Download AP Biology - Franklin High School

Evidence for
Evolution
by
Natural Selection
AP Biology
2006-2007
Darwin…
1831-1836
AP Biology
22 years old!
Then along comes Darwin…
& those dang finches!
Descendant
species
Warbler finch
Cactus finch
Ancestral
Woodpecker finch
species
Sharp-beaked finch
Small insectivorous
tree finch
Small ground
finch
Large
insectivorous
tree finch
Cactus
eater
Medium
ground finch
Insect eaters
Seed eaters
Vegetarian
tree
finch
AP
Biology
Bud eater
Large
ground finch
Correlation of species to food source
Seed
eaters
Flower
eaters
Insect
eaters
Rapid speciation:
new species filling niches,
because they inherited
successful adaptations.
AP Biology radiation
Adaptive
Beak variation in Galapagos finches
(a) Cactus eater. The long,
sharp beak of the cactus
ground finch (Geospiza
scandens) helps it tear
and eat cactus flowers
and pulp.
AP Biology
(c) Seed eater. The large ground
finch (Geospiza magnirostris)
has a large beak adapted for
cracking seeds that fall from
plants to the ground.
(b) Insect eater. The green warbler
finch (Certhidea olivacea) uses its
narrow, pointed beak to grasp insects.
Glyptodont fossils
Sloth fossils
Modern sloth
Modern armadillos
AP Biology
Why should extinct
species & living species
be found on the
same continent?
Big Idea 1
 The process of evolution drives the
diversity and unity of life
cells
DNA
AP Biology
What are the 4 lines of evidence that
support Darwin’s ideas?…
Human Macaque Dog Bird
8
32 45
Frog
Lamprey
67
125
0 10 20 30 40 50 60 70 80 90 100 110 120
AP Biology
1. What are the lines of evidence that support Darwin’s ideas?
Fossil record
550
500
Body size (kg)
450
Equus
400
350
300
250
Merychippus
200
150
Mesohippus
Hyracotherium
100
50
Dragonfly from Brazil more than 100 million years
old
AP Biology
Nannippus
60 55 50 45 40 35 30 25 20 15 10 5 0
Millions of years ago
Fossils
 Layers of sedimentary rock contain fossils
new layers cover older ones, creating a
record over time
 Show that a succession of organisms have
populated Earth throughout a long period
of time

AP Biology
Evolution of birds
 Archaeopteryx


lived about 150 mya
links reptiles & birds
Smithsonian Museum,
AP Biology
Washington,
DC
Evolution of land animals
 2006 Fossil Discovery of Early Tetrapod
“Tiktaalik”
 “missing link” from sea to land animals

 from swimming (0 legs) to walking (4 legs)
AP Biology
Evolution of
marine mammals
Land Mammal
?
?
?
?
But then,
they actually
found my fossil!
At first,
I was just
a joke
!
AP
Biology
Aquatic Mammal
2. What are the lines of evidence that support Darwin’s ideas?
Terminal
bud
Lateral
buds
Cabbage
Artificial selection
Brussels
sprouts
Leaves
Flower cluster
Kale
Cauliflower
Stem
Flower
and
stems
Broccoli
AP Biology
Wild mustard
Kohlrabi
Selective
breeding
the raw genetic
material (variation)
is hidden there
AP Biology
Natural selection
in action
AP Biology
MRSA
Evolution of drug resistance in HIV
Patient
No. 1
Patient No. 2
Patient No. 3
AP Biology
Weeks
3. What are the lines of evidence that support Darwin’s ideas?
Anatomical evidence
AP Biology
Homologous structures
spines
leaves
succulent leaves
Don’t forget
our plant friends!
AP Biology
needles
colored leaves
tendrils
Homologous Structures

similarities in characteristics resulting
from common ancestry
 Similar development
 Similar structure
 Different functions
 Evidence of close
evolutionary relationship

AP Biology
recent common
ancestor
Analogous structures
 Separate evolution of structures
similar functions
 similar external form
 different internal structure & development
 different origin
 no evolutionary relationship

Don’t be fooled
by their looks!
Solving a similar problem with a similar solution
AP Biology
Analogous structures
Convergent
Don’t
be fooled
by evolution
their looks!
Those
& tails
Does fins
this mean
& sleek
they bodies
have a are
recent
common
ancestor?
analogous
structures
!
Solving a similar problem with a similar solution
AP Biology
Convergent evolution
 Flight evolved in 3 separate animal groups

analogous structures
Does this mean
they have a
recent common
ancestor?
AP Biology
Convergent evolution
marsupial
mammals
AP Biology
These animals
look very similar but does
that mean they have a
recent common ancestor?
What is this
evidence of?
placental
mammals
Parallel/convergent evolution
Niche
Burrower
Placental Mammals
Mole
Convergent evolution
of analogous
Marsupial mole
burrowing characteristics
Australian Marsupials
Anteater
Anteater
Nocturnal
insectivore
Mouse
Climber
Numbat
Marsupial mouse
Spotted cuscus
Lemur
Glider
Stalking
predator
AP Biology
Chasing
predator
Sugar glider
Flying
squirrel
Ocelot
Tasmanian cat
Wolf
Tasmanian “wolf”
Vestigial Organs
 Structures that serve little or no function
remnants of structures that were
functional in ancestral species
 deleterious mutations accumulate in genes
for non-critical structures without reducing
fitness
 snakes & whales — remains of pelvis &
leg bones of walking ancestors
 eyes on blind cave fish
 human
This istail
not bone

LaMarck’s loss
from “disuse”!
AP Biology
Vestigial organs
These are
Why would whales
remnants of
have pelvis & leg bones
structures that were
if they were always
functional in
sea creatures?
ancestral species
AP Biology
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.
AP Biology
Anatomical similarities in vertebrate
embryos
Pharyngeal
pouches
Post-anal
tail
Chick embryo
AP Biology
Human embryo
4. What are the lines of evidence that support Darwin’s ideas?
Human
Macaque
Dog Bird
Frog
Lamprey
The sequence in
DNA
proteins
Why &compare
is a &molecular
DNA
proteins
record
of evolutionary
across
species?
relationships.
Comparative hemoglobin structure
8
32
45
67
125
Why compare
these genes?
0
10 20 30 40 50 60 70 80 90 100 110 120
compare common genes
Number of amino acid differencesbetween
hemoglobin (146 aa) of vertebrate species and that
of humans C (respiration)
 cytochrome
AP Biology
 hemoglobin (gas exchange)
Molecular Record
 Comparing DNA & protein structure

universal genetic code!
 DNA & RNA

Why compare
these genes?
compare common genes
 cytochrome C (respiration)
 hemoglobin (gas exchange)
Human/kangaroo
100
 A molecular record of evolutionary
relationships
Dog/
cow
75
Nucleotide substitutions
Closely related species have
sequences that are more similar
than distantly related species
Human/
cow
Rabbit/
rodent
50 Horse/
donkey
Sheep/
goat
25
Human/rodent
Llama/
cow
Horse/cow
Pig/
cow
Goat/cow
0
AP Biology
0
25
50
75
Millions of years ago
100
125
Building “family” trees
AP Biology
"Nothing in biology
makes sense except in
the light of evolution."
-- Theodosius Dobzhansky
March 1973
Geneticist, Columbia University
(1900-1975)
AP Biology
2006-2007
Evolution is "so overwhelmingly
established that it has become
irrational to call it a theory."
-- Ernst Mayr
What Evolution Is
2001
Professor Emeritus, Evolutionary Biology
Harvard University
(1904-2005)
AP Biology
2006-2007
Just Because Things Seem Obvious
Doesn’t Mean They Don’t Need To Be Supported
AP Biology
Peppered Moths
 Dark vs. light variants
Year
1848
1895
1995
AP Biology
% dark
5
98
19
% light
95
2
81
Peppered moth
 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

AP Biology
Industrial melanism
Rosemary and Peter Grant
Dry year
Dry year
Dry year
1977
1980
1984
10
9
Medium ground finch
8
AP Biology
1982
11
Beak depth of
offspring (mm)
Since dry years
produce thicker
shelled seeds,
then in dry years,
larger beaks will
be more frequent
in the population.
 Data…
Beak depth
Evolution in Darwin’s finches now
 Prediction:
Wet year
8
9
10
11
Mean beak depth of parents (mm)
Natural selection in action
 Insecticide &
drug resistance
Resistance…
NOT immunity!
insecticide didn’t
kill all individuals
 resistant survivors
reproduce
 resistance is inherited
 more of population is
resistant

 insecticide becomes less
Pesticide
molecule
Resistant
target site
Target site
Insect cell
membrane
Target site
& less effective
AP Biology
Decreased number of target sites
Genome sequencing
 What can data from whole
genome sequencing tell us
about evolution of humans?
AP Biology
Primate Common Ancestry?
Chromosome Number in
the Great Apes
(Hominidae)
orangutan (Pogo)
gorilla (Gorilla)
chimpanzee (Pan)
human (Homo)
48
48
48
46
Could we have
just lost a pair of
chromosomes?
Hypothesis:
Change in chromosome number?
If these organisms share a common
ancestor, then is there evidence in
the genome for this change in
AP Biology
chromosome
number
Chromosomal fusion
Testable prediction:
If common ancestor had 48 chromosomes (24 pairs),
then humans carry a fused chromosome (23 pairs).
What we should find:
Ancestral
Chromosomes Fusion
Chromosome Number in
the Great Apes
(Hominidae)
orangutan (Pogo)
48
gorilla (Gorilla)
48
Testable!48
chimpanzee (Pan)
This is what makes
human (Homo)
46
evolution science
AP Biology
& not belief!
Homo sapiens
Inactivated
centromere
Telomere
sequences
in middle of
chromosome
Centromere: bonding point between
chromosomes
Telomere: at ends of chromosomes
Hillier et al (2005) “Generation and Annotation of the DNA
sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.
Guess
what
we
found?!?
Ancestral
Chromosome 2 in
Chromosomes Fusion Homo sapiens
“Chromosome 2 is unique to the human
lineage of evolution, having emerged as a
result of head-to-head fusion of two
chromosomes that remained separate in
Inactivated
other primates. The precise fusion site has
centromere
been located in 2q13–2q14.1, where our
analysis confirmed the presence of multiple
Telomere
subtelomeric duplications to chromosomes
sequences
in middle of
1, 5, 8, 9, 10, 12, 19, 21 and 22. During the
chromosome formation of human chromosome 2, one of
the two centromeres became inactivated
(2q21, which
corresponds
to the centromere
Well
I’ll
from chimp chromosome 13) and the
be a monkey’s
centromeric structure quickly deterioriated.”
…or an ape’s…
uncle!
Human Chromosome #2 shows the exact
AP Biology
point
at which this fusion took place