AP Biology: Your Inner Fish

The further examination of Tiktaalik’s fins revealed that it had wrists, similar to a human body. Tiktaalik’s wrists allowed it to maneuver its way to the base of shallow bodies of water.

The book begins by talking about bones and fossils. It explains how much scientist know about the past, and what type of fossil they were looking for. They had a fossil from 185 million years ago that was fully fish, and also a fossil from 165 years ago that was full amphibian. They were looking for a fossil in the middle to fill in the holes. A fossil in between these time periods would help us to understand how fish began to evolve to

Explain why the author and his colleagues chose to focus on 375 million year old rocks in their search for fossils. Be sure to include the types of rocks and their location during their paleontology work in 2004.

It’s an alligator! It’s a crocodile! It’s a lizard! It’s.. a fish? All educated guesses even preschoolers can notice. The discovery of Tiktaalik has given many scientists something to think about. The first being that humans may after all be closely related to fish. When first hearing this theory, for anyone it is hard to believe. Humans have fingers and fishes have fins! They have gills and we have lungs! Many things point towards the fact that humans have nothing in common with fish until one looks at the bone structure of each and how exceptionally similar they are. The reason for the similarity is because both species share a common ancestor.

Sedimentary rocks interpret dinosaur habitats through encased environmental structures of the past. Through sedimentary rocks, paleoecologists’ can examine the arranged formation of sedimentary structures to specify what type of environment the dinosaurs’ lived in. An example of a specific sedimentary rock structure can be seen through formed weathering and ripple marks by how wind and sand formed distinct patterns in the past layered sediment. These arrangements provide interpretations on the structure of the sediment and the habitat of encased fossils, through modern day comparisons

These two features earlier are examples that we can see with our naked eyes, but the DNA make up that we cannot see with our eyes alone are also laid out the same as well. In the evolutionary pathway, the genes that turn on and off for humans and fish are related through the instructions on how they function. All living things with limbs have in common the Sonic hedgehog gene (Shubin, p. 53). The Sonic hedgehog gene can control the development of the limbs in these creatures. To determine if the development of vertebrate animals can be interpreted in the same way, or have the same effect, the injection of vitamin A was used to inject into a shark, mice, and chicken embryos to see if the results were the same. The results turned out that the injection of vitamin A has indeed changed the development of limbs in these embryos. The effects cause the shark to have a mirror image of its fin, and the mice and chicken have duplication of bones in the limbs (Shubin, p.56-57). It becomes clear of what will happen if

At the time, although it was understood that fossils were the hardened remains of dead animals, it was not yet accepted that these animals might be extinct species from hundreds of millions of years ago. So, when Anning showed up with a giant marine reptile fossil (the world’s first Ichthyosaur) it caused quite a stir, because at the time the Bible was widely used for interpreting scientific ideas and religion ruled people’s lives. Hence Anning’s findings encouraged the largely creationist population, to rethink the history of the Earth. Her fossils had helped scientists understand how things

The author and his colleagues chose to focus on 375 million year old rocks in their search for fossils because amphibians that look dissimilar to fish were discovered in 365 million year old rocks, while fish without amphibian characteristics were discovered in 385 million year old rocks. Thus, it is possible that the evolutionary intermediary, or the “missing link” between fish and amphibians, would be discovered in 375 million year old rocks, between the two time periods. The rocks examined were sedimentary in composition, as the gradual and relatively gentle formation of sedimentary rock under conditions of mild pressure and low heat are conducive to the fossilization of animal remains. Sedimentary rock is also often formed in rivers and seas, where animals are likely to live. This site provides a resource that describes means by which fossils are formed and how the fossil record may be interpreted, and shows some examples of fossils demonstrating evolution through geological periods: http://www.fossilmuseum.net/fossilrecord.htm. In 2004, Shubin and his colleagues were looking for fossils on Ellesmere Island, in northern Canada. This location was chosen because of its lack of human development, as well as of obstructing natural formations and life forms such as trees, which

In the science of paleontology, the history of life is studied. Paleontologists study fossils to learn the past ecologies, evolution, and the origins of humans. In order to understand the processes that have led to both the origination and destruction of organisms since life began, paleontologists incorporate both scientific knowledge and studies. Fossil findings are critically important for confirming predictions of evolution theory. Of the many discoveries that are made yearly to add depth to the understanding of evolution, an example is a recent discovery of a creature they named Tiktaalik. The Tiktaalik was uncovered to be a transitional animal between shallow-water fishes and limbed animals. The creature supports the idea that it emerged from both mammals and reptiles, suggesting that the two are related. These findings support prediction of evolution, contradicting the belief that God

One experiment that proved to be both successful and useful was putting mice sonic hedgehog protein into the skeletal rods of a skate to see if it would “make these rods different from one another, like our digits” (Coyne, 2010 p. 57), the outcome was to the better extreme, “not only did the rods end up looking different from one another, they responded to Sonic hedgehog, much like fingers do. This result according to Coyne (2010) meant, “all appendages, whether they are fins or limbs, are built by similar kinds of genes” (p. 58).

The process of diagenesis encodes information regarding the physical and chemical processes operating in nature, which precedes the taphonomical journey of a bone into the lithosphere. When decoded, a fossil or an archaeological bone entails a series of natural processes of modification that perhaps decided the ‘destiny’ of a bone to transform into a fossil over the years of its residence into the sedimentary environment. Understanding these processes involved in the bone diagenesis is crucial to the reconstruction of ecological settings of an area(cite the papers on bone diagenesis and process of fossilization e.g. papers in “Archaeometry 2002 issue on bone diagenesis and also the proceesings of the Conference on “Bone Diagenesis” held

Because of the antiquity of the Pliocene environments, the only remaining witnesses of the behaviours are the bones and the stones. One of the main approaches to this type of issue is using the faunal remains. They are more abundant than the hominid fossils, and some indicator species are excellent proxies for paleoecological inferences. In addition, we can study their taphonomic signature, i.e. the processes that affect a bone between the death of the animal and its discovery as a fossil, and how these processes affect information in the fossil record (6). By looking at the different kinds of traces (grooves, cuts, abrasions, or any physical or chemical deformation) on a bone, a researcher can study its individual history. By identifying these traces on all animal fossils collected from a particular site, we can address the question of what the local environment was like. To evaluate taphonomy, the researcher looks at the surface of each bone with a handheld magnifying lens and records the type and intensity of the traces on each bone. Extant floral and geological data will also be exploited.

: Fossils are the remains or traces of ancient organisms which have been preserved. For example, a fossil can exist as skeletal remains or even as a footprint. Such organisms are subjected to a slow rate of decaying since they have been rapidly buried under conditions that facilitate this. It is common for fossils to occur as hard-bodied organisms as these are more resistant to environmental influences. Fossils are usually found embedded in rock. The layers of rock are of different age and makeup. Hence fossils found in one layer would vary in characteristics from those found in another layer. They can be observed and analyzed through visual as well as radiometric means so that the age and morphology can be determined. These features indicate

One of the main discoveries that has helped paleontologists and microbiologists alike is fossils discovered in China in 1998. These fossils “have transported paleontologists across a great divide in the history of life on Earth, taking them deep into virtually unexplored time, showing them the earliest known forms of tiny ancestral animals and pointing out where they should be searching next for evidence of the origins of the first such complex life.” (John, N.W. 1998)

In this same section, Shubin included Charles Darwin’s statement that makes it easier to understand. Humans have the same layout as other vertebrate creatures because we all came from a common descent (Shubin p. 32). Finally, the ancient fish, the Eusthenpteron, which we shared this limbs structure with was discovered in Devonian rocks around 380 million years old. It had the exact limbs structure as Owen described, however for this fish, the bones of the limbs were inside a fin (Shubin, p.33). This ancient fish unlocked the mystery that we are derived from a common ancestor that enable us to hold tools to do our everyday life tasks.