Download Evidence of Evolution

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Several types of information support
Darwin’s theory of evolution.
◦ anatomy
 homologous, analogous, and vestigial
structures
◦ embryology
 The study of fetal development.
◦ macromolecules
 DNA, RNA, proteins, etc.
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Homologous Structures
◦ Structures that are similar/same (homo) and have
originated from a common ancestor.
◦ May look different on the outside, but have
similar/same (homo) structure inside.
◦ Indicates that organisms may have shared a recent
common ancestor.
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The limbs of different organisms serve
different functions, but have the same bone
structure inside.
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Analogous Structures
◦ Structures that serve identical
functions, but have different
internal anatomy.
◦ Ex: wings of birds and insects
 Both allow organisms to fly, but
have different development and
structure.
◦ Shows a more distant
relationship than homologous
structures.
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Vestigial – structures that were useful in ancestors
but are no longer used by modern organisms
Shows relationship between organisms with
vestigial structure and those with a working
version.
ie. humans have tailbones homologous to tails of
other animals
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Some organisms have genes that are conserved.
◦ Genes that have remained unchanged, but may be “turned off”.
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ie. whales have genes for hind legs
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Can give clues about early development of a species.
◦ ie. whales may have descended from an ancestor who lived on
land
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Embryology – study of early development
Many organisms share similarities within the
early stages of development.
Can indicate a common ancestry among
different species.
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Similarities within DNA, RNA and proteins of
different species
◦ Genetic code is universal – all living things share
the same code
◦ Closely related species have very similar gene
sequences and protein sequences.
 Ex: hemoglobin in humans and gorillas differs by only 1
amino acid
◦ Can confirm ideas suggested by fossils and
anatomy.