Inner Fish Chapter Summary
INNER FISH CHAPTER 1
1. The author and his colleagues wanted to use 375 million old rock, because in the 385 million year old rocks they found what look like fish. In the 365 million year old rocks they found amphibians that did not look like fish, so to find the change the look at the 375 million year old rock to find transition between the two. In their paleontology work in 2004 they found sedimentary rocks in Pennsylvania and on the east coast of Greenland, but their most successful rock was found in the Artic of Canada.
2. The fossil Tiktaalik has a flat head with eyes on top, it is similar to an alligator. Tiktaalik also looks like a fish because of the scales and fins. This fossil confirms prediction because the fish contains a part of us.
3. Neil Shubin thinks that Tiktaalik says something about our own bodies, because of the neck. In Tiktaalik “the head is completely free of the shoulders” (26). The fish before Tiktaalik had bones connected the skull and the shoulders together. The arrangement is shared with other animals and humans. Shubin believes that this fossil is a part of our history.
Dispute:
If this statement was true, humans would have the answer …show more content…
to evolution and the controversy behind it would have also been ended. Also, Shubin’s expedition to the Canadian Arctic would not have been a big story and he would not have traveled to the Arctic if fossils were easily found. The fact show that this statement is false, because there are changes in the earth that disallow for fossils to remain in exemplary conditions or be found at all. One example, Shubin discussed in the first chapter regarding the changing temperatures in the Arctic, which “crumbles the surface rocks and fossils” (Shubin 20). Also the seismic and volcanic activity would either destroy the fossils present, or it would cover the fossils with debris and rock which would make them inaccessible.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH: CHAPTER 2
1. The patterns discovered by Sir Richard Owen was found in all the bones observed of mammal limbs. The “one bone- two bone- lotsa blobs-digits pattern” refers to the bone position of the arm and the legs. This relates to his ideas of exceptional similarities, which is that all creatures with limbs have a common structure. The patterns that he refers to is or was the blueprint for mammal limbs.
2. Charles Darwin said that bat’s wings and human’s arms once shared a common ancestor that had common skeletal patterns.
3. After examination of Tikataalik’s fin, it was certain that the fish had a wrist. The wrist was similar to the human wrist it could bens, and could push up. The movement was useful for the fish to navigate to the bottom of the lake or pond.
Dispute:
The fish and human are different, our environment, needs, diet, social interaction, place in the food chain, etc. Shubin’s main message in the second chapter is discovering what’s underneath the surface. By just a glance, fish and human may seem to be different, but when we look past the skin, there are some similarities. The first one being bone structure as explained by Shubin. Shubin discussed the Owen bone structure “one bone, two bone, lotsa blobs, and five toes” (32). This structure is present in the fish and the human. Furthermore, not only do the fish and human have a common limb structure, we may also have a common ancestry. Shubin claims that the fish he found could be an ancestor of both fish and humans in which case, fish and humans are similar.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion- Year- History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 3
1. Biologist Edgar Zwilling and John Saunders observed chicken embryos by cutting and moving tissue to discover the embryos effect. Using microsurgery they discovered two patches of tissue that control matter in the bone pattern. When the tissue was removed only the upper arm developed. When it was removed later the arm completely developed. The findings of this observation lead to the knowledge that all appendages are built by similar genes. Findings also suggests that the evolutionary transformation of fins into limbs did not involve new DNA just genes working together in different ways.
2. Hedgehog gene was originally found in fruit flies as a gene that makes different region effects similar to chicken region effects. The chicken hedgehog was discovered and renamed the Sonic Hedgehog. The gene was found in the chicken’s wing bud. Every animal with limbs had the hedgehog gene. If the sonic hedgehog gene does not activate in the normal embryo it can result in an extra pinky or thumb. This experiment confirmed that the sonic hedgehog gene contributes to the development of appendages.
Dispute:
The human body has specialized cells, leading to specialized tissues, organs, and so forth. The specialization is not due to the unique set of DNA because the DNA in each of our bodies is the same for every individual. But rather, it is the gene in our DNA like the Sonic Hedgehog one that controls the specialization in our cells. Tabin, McMahon, and Ingham saw that “this gene made one end of a body segment look different from the other” (Shubin 52). The hedgehog gene creates a unique DNA by turning on and off at set times, the gene is able to create deformities in certain cells. These deformities are what create the cells in our body become muscle cells or skin cells. Therefore, it is not a unique set of DNA, but genes activated at certain times that allow cells to build muscles whereas others are arms.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5- Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 4
1. Teeth are hard as rocks because of the high content of hydroxyapatite, seen more in teeth than in bones. Teeth are less likely to decay and will be the best preserved part of a fossil.
2. Conodonts are organisms with spikes protecting out of their bodies. They became used mostly by jawless fish to use up their food. Overtime the fish required the Conodonts gene to produce teeth through the process endosymbiosis.
3. Scale, feathers, breast, and teeth start the lower layers of the skin folded inward. From each fold the structures emerges. Shubin claims that teeth came first then changed to creating other skin surfaces.
Dispute:
First off, the earliest recording of any hard body part bone or tooth was the “Conodonts” in the primitive lampreys and those were teeth (Shubin 75). The lamprey is not a predator or prey, rather it is a parasite. The lamprey uses its hard body part for its own gain. Similarly, we can turn to one of the ocean’s most primitive fish and its most feared predator, the shark. The shark’s inner supporting system is that made of cartilage, not bone, and its hard part is its tearing teeth. The shark and lamprey are two examples that bones came after teeth as an adaptation for protection. The teeth came as a beneficial adaptation for predators since the advent of teeth allowed predators to tear apart its prey. Bones came as a sort of body armor against the tearing teeth.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 5
1. The trigeminal and facial cranial nerves appear to just be a mass of tangled muscle and nerves, without order, but they demonstrate “a pattern that reveals the order in what initially seems chaotic” (Shubin 82). Cranial nerves comes directly from the brain, arising from the base of the brain to be exact, and these nerves control facial actions such as chewing, talking, and moving our eyes and head. The trigeminal and facial cranial nerves are the two cranial nerves that are “very complex functions and take tortuous paths through the head to do their job” (Shubin 84). The trigeminal and facial nerve are mention when it comes to complicated nervous pathways. The trigeminal nerve branches out into an array of branches forming a network of nerves, and serving the main function of transferring information from our face back to our brain. The branches of the trigeminal nerve however also serve for feeling sensation in the roots of some teeth, along with providing feeling to the entire face through their complicated network of nerve endings. The facial cranial nerve also controls muscles and sends information to and from the brain, and it is “the main nerve that controls muscles of facial expression” (Shubin 85). There seems to be no reason to the numerous and varied functions of these nerves.
2. There are four main arches involved in embryonic development: the first arch forms the upper and lower jaws, malleus and the incus, which are two ear bones. The second arch forms a small ear bone called the stapes, a throat bone, and muscles involved in facial expression control. The third arch from bones, muscles, and nerves deeper in the throat use to swallow. The fourth arch forms the deepest parts of the throat (Shubin 87).
3. Hox genes are so important because they “instruct cells to make the different portions of our head” (Shubin 93). Each gill arch has a different parts of Hox genes in it, allowing the arch to develop into the structure of the head, whether that is the jaw, throat, nose, or other structures. With knowledge of how Hox genes work, we can make a map of our gill.
4. The Amphioxus an invertebrate, but it shares many characteristics with vertebrates, it is a good specimen for study, because it helps when analyzing the differences and similarities between vertebrates and invertebrates. Even though the Amphioxus does not have a back bone, it shares the characteristic of having a nerve cord that runs along its back like vertebrates. Rather than having a spine for support, the Amphioxus has a “notchcord” that is filled with a jelly-like substance. While the Amphioxus keeps its “notchcord”, ours breaks up and ultimately becomes “part of the disks that lie between or vertebrate” (Shubin 94).
Dispute:
Sharks and humans do look different.
However, the gill arches during the embryonic stage create similar structure in use, not appearance. The first gill arch creates “the trigeminal nerve in both humans and sharks” (Shubin 91). The cells of the second gill arch gives us cartilage and muscle that helps the creation of the stapes, as well as another bone, the hyoid, that assists in swallowing. In a shark, the same arch “helps with jaw production” that compares to hyoid (Shubin 92). In the third and fourth gill arch, for humans it produces structures necessary for speech and swallow and for sharks it includes parts of tissues that support the gills. Sharks and humans have gill arches in the embryonic stage, but unlike the statement proposes, they do develop into related structures in each
organism.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 6
1. A. “Ectoderm – Epidermis of skin and its derivatives (including sweat glands, hair follicles), Epithelial lining of mouth and anus, Cornea and lens of eye, Nervous system, Sensory receptors in epidermis, Adrenal medulla, Tooth enamel, Epithelium of pineal and pituitary glands, Notochord, Skeletal system (Shubin 101).”
B. “Mesoderm – Muscular system, Muscular layer of stomach and intestine, Excretory system, Circulatory and lymphatic systems, Reproductive system (except germ cells), Dermis of skin, Lining of body cavity, Adrenal cortex” (Shubin 102)
C. “Endoderm – Epithelial lining of digestive tract, Epithelial lining of respiratory system, Lining of urethra, urinary bladder, and reproductive system, Liver, Pancreas, Thymus, Thyroid and parathyroid glands” (Shubin 102).
2. The fertilized egg continues to divide which leads to the creation of an inner group of cells with an outer shell. This stage is referred to as a blastocyst. The inner group of cells develop into an embryo while the outer group of cells turns into the membranes that support and shield it. The blastocyst reaches the uterus around day 5, and implants into the uterine wall on about day 6. The mother’s menstrual cycle causes the lining of the uterus to grow and prepare to support a human fetus and ultimately a baby. During the pregnancy the blastocyst sticks tightly to the uterus where it receives nourishment through the mother bloodstream. (Shubin 100-101)
3. “Ontogeny recapitulates phylogeny” means the study of the development of an embryo that shows the repetition of an evolutionary stage during development and growth of a group of organisms (Shubin 103). While studying embryos, a trend could be seen that the further along you go in the phylogenetic tree, the more stages of development the organism would pass through, but there are many examples of organisms who do not resemble previous evolutionary ancestors when they are developing.
4. Noggin is a type of HOX gene that helps with the body plan, and it is also involved with other organs. It is also associated with another gene called “BMP-4 when determining the top-bottom axis, where BMP-4 is the bottom gene and Noggin is the top gene” (Shubin 112).
5. The body-building genes of sea anemones and humans are the same. Sea anemones and humans have similar major body plan genes along mammalian head-to-anus axis of anemones. Sea anemones have similar belly-to-back genes to humans, but instead of along a belly-to-back axis, it was along a hidden axis called a directive axis that differentiates the sides of the organism into a left and right side. Humans and sea anemones may appear different, long time of modification accounts for the visible difference between the body plans of a human and a sea anemone.
Dispute:
First of all, scientists do not work in isolation. Throughout all the examples provided by Shubin and in all scientific education, it is evident that a scientist cannot simply work alone and achieve a scientific breakthrough. In the event of the “Organizer’s” discovery it was not only Mangold but also Spemann who helped come up with that idea (Shubin 106). Furthermore, it is not counter-productive to repeat another scientist’s experiments or to consider their research because most of the time it is the research and experiments of earlier times that give us insight and the background information necessary to produce new information. Trying the experiments of others and using their research is not counter-productive, because their successes and failures can help other scientist to find and fix the previous mistake.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 7
1. The most interesting thing about the timescale is how recently modern humans came into existence. This is surprising to me, because the events we learn in history seem so numerous and ancient, and it is difficult to imagine an earth without human life.
2. The most common protein found in the human body is “collagen” (Shubin 125). When magnified it resembles a rope, with a lot of tiny molecular fibers. Collagen is “like rope, it is strong when pulled, but weak” when relaxed (Shubin 125).
3. Cells are held together by a biological ‘glue’ that also allows them to communicate. It contains a variety of different molecules and gives our tissues and organs their distinct appearance and function. Some tissues have cells in organized strips, while others have cells that are randomly scattered or loosely attached to each other. For example, the molecules in between bone cells determine the strength of the bone and more loosely attached proteins in eyes make them more squishy and yielding.
4. Cells generally communicate with one another by sending molecules back and forth. Basic cell-to-cell communication involves one cell emitting a signal that attaches to the membrane of the cell receiving the signal. Once attached to the outer membrane, the molecule sets off a chain reaction of molecular events that travels from the outer membrane all the way, in many cases, to the nucleus of the cell.
5. “Choanoflagellates are single-celled microbes, known to be the closest microbe relatives of animals with bodies and sponges. Because of the discovery of choanoflagellates, the genetic distinction between ‘single-celled microbe’ and ‘animal with body’ completely broke down because most of the genes active in choanoflagellates are also active in animals, with many of those genes serving as part of the machinery that builds bodies. These organisms gave biologists a road map for comparing the bodybuilding apparatus to microbes” (Shubin 133-134).
6. Theories explaining the appearance of bodies include a very simple one: bodies arose when microbes developed new ways to eat each other or avoid being eaten. Another explanation for development of bodies was obviously evolutionary function. Levels of oxygen were not high enough on ancient earth until roughly a billion years ago, when the amount of oxygen increased dramatically and when enough oxygen was present to support them, bodies popped up.
Dispute:
First of all, tissues in the human body have cells similar in relation to cells within that same tissue. For example, cells in brain tissue will be similar to other cells in the same brain tissue, not to cells in a heart tissue. Not all cells connect the same way and there is not always a common cell membranes. Rather that while there are certain kinds of cells like muscle cells that might do that other cells like bone cells don’t. Bones stick “by means of tiny molecular rivets”, and some bind cells like “cement holds with the soles of shoes together” (Shubin 127). This rivet sticks to cell membrane of one cell and another cell and acts like a glue. Thus, forming a bond that holds these bones together. These rivets only bond to the same kind of rivet. Hence, not all similar cells connect to each other in a similar fashion. Furthermore, not all tissues in the human body are made of similar cells.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 8
1. Floating in the air are tiny molecules that we register as odor with our noses. We suck in these odor molecules in our nostrils as we breathe or sniff. From there, the odor molecules go to an area behind our nose where they are trapped by the mucous lining of our nasal passages. Inside this lining is a patch of tissue containing millions of nerve cells, each with little projections into the mucous membrane. When the molecules in the air bind to the nerve cells, signals are sent to our brain and our brain then records these signals as a smell.
2. This occurrence makes sense because mammals are highly specialized smelling animals, which requires a large number of odor genes in order to recognize the odor. A larger number of odor genes is possible because the “extra” genes in mammals are all variations of a theme: they look like copies, albeit modified ones, of the genes in jawless fish. This means that our large number of odor genes arose by many rounds of duplication of the small number of genes.
Dispute:
First of all, “three percent of the human genome is dedicated to olfactory senses”, which is needed to detect different odors. (Shubin 144. The only thing true and connected regarding olfactory genes and animals is that they are present in the same number in all organisms capable of detecting smell. If this statement were true, dogs and humans would have the same sense of smell as each other. The only thing similar is the number, other than that everything else is different. For example, although humans and dogs both have 3 percent of genome dedicated to the smelling of odors, the dog will have more of their 3 percent actually functioning compared to humans.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 9
1. Humans and Old World monkeys have similar vision due in major part to the analogous structures of the optical systems. Both humans and the Old World monkeys are enabled to have this vivid color vision because of the three unique light receptors that enable the perception of different kinds of light. Diversity in plant life gave the old world monkeys an evolutionary benefit to being able to perceive different colors in order to differentiate different fruits, berries and such.
2. “Eyeless genes were originally discovered when Mildred Hoge observed fruit flies that lacked eyes in their entirety. This gene when present in other species can lead to deformities in the eyes of the given species. Deformities in humans due to the eyeless gene can cause conditions such as acarida. It has been observed that eyes in flies, mice and humans all stems from similar sequences of DNA of the eyeless genes. These eyeless genes and the DNA fragment primarily responsible have been studied a great deal. Biologist Walter Gehring was able to use the eyeless gene to active the DNA sequence similar in other areas of the body. In areas of activation of the gene, an eye would grow. This was an astonishing discovery. The analogous structure to eyeless genes in mice, Pax 6, showed similar results when activated. Based on these findings it can be determined that eyeless, or Pax 6 is the overarching control gene of eye production in all animals that have eyes” (Shubin 156).
Dispute:
All organisms with vision do not have similar eyes. When looking at the diagram on page 151, he makes a clear distinction in the eyes of humans, scallops, nautili, and limpet. There is a clear distinction provided in the graphics of the structure of their eyes, hence their vision. Even when we look at the closely related fly, their eyes are not similar to that of humans. Humans have one vision and our eye structure is more like that of a camera, not a kaleidoscope. Monkeys would benefit because “color vision enabled them to discriminate better among many kinds of fruits and leaves and select the most nutritious” among them (Shubin 153).
Citations:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 10
1. There are three parts to the ear; the inner ear, middle ear, and outer ear. The pinna, or the flap of the external ear, is the only unique body part found in mammals.
2. The discovery that the ear bones of mammals may have some correlation to the jaw bones of reptiles began with Karl Reichert, a German anatomist. Mammals have three bones in the middle ear, while reptiles and amphibians have only one. Thus, these bones had to come from somewhere. He observed gill arches in several species to see where they ended up within the skull, and discovered that two of the ear bones present in mammals corresponded to bones in the jaws of reptiles. He concluded that “the same gill arch that formed part of the jaw of a reptile formed ear bones in mammals” (Shubin 160). By 1913, embryologists and paleontologists began to work together, and with Gaupp’s theory, began to look at these fossilized skeletons. They discovered that the most reptilian of these skeletons only had a single bone in the middle ear, just like current reptiles do, and a jaw composed of many bones. However, the more mammalian of these skeletons showed the bones at the back of the reptilian jaw getting smaller until they eventually became part of the middle ear of mammals. This proved that the malleus and incus evolved from jawbones.
3. The Pax 2 gene is active in the ear and starts a chain reaction that allows for the inner ear to develop. If a mutation in humans or mice knows this gene out the inner ear cannot properly form. This is a major gene that is essential for proper development.
Dispute:
Birth defects to the ear often effects the eye, and vice versa. This is because the use of the ear is way more than just listening. The ear gives us a sense of balance and direction via the rocks, gel, and nerves in the inner ear. Every time our “head tilts or moves, the rocks sitting on the gel in our inner ear moves” as well (Shubin 165). This stimulated the nerve hairs in our inner ear. The nerves report this shift to the “brain and our brain tells the eight muscles in our eye to direct our eye” as well (Shubin 167). It’s a chain reaction. If this statement proposed were true, and the eye and ear were independent to each other, our eyes would be looking dead ahead even though our head might be rotated a full ninety degrees. This would happen because the head would tilt but here’s the thing. There is a little thing called the brain that makes the connection between the brain and the eye. Every time our head tilts fast, our eyes aren’t able to clearly catch what is in front of us because the fast tilting does not give the brain enough time to send the signal to our eyes for every position of our head. In the end, the eye, the ear, and the brain are all connected.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 11
1. Shubin’s biological “law of everything” is that every living thing on Earth has parents and this law is so important because it is one true law that everyone can agree upon. This allows scientists and taxonomy experts to hypothesize parental lineages as this law “defines parenthood in a way that gets to the actual biological mechanism of heredity and allows us to apply it to creatures like bacteria that do not reproduce the way we do” (Shubin 174). This pattern of descent with modification defines an organism’s family lineages and, more importantly, is the undeniable “law of everything” (Shubin 174).
2. By incorporating the “Bozo example” in his text, Shubin is able to accurately explain to his readers how descent with modification can be used to create hypothesized family lineages by unlocking biological history. For example, “Let’s take a hypothetical humorless, quite unclown-like couple who have children. One of their sons was born with a genetic mutation that gave him a red rubber nose that squeaks. This son grows up and marries a lucky woman. He passes his mutated nose gene to his children, and they all have his red rubber nose that squeaks. Now, suppose one of his offspring gets a mutation that causes him to have huge floppy feet. When this mutation passes to the next generation, all of his children are like him: they have a red rubber nose that squeaks and huge floppy feet. When this mutation passes to the next generation, all of his children are like him: they have a red rubber nose that squeaks and huge floppy feet. Go one generation further. Imagine that one of these kids…has another mutation: orange curly hair. When this mutation passes to the next generation, all of his children will have orange curly hair, a rubber nose that squeaks, and giant floppy feet…” (Shubin 175).
3. Obesity: Obesity has become one of the leading causes of death in humans today and much of it is due to the fact that humans have a body for an active animal; however, we now have a lifestyle of a lazy couch potato. In 1962, James Neel suggested that “human ancestors were adapted for a boom-bust existence” (Shubin 187). He believed that our ancestors were hunters and gatherers that constantly undergo a cycle of feast and famine, and this led to increased rates of obesity. As our bodies were made to store food for times of need. This leads to obesity as humans eat excessive amounts of food, but there are no periods of famine to use up the saved fat (energy), causing humans to then become overweight.
Dispute:
Shubin made the analogy of human evolution to that of the Volkswagen Beetle. He said that the humans are basically a beefed-up Beetle. All the improvements made had a side-effect of making the car uglier. The maladies in the human body are just like that. The examples brought up in the book include the “hiccup and hernias” (Shubin 186). The glottis, the organ causing hiccups in humans, is an evolutionary remnant from when mammals were formerly amphibians. Now instead of being useful, the glottis has become a constant pain in the human’s life. The maladies don’t just apply to the useless parts of our body, but even those useful. But in the end, everything in our body is a result of our evolutionary past.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH AFTERWORD
1. Most fish have a plate of bone called the operculum. The operculum creates a shield that covers the gills and helps push water over them. Tiktaalik not having this bone showed that relied on breathing through its mouth like other land animals.
2. Tiktaalik was able to have a "true neck", that could move freely from its body, which is like other land animals.
3. The Arctic may be cold and snowy, and Tiktaalik fossil were found there, but Tiktaalik lived tropical landscape. Therefore, this species never had to survive in the cold Arctic as we know it. Tiktaalik tropical was found in the Artic because of either global climate change or moving continents. Since this species lived 375 million years ago, the climate was different than it is now.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
1. The author and his colleagues wanted to use 375 million old rock, because in the 385 million year old rocks they found what look like fish. In the 365 million year old rocks they found amphibians that did not look like fish, so to find the change the look at the 375 million year old rock to find transition between the two. In their paleontology work in 2004 they found sedimentary rocks in Pennsylvania and on the east coast of Greenland, but their most successful rock was found in the Artic of Canada.
2. The fossil Tiktaalik has a flat head with eyes on top, it is similar to an alligator. Tiktaalik also looks like a fish because of the scales and fins. This fossil confirms prediction because the fish contains a part of us.
3. Neil Shubin thinks that Tiktaalik says something about our own bodies, because of the neck. In Tiktaalik “the head is completely free of the shoulders” (26). The fish before Tiktaalik had bones connected the skull and the shoulders together. The arrangement is shared with other animals and humans. Shubin believes that this fossil is a part of our history.
Dispute:
If this statement was true, humans would have the answer …show more content…
to evolution and the controversy behind it would have also been ended. Also, Shubin’s expedition to the Canadian Arctic would not have been a big story and he would not have traveled to the Arctic if fossils were easily found. The fact show that this statement is false, because there are changes in the earth that disallow for fossils to remain in exemplary conditions or be found at all. One example, Shubin discussed in the first chapter regarding the changing temperatures in the Arctic, which “crumbles the surface rocks and fossils” (Shubin 20). Also the seismic and volcanic activity would either destroy the fossils present, or it would cover the fossils with debris and rock which would make them inaccessible.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH: CHAPTER 2
1. The patterns discovered by Sir Richard Owen was found in all the bones observed of mammal limbs. The “one bone- two bone- lotsa blobs-digits pattern” refers to the bone position of the arm and the legs. This relates to his ideas of exceptional similarities, which is that all creatures with limbs have a common structure. The patterns that he refers to is or was the blueprint for mammal limbs.
2. Charles Darwin said that bat’s wings and human’s arms once shared a common ancestor that had common skeletal patterns.
3. After examination of Tikataalik’s fin, it was certain that the fish had a wrist. The wrist was similar to the human wrist it could bens, and could push up. The movement was useful for the fish to navigate to the bottom of the lake or pond.
Dispute:
The fish and human are different, our environment, needs, diet, social interaction, place in the food chain, etc. Shubin’s main message in the second chapter is discovering what’s underneath the surface. By just a glance, fish and human may seem to be different, but when we look past the skin, there are some similarities. The first one being bone structure as explained by Shubin. Shubin discussed the Owen bone structure “one bone, two bone, lotsa blobs, and five toes” (32). This structure is present in the fish and the human. Furthermore, not only do the fish and human have a common limb structure, we may also have a common ancestry. Shubin claims that the fish he found could be an ancestor of both fish and humans in which case, fish and humans are similar.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion- Year- History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 3
1. Biologist Edgar Zwilling and John Saunders observed chicken embryos by cutting and moving tissue to discover the embryos effect. Using microsurgery they discovered two patches of tissue that control matter in the bone pattern. When the tissue was removed only the upper arm developed. When it was removed later the arm completely developed. The findings of this observation lead to the knowledge that all appendages are built by similar genes. Findings also suggests that the evolutionary transformation of fins into limbs did not involve new DNA just genes working together in different ways.
2. Hedgehog gene was originally found in fruit flies as a gene that makes different region effects similar to chicken region effects. The chicken hedgehog was discovered and renamed the Sonic Hedgehog. The gene was found in the chicken’s wing bud. Every animal with limbs had the hedgehog gene. If the sonic hedgehog gene does not activate in the normal embryo it can result in an extra pinky or thumb. This experiment confirmed that the sonic hedgehog gene contributes to the development of appendages.
Dispute:
The human body has specialized cells, leading to specialized tissues, organs, and so forth. The specialization is not due to the unique set of DNA because the DNA in each of our bodies is the same for every individual. But rather, it is the gene in our DNA like the Sonic Hedgehog one that controls the specialization in our cells. Tabin, McMahon, and Ingham saw that “this gene made one end of a body segment look different from the other” (Shubin 52). The hedgehog gene creates a unique DNA by turning on and off at set times, the gene is able to create deformities in certain cells. These deformities are what create the cells in our body become muscle cells or skin cells. Therefore, it is not a unique set of DNA, but genes activated at certain times that allow cells to build muscles whereas others are arms.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5- Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 4
1. Teeth are hard as rocks because of the high content of hydroxyapatite, seen more in teeth than in bones. Teeth are less likely to decay and will be the best preserved part of a fossil.
2. Conodonts are organisms with spikes protecting out of their bodies. They became used mostly by jawless fish to use up their food. Overtime the fish required the Conodonts gene to produce teeth through the process endosymbiosis.
3. Scale, feathers, breast, and teeth start the lower layers of the skin folded inward. From each fold the structures emerges. Shubin claims that teeth came first then changed to creating other skin surfaces.
Dispute:
First off, the earliest recording of any hard body part bone or tooth was the “Conodonts” in the primitive lampreys and those were teeth (Shubin 75). The lamprey is not a predator or prey, rather it is a parasite. The lamprey uses its hard body part for its own gain. Similarly, we can turn to one of the ocean’s most primitive fish and its most feared predator, the shark. The shark’s inner supporting system is that made of cartilage, not bone, and its hard part is its tearing teeth. The shark and lamprey are two examples that bones came after teeth as an adaptation for protection. The teeth came as a beneficial adaptation for predators since the advent of teeth allowed predators to tear apart its prey. Bones came as a sort of body armor against the tearing teeth.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 5
1. The trigeminal and facial cranial nerves appear to just be a mass of tangled muscle and nerves, without order, but they demonstrate “a pattern that reveals the order in what initially seems chaotic” (Shubin 82). Cranial nerves comes directly from the brain, arising from the base of the brain to be exact, and these nerves control facial actions such as chewing, talking, and moving our eyes and head. The trigeminal and facial cranial nerves are the two cranial nerves that are “very complex functions and take tortuous paths through the head to do their job” (Shubin 84). The trigeminal and facial nerve are mention when it comes to complicated nervous pathways. The trigeminal nerve branches out into an array of branches forming a network of nerves, and serving the main function of transferring information from our face back to our brain. The branches of the trigeminal nerve however also serve for feeling sensation in the roots of some teeth, along with providing feeling to the entire face through their complicated network of nerve endings. The facial cranial nerve also controls muscles and sends information to and from the brain, and it is “the main nerve that controls muscles of facial expression” (Shubin 85). There seems to be no reason to the numerous and varied functions of these nerves.
2. There are four main arches involved in embryonic development: the first arch forms the upper and lower jaws, malleus and the incus, which are two ear bones. The second arch forms a small ear bone called the stapes, a throat bone, and muscles involved in facial expression control. The third arch from bones, muscles, and nerves deeper in the throat use to swallow. The fourth arch forms the deepest parts of the throat (Shubin 87).
3. Hox genes are so important because they “instruct cells to make the different portions of our head” (Shubin 93). Each gill arch has a different parts of Hox genes in it, allowing the arch to develop into the structure of the head, whether that is the jaw, throat, nose, or other structures. With knowledge of how Hox genes work, we can make a map of our gill.
4. The Amphioxus an invertebrate, but it shares many characteristics with vertebrates, it is a good specimen for study, because it helps when analyzing the differences and similarities between vertebrates and invertebrates. Even though the Amphioxus does not have a back bone, it shares the characteristic of having a nerve cord that runs along its back like vertebrates. Rather than having a spine for support, the Amphioxus has a “notchcord” that is filled with a jelly-like substance. While the Amphioxus keeps its “notchcord”, ours breaks up and ultimately becomes “part of the disks that lie between or vertebrate” (Shubin 94).
Dispute:
Sharks and humans do look different.
However, the gill arches during the embryonic stage create similar structure in use, not appearance. The first gill arch creates “the trigeminal nerve in both humans and sharks” (Shubin 91). The cells of the second gill arch gives us cartilage and muscle that helps the creation of the stapes, as well as another bone, the hyoid, that assists in swallowing. In a shark, the same arch “helps with jaw production” that compares to hyoid (Shubin 92). In the third and fourth gill arch, for humans it produces structures necessary for speech and swallow and for sharks it includes parts of tissues that support the gills. Sharks and humans have gill arches in the embryonic stage, but unlike the statement proposes, they do develop into related structures in each
organism.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 6
1. A. “Ectoderm – Epidermis of skin and its derivatives (including sweat glands, hair follicles), Epithelial lining of mouth and anus, Cornea and lens of eye, Nervous system, Sensory receptors in epidermis, Adrenal medulla, Tooth enamel, Epithelium of pineal and pituitary glands, Notochord, Skeletal system (Shubin 101).”
B. “Mesoderm – Muscular system, Muscular layer of stomach and intestine, Excretory system, Circulatory and lymphatic systems, Reproductive system (except germ cells), Dermis of skin, Lining of body cavity, Adrenal cortex” (Shubin 102)
C. “Endoderm – Epithelial lining of digestive tract, Epithelial lining of respiratory system, Lining of urethra, urinary bladder, and reproductive system, Liver, Pancreas, Thymus, Thyroid and parathyroid glands” (Shubin 102).
2. The fertilized egg continues to divide which leads to the creation of an inner group of cells with an outer shell. This stage is referred to as a blastocyst. The inner group of cells develop into an embryo while the outer group of cells turns into the membranes that support and shield it. The blastocyst reaches the uterus around day 5, and implants into the uterine wall on about day 6. The mother’s menstrual cycle causes the lining of the uterus to grow and prepare to support a human fetus and ultimately a baby. During the pregnancy the blastocyst sticks tightly to the uterus where it receives nourishment through the mother bloodstream. (Shubin 100-101)
3. “Ontogeny recapitulates phylogeny” means the study of the development of an embryo that shows the repetition of an evolutionary stage during development and growth of a group of organisms (Shubin 103). While studying embryos, a trend could be seen that the further along you go in the phylogenetic tree, the more stages of development the organism would pass through, but there are many examples of organisms who do not resemble previous evolutionary ancestors when they are developing.
4. Noggin is a type of HOX gene that helps with the body plan, and it is also involved with other organs. It is also associated with another gene called “BMP-4 when determining the top-bottom axis, where BMP-4 is the bottom gene and Noggin is the top gene” (Shubin 112).
5. The body-building genes of sea anemones and humans are the same. Sea anemones and humans have similar major body plan genes along mammalian head-to-anus axis of anemones. Sea anemones have similar belly-to-back genes to humans, but instead of along a belly-to-back axis, it was along a hidden axis called a directive axis that differentiates the sides of the organism into a left and right side. Humans and sea anemones may appear different, long time of modification accounts for the visible difference between the body plans of a human and a sea anemone.
Dispute:
First of all, scientists do not work in isolation. Throughout all the examples provided by Shubin and in all scientific education, it is evident that a scientist cannot simply work alone and achieve a scientific breakthrough. In the event of the “Organizer’s” discovery it was not only Mangold but also Spemann who helped come up with that idea (Shubin 106). Furthermore, it is not counter-productive to repeat another scientist’s experiments or to consider their research because most of the time it is the research and experiments of earlier times that give us insight and the background information necessary to produce new information. Trying the experiments of others and using their research is not counter-productive, because their successes and failures can help other scientist to find and fix the previous mistake.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 7
1. The most interesting thing about the timescale is how recently modern humans came into existence. This is surprising to me, because the events we learn in history seem so numerous and ancient, and it is difficult to imagine an earth without human life.
2. The most common protein found in the human body is “collagen” (Shubin 125). When magnified it resembles a rope, with a lot of tiny molecular fibers. Collagen is “like rope, it is strong when pulled, but weak” when relaxed (Shubin 125).
3. Cells are held together by a biological ‘glue’ that also allows them to communicate. It contains a variety of different molecules and gives our tissues and organs their distinct appearance and function. Some tissues have cells in organized strips, while others have cells that are randomly scattered or loosely attached to each other. For example, the molecules in between bone cells determine the strength of the bone and more loosely attached proteins in eyes make them more squishy and yielding.
4. Cells generally communicate with one another by sending molecules back and forth. Basic cell-to-cell communication involves one cell emitting a signal that attaches to the membrane of the cell receiving the signal. Once attached to the outer membrane, the molecule sets off a chain reaction of molecular events that travels from the outer membrane all the way, in many cases, to the nucleus of the cell.
5. “Choanoflagellates are single-celled microbes, known to be the closest microbe relatives of animals with bodies and sponges. Because of the discovery of choanoflagellates, the genetic distinction between ‘single-celled microbe’ and ‘animal with body’ completely broke down because most of the genes active in choanoflagellates are also active in animals, with many of those genes serving as part of the machinery that builds bodies. These organisms gave biologists a road map for comparing the bodybuilding apparatus to microbes” (Shubin 133-134).
6. Theories explaining the appearance of bodies include a very simple one: bodies arose when microbes developed new ways to eat each other or avoid being eaten. Another explanation for development of bodies was obviously evolutionary function. Levels of oxygen were not high enough on ancient earth until roughly a billion years ago, when the amount of oxygen increased dramatically and when enough oxygen was present to support them, bodies popped up.
Dispute:
First of all, tissues in the human body have cells similar in relation to cells within that same tissue. For example, cells in brain tissue will be similar to other cells in the same brain tissue, not to cells in a heart tissue. Not all cells connect the same way and there is not always a common cell membranes. Rather that while there are certain kinds of cells like muscle cells that might do that other cells like bone cells don’t. Bones stick “by means of tiny molecular rivets”, and some bind cells like “cement holds with the soles of shoes together” (Shubin 127). This rivet sticks to cell membrane of one cell and another cell and acts like a glue. Thus, forming a bond that holds these bones together. These rivets only bond to the same kind of rivet. Hence, not all similar cells connect to each other in a similar fashion. Furthermore, not all tissues in the human body are made of similar cells.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 8
1. Floating in the air are tiny molecules that we register as odor with our noses. We suck in these odor molecules in our nostrils as we breathe or sniff. From there, the odor molecules go to an area behind our nose where they are trapped by the mucous lining of our nasal passages. Inside this lining is a patch of tissue containing millions of nerve cells, each with little projections into the mucous membrane. When the molecules in the air bind to the nerve cells, signals are sent to our brain and our brain then records these signals as a smell.
2. This occurrence makes sense because mammals are highly specialized smelling animals, which requires a large number of odor genes in order to recognize the odor. A larger number of odor genes is possible because the “extra” genes in mammals are all variations of a theme: they look like copies, albeit modified ones, of the genes in jawless fish. This means that our large number of odor genes arose by many rounds of duplication of the small number of genes.
Dispute:
First of all, “three percent of the human genome is dedicated to olfactory senses”, which is needed to detect different odors. (Shubin 144. The only thing true and connected regarding olfactory genes and animals is that they are present in the same number in all organisms capable of detecting smell. If this statement were true, dogs and humans would have the same sense of smell as each other. The only thing similar is the number, other than that everything else is different. For example, although humans and dogs both have 3 percent of genome dedicated to the smelling of odors, the dog will have more of their 3 percent actually functioning compared to humans.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 9
1. Humans and Old World monkeys have similar vision due in major part to the analogous structures of the optical systems. Both humans and the Old World monkeys are enabled to have this vivid color vision because of the three unique light receptors that enable the perception of different kinds of light. Diversity in plant life gave the old world monkeys an evolutionary benefit to being able to perceive different colors in order to differentiate different fruits, berries and such.
2. “Eyeless genes were originally discovered when Mildred Hoge observed fruit flies that lacked eyes in their entirety. This gene when present in other species can lead to deformities in the eyes of the given species. Deformities in humans due to the eyeless gene can cause conditions such as acarida. It has been observed that eyes in flies, mice and humans all stems from similar sequences of DNA of the eyeless genes. These eyeless genes and the DNA fragment primarily responsible have been studied a great deal. Biologist Walter Gehring was able to use the eyeless gene to active the DNA sequence similar in other areas of the body. In areas of activation of the gene, an eye would grow. This was an astonishing discovery. The analogous structure to eyeless genes in mice, Pax 6, showed similar results when activated. Based on these findings it can be determined that eyeless, or Pax 6 is the overarching control gene of eye production in all animals that have eyes” (Shubin 156).
Dispute:
All organisms with vision do not have similar eyes. When looking at the diagram on page 151, he makes a clear distinction in the eyes of humans, scallops, nautili, and limpet. There is a clear distinction provided in the graphics of the structure of their eyes, hence their vision. Even when we look at the closely related fly, their eyes are not similar to that of humans. Humans have one vision and our eye structure is more like that of a camera, not a kaleidoscope. Monkeys would benefit because “color vision enabled them to discriminate better among many kinds of fruits and leaves and select the most nutritious” among them (Shubin 153).
Citations:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 10
1. There are three parts to the ear; the inner ear, middle ear, and outer ear. The pinna, or the flap of the external ear, is the only unique body part found in mammals.
2. The discovery that the ear bones of mammals may have some correlation to the jaw bones of reptiles began with Karl Reichert, a German anatomist. Mammals have three bones in the middle ear, while reptiles and amphibians have only one. Thus, these bones had to come from somewhere. He observed gill arches in several species to see where they ended up within the skull, and discovered that two of the ear bones present in mammals corresponded to bones in the jaws of reptiles. He concluded that “the same gill arch that formed part of the jaw of a reptile formed ear bones in mammals” (Shubin 160). By 1913, embryologists and paleontologists began to work together, and with Gaupp’s theory, began to look at these fossilized skeletons. They discovered that the most reptilian of these skeletons only had a single bone in the middle ear, just like current reptiles do, and a jaw composed of many bones. However, the more mammalian of these skeletons showed the bones at the back of the reptilian jaw getting smaller until they eventually became part of the middle ear of mammals. This proved that the malleus and incus evolved from jawbones.
3. The Pax 2 gene is active in the ear and starts a chain reaction that allows for the inner ear to develop. If a mutation in humans or mice knows this gene out the inner ear cannot properly form. This is a major gene that is essential for proper development.
Dispute:
Birth defects to the ear often effects the eye, and vice versa. This is because the use of the ear is way more than just listening. The ear gives us a sense of balance and direction via the rocks, gel, and nerves in the inner ear. Every time our “head tilts or moves, the rocks sitting on the gel in our inner ear moves” as well (Shubin 165). This stimulated the nerve hairs in our inner ear. The nerves report this shift to the “brain and our brain tells the eight muscles in our eye to direct our eye” as well (Shubin 167). It’s a chain reaction. If this statement proposed were true, and the eye and ear were independent to each other, our eyes would be looking dead ahead even though our head might be rotated a full ninety degrees. This would happen because the head would tilt but here’s the thing. There is a little thing called the brain that makes the connection between the brain and the eye. Every time our head tilts fast, our eyes aren’t able to clearly catch what is in front of us because the fast tilting does not give the brain enough time to send the signal to our eyes for every position of our head. In the end, the eye, the ear, and the brain are all connected.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH CHAPTER 11
1. Shubin’s biological “law of everything” is that every living thing on Earth has parents and this law is so important because it is one true law that everyone can agree upon. This allows scientists and taxonomy experts to hypothesize parental lineages as this law “defines parenthood in a way that gets to the actual biological mechanism of heredity and allows us to apply it to creatures like bacteria that do not reproduce the way we do” (Shubin 174). This pattern of descent with modification defines an organism’s family lineages and, more importantly, is the undeniable “law of everything” (Shubin 174).
2. By incorporating the “Bozo example” in his text, Shubin is able to accurately explain to his readers how descent with modification can be used to create hypothesized family lineages by unlocking biological history. For example, “Let’s take a hypothetical humorless, quite unclown-like couple who have children. One of their sons was born with a genetic mutation that gave him a red rubber nose that squeaks. This son grows up and marries a lucky woman. He passes his mutated nose gene to his children, and they all have his red rubber nose that squeaks. Now, suppose one of his offspring gets a mutation that causes him to have huge floppy feet. When this mutation passes to the next generation, all of his children are like him: they have a red rubber nose that squeaks and huge floppy feet. When this mutation passes to the next generation, all of his children are like him: they have a red rubber nose that squeaks and huge floppy feet. Go one generation further. Imagine that one of these kids…has another mutation: orange curly hair. When this mutation passes to the next generation, all of his children will have orange curly hair, a rubber nose that squeaks, and giant floppy feet…” (Shubin 175).
3. Obesity: Obesity has become one of the leading causes of death in humans today and much of it is due to the fact that humans have a body for an active animal; however, we now have a lifestyle of a lazy couch potato. In 1962, James Neel suggested that “human ancestors were adapted for a boom-bust existence” (Shubin 187). He believed that our ancestors were hunters and gatherers that constantly undergo a cycle of feast and famine, and this led to increased rates of obesity. As our bodies were made to store food for times of need. This leads to obesity as humans eat excessive amounts of food, but there are no periods of famine to use up the saved fat (energy), causing humans to then become overweight.
Dispute:
Shubin made the analogy of human evolution to that of the Volkswagen Beetle. He said that the humans are basically a beefed-up Beetle. All the improvements made had a side-effect of making the car uglier. The maladies in the human body are just like that. The examples brought up in the book include the “hiccup and hernias” (Shubin 186). The glottis, the organ causing hiccups in humans, is an evolutionary remnant from when mammals were formerly amphibians. Now instead of being useful, the glottis has become a constant pain in the human’s life. The maladies don’t just apply to the useless parts of our body, but even those useful. But in the end, everything in our body is a result of our evolutionary past.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.
INNER FISH AFTERWORD
1. Most fish have a plate of bone called the operculum. The operculum creates a shield that covers the gills and helps push water over them. Tiktaalik not having this bone showed that relied on breathing through its mouth like other land animals.
2. Tiktaalik was able to have a "true neck", that could move freely from its body, which is like other land animals.
3. The Arctic may be cold and snowy, and Tiktaalik fossil were found there, but Tiktaalik lived tropical landscape. Therefore, this species never had to survive in the cold Arctic as we know it. Tiktaalik tropical was found in the Artic because of either global climate change or moving continents. Since this species lived 375 million years ago, the climate was different than it is now.
Citation:
Shubin, Neil. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Pantheon, 2008. Print.