Your Inner FIsh
All organisms with vision do not have similar eyes. There are many groups that have similar eyes, but not every single organism have similar eyes. Since most of the picture processing happens in the brain, the function of the eye is just to capture light to carry to the brain for processing of an image.
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Human’s camera-like eyes are similar and common to every creature with a skull. However many different types of eyes exist in other animal groups. Other eyes range from small, simple patches of cells that are specialized in capturing light to even more complicated versions of a human eyes with many layers, like eyes of flies. (150) There are basically two different types of animal eyes however; one seen in invertebrates and one in vertebrates.
The main idea being that there are two different ways of increasing the surface area in eye tissue that gathers light. Invertebrates do this by having numerous folds in the eye tissue. However vertebrates expand the surface area of the eye tissue by having lots of tiny projections extending from the tissue. (156) However, all organisms do indeed share similar vision genes. Eyes may look the same, but the genetics that make them are the same. (157)
Dispute: There are few genes dedicated to olfactory sense and they are similar in all organisms capable of detecting smell.
A major breakthrough in understanding our sense of smell occurred in 1991 when Richard Axel and Linda Buck discovered the large family of genes that give us our sense of smell. (143) They discovered that there are a huge number of genes dedicated to olfactory sense. They also discovered that only three percent of our entire genome is dedicated to genes for detecting and processing different odors. For this discovery, Axel and Buck received and shared the Nobel Prize in 2004. (144)
Dispute: Humans and sharks both have four gills arches as embryos, but the germ layers and arches develop into unrelated structures in each organism.
Humans and sharks do both have four gill arches as embryos. However, the germ layers and arches do not develop into unrelated structures in each organism. In fact, they are extremely important and are a ‘roadmap’, so to speak, for major parts of the skull. (89)
The first arch forms the jaws. The human’s first arch also forms some ear bones that sharks do not form. The second arch or gill turns into a bar of cartilage and muscle. This gill allows us to take a gulp of a drink or listen to music. This gill allows sharks to extend and retract their upper jaw to eat something. The third and fourth arches allow us to swallow and talk. They allow sharks (and fish) to move their gills. (91, 92)
Dispute: Most organisms fossilize after death, so fossils in exemplary condition are easily found all over the world.
Fossil sites are actually rare and there are many specifications to make a place a good fossil site. You have to find rocks that are of the right age, of the right type (which would be sedimentary rock), and well exposed. The best fossil sites have little soil cover, little vegetation, and have been subject to little human disturbances. (12)
Though organisms have lived all across the world, that isn’t really a guarantee that fossils can be found just about anywhere. Also, just because you find a fossil doesn’t mean it will exactly be in perfect shape. There are fossils of animals and organisms that have been dead and buried for so long their bodies are very rarely preserved. Over ninety-nine percent of all species to ever live are now extinct, from that a very small fraction are preserved as fossils, and an even smaller fraction of that are even found at all. (3) We are lucky we can find any fossils at all, let alone fossils in good shape.
Dispute: In humans, eyes and ears function independently of one another; sensation in one does not affect sensation in the other.
The eyes and ears are actually connected. The easiest way to understand the connection between the two is to interfere with it. Humans do this all the time by drinking too much alcohol. Drinking too much alcohol causes the fluid in the inner ear to become less dense. This causes our brains to think that we are moving.
This is how it connects with the eyes. Our brains think that we are spinning and passes this information to our eyes. This causes the eyes to twitch to one direction, usually being the right. This basically happens again the day after a night of drinking, often referenced to as a hangover. Your liver gets all the alcohol out of your bloodstream, except for the alcohol in your inner ear. The alcohol then diffuses from the gel back into the blood stream. This causes the brain to think you’re spinning again, and also causes the eye to twitch. (168)