Evidence for Evolution Presentations – Facts I’m looking for
Fossil record
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Paleontology - provides fossils that reveal the prehistoric existence of extinct species. As a
result, changes in species and the formation of new species can be studied
Dating Fossils
o Strata to determine relative age (oldest – bottom and youngest – top)
 Can be used to see transition of species in each layer
o Radioactive dating techniques – C-14 dating
 Uses natural decay rate of radioactive isotope of carbon (C-14)
Extinctions
Comparative anatomy
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Divergent Evolution
o Homologous structures (or homology)
Vestigial Structures
o Look for examples such as some snakes still have vestiges of the pelvis and leg bones of
walking ancestors
o Cetaceans (whales and dolphins) still have vestiges of hind limbs
 In these 2 classes, we would not expect to see vestigial structures if snakes and
whales had origins separate from other vertebrate animals
Convergent evolution – What is not evolution ex.
o Analogous structures
Comparative biochemistry
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This could also be called molecular biology, but I want you to focus on difference in amino acid
structure here and how this interpretation differs from DNA comparison
In addition to all living things sharing the same generation code, they also show the same basic
biochemical pathways, including those for replication, protein synthesis, respiration, and
photosynthesis.
Description of importance of proteins (why do we care?)
Detail about why comparing amino acid sequences can show evolution
Why in some cases can comparing amino acid sequences be even better than comparing DNA
sequences? – It’s okay if they don’t know this one, but the answer is the lots of DNA / RNA is
spliced or not used. Also, the eventual goal of DNA / RNA is to make amino acids so making the
same amino acids means making the same protein which means the same phenotype.
Comparative embryology
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Reveals similar stages in development (ontogeny) among related species
Can reveal additional anatomical homologies (homologous structures) not visible in adult
organisms
At some point in development, all vertebrate embryos have a tail located posterior to the anus
as well as
Pharyngeal (throat) pouches
o These pouches ultimately develop into structures with very different functions, such as
gills in fishes and parts of the ears and throat in humans and other mammals
Molecular biology
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All forms of life use the same genetic language of DNA and RNA (even bacteria and viruses)
o Explanation of how to interpret
The genetic code is essentially universal – An example of a homology that is shared by all
because the ancestor dates back so far.
Species as distant as humans and bacteria share genes inherited from a very distant common
ancestor.
Biogeography
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Continental drift (slow movement of Earth’s continents over time)
o So species that used to be located together no longer are. We can see how different
environmental influences have shaped their evolution.
Pangea
We can use our understanding of evolution and continental drift to predict where fossils of
different groups of organisms might be found.
Endemic – islands generally have many species of plants and animals that are found nowhere
else in the world
o Even so, species on these islands are closely related to species from the nearest
mainland or neighboring island bc the island is colonized by species from nearest
mainland
o These colonist give rise to new species because environmental pressures are different
on these islands than on the mainland
 This is why species on 2 separate islands that have similar climates do not
resemble each other. Rather they resemble species from the mainland.
 Once again, natural selection does not “create” phenotypes so even
though the environment is similar they are still modified from whatever
colonists originated on the island
Can show convergent evolution with unrelated species in similar habitats bearing resemblance
to one another