Download Evidence for Evolution

Evidence for Evolution
Evidence of Evolution
Essential Questions
• What is the anatomical evidence of evolution?
• How are fossils used as evidence of evolution?
• What evolutionary evidence do we have from
the field comparative embryology?
• How does biogeography provide evidence for
evolution?
• How does genetics and biochemistry provide
evidence for evolution?
Evidence for Evolution
• Scientists have found evidence for evolution in
multiple disciplines
– Anatomy, paleontology, comparative embryology,
biochemistry, genetics, etc.
Evidence for Evolution: Anatomy
• Homologous structures: structural features
with a common evolutionary origin
Evidence for Evolution: Homology
• Homology: similarity resulting from common
ancestry
• Homologous structures illustrate the structural
similarities between seemingly unrelated species
Homologous structure example: quadruped limbs
-All creatures with four limbs have the same bone structure
-This is true of mammals, birds, and reptiles
The similarities in quadruped bone structure point
to their descent from a common ancestor.
It would have been impossible for these
homologous structures to have arisen randomly in
seemingly unrelated species.
They must have
shared a common
ancestor.
• How do we know that species with homologous
structures are evolutionarily related?
• Because we can compare homologous structures with
analogous structures
• Analogous structures: the body parts of organisms
that do not have a common evolutionary origin but
are similar in function
• Analogous structures are examples of
convergent evolution
– Convergent evolution: the independent evolution
of similar features in seemingly unrelated species
• Analogous structures are examples of
convergent evolution
– Convergent evolution: the independent evolution
of similar features in seemingly unrelated species
(Analagous)
Evolutionarily Related
Evolutionarily UNrelated
Further Anatomical Evidence for
Evolution
Vestigial structures: structures in a present
day organism that no longer serves as its
original purpose
Vestigial structures
illustrate that as species
evolve over time,
unused structures
shrink and disappear
Vestigial Structure
Body part that has lost its original function through evolution
Remainders of hind limb bones in whales suggest that at some point,
this species no longer had a need for them.
Evidence for Evolution: Fossils
• Fossils provide a record of early life and evolutionary history
Evidence for Evolution: Fossils
• Most fossil plants and animals are found at
specific time periods in the geological column.
• No single fossil has ever been found out of
order in this record of life on earth.
Evidence for Evolution: Fossils
• Fossil evidence can be used to put together a
chronological history of a species’ evolution
over time.
Smithsonian Whale Evolution
Evidence of Evolution: Embryology
• Embryo: the earliest stage of development in
plants and animals
• Comparative embryology proves that the
embryos of many species are extremely
similar
• Developing organisms look very similar to one
another and often pass through
developmental stages that resemble the
organisms from which they evolved.
Evidence of Evolution: Biogeography
• Biogeography: the branch of biology that
deals with the geographical distribution of
plants and animals
• Pangaea: the single large continent that
existed 250 million years ago
Evidence of Evolution: Biogeography
• Isolated islands such as
Madagascar are missing
common species found
on the mainland
• The unique species they
contain (like lemurs)
evolved from a common
ancestor into a new
species due to
geographical isolation
– Endemic species: a
species whose existence
is restricted to a certain
area
Evidence for evolution: Adaptations
• Structural adaptations have arisen over time
– Mimicry: a structural adaptation that allows one
species to resemble another species
Adaptations like this
show that over time,
species can begin to
resemble other species
that are successful
Evidence for evolution: Adaptations
• Structural adaptations have arisen over time
– Mimicry: a structural adaptation that allows one
species to resemble another species
– Camouflage: an adaptation that allows species to
blend in with their environment
Evidence for Evolution: Biochemistry
• Genetics now
provides evidence
that all life on earth is
linked, as all life on
earth uses the same
genetic molecules
(DNA & RNA)
• The more closely
related the
organisms, the more
DNA they share
Evidence for Evolution: Observation
• Evolution of drug-resistant bacteria
• Artificial selection: modification of species due
to human selected breeding
Evidence for Evolution: Observation
• Evolution of drug-resistant bacteria
• Artificial selection: modification of species due
to human selected breeding
Evidence of Evolution
Evidence of Evolution
Essential Questions
• What is the anatomical evidence of evolution?
• How are fossils used as evidence of evolution?
• What evolutionary evidence do we have from
the field comparative embryology?
• How does biogeography provide evidence for
evolution?
• How does genetics and biochemistry provide
evidence for evolution?