2. Evidence supporting evolution
Fossil record
shows change over time
Anatomical record
comparing body structures
homology & vestigial structures
embryology & development
Molecular record
comparing protein & DNA
sequences
Artificial selection
human caused evolution
Regents Biology
3. 1. Fossil record
Layers of rock contain fossils
new layers cover older ones
creates a record over time
fossils show a series of organisms have
lived on Earth
over a long period of time
Regents Biology
4. Fossils tell a story…
the Earth is old
Life is old
Life on Earth has changed
Regents Biology
5. Evolution of birds
Today’s organisms
descended from
ancestral species
Fossil of Archaeopteryx
lived about 150 mya
links reptiles & birds
Regents Biology
6. We found the fossil — no
joke!
Land Mammal
?
e
e th
r ?
re a iate
Whe rmed
inte sils?
fos
Complete series
of transitional
fossils
Someone’s idea of a joke!
Regents Biology
But the joke’s
on them!!
Ocean Mammal
?
?
7. Evolution from sea to land
2006 fossil discovery of early tetrapod
4 limbs
Missing link from sea to land animals
Regents Biology
8. 3. Anatomical record
Animals with different
structures on the surface
But when you look under
the skin…
It tells an evolutionary story
of common ancestors
Regents Biology
9. Compare the bones
The same bones under the skin
limbs that perform different functions
are built from the same bones
How could these
very different animals
have the
same bones?
Regents Biology
10. Homologous structures
Structures that come from the same origin
homo- = same
-logous = information
Forelimbs of human, cats, whales, & bats
same structure
on the inside
same development in embryo
different functions
on the outside
evidence of common ancestor
Regents Biology
11. But don’t be fooled by these…
Analogous structures
look similar
on the outside
same function
different structure & development
How is a bird
like a bug?
on the inside
different origin
no evolutionary relationship
Solving a similar problem with a similar solution
Regents Biology
12. Analogous structures
Dolphins: aquatic mammal
Fish: aquatic vertebrate
both adapted to
life in the sea
not closely related
Watch the tail!
Regents Biology
13. Convergent evolution
3 groups with wings
Does this mean they have a
recent common ancestor?
They just
came up
with the
NO!
same answer!
Regents Biology
Flight evolved 3
separate times —
evolving similar
solutions to similar
“problems”
14. Convergent evolution led to mimicry
Why do these pairs look so similar?
Monarch male
Viceroy male
poisonous
edible
Which is the moth vs. the bee?
fly vs. the bee?
Regents Biology
fly
bee
moth
bee
15. Vestigial organs
Hind leg bones on whale fossils
Why would whales
have pelvis & leg
bones if they were
always sea creatures?
Because they
used to
walk on land!
Regents Biology
16. Comparative embryology
Development of embryo tells an
evolutionary story
similar structures during development
all vertebrate embryos have a “gill
pouch” at one stage of development
Regents Biology
17. 3. Molecular record
Comparing DNA & protein structure
everyone uses the same genetic code!
DNA
Human
Macaque
Dog Bird
Frog
Lamprey
8
32 45
67
125
compare common genes
compare common proteins
number of amino acids different
from human hemoglobin
0 10 20 30 40 50 60 70 80 90 100 110 120
Regents Biology
19. 4. Artificial selection
How do we know natural selection can
change a population?
we can recreate a similar process
“evolution by human selection”
“descendants” of wild mustard
Regents Biology
26. Natural Selection of Strawfish
How does natural selection affect genes?
How do genes affect evolution?
Regents Biology
2006-2007
27. 1. No Predator Preferences
FISH
blue
ALLELES
green
yellow
blue
yellow
Gen. 1
25% 50%
25%
50% 50%
Gen. 4
27% 55%
18%
55% 45%
No selection force in one specific direction.
No clear pattern of change.
Regents Biology
28. 2. Predator Prefers BLUE
FISH
blue
ALLELES
green
yellow
blue
yellow
Gen. 1
25% 50%
25%
50% 50%
Gen. 4
13% 50%
37%
38% 62%
Selection against blue.
Fewer
Regents Biology blue fish and fewer blue alleles.
29. 3. Predator Prefers GREEN
FISH
blue
ALLELES
green
yellow
blue
yellow
Gen. 1
25% 50%
25%
50% 50%
Gen. 4
36% 28%
36%
50% 50%
Selection against green.
Fewer
Regents Biologygreen fish but same variation in alleles.
30. 4. GREEN is Camouflaged
FISH
blue
ALLELES
green
yellow
blue
yellow
Gen. 1
25% 50%
25%
50% 50%
Gen. 4
20% 60%
20%
50% 50%
Selection against blue & yellow.
More green fish but same variation in alleles.
Regents Biology
31. Parallel Evolution
Niche
Placental Mammals
Burrower
not closely related
Mole
Anteater
Anteater
Nocturnal
insectivore
Climber
marsupial
mammal
Glider
Stalking
predator
Chasing
predator
Regents Biology
Australian Marsupials
Mouse
Marsupial mole
Numbat
Marsupial mouse
placental
mammal
Spotted cuscus
Lemur
Flying
squirrel
Ocelot
Sugar glider
Tasmanian cat
filling similar roles in nature,
Wolf
so have similar adaptations “wolf”
Tasmanian
32. Vestigial organs
Structures on modern animals that have
no function
remains of structures that were functional
in ancestors
evidence of change over time
some snakes & whales have pelvis bones &
leg bones of walking ancestors
eyes on blind
cave fish
human tail bone
Regents Biology
Hinweis der Redaktion
The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. Alonso et al. (2004) investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. A reconstruction of the braincase and endocasts of the brain and inner ear suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. Alonso et al. (2004) concluded that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.
There are innumerable intermediate & transitional forms
Whales as land creatures returning to the water….
Where are the intermediate forms of whale ancestors?
Cartoon making fun of this idea.
The cartoons disappeared 10-12 years ago when this fossil was found.
Ambilocetic natans = “Walking whale who likes to swim”
4-5 intermediate forms all found in last 2 decades
Indus River valley in between India & Pakistan.
The evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.
The results of application of new insecticide are typically encouraging, killing 99% of the insects.
However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.