1. 5.1 Evidence for Evolution
Essential idea: There is overwhelming evidence for the
evolution of life on Earth.

2. Understandings
Statement Guidance
5.1 U.1 Evolution occurs when heritable characteristics of a species
change.
5.1 U.2 The fossil record provides evidence for evolution.
5.1 U.3 Selective breeding of domesticated animals shows that artificial
selection can cause evolution.
5.1 U.4 Evolution of homologous structures by adaptive radiation explains
similarities in structure when there are differences in function.
5.1 U.5 Populations of a species can gradually diverge into separate species
by evolution.
5.1 U.6 Continuous variation across the geographical range of related
populations matches the concept of gradual divergence.

3. Applications and Skills
Statement Guidance
5.2 A.1 Development of melanistic insects in polluted areas.
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds, amphibians
and reptiles with different methods of locomotion.

4. Evolution is the accumulated inherited changes in a
population over time
Evolution is one of the most powerful unifying concepts in
science and is a critical underpinning to modern biology.
It has been stated that without evolution biology,
biology makes no sense.
Dobzhansky, 1973
5.1 U.1 Evolution occurs when heritable characteristics of a
species change.

6. But the Fossil recordBut the Fossil record ……
OBSERVATIONOBSERVATION

15. Evidence supporting evolution
I. Fossil record
• transition species
I. Anatomical record
• homologous & vestigial structures
• embryology & development
I. Biogeography (Contential Drift)
II. Molecular record (Neo-Darwinsim)
• protein & DNA sequence
5.1 U.1 Evolution occurs when heritable characteristics of a species change.

17. 5.1 U.1 Evolution occurs when heritable characteristics of a
species change.
The raw genetic material
(variation) is hidden there
http://upload.wikimedia.org/wikipedia/commons/9/90/Rock_Dove_
(Feral_Pigeon)_(Columba_livia)_-_geograph.org.uk_-_1309587.jpg

18. 5.1 U.1 Evolution occurs when heritable characteristics of a
species change.

19. 5.1 U.1 Evolution occurs when heritable characteristics of a species change.
http://4.bp.blogspot.com/-
6EXGifOabDY/T75wOIZARKI/AAAAAAAAEkk/OSmkn
25kUhE/s1600/darwin-finches.jpg

20. 5.1 U.2 The fossil record provides evidence for evolution.
Mount Everest
29,002 ft above sea level29,002 ft above sea level

21. Hillary’s Step
Fossilized
sea shells located
just a few feet
away from the
top of the world

22. 5.1 U.2 The fossil record provides evidence for evolution.
Fossil Record
• Sedimentary rock is laid down
over time… new on top, older
rocks below
• As one digs down, find related
fossils, which are progressively
older as one digs deeper
• Consistent and steady
increases in size/complexity of
structures or the whole
organism, or just the opposite,
are seen in successive
stratigraphic layers
Oldest
Youngest

23. 5.1 U.2 The fossil record provides evidence for evolution.
• 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

24. The fossil record provides the dimension of time to the study of
evolution – the layer of rock in which a fossil is found can be dated and
therefore used to deduce the age of the fossil.
http://sciencelearn.org.nz/Contexts/Dating-the-Past/Sci-Media/Images/Fossils-in-sedimentary-rock
5.1 U.2 The fossil record provides evidence for evolution.

25. http://sciencelearn.org.nz/Contexts/Dating-the-Past/Sci-Media/Images/Fossils-in-sedimentary-rock
5.1 U.2 The fossil record provides evidence for evolution.
There are gaps in the fossil record due to:
•Special circumstances are required for fossilization to occur
•Only hard parts of an organism are preserved
•Fossils can be damaged so that only fragments remain to be discovered
The fossil record is the sum of all
discovered and undiscovered fossils
and their relative placement in rock.

26. Fossil Preservation
• Petrified
• Prints and molds
• Resins which turn to Amber
• Tar
• Peat which is acidic preventing decay
• Frozen in Ice or Snow
• Sediments which turn to rock
5.1 U.2 The fossil record provides evidence for evolution.
http://upload.wikimedia.org/wikipedia/commons/d/de/Ambre_Dominique_Moustique.jpg

27. 5.1 U.2 The fossil record provides evidence for evolution.

28. 5.1 U.2 The fossil record provides evidence for evolution.
Radioactive Dating
• Unstable atomic isotopes that decay
over time. Organisms incorporate
these isotopes in their bodies. This
can be detected and used to
radioactive dating a fossil, because
radioactive decay follows a
predictable exponential decay with
time.
Half-life is the period of time it
takes for a substance undergoing
decay to decrease by half. Example
below

29. 5.1 U.2 The fossil record provides evidence for evolution.
• For instance, organisms take
up C, both as 14
C and 12
C but the
14
C decays away, so that one
can determine how old the
fossil is by the ratio of 14
C to 12
C
in the fossil. The older it is, the
greater the relative quantity of
12
C vs. 14
C.
Then, as with 14
C dating,
the age in half lives can
be deduced from the
decay curve
Half life of 14
C is 5730
years, so it is useful for
dating samples that are
between 1000 &
100,000 years old

30. 5.1 U.2 The fossil record provides evidence for evolution.
Potassium-Argon dating
• Proportions of parent 40
K atoms and daughter 40
Ar atoms are
measured
• Half-life of 40
K is 1250 million years so it is very useful for dating
samples older than 100,000 years old.

31. 5.1 U.3 Selective breeding of domesticated animals shows
that artificial selection can cause evolution.
Artificial selection Wild Mustard Plant
http://www.evolutionevidenc
e.org/wp-
content/uploads/2013/08/mu
stardselection1.jpg
http://upload.wikimedia.org/wikipedia/commons/2/2f/Wi
ld_Mustard.jpg

32. 5.1 U.3 Selective breeding of domesticated animals shows
that artificial selection can cause evolution.
https://phaven-prod.s3.amazonaws.com/files/image_part/asset/954254/z9zJXMj-QvJF-
DjAAnbdUsdnL2I/large_Brassica_oleracea_cauliflower_broccoli_etc_DP347.jpg

33. Selective breeding
5.1 U.3 Selective breeding of domesticated animals shows
that artificial selection can cause evolution.

34. Comparative Anatomy
• Homologous structures
• Analogous structures
Convergent evolution
Parallel Evolution
• Vestigial Organs
• Embryology
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds, amphibians
and reptiles with different methods of locomotion.

35. Homologous structures Pentadactly limb)
similarities in characteristics resulting from common ancestry
Divergent Evolution
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds, amphibians
and reptiles with different methods of locomotion.

36. Homologous structures
• Similar structure
• Similar development
• Different functions
• Evidence of close evolutionary
relationship
– recent common ancestor
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds,
amphibians and reptiles with different methods of locomotion.

37. Vestigial Structures
• describes a characteristic of organisms that
have seemingly lost all or most of its original
function through evolution.
• Fossil record supports the hypothesis that
whales are derived from ancient vertebrates
• Vestigial hind limbs are present in modern
whales internal bones. Vestigial limbs are
found in many animals, including the python.
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds,
amphibians and reptiles with different methods of locomotion.

38. Embryology
• Similar features seen in developmental stages of related organisms
• Gill pouches and tails seen in developing vertebrates
• They have a common ancestor
5.2 A.2 Comparison of the pentadactyl limb of mammals, birds,
amphibians and reptiles with different methods of locomotion.

39. The climate of the
Galapagos Islands
varies seasonally and
yearly. Coastal areas
and higher
elevations also show
a large temperature
difference.
Ages of the Galapagos Island
5.1 U.4 Evolution of homologous structures by adaptive radiation explains
similarities in structure when there are differences in function.

40. Darwin found… birds
Finch?
Sparrow?
Woodpecker? Warbler?
Collected manyCollected many
different birds on thedifferent birds on the
Galapagos Islands.Galapagos Islands.
Thought he foundThought he found
very different kinds…very different kinds…

41. Darwin was amazed to
find out:
All 14 species of birds
were finches…
Finch?
Sparrow?
Woodpecker? Warbler?
But Darwin found… a lot of finches
Large Ground
Finch
Small Ground
Finch
Warbler Finch
But there is only one
species of finch on the
mainland!
Veg. Tree Finch

42. Correlation of species to food source
SeedSeed
eaterseaters
FlowerFlower
eaterseaters
InsectInsect
eaterseaters

43. Hawaiian violets (Viola)
– Nine taxa, seven species distributed over most islands
– Species occupy several different habitats across five islands
• Dry forest
• Dry cliff
• Stream bank
• Swamp (cloud) forest
• Open bog
– Species growing in same habitat on different islands are almost
identical morphologically, anatomically
5.1 U.5 Populations of a species can gradually diverge into separate
species by evolution.

44. Ages of the Hawaiian Islands
Kauai = 5.1 my
Hawaii =
400,000-180,000 my
Maui Nui complex =
1.9 my-800,000 y
Oahu = 3.7-2.6 my

45. Topography of Kauai
Waimea Canyon
(extremely arid)
Alakai Swamp/Mt Waialeale
(wettest place on earth)
Sandy or rocky
Coastal sites
Low-elevation
Moist forest
High-elevation
wet forest, cliffs

46. Some Viola species on Kauai
Viola tracheliifolia
(treelet, dry forest)
Viola wailenalenae
(shrub, swamp)
Viola kauaiensis
(herb, open bog)

47. 5.1 A.1 Development of melanistic insects in
polluted areas.
http://upload.wikimedia.org/wikipedia/commons
http://en.wikipedia.org/wiki/Peppered_moth_evolution
#mediaviewer/File:Biston.betularia.f.carbonaria.7209.jp
g
Example of evolution taking place
•The peppered moth…. Two forms
(morphs) the gray mottled form and the
dark form. Changes in relative numbers was
hypothesized to be the result of selective
predation by birds. High industrial
pollution make the darker moth less likely
to be seen.
•Melanin gives color to moths
Black is a mutation of the white form
(morphs), it is dominant.
With industrial pollution the black allele
became favorable. Increase in
population of the dominant allele.
Clean air, return of lichen , increase in
recessive allele.

48. 5.1 A.1 Development of melanistic insects in
polluted areas.
http://upload.wikimedia.org/wikipedia/commons/b/b7/Lichte_en_zwarte_versie_berkenspanner.jpg

49. 5.1 U.6 Continuous variation across the geographical range of related
populations matches the concept of gradual divergence.
• Geographic variation is the term used to refer to differences
between populations. Differences in phenotype associated with local
environment
• For instance, yarrow plants vary with geographical location across
the Sierra Nevada