1. er
Warbl
finch
Gr
es
ch
ou
Cactus
fin
nd
eater
ee
fi n
Insect eaters
Tr
ch
Seed eaters
s e
Bud eater
2006-2007
2. A. Proposed a way how
evolution works
1. How did creatures
change over time?
2. By natural selection
B. Collected a lot of
evidence to support
his ideas
1. 1809-1882
2. British naturalist
3. A. Darwin invited to travel around the world
• 1831-1836 (22 years old!)
• made many observations of nature
• mission of the Beagle was to chart
South American coastline
Robert Fitzroy
5. Recently formed volcanic
islands. Most of animals on
the Galápagos live nowhere
else in world, but they look
like species living on South
American mainland.
800 km west of Ecuador
6. Many of Darwin’s observations made him wonder… Why?
Why were these creatures found only on the Galapagos Islands?
7. Evidence showed that
creatures had changed
over time
present day Armadillos
Darwin asked:
Why should extinct
armadillos & modern
ancient Armadillo armadillos be found on
same continent?
8. Evidence showed that
creatures had changed
over time
(extinct) Giant ground sloth
present day Sloth
Darwin asked:
Why should
extinct sloths &
modern sloths be
found on the same
continent?
9. Darwin found...different shells on
tortoises on different islands
Darwin asked:
Is there a relationship
between the
environment & what an
animal
looks like?
11. Darwin was amazed to
find out:
All 14 species of birds
were finches…But there
is only one species of
finch on the mainland! QuickTime™ and a
Photo - JPEG decompressor
Finch?
are needed to see this picture.
Sparrow?
Darwin asked:
If the Galapagos finches
came from the mainland,
why are they so different
now?
Woodpecker? Warbler?
12. Darwin found: different beaks are
The differences inherited variations
between species of serve as adaptations
finches were that help birds compete
for food
associated with the these birds survive &
different food they reproduce
ate. pass on the genes for
those more fit beaks
over time nature selected
for different species with
different beaks
13. Warbler finch Cactus finch
Woodpecker finch Sharp-beaked finch
Small er Small
insectivorous Warbl ground
tree finch finch finch
Gr
es
Cactus
ou
ch
Large Medium
nd
in
eater
f
insectivorous ground
fin
ee
tree finch Insect eaters finch
Tr
ch
es
Vegetarian Seed eaters Large
tree finch ground
Bud eater
finch
natural selection for best
variation survival & reproduction
14.
15. A. Darwin’s conclusions
1. Variations in beaks
in original flock
adaptations to foods available on islands
2. Natural selection for most fit
over many generations
finches were selected for specific beaks & behaviors
3. Offspring inherit successful traits
over many generations
finches were selected for specific
4. Separate into different species
16. LaMarck
• evolution by acquired
traits
creatures developed traits
during their lifetime
give those traits to their
offspring
• example
in reaching higher
leaves giraffes stretch their
necks & give the acquired
longer neck to offspring
• not accepted as valid
17. Giraffes that already
have long necks
survive better
Leave more offspring
that inherit long
necks
variation
selection & survival
reproduction &
inheritance of more
fit traits
18. A. Fossil record
Shows change over time
B. Anatomical record
Comparing body structures
1. homology & vestigial structures
2. embryology & development
C. Molecular record
Comparing protein & DNA
sequences
D. Artificial selection
Human caused evolution
19. 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
20. the Earth is old
Life is old
Life on Earth has changed
21. In 2006 fossil
discovery of
early
tetrapod
4 limbs
Missing link
from sea to
land animals?
22. Land Mammal
? the
are
ere a diate
W h me
inter sils?
fos ?
Complete series
of transitional ?
fossils
We found the fossil — no joke!
Ocean Mammal
24. Animals with different
structures on the surface
But when you look under
the skin…
It tells an evolutionary story
of common ancestors
25. 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?
26. Structures that come from the same origin
Homo = same
logous = information
Forelimbs of human, cats, whales, & bats
are homologous
same structure
on the inside
same development in embryo
different functions
on the outside
evidence of common ancestor
27. Don’t be fooled by these!
look similar
on the outside
same function
different structure &
How is a bird development
like a bug?
on the inside
different origin
no evolutionary relationship
Solving a similar problem with a similar solution
28. Dolphins: aquatic mammal
Fish: aquatic vertebrate
both adapted to
life in the sea
not closely related
29. Flight evolved 3
separate times —
evolving similar
3 groups with wings solutions to similar
• Does this mean they have a “problems”
recent common ancestor?
They just
came up
with the
NO!
same answer!
30. Why do these pairs look so similar?
Monarch male Viceroy male
poisonous edible
Which is the moth vs. the bee?
fly vs. the bee?
fly bee moth bee
31. 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!
32. 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
33. Development of embryo tells an
evolutionary story
• similar structures during development
all vertebrate embryos have a “gill
pouch” at one stage of development
34. Comparing DNA & protein structure
• everyone uses
the same
genetic code! Human Macaque Dog Bird Frog Lamprey
DNA
compare common genes
compare common proteins
8 32 45 67 125
number of amino acids different
from human hemoglobin
0 10 20 30 40 50 60 70 80 90 100 110120
36. How do we know natural selection can
change a population?
• we can recreate a similar process
• “evolution by human selection”
“descendants” of wild mustard
What did Darwin say? What evidence supports Evolution by Natural Selection? What impact did Evolution have on biology?
After graduation Darwin was recommended to be the conversation companion to Captain Robert FitzRoy, preparing the survey ship Beagle for a voyage around the world. FitzRoy chose Darwin because of his education, his similar social class, and similar age as the captain. Darwin noted that the plants and animals of South America were very distinct from those of Europe
The origin of the fauna of the Galapagos, 900 km west of the South American coast, especially puzzled Darwin. On further study after his voyage, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland. It seemed that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands
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 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.
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.
