Evidence of Evolution

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 • 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. • 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 • 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 the ancestor of an iguana is iguanodon Iguanodon tooth

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 • http://www.ucmp.berkeley.edu/education/explorations/tours/stories/middle/C7.html • http://evolution.berkeley.edu/evolibrary/article/lines_02 • http://txtwriter.com/Backgrounders/Evolution/EVpage02.html • http://www.shmoop.com/evidence-evolution/molecular-biology.html • http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1299088/ • http://evolution.berkeley.edu/evosite/lines/IIAanatomy.shtml • 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

Evidence of Evolution