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Project by Kristalyn Hayes and Joseph Kirk

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Project by Kristalyn Hayes and Joseph Kirk

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Period 5

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VIST stands for
Variation
Inheritance
Selection
Time
Evolution requires these four things to take place.

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Variation in evolution is the various genes and differences between said genes. New variations of genes may show up due to mutations either for good or worse. Another way new genes may be introduced is by migration/gene flow. If one species moves to somewhere there is another group it can cause variations within the new breeds.

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Inheritance in evolution is genes being passed on. For example, if a variation occurs in genes, it'll get passed down to different generations. Some proof of inheritance is vestigial organs. To some species vestigial organs may be useful and to some they may be less so, it could have been passed down from a common ancestor. Another example of inheritance is homologous structures, or bones/organs different animals have in common. These could indicate a common ancestor between them. For example, humans, dogs, and cats have similar pelvises.

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Without selection, evolution could not happen. An example of selection is natural selection. Natural selection is the process of better adapted organisms surviving and producing more offspring. This can cause some features to disappear from a species. Another example of selection is sexual selection. Sexual selection is part of natural selection. Sexual selection is the preference one sex has for the other sex. If females don't like certain features on a male, that male may not produce any offspring, causing their features to not get passed down. On the other hand, if females like a certain feature on a male, that feature is more likely to be passed on.

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A very important aspect for the time section of VIST is molecular evolution. Molecular evolution is the process of change in stuff like DNA and RNA. This often takes a lot of time. There's also events of chance, or genetic drift. This is when a certain event occurs in the environment to either aid or damage. A phrase made by Ernst Haeckel, though disproved tells us how humans differentiate between other animals in the womb, and how we all look similar at the start.

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The different types of evolution are divergent, parallel, and convergent.

Parallel evolution is when two unrelated species evolve roughly the same due to the similar life styles. For example, both bob cats and wolves are fast, efficient hunters but show no relations.

Convergent evolution is different organisms with different ancestors become more alike over time. For example, insects that fly and birds/bats.

Divergent evolution is when even though two species have similar ancestors they become less similar over time. a example of this is is grey wolfs and domesticated dogs. One is a hunter with a rough hide and better cold resistance while one is a friendly and timid, soft cuddle buddy.

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All animals go through evolution, be that whales, people, giraffes, or the common household cat. As to be demonstrated, evolution takes a really long time, to us at least, and change the ancestors of some of our favorite animals into what we see today

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Before cats were small soft balls of fur who are (mostly) friendly and coexist by people. However, its first ancestor lived differently, instead of lounging around while their servants give them a constant flow of food. ~Twenty-five million years ago the first ancestor, proailurus, or before the cat, roamed earth. It was roughly 20 lbs with a large tail and eyes. As well as very sharp teeth and retractable claws and was of course carnivours like many of the big cats today.

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After the predecessor to Proailurus cats began splitting apart into three subfamilies; Pantherinae, Machairodontinae, and felinae.

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A fan favorite of the three subfamilies is Felinae, these are the huggable small/medium sized cats we see as more friendly. Though some big cats are in this mix, such as the cheetah, or couger. The first felinae was found to be alive roughly 9 MYA
(A member of the felinae family, jaguarundi)

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After the first feline we know of, roughly 20-8 MYA the Pseudaelurus came into play. This new feline lived in North-America, Europe, and Asia. Though not much of them has changed it is believed that due to their slender builds and Viverridae legs they were efficient at climbing trees. Due to coming right from proaliurus it is the ancestor to the big cats of today, household and smaller cats, as well as the long gone sabertooth tiger
(Fossilized pieces of Pseudaelurus)

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The much scarier looking felines that you think about when you think of a big cat is more often than not part of the Pantherinae subfamily. Some differences between these and the Felinae is that they are capable of distending the back of the mouth. As well as they can roar while Felinae family members can not. The split between Pantherinae and Felinae is believed to of happened around 6-10 MY
(A popular member of the Pantherinae family, a tiger, presumably on the prowl. Or just trying to look good for the camera)

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The final subfamily is one that is no longer around, but instead went extint around eleven thousand years ago. Machairodontinae are the big cats you may see on a documentary, or in a museum, that have large canine teeth that protrude from their mouth. It is speculated that the large teeth were used for sexual selection, or perhaps an evolutionary advancement for fighting. Felines use their mouth snd teeth to clamp into the prey's throat, and in a form strangling their prey. With the large and sharp teeth, the neck would have been punctured severely, to insta kill the prey.
(What remains of a Machairodont, the smilodon fatalis)

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So as shown, it has been twenty-five Million years since cats have been here, but only around eight Million years have the subfamily of Felinae exist. That means that for almost 17 Million years all of the cats that roamed were similar in levels of dangerousness to the big cats we have today. Even the small ones such as Proailurus. It then took even more time for any of the cats to become docile enough to keep in our homes without killing us through strangulation. Though in the whole scope of the universe, 25 million years isn't that long at all.