solving a similar problem with a similar solution
Convergent Evolution
Flight evolved in 3 separate animal groups
evolved similar “solution” to similar
“problems”
analogous structures
Convergent Evolution
Fish: aquatic vertebrates
Dolphins: aquatic mammals
similar adaptations to
life in the sea
not closely related
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Colonie High AP Biology DeMarco/Goldberg
Parallel Evolution
Parallel, but separate, evolutionary paths
filling similar ecological roles in similar environments, so similar adaptations were selected
but are not closely related
marsupial
mammals placental
mammals
Parallel Evolution Niche Placental Mammals Australian Marsupials
Burrower Mole
Anteater
Mouse
Lemur
Flying squirrel
Ocelot
Wolf Tasmanian “wolf”
Tasmanian cat
Sugar glider
Spotted cuscus
Numbat
Marsupial mole
Marsupial mouse
Anteater
Nocturnal insectivore
Climber
Glider
Stalking predator
Chasing predator
Vestigial Organs Modern animals may have structures
that serve little or no function
remnants of structures that were functional in ancestral species
evidence of change over time
some snakes & whales show remains of the pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone
Comparative Embryology Similar embryological development in
closely related species
all vertebrate embryos have similar
structures at different stages of
development
gill pouch in fish, frog, snake, birds, human, etc.
Molecular Record
0 25 50 75 100 125 0
25
50
75
100
Millions of years ago
Horse/ donkey
Sheep/ goat
Goat/cow
Llama/ cow
Pig/ cow
Rabbit/ rodent
Horse/cow
Human/rodent
Dog/ cow
Human/ cow
Human/kangaroo
Nu
cle
oti
de s
ub
sti
tuti
on
s
Comparing DNA & protein structure
universal genetic code!
DNA & RNA
compare common genes cytochrome C (respiration)
hemoglobin (gas exchange)
Closely related species have
sequences that are more
similar than distantly related
species
DNA & proteins are a molecular
record of evolutionary
relationships
cytochrome c from 33 species
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Colonie High AP Biology DeMarco/Goldberg
Comparative Hemoglobin Structure
10 0 20 30 40 50 60 70 80 90 100 110 120
Lamprey Frog Bird Dog Macaque Human
32 8 45 67 125
Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans
Globin Gene Family Tree
looking at the DNA sequences of the
different globins can show approximate time
of divergance
Building “Family” Trees Closely related species (branches) share same line of descent until their divergence from a common ancestor more like evolutionary “bushes”
Archaebacteria
&
Bacteria
Classification Old 5 Kingdom system
Monera
Protists
Plants
Fungi
Animals
New 3 Domain system
Bacteria
Archaebacteria
Eukaryotes
Protists
Plants
Fungi
Animals
Prokaryote
Eukaryote
Linnaen Nesting
KPCOFGS
not used so
much more as
phylogenetics
developed
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Colonie High AP Biology DeMarco/Goldberg
Phylogenetic Trees Plant Diversity
Bryophytes
non-vascular
land plants
Pteridophytes
seedless
vascular plants
Gymnosperm
pollen &
“naked” seeds
Angiosperm
flowers & fruit
seed plants
vascular plants
mosses ferns
conifers flowering plants
colonization of land
synapomorphies
Cnidaria
Platyhelminthes
sponges jellyfish flatworms roundworms
Nematoda
Mollusca Arthropoda Chordata
Annelida Echinoderm
mollusks
multicellularity; diploblastic
Ancestral Protist
tissues
bilateral symmetry; triploblastic
body cavity
segmentation
Porifera
Animal Diversity
coelom
starfish vertebrates segmented
worms insects spiders
backbone
protostomes deuterostomes
synapomorphies
synapomorphies
Evidence of Evolution
by Natural Selection
Testable Hypotheses
Peppered Moths
Dark vs. light variants
Year % dark % light
1848 5 95
1895 98 2
1995 19 81
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Colonie High AP Biology DeMarco/Goldberg
Peppered Moths
What was the selection factor?
early 1800s = pre-industrial England
low pollution
lichen growing on trees = light colored bark
late 1800s = industrial England
factories = soot coated trees
killed lichen = dark colored bark
mid 1900s = pollution controls
clean air laws
return of lichen = light colored bark
industrial melanism
Genome Sequencing
What can data from whole genome sequencing tell us about evolution of humans?
Primate Common Ancestry?
Chromosome Number
in the Great Apes
(Hominidae)
orangutan (Pogo) 48
gorilla (Gorilla) 48
chimpanzee (Pan) 48
human (Homo) 46
Hypothesis:
Change in chromosome number?
If these organisms share a
common ancestor, then is there
evidence in the genome for this
change in chromosome number?
Chromosomal Fusion
Testable prediction:
If common ancestor had 48 chromosomes (24 pairs),
then humans carry a fused chromosome (23 pairs).
Centromere
Telomere
Ancestral
Chromosomes Fusion Homo sapiens
Inactivated
centromere
Telomere
sequences
Chromosome Number
in the Great Apes
(Hominidae)
orangutan (Pogo) 48
gorilla (Gorilla) 48
chimpanzee (Pan) 48
human (Homo) 46
Testing the Human Genome
“Chromosome 2 is unique to the human
lineage of evolution, having emerged as a
result of head-to-head fusion of two
acrocentric chromosomes that remained
separate in other primates. The precise
fusion site has been located in 2q13–
2q14.1, where our analysis confirmed the
presence of multiple subtelomeric
duplications to chromosomes 1, 5, 8, 9, 10,
12, 19, 21 and 22. During the formation of
human chromosome 2, one of the two
centromeres became inactivated (2q21,
which corresponds to the centromere from
chimp chromosome 13) and the centromeric
structure quickly deterioriated.”
Hillier et al (2005) “Generation and Annotation of the DNA
sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.
Human Chromosome #2 shows
the exact point at which this
fusion took place…
Chr 2
Ancestral
Chromosomes Fusion Homo sapiens
Inactivated
centromere
Telomere
sequences
On the left is a copy
of the human
chromosome „set‟.
On the right is the
respective
chromosome for
the chimpanzee—
our nearest cousin
outside our
species