Transcript Evidence of Evolution

Evidence of
Evolution
By Madalyn Incognito
The 5 evidences of evolution:
 Fossils
 Biogeography
 Comparative
embryology
 Comparative anatomy
 Comparative DNA (Biochemistry)
Fossils
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A fossil is a remnant or trace of a once
living organism
How are fossils formed:
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The animal dies
Soft parts of the animal are eaten or
decay; the bones remain
The bones or hard parts are covered in
dust and soil
Bones are buried in layers of soil
The layers of soil turn to stone. The remains
turn to stone and form a fossil
Fossils show that life forms found in fossils
from millions of years ago have similar
characteristics to modern life forms. It
proves they originated from a common
ancestor.
Dating of Fossils
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The age of rocks can be determined using radioactive
dating
The age of rocks can also be determined by
correlating the fossils found in them with rocks of know
age
The oldest sedimentary rocks contain no fossils; no
evidence of life
Older fossils are from organisms which were:
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Simple
Water living
Younger fossils are from organisms which were:
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Both simple and complex
Both water and land living
Biogeography
 Biogeography
is the study of living things in
relation to geographical regions
 Darwin and Wallace used biogeography as
evidence of evolution.
 They
noticed that species living in the same area
were more similar to each other than to species living
in similar habitats far apart
 This shows that species evolved due to the selective
pressure of their own habitats
Emu-Australia
Rhea-South America
Ostrich-Africa
Biogeography tells us that
organisms migrate from a
place of origin and evolve
into new species.
Comparative Embryology
 Comparative
Embryology is the branch of
Embryology that compares and contrasts
embryos of different species.
 Comparative Embryology determines that
relatedness of species. Organisms with
similar
structures are
argued to
have acquired
their traits from
a common
ancestor.
Comparative anatomy
 The
anatomy of different species can be
compared to look for evidence of evolution
from a common ancestor.
 Homologous structures:
 Structures
found in plants or animals that have
the same origin, but not necessarily exactly the
same form or the same function
 Example: Pentadactyl limb of vertebrae animals
(mammals, reptiles and amphibians)
 All
vertebrae
animals have limbs
with five digits
(finger-like
structures) which
have the same
basic structural
plan but have
altered to different
environments and
lifestyles
 This suggests that
all these groups of
animals originated
from a common
ancestor
Comparative DNA sequencing
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Comparison of the DNA sequences allows organisms to
be grouped by sequence similarity and as a result
allows the construction of evolutionary trees
Comparative DNA sequencing shows that we all come
from a common ancestor
We all have the same bases in our DNA, they are just
arranged in different order
The more closely related the animals are the more
similar their DNA sequence is
Example:
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If 2 new species evolved from a common ancestor, their
DNA and protein molecules would change and become
different. The number of differences is proportional to the
time since they separated