1. The document discusses several theories of evolution including Lamarckism, Darwinism, and punctuated equilibrium. 2. Lamarckism proposed that acquired traits could be inherited, while Darwinism proposed evolution through natural selection acting on inherited variation. 3. The punctuated equilibrium model suggests that evolution occurs in short bursts separated by long periods of stasis, rather than through the gradual process proposed by Darwin.

6. • Some science findings have been observed and
others inferred.
• A scientific theory is an explanation of
phenomena that is supported by scientific data.
• A scientific theory is therefore based on evidence.
Birds that lay large eggs do not fly.

7. Review of the Nature of Science
OBSERVATION
Birds that lay large
eggs are less likely
to fly.

8. Ask a QUESTION
I wonder if birds
that lay large eggs
are less likely to fly?

9. Hypothesis
Birds that lay large
eggs are less likely
to fly.

10. Prediction
This is true: Birds
that lay large eggs
are less likely to
fly.

11. Experiment to test hypothesis
S/He weighs large eggs
and determines which
of these birds can or
cannot fly.

12. Hypothesis Supported
S/he finds that
birds that lay large
eggs are less likely
to fly.

13. • Observation
• Question
• Hypothesis
• Prediction
• Experiment to test Prediction
• Hypothesis Supported

15. 200 years old
Based on evidence
from …
Fossil
record
Comparative
anatomy
Biogeography
Genetics

16. Organisms look different
from each other because of
environmental changes.

17. Evidence for EvolutionEvidence for Evolution
• Fossil Record
• Modification by descent
• Biogeography
• Genetics
• Comparative embryology

18. Fossil RecordFossil Record
The science of
discovering and
studying the fossil
record…
paleontologypaleontology

19. Paleontologists want toPaleontologists want to
knowknow
• Structure and
adaptation of
organism.
• How did the
organism interact
with others.
• Physical environment
at that time.

20. FossilsFossils
• Are the traces of dead
organisms.
• May be a whole
organism, fragments or
traces e.g. footprints or
droppings.

21. NOTE:NOTE:
Normally organisms die andNormally organisms die and
vanish without a trace.vanish without a trace.
However under certainHowever under certain
circumstances an organism’s bodycircumstances an organism’s body
may be preserved as amay be preserved as a FOSSILFOSSIL..

22. Types of fossilsTypes of fossils
• Petrification
• Permineralisation
• Moulds
• Casts
• Compression
• Coalification
• Amber
• Trace

23. Fossilisation may occur inFossilisation may occur in
different ways:different ways:
• An entire animal may be preserved e.g.
mammoth or insects trapped in amber.
• Fossils that have been caught up in the
sedimentat ion process and may have
had their bones replaced by another
chemical.

24. Living fish A
Dies
Enclosed in sediment
Hard parts fossilised
Living fish B
Dies
Enclosed in sediment
Hard parts fossilised
Fish B becomes a fossil much later than fish A
The sediment eventually becomes rock
The deeper the rock layer, the older the fossil
4

25. living fish sediment from river
fish skeleton partly buried by sediment
5

26. fish skeleton fossilised
older sediment
becomes rock
more recent sediment collects
6

27. land raised above
water level
recent rock
older rock
7

28. earth movements
fracture rock
fossilised skeleton exposed
8

29. Death Sedimentation
Organism is compacted
Continental
Drift
Erosion
FossilizationFossilization

30. How fossils form inHow fossils form in
sedimentary rocksedimentary rock
The sequence of fossils
within every set of
undisturbed
sedimentary rock
shows a change from
simpler to more
complex organisms in
the youngest layers.

31. The sedimentary rocks
provide a fossil record of
the history of the Earth.

32. The fossil record is
incomplete and is likely to
remain so for TWO reasons:
• Fossilization is a rare event.
• Soft bodied organisms are
unlikely to be fossilized.

33. From the fossil record…
1. The Earth is 4.5 billion years old4.5 billion years old.
2. First life formslife forms appeared 3.8 billion3.8 billion
years agoyears ago.
3. Today’s life forms are more complexmore complex
than those of long ago.
4. Many life forms have gone extinct.extinct.

35. The basic pattern of the vertebrate limb is represented by the
human arm skeleton shown below.
ball and
socket joint
hinge joint
single bone two
bones
group of
small
bones
five jointed
digits
17
2. Modification by descent.

36. Comparative AnatomyComparative Anatomy
Similar structures occurring in a
range of organisms due to common
ancestry but with different functions
are termed
HOMOLOGOUS
STRUCTURES.

37. Lizard
Bird
Dolphin Bat
The basic pattern suggests they have evolved from a
common ancestor.common ancestor.
19

38. Analogous Structure
(convergent evolution)
No common ancestor.
Structures arise independently to
perform a similar function.

39. BiogeographyBiogeography
• Study of distribution
of plants and
animals throughout
the world.
• Such distributions
are consistent with
the hypothesis that
related forms
evolved from one
locale and then
spread out.

42. Physical Factors:
location of continents determine
where a population can spread.
Euphorbia- African Cactus - American

43. No snakes in New Zealand:
continental drift.

44. 4. Evidence from molecular biology and genetics.4. Evidence from molecular biology and genetics.

47. The
SIMILARITYSIMILARITY of
all living
organisms is
more impressive
than their
DIVERSITYDIVERSITY.

50. Overview of the history of differentOverview of the history of different
theories of developmenttheories of development
(a)(a) LamarkismLamarkism
(b)(b) DarwinismDarwinism
(c)(c) PunctuatedPunctuated
equilibriumequilibrium

51. Jean Baptiste de Lamarck (1744-
1829)
1 The two “LAWS” of Lamarck.
2 Examples of the Application of Lamarck’s
Theory.
3 Lamarck’s Theory is not accepted by most
Life Scientists.

52. Jean Baptiste de LamarckJean Baptiste de Lamarck
He accepted the
ideas that
life forms
evolve from
simpler to more
complex forms.

53. Lamarck’s Evolution is based on TWO
conditions
• The Law of Use and Disuse.
• The Law of Inheritance of Modified
Characteristics.

54. The Law of Use and Disuse
If organs were usedused
they would increaseincrease
in size or efficiency.
If organs were not
used they would get
smaller and
disappear.

56. Eyes of moles have stopped functioning
because of disuse.

57. Legs of snakes have been reduced due to
disuse.

58. Webbed feet in birds are the result of
spreading the toe bones and the skin between
them in order to swim to find food and escape
predators.

59. The Law of Inheritance of ModifiedThe Law of Inheritance of Modified
Characteristics.Characteristics.
The physical changes acquired by parents
during their lifetime could be passed on
to their offspring.

60. Lamarck’s Theory is NOTLamarck’s Theory is NOT
accepted for the followingaccepted for the following
reasons.reasons.
Changes within organisms occur
randomly. (The organism did not
evolve because it wanted to).
Little evidence to support the idea that
acquired characteristics are passed on
to future generations.

61. Charles Darwin (1809-1882)Charles Darwin (1809-1882)
• Darwin’s Story.
• Darwin’s Theory of
Evolution by Natural
Selection.
• Differences between
Lamarck and Darwin.

62. Darwin’s StoryDarwin’s Story
Charles Darwin undertooka 5 yearvoyage on
the HMS Beagle as an unpaid workerstudying
the plants and animals he came across.

63. Darwin noticed the following on his
journey:
There were large
armadillo fossils
which seemed to be
related to the
smaller ones alive
today.

64. The rhea’s in South
America seemed to
be related to ostriches
and emus. Yet they
seemed to be different
species.

65. Why were
fossilized marine
animals found
inland?

66. Species of
animals found on
nearby islands
were slightly
different to those
found on the
mainland.

67. • 1844: He wrote
THEORY OF EVOLUTIONTHEORY OF EVOLUTION
BY NATURALBY NATURAL
SELECTIONSELECTION
• 1858 Russell and
Wallace put forward the
same theory.
• Together with an article
by Wallace Darwin’s
Theory was read before
the Linnaean Society in
1858.

68. Darwin wrote his book
On the Origin of SpeciesOn the Origin of Species..

69. • Within a population there is a large number oflarge number of
individualsindividuals which produce many offspring.
• Within a population organisms varyvary..
• Some organisms are “better off”“better off” than others and
produce more offspring.
• Better off individuals produce offspringproduce offspring that are
better off.
• The better off trait increases in the population.
• So natural selectionnatural selection causes a population to change
in favour of the “better off” individuals.
• As natural selection occurs from generation to
generation there is continual, gradual change in
populations leading to the evolution of new speciesevolution of new species.

71. Elements of Darwin’s Theory

72. Explanation of the long legs and necks in
giraffe using Darwinian Evolution

76. Differences between Lamarck and
Darwin’s Theory
Darwin
Lamarck
1
Genetic change is random;
adaptive changes arise by
chance, before any need for
them arises. The
environment selects the
best-adapted individuals
from the population.
1
Genetic change occurs in
response to need; ie the
environment causes
adaptations to develop.
2
Changes in the body
(somatic changes) acquired
during the life are not
handed on to the offspring.
2
Adjustments resulting from
sustained use of the body are
handed on to the offspring.

77. ACTIVITY 3
Darwin’s Natural Selection Worksheet
Read the following situations below and identify the 5 points of Darwin’s natural
selection. There are 2 types of worms: worms that eat at night (nocturnal) and
worms that eat during the day (diurnal). The birds eat during the day and seem to
be eating ONLY the diurnal worms. The nocturnal worms are in their burrows
during this time. Each spring when the worms reproduce, they have about 500
babies but only 100 of these 500 ever become old enough to reproduce.
a. What worm would be naturally selected for?
Darwin's 5 points: Identify the 5 points in the scenario above.
Population has variations.
_________________________________________________________________
Some variations are favorable.
_________________________________________________________________
More offspring are produced than survive
_________________________________________________________________
Those that survive have favorable traits.
_________________________________________________________________
A population will change over time.
_________________________________________________________________

78. There are 3 types of polar bears: ones with thick coats, ones with thin
coats and ones with medium coats. It is fall, soon to be winter. The
temperatures are dropping rapidly and the bears must be kept warm,
or they will freeze to death. Many of the bears have had ~2 cubs each
but due to the extreme temperatures, many mothers only have one
cub left.
a. What bear will be naturally selected for?
__________________________________
Darwin's 5 points: Identify the 5 points in the scenario above.
Population has variations.
_____________________________________________________________
_
Some variations are favorable.
_____________________________________________________________
_
More offspring are produced than survive
._____________________________________________________________
Those that survive have favorable traits.
_____________________________________________________________
A population will change over time.

79. In ostriches, there are 2 types: ones that run fast and those that run slowly. The
fast birds can reach up to 40 miles an hour. Jackals love to eat ostrich, and they
can reach speeds of up to 35-40 miles per hour. A flock of ostrich will lay 10
eggs (each mother only lays 1),but many rodents break into the eggs and eat the
foetus before they hatch.
a. What ostrich will be naturally selected for?
Darwin's 5 points: Identify the 5 points in the scenario above.
Population has variations.
__________________________________________________________________
Some variations are favorable.
__________________________________________________________________
More offspring are produced than survive.
__________________________________________________________________
Those that survive have favorable traits.
__________________________________________________________________
A population will change over time.
__________________________________________________________________

82. Discontinuous variationDiscontinuous variation
Distinct
categories.
You either have
the characteristic
or you don’t.
Controlled by a
single gene. Environment has little effect.

83. Bell shaped
curve

84. Influenced by environmental
influences.
Combined effect of many genes:
POLYGENIC INHERITANCE.
Think of as many factors that you
can that would influence the
amount of milk a cow produces.

87. 87

88. Graph of Gradual Evolution
Some biologists claim that most evolutionary change
takes place as a result of a series of very small changes
(‘gradualism’).

89. 89

91. 91Evolution
Time
Rapid speciation
Rapid speciation
Rapid speciation
Stasis
Stasis
Stasis
Species W
Species X
Species Y Species Z

92. THE PUNCTUATED EQUILIBRIUM MODEL.THE PUNCTUATED EQUILIBRIUM MODEL.
• Gould and Eldredge formulated this
model (1972) .
• They observed that the fossil recordfossil record
gives a different picturegives a different picture of evolution.
• They claim that there were longlong
periods of stasisperiods of stasis (4-10 million years)
involving little evolutionary change .
• Then occasional rapid formation ofrapid formation of
new speciesnew species (5,000 - 50,000 years).
Stephen Gould
Niles Eldredge

93. Two models
93

94. DarwinismDarwinism Punctuated EquilibriumPunctuated Equilibrium
1. This type of speciation
happens gradually. A
species gradually
changes to form a
new one, diverging
from the original.
1. This type of speciation
happens abruptly. Many
species remain the same for a
long period of time (stasis)
and then there is a quick
change due to change in the
environment.
Table comparing Darwinism and Punctuated
Equilibrium

95. 95

96. There are different phases in evolution
Stasis (Gradualism)
Rapid change
(Punctuated equilibrium)

97. 97
Living ,dying and being fossilized - little observable
evolution.

98. Isolation – lake forms and isolate small
population 98

99. 99

100. 100

101. 101
Sea level rise, reuniting the isolated molluscs with
their sister lineage.

102. Expansion and stasis: The isolated population expand
into its past range, the isolated branch might
outcompete their ancestral population ,causing it to go
extinct like it is shown in this example.

103. Larger population size and large range move
back to step 1 stasis with fossil preservation.

104. This process would produce the following pattern in
the fossil record:
104

105. 105

107. 107

108. 1. Plant and animals breeders selectselect those organisms with
desired traits and breed with them.
2. Example: pink grape fruit, cows that produce lots of milk,
hen that lay lots of eggs.
3. New species are only produced after selective breeding
over a number of generationsnumber of generations.
4. Natural selection takes place in nature, artificial selection
takes place by humans selecting which organisms to breed
with.

111. Artificial Selection Natural Selection
1. People decide which
characteristics are
desirable.
1. The environment
determines which
characteristics will
survive.
2. May involve breeding two
or more species, though
can also occur within one
species.
2. Occurs only within one
species.
3. A rapid process resulting
in new breeds or hybrids
after only a few
generations.
3. Usually a very slow
process.
Table comparing artificial and natural selection

113. POPULATION:POPULATION:
a group of organisms of the same
species, living in the same area at the same
time and capable of random interbreeding.

114. SPECIES:
a group of organisms of
similar characteristics that
are able to interbreed. The
offspring is fertile.

119. SpeciationSpeciation
This involves the geneticgenetic
changeschanges in a subgroup
of a population which
makes the newnew
population incapablepopulation incapable
of producing offspringproducing offspring
with the originaloriginal
population.population.

120. Process by which all individuals of a
particular species die out.

122. Types of Speciation
• Allopatric Speciation
• Sympatric Speciation

123. Allopatric SpeciationAllopatric Speciation : individuals are: individuals are
separated because of a geographicalseparated because of a geographical
barrier.barrier.

128. Activity 5
Write an essay where you
discuss allopatric speciation in
terms of the Galapagos tortoises.
Isaacs p. 208.

129. Sympatric Speciation
Individuals in aIndividuals in a
population living inpopulation living in
the same habitatthe same habitat
develop uniquedevelop unique
mutations thatmutations that
prevent them fromprevent them from
mating with themating with the
original population.original population..

130. SpeciationSpeciation

131. D. Mechanisms ofD. Mechanisms of
Reproductive Isolation.Reproductive Isolation.
1.1. Breeding at different times of the year.Breeding at different times of the year.
2.2. Species-specific courtship behaviour.Species-specific courtship behaviour.
3.3. Adaptation of different pollinators.Adaptation of different pollinators.
4.4. Infertile offspring.Infertile offspring.

132. Breeding at different timesBreeding at different times
of the year.of the year.
Apple maggot flies
Hawthorns
Apples

133. Gene flow has been reduced between fliesGene flow has been reduced between flies
that feed on different food varieties, eventhat feed on different food varieties, even
though they both live in the same geographicthough they both live in the same geographic
area.area.

134. Courtship behaviours allows birds of the same species to
recognise each other as potential mates.
Courtship is reinforced by distinctive callscalls and plumageplumage.

135. Flowers are adapted to promote pollination by one
species of animal.
This prevents cross breeding.

137. 62 chromosomes 64 chromosomes
63 chromosomes

141. Antibiotics are used toAntibiotics are used to
treat bacterial infections.treat bacterial infections.

145. Treatment
for MDR TB
lasts 24
months.
Treatment forMDR TB is 100Xmore expensivethan TB.
Treatment
for MDR TB
has more
side effects
than TB.

146. If MDR TB antibiotics are not taken
correctly…
MDR TB may mutate to XDR TB.