Evidence of Evolution
Taylor Zewe, Brooke Loomis, Allison Linton
Pd-2
Anatomy and Physiology
Evidence for evolution can come in the form of anatomy and physiology. For
example vestigial, analogous, and homologous structures.
Vestigial Structure: The concept of vestigiality applies to genetically
determined structures or attributes that have apparently lost most or all of
their ancestral function in a given species. An example is the human
appendix.
Analogous Structure: Body part in different species that is similar in function
but not in structure that evolved in response to a similar environmental
challenge. An example are the wings of moths, compared to the wings of
birds or even bats.
Homologous Structure: A homologous structure is an example of an organ
or bone that appears in different animals, underlying anatomical
commonalities demonstrating descent from a common ancestor.
Anatomy and Physiology
Two different species, apes and humans, have chests that are built broader
than they are deep. Both species, though different, have similar
structures of the chest, evidence that supports that these two animals
came from a common ancestor. The structure of the chest in the
common ancestor allowed for them to suspend themselves using their
upper limbs.
Anatomy and Physiology
The tailbone in a human has no specific
function. The tailbone, however, does
appear in other animal species having a
function in those organisms. Nonetheless,
the appearance of a tailbone in the human
proves that the common ancestor of all
organisms had a tailbone. The specific
structure of the tailbone was passed down
to offspring. However, in some species,
like humans, the function of the tailbone
was lost.
Anatomy and Physiology
Penguins, alligators, humans, and bats are very different creatures.
Nonetheless, they all have very similar appendage structures. Each have a
humerus, radius, ulna, and carpels in their forelimbs. Although each bone
looks different in each species, the bones serve similar functions in the
different organisms.
Anatomy and Physiology
Moths, bats, and birds all have wings but they are all structured differently.
Each of these animals has the same type of adaptation (wings to fly) which
allows them to survive in similar habitats. The underlying structure of the
wing is very different when comparing the moth to the bird or the moth to
the bat. They are distantly related. The underlying structure of the wing is
very similar when comparing a bird and a bat. They have a more recent
common ancestor.
Anatomy and Physiology
Evidence for evolution is shown in the
human appendix, a vestigial
structure. Organisms that are
herbivores have bigger appendixes,
used to break down their diet.
However, in humans the appendix
have no function. It is connected to
the intestines, but it does not assist
either one. Humans can live without
an appendix. The appendix is
evidence that humans were
descended from a plant eating
organism that at one point needed
the appendix.
Molecular Biology
•
Scientists use molecular biology to look at the proteins and other
molecules that control life processes. The changes that occur over time
in these molecules can help shed light on past evolutionary events.
Molecular biology uses the hypothesis of neutral evolution where the
variability in molecular structure does not affect the molecule’s
functionality. According to molecular biology, living things can be
evolved from one another through series of connected and similar gene
patterns.
•
Evidence
o In 2006, an international group of scientists sequenced genes from
extinct wooly mammoths. Mammoths are often found in permafrost
which provides ideal conditions for preserving DNA. The research
team compared mammoth gene sequences to two different kinds of
elephants living today: modern Asian and African elephants. They
discovered that the closest living relatives of mammoths are Asian
elephants through the gene sequence. Therefore Asian elephants
could have evolved from mammoths and they share more of their
DNA and are more common ancestor than modern Asian and African
elephants.
o Roundworms, for example, share 25% of their genes with humans.
These genes are slightly different in each species, but their striking
similarities reveal their common ancestry. In fact, the DNA code
itself is a homology that links all life on Earth to a common ancestor.
•
More evidence
o
o
Chimps and gorillas have fewer differences from
humans in the DNA sequence than most other
vertebrates, like dogs, making them have a
common ancestor. This way they could have
evolved from each other with few differences in
the DNA chain.
Dogs, wolves, and other members of the genus
Canis still share 99.8% of their genes making them
have a similar gene pattern and exhibit certain
traits.
Asian Elephant and Wooly Mammoth
Wolf and a Husky
Paleontology
Fossils can be used as evidence for evolution by showing the similarity in
like organisms. through fossils you could identify how features evolved,
and how long they lived.
Evidence:
•
One piece of fossil evidence that supports the theory of evolution is from
the 17th century. Nicholas Steno observed a shark tooth fossil was
identical to an drawing of an extinct shark and made the jump that the
fossil came from that shark.
•
•
Another example of evidence to support evolution was found by Mary Ann
Mantell and her husband Gideon. They found a tooth which they thought
to be an iguana tooth but turned out to be a dinosaur called iguanodon.
This shows the similarity between organisms and how similar traits can
carry on throughout generations.
Through the discovery of fossils paleontologists have been able to
determine the evolution of whales. They were able to witness their
development from being land animals to becoming suited and more fit to
be aquatic animals. Everything from skull shape, humerus length, and
finger size evolves to fit the environment.
Skeletal
Evolution of
whales
Iguanodon tooth
the ancestor of an
iguana is
iguanodon
•
Paleontologists have also been able to track the evolution of oyster
shells. Over 12 million years the shell have become larger, flatter, and
thinner. These organisms rest on the floor of the ocean and these
adaptations made them more fit for their environment. It allowed them
to be more stable for during water movements.
Evolution of Oyster
shape
Oysters Today
Citations
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http://www.ucmp.berkeley.edu/education/explorations/tours/stories/middle/C7.html
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http://evolution.berkeley.edu/evolibrary/article/lines_02
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http://txtwriter.com/Backgrounders/Evolution/EVpage02.html
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http://www.shmoop.com/evidence-evolution/molecular-biology.html
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1299088/
http://evolution.berkeley.edu/evosite/lines/IIAanatomy.shtml
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http://bioweb.cs.earlham.edu/9-12/evolution/HTML/live.html
http://www.britannica.com/EBchecked/topic/22462/analogy
http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html