2. What characteristics of the following animals improve
their ability to survive?
Change Over Time
ADAPTATION: a
characteristic that improves
an individual’s ability to
survive and reproduce in a
particular environment.
3. What is a species?
Change Over Time
SPECIES: a group of
organisms that are closely
related and can mate to
produce fertile offspring.
4. What is a species?
Change Over Time
A mule is the offspring of
a male donkey and a
female horse. Mules are
not fertile. Are horses
and donkeys from the
same species?
5. Do species change over time?
Change Over Time
The planet is
4.6 billion
years old. In
this time,
many
species
have died
out, and
many new
species
have
appeared.
The processes that have
transformed life on Earth from
its earliest forms to the vast
diversity that characterizes it
today is known as
EVOLUTION.
6. Evidences of evolution
Change Over Time
Fossil Record A fossil is the preserved remains or traces of any
organism from the remote past
Fossil evidence may be one of two types
• Direct or body fossils (bones, teeth,
shells, leaves, etc.)
• Indirect or trace fossils (footprints,
tooth marks, burrows, etc.)
7. Evidences of evolution
Change Over Time
Fossil Record
Fish to
amphibians
Fossils show a
chronological (time)
sequence in which
characteristics appear
and develop in
complexity
8. Evidences of evolution
Change Over Time
Fossil Record
Fossils have been discovered
of many types of organism
that no longer exist, e.g.
trilobites and dinosaurs.
In most cases no fossils can
be found of organisms that
do exist today.
This suggests that the
ancestral species evolved into
the modern species
9. Evidences of evolution
Change Over Time
Fossil Record
TIKTAALIK. This creature is a mosaic
of fish and land features. It has scales
and fins like a fish but flat head with
eyes on top, a neck, shoulder, elbow,
and wrist. It is telling us that this is a
fish that can live in the shallows and
even make short excursions on to land.
ARCHAEOPTERYX. Combination of
reptilian and distinctly bird-like
characteristics, mouth full of teeth, long
tail and feathery, clawed arms,
appeared to be a true missing link
between reptiles and birds.
Bird-reptile transition Land-sea transition
Transitional fossils show the links between groups or species by
exhibits traits common to both the ancestral group/species and its
derived descendant group/species.
10. Evidences of evolution
Change Over Time
Fossil Record
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.
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.
11. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons Human beings have approx. (genes in common with):
96% with chimpanzees
90% with cats
80% with cows
75% with mice
12. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons Human beings have approx. (genes in common with):
This does not prove that
Beyonce evolved from
chimpanzees or cats,
though, only that we shared
a common ancestor in the
past. And the amount of
difference between our
genomes corresponds to
how long ago our genetic
lines diverged.
13. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Phylogenetic tree is a diagram
showing the evolutionary interrelations
of a group of organisms derived from
a common ancestral form.
The ancestor is in the tree “trunk”;
organisms that have arisen from it are
placed at the ends of tree “branches.”
The distance of one group from the
other groups indicates the degree of
relationship;
i.e., closely related groups are located
on branches close to one another.
14. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Place the following organisms in the
phylogenetic tree:
•Human
•Fish
•Chicken
•Mouse
•Frog
15. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Place the following organisms in the
phylogenetic tree:
•Human
•Fish
•Chicken
•Mouse
•Frog
16. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
Homologous structures or
comparative anatomy of
groups of animals or
plants shows certain
structural features are
basically similar.
Structures or anatomical
features having similar
basic structure as in other
species said to be
homologous.
17. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
homologous structures used in
different ways in different species
18. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
The structural similarities imply
a common ancestry
This illustrates adaptive radiation since
the basic structure adapted to different
niches
The more exclusive the shared
homologies the closer two organisms
are related.
19. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
Vestigial Structures
A very interesting type of homologous structure is the
one that may have served a function in the evolutionary
past, but in the modern species has no function at all.
The pelvis and femur of a whale are examples.
The structural similarities imply
a common ancestry
20. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
Vestigial Structures
A very interesting type of homologous structure is the
one that may have served a function in the evolutionary
past, but in the modern species has no function at all.
The pelvis and femur of a whale are examples.
The structural similarities imply
a common ancestry
21. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
Vestigial Structures
Initially, all chordate embryos
strongly resemble each
other. These could only be
possible if all Chordata
descended from a common
ancestor mans, dogs, snakes,
fish, monkeys, eels are all
considered "chordates" (belong
to the phylum Chordata).
Embryology & Development
22. Evidences of evolution
Change Over Time
Fossil Record
DNA Comparisons
Homologous Structures
Vestigial Structures
One of the features of this phylum is that, as
embryos, all these life forms have gill slits, tails,
and specific anatomical structures. For humans,
gill slits reform into the bones of the ear and jaw at
a later stage in development.Embryology & Development
23. Evidences of evolution
Change Over Time
Scientists believe that whales evolved from land-based mammals.
What three pieces of evidence support possibility?
• Existence of
unused hip
bones in modern
whales
• Whales are
mammals
• Existence of a
large number of
fossils.
24. Evidences of evolution
Change Over Time
How do scientists use the location of fossil discoveries to determine
the order in which different organisms lived on Earth?
Since the layers of
the Earth form in
an orderly fashion,
scientists know
that the deeper
layers were formed
before the upper
layers. By knowing
the layers in which
fossils were found,
scientists can
determine the
relative ages of
different fossil.
25. Charles Darwin
How Does Evolution Happen?
Charles Darwin's theory of evolution by natural selection made us
rethink our place in the world.
The man
who
struggled
with his
own
ideas
The idea that humans shared a common ancestor with apes was a
challenge to the foundations of western civilization
26. Charles Darwin
How Does Evolution Happen?
Setting sail around the world
Darwin’s tutor at Cambridge recommended him
as a ‘gentleman naturalist’ on a voyage around
the world on HMS Beagle. Darwin jumped at the
chance.
Over the following five years, Darwin visited four
continents, spending much of his time on land
collecting specimens and investigating the local
geology.
27. Charles Darwin
How Does Evolution Happen?
Darwin’s Finches
Darwin noticed that each island supported its
own form of finch which were closely related
but differed in important ways.
What difference did Darwin observe among
the different species of Galápagos finches?
Their different beaks are
adaptations that evolved because
the different finches needed to get
food in different ways.
Why do the Galápagos finches
have different beaks?
28. Charles Darwin
How Does Evolution Happen?
Darwin’s Thinking
Breeding Population Earth’s History
29. Charles Darwin
How Does Evolution Happen?
Darwin’s Thinking
Breeding Population Earth’s History
Farmers and breeders had
produced many kinds of
plants and animals with the
desired characteristics
(selective breeding).
Species can produce many
offspring, but populations
are limited by starvation,
disease, competition and
predation. Only a limited
number of individuals
survive to reproduce.
The Earth was very old and
species could evolved over
this time.
30. Charles Darwin
How Does Evolution Happen?
Darwin’s Thinking
Breeding Population Earth’s History
Is the process by which individuals that are better adapted to their environment survive
and reproduce more successfully than less well adapted individuals.
Theory of natural selection
• Phenotypic variation exists among
individuals and the variation is heritable.
• More individuals are produced each
generation that can survive.
• When reproductive isolation occurs new
species will form.
• Those individuals with heritable traits better
suited to the environment will survive.
31. Charles Darwin
How Does Evolution Happen?
Darwin’s Thinking
Breeding Population Earth’s History
Is the process by which individuals that are better adapted to their environment survive
and reproduce more successfully than less well adapted individuals.
Theory of natural selection
Sketch the four parts of natural
selection providing an example
(different from tarantulas and
giraffes)
32. Charles Darwin
How Does Evolution Happen?
Changes in Population
The Theory of Natural Selection explains how populations are change in response to
the environment.
Peppered Moth ('Darwin's moth‘)
There is also a naturally
occurring genetic mutation
which causes some moths to
have almost black wings.
Are normally
white with black
speckles
across the
wings
(camouflaged
against lichen-
covered tree
trunks).
33. Charles Darwin
How Does Evolution Happen?
Changes in Population
The Theory of Natural Selection explains how populations are change in response to
the environment.
Peppered Moth ('Darwin's moth‘)
These black forms are not as well camouflaged on the
lichen as normal 'peppered' forms and so they are more
likely to be eaten by birds and other predators.
Industrialization and
domestic coal fires
had caused sooty air
pollution which had
killed off lichens and
blackened urban
tree trunks and
walls.
In the mid-twentieth century controls
were introduced to reduce air
pollution and as the air quality
improved tree trunks became
cleaner and lichen growth
increased.
What was the effect in moth’s population?
34. Charles Darwin
How Does Evolution Happen?
Changes in Population
The Theory of Natural Selection explains how populations are change in response to
the environment.
Peppered Moth ('Darwin's moth‘)
Use this information to create a graph of
the paper Moth population over time
35. Charles Darwin
How Does Evolution Happen?
Changes in Population
The Theory of Natural Selection explains how populations are change in response to
the environment.
Peppered Moth ('Darwin's moth‘)
In the mid-twentieth century controls
were introduced to reduce air pollution
and as the air quality improved tree
trunks became cleaner and lichen growth
increased.
Use this information to create a graph of
the paper Moth population over time
Continue the graph with the new information
36. Charles Darwin
How Does Evolution Happen?
Changes in Population
The Theory of Natural Selection explains how populations are change in response to
the environment.
Peppered Moth ('Darwin's moth‘)
In the mid-twentieth century controls
were introduced to reduce air pollution
and as the air quality improved tree
trunks became cleaner and lichen growth
increased.
Use this information to create a graph of
the paper Moth population over time
Continue the graph with the new information
37. Charles Darwin
How Does Evolution Happen?
Defend Evolution!
Record a video-interview, video debate, theater play or any other video explaining
evolution and its evidences.
