Among could be similar because they descended from


Among
the hypothesis and observations of natural selection, there is more evidence
for evolution. This evidence includes biogeography which is the study of the
geographical distribution of organisms. Darwin saw that many species that lived
close together appeared similar (a result of common ancestry); whereas species
living in the same kind of habitat but in different locations did not appear
similar.  But some species can look
similar, not because of shared ancestry, but because of convergent evolution.
This is when unrelated species evolve to look similar not because of common
ancestry but because they adapted to similar environments in similar ways. Biogeography suggests that the many
species of finches on the Galapagos Islands arose by adaptive radiation which
is when members of an ancestral species move into new environments &
eventually become several new species, each adapted to a habitat/lifestyle. (Reece
2016)

Another
compelling piece of evidence is fossil evidence. The pattern of fossils in the
rock layers in the Grand Canyon, for example, suggests that organisms have
changed over time or evolve.  Fossil
organisms in close, more recent, layers are similar yet still different, so there
has been change over time. Also, fossil organisms in far-apart layers are less
similar and separated by longer time. New species appear that didn’t exist in
lower layers which suggest change of species over time. Lastly, many species in
older layers don’t exist today which suggests extinction. Fossils reveal
intermediate species leading to more modern species which suggests evolution
over time, yet fossils also reveal other related lineages that did not
survive. (Reece 2016)

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            Additionally, evidence for evolution comes from
comparative anatomy. The anatomy of different organisms could be similar
because they descended from a common ancestor. For example, the same bones
having the same relative position in the forelimbs of all mammals suggests that
mammals evolved from a common ancestor who had this basic forelimb ground plan.  Forelimbs later evolved different functions
in different groups of mammals. (Kirkpatrick 1982)

            Evidence for evolution comes from comparative embryology.
Early embryos of different vertebrates share many general features. But as
development proceeds, similarity persists only among more closely related
vertebrates. Reptile & human early embryos are similar, but pig & human
later embryos look similar. (Nei 1975)

            Lastly, evidence for evolution comes from molecular
biology. For example, protein and DNA sequence comparisons. The more recently two species shared a common
ancestor, the more similar their proteins & DNA. This and all the
aforementioned topics of evidence suggest that evolution is the best
representation and explanation for life on Earth. (Reece 2016)

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