Download Evidence for Evolution

Evidence for Evolution
Olivia Taylor
March 28, 2010
Period 3
Fossil Evidence
Through fossil evidence paleontologists, biologist, zoologist, and archeologist can gain insight on how
transition from one species into another, as well as the origin of new physical features. Fossil Evidence is
different from other evolutional evidence because it provide a time perspective, and shows how things were
decades before. Fossil allow scientist to take glimpses of the past, and study extinct animals/plants. Some
document fossil evidence records creatures moving from one habitat to another, and why they moved. By
studying fossils of whale ancestors’ specialist make conclusion and gain more knowledge on how, mammals
which evolved on land, transitively started evolving into water environment (whales), and also what were the
reasons for the move. Evidence proves that whales have been living in the water for millions of years, but like
us they too are mammals; meaning they’re breathe air, give birth, and produce milk (if female), thus they had to
have evolved into the water at some time. From the first 10 million years fossils were found of relative of
whales, Ambulocetus and Pakicetus, limbs like land-living mammals, which they are believed to have been
related to. Also they had characteristic that are today only seen in the ears of whale, technically these animals
had already went through the land animal to water animal transaction. Later fossils were found that linked the
land creature that whales could have possibly evolved from, the species was called raoellids. A Raoellids would
have looked similar to a dog, but was closely related to even-toed ungulates, animals such as cows, hippos, deer,
sheep, etc. Molecular evidence has led scientist come to the conclusion that whales and raoellids have an
evolutional connection. A later fossil was found of Indohyus, which was a Raoellid. Indohyus are similar to
whales, and not similar to ungulates. The diet of a raoellids was very different from that of a whale which
suggests that they change to water may have been because of food/ a dietary change. Aside from land animals
moving into water, fossil evidence can also help unscramble how modern day birds came to be, from what they
evolved from, and also evidence on what made this specific find bird like. Many zoologists and paleontologist
say that dinosaurs are directly related to birds, opposed to the idea that birds are related to reptiles. Common
traits shared by birds and their dinosaur ancestors were their skeletal features, laying shelled eggs, and
possession of scales (birds have scales on their legs). Modern birds even have embryos even had rudimentary or
imperfectly or incompletely developed fingers on their wings, similar to dinosaurs. Opisthocomus hoazin, a
South American bird has big moveable claws on the first and second digits, and they are used to grab branches.
In 1861 the first nearly completed fossil of an ancestor that linked reptile-bird, were discovered Germany.
Fossils of the Archaeopteryx lithographica which were 150 million years old were found. “The skeleton of
Archaeopteryx is clearly dinosaurian. It has a long bony tail, three claws on each wing, and a mouth full of
teeth.” Unlike other reptiles the Archaeopteryx had feathers and feathers on its long bony tail. After studying the
Archaeopteryx more can classify that birds are related to dinosaurs.
"Acanthostega." wikipedia.org. N.p., n.d. Web. 27 Mar. 2010. <http://en.wikipedia.org/wiki/
Acanthostega#cite_note-3>. "Evolution of birds." agiweb.org. The Paleontological Society, n.d. Web. 28 Mar. 2010.
<http://www.agiweb.org/news/evolution/examplesofevolution.html>. "15 Evolutionary gems." nature.com. N.p., n.d. Web. 27 Mar. 2010.
<http://www.nature.com/nature/newspdf/evolutiongems.pdf>.
Anatomical Evidence
Anatomy is a branch of biology and medicine that studies individual parts of living things. By studying
parts of living things we can openly compare and contrast parts from different organisms, and also find out how
closely related organisms are. Take for an example the bones in a bat’s wing and the bones in a human hand are
very similar, which suggests that there’s a link to the two animals. It is very much like a human arm and hand,
except it has a thin membrane of skin called patagium, that extends between the "hand" and the body, and
between each finger bone.The first finger on the bat’s hand is its thumb, which is small and ends in a claw that
is used for crawling and catching food. Long arm bones, with extra-long extended finger bones, are covered
with a double layer of thin skin called a membrane. A bat's wing consists of bones that are very similar to the
bones in a human hand. Both the bat’s hand and the human hand have a thumb and four fingers. Also studying
anatomical evidence can help scientist explain common descent through comparative anatomy. An example of
common descent would be the forearms of humans, bats, and mice. Despite the different environment, and
living situations the skeletons of humans, mice, and bats are unlike. The correspondences of the bones in each
of the animals are in the similar position, and have the same general structure. A bat wing, a mouse forelimb,
and a human arm serve very different purposes, but they have the same basic components. Scientist classifies
these animals as being of common descent, or having common ancestors. In anatomical studies paleontologist,
biologist, anatomist and zoologists study vestigial structures, or “left-over structures that don’t serve a purpose
in an organism, but often homologous, or similarity between characteristics of organisms that is due to their
shared ancestry, to organs that are fully functional in other species. So basically scientists think that there is a
link between animals with these vestigial structures, and animals with the same structure that works. Whales
have remains of pelvic and thigh bones, and humans have an internal tail bone. Example of this is the human
vestigial tail bone, or coccyx which is homologous to the tail of other primates. Studying anatomical structures
help us gain insight on common descent, how animals can use a structure while other who possess it don’t
(vestigial parts), form linkages between animals that may seem unlike (mice and humans), and also find out
how closely related animals are.
"common structures." nap.edu. N.p., n.d. Web. 27 Mar. 2010. <http://www.nap.edu/
openbook.php?record_id=6024&page=14>. Jacobus. "Anatomy." Evidence for Evolution packet. Print.
wikipedia.org. N.p., n.d. Web. 27 Mar. 2010. <http://en.wikipedia.org/wiki/Ba>.
Embryology Evidence
An Embryo is an organism in its very early stages of development, before its birth. Studying the embryo
of animals as they develop is a field of science called Embryology. An organism's embryonic development
provides clues to its evolutionary past. By comparing the different embryos of living things biologist, anatomist,
and embryologists can see how they are alike. Also similar embryos probably evolved from a common ancestor.
The hypothesis “ontogeny recapitulates phylogeny, states that basically, as an organism goes through its
embryonic development, it repeats its evolutional history” (cas.bellarmine). An example of this theory is the
human embryo at the 5 week stage contain a set of gill slits, this says that we passed through the aquatic phase
of our evolutionary history. Evolution and Embryology is a very complex system, but related organisms do
show similarities in their embryonic development. Though gill slits are unneeded in adult humans, if the step
were to be taking out of the embryo development tissue around slits would change in arrangement, and possible
it could affect unrelated structures. So a valuable gain from studying embryology evidence is it shows
evolutional history. Another valuable gain from studying embryology evidence is that it allows scientist to see
what organism have similar ancestry, and transformation of species through evolutionary change. An example
of a conclusion made by studying embryo is that vertebrate animals in the beginning stages all are very similar.
When comparing the embryos of one amphibian (the salamander), one bird (the chicken), and three mammals
(the pig, monkey, and human) the fertilized eggs all are very similar except for the size differences, by the late
cleavage stage the embryos look alike and the only difference is their cleavage patterns. When the body
segment forms all three mammals look identical, they all have the ancestral gill slits, and they have umbilical
cords, while the salamander and chick are nourished by the yolk in the egg. In the late fetal stage the limbs start
developing as they would look in their adult stages. “The striking similarities in the late fetal stage between
monkey and human reflect their close phylogenetic, or study of evolutionary relatedness among various groups
of organisms, relationship. The main difference lies in the absence of a tail in the human fetus.” After the late
fetal stage are the hatching (salamander, chick)/birth (pig, monkey, human) stages. All vertebrates follow
common development stages due to having a set of genes that gives the same instructions. This has led
scientists to believe that early developmental sequences of all vertebrates are similar due to common ancestry.
"Embryology." casbellarmine.edu. N.p., n.d. Web. 28 Mar. 2010. <http://cas.bellarmine.edu/tietjen/
Ec&Ev_Distance_learning/Evidence/evidence_main.htm>.
Jacobus. "Embryology." Evidence for Evolution Packet. Print. "the vertebrate body." pbs.org. N.p., n.d. Web. 28 Mar. 2010.
<http://www.pbs.org/wgbh/evolution/ library/04/2/pdf/l_042_03.pdf>.
Biochemistry Evidence
Biochemistry is the study of the chemical processes in living organisms. It deals with the structures and
functions of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
Biochemistry allows zymologist, chemist, and biochemist, to use the gathered molecular evidences to go
beyond the paleontologist evidence. Biochemistry evidence shows common ancestry between organisms
through molecular evidence, and also reveals similarities between organisms of different species. An example is
that it was pronounced that whales descended from land mammals that had returned from to the sea. Anatomical
and paleontological evidence showed that the whales’ closest living land relatives are the even-toed hoofed
mammals. In recent comparisons of beta-casein and kappa-casein, which are milk protein genes suggests that a
whales closes land-living related animal may be the hippopotamus. By comparing the two organism’s milk
protein genes a linkage to a hippopotamus and a whale were found. Biochemistry also reveals similarity
between organisms of different species. An example would be by the protein cytochrome c, which is important
in aerobic respiration, and is a universal compound. The fact that organism that use aerobic respiration have
cytochrome c, says that there is a possible that all these organism descended from a common ancestor. The fact
that blood proteins and cytochrome c is so complex makes it unlikely that the same compounds would have
evolved independently in widely different organisms. By studying more into cytochrome c it was found that in
different species there are different amino acid sequences. An example is that the cytochrome c in monkeys and
cows is more similar then that of a monkeys and fish. This evidence suggests that monkeys and cows are more
closely related than monkeys and fish. “Scientists have similarly compared the biochemistry of universal blood
proteins. Their studies reveal evidence of degrees of relatedness between different species. This evidence
implies that some species share a more recent common ancestor than other species do.” By studying
biochemistry evidence scientist get evidence from the actual make-up of organism, at the molecular level of
different organisms.
"Biochemistry." bioweb.cs.earlham.edu. N.p., n.d. Web. 28 Mar. 2010.
<http://bioweb.cs.earlham.edu/9-12/evolution/HTML/live.html>.
Jacobus, and Jacobus. "Biochemistry." Evidence for evolution Packet. Print.