Evolution
Evolution is the process of change over time. As animals evolve they become more and more complex, from one celled to multi cellular, from aquatic to land living, amphibian to reptile, the list is endless. Specifically, evolution occurs because of a change in Allele frequency.
Evidence of Evolution
One way we know Evolution occurred is because of fossils. Fossils are remains of plants and animals that date back millions of years ago. The farther down into the earth the fossils are the older they are. These fossils are similar to some animals and plants today but seem more rudimentary, this is because the animal or plant has evolved and changed over time. Another piece of evidence for the essay of evolution is geography. Some species on our current different continents look similar, and we can see if they had a common ancestor by checking the fossils. Camels and llamas look similar, and although they live in different places, they live on a migratory path that could have existed when our earth had the super continent Pangea.
One way we know Evolution occurred is because of fossils. Fossils are remains of plants and animals that date back millions of years ago. The farther down into the earth the fossils are the older they are. These fossils are similar to some animals and plants today but seem more rudimentary, this is because the animal or plant has evolved and changed over time. Another piece of evidence for the essay of evolution is geography. Some species on our current different continents look similar, and we can see if they had a common ancestor by checking the fossils. Camels and llamas look similar, and although they live in different places, they live on a migratory path that could have existed when our earth had the super continent Pangea.
Allele Frequency
Mutation, Genetic drift, Natural selection and Migration
Evolution occurs because of a change in allele frequency. Allele frequency is defined as "the proportion of a particular allele (variant of a gene) among all allele copies being considered." This means when one type of allele inscreases the proportion changes and the frequency changes. Four factors can drive Allele frequency, mutation, migration, natural selection and genetic drift.
Natural selection
Natural selection, the most well know form of evolution, which is also called survival of the fittest, which means those best suited to the environment will survive and reproduce. This means only the most adapted will pass on their genes, so their offspring will also be strong and well adapted. This theory was "discovered" by Charles Darwin in the 1830's. There are three types of natural selection, stabilizing, directional and disruptive.
For natural selection to occur there are three conditions needed. First, there must be a variation in a trait. For instance, in beetles there can be three colors, green, brown and red. The second condition is that the trait must be heritable, color is heritable. Personality and preference are not. Lastly the species with carried heritable traits must have different reproductive success. Some of the individuals must fail to reproduce because of environmental causes (such as weather, predators, lack of food) some must have many offspring because they have traits that help them survive. With the example of the beetles, the red beetle is very easy to spot and is thus being eaten by birds and is not reproducing. The brown beetle can hide in the bark but is easily spotted by a specific bird and thus has few offspring. The green beetle, since it can camouflage in the leaves, hides from the birds and has many offspring. This is natural selection; only the green bugs are reproducing because they are the "fittest" and thus pass down their genes
Natural selection, the most well know form of evolution, which is also called survival of the fittest, which means those best suited to the environment will survive and reproduce. This means only the most adapted will pass on their genes, so their offspring will also be strong and well adapted. This theory was "discovered" by Charles Darwin in the 1830's. There are three types of natural selection, stabilizing, directional and disruptive.
For natural selection to occur there are three conditions needed. First, there must be a variation in a trait. For instance, in beetles there can be three colors, green, brown and red. The second condition is that the trait must be heritable, color is heritable. Personality and preference are not. Lastly the species with carried heritable traits must have different reproductive success. Some of the individuals must fail to reproduce because of environmental causes (such as weather, predators, lack of food) some must have many offspring because they have traits that help them survive. With the example of the beetles, the red beetle is very easy to spot and is thus being eaten by birds and is not reproducing. The brown beetle can hide in the bark but is easily spotted by a specific bird and thus has few offspring. The green beetle, since it can camouflage in the leaves, hides from the birds and has many offspring. This is natural selection; only the green bugs are reproducing because they are the "fittest" and thus pass down their genes
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Evolution of a Cuttlefish
The cuttlefish before the cuttlefish
Before the cuttlefish, there was an animal called "a hypothetical archimollusc". The "hypothetical archimollusc", is the ansesctor of all mullusk and is predicted to have looked like the picture on the right. While this animal is hypothetical, there are no fossils of it, it is very likely it exsisted and scientists have produced this diagram through extensive research of the mollusc anatomy and the course of evolution in general. It is believed to have exsisted in the cambrian period. |
Special Adaptations
Through the process of evolution special adaptations are made to ensure the species survival. These are just a few of the Flamboyant Cuttlefish's special adaptations.
- Three layers of skin photophores that change color and pattern to mimic surroundings if they sense danger. They can cross dress.
- Cuttlefish have w shaped eyes that are supperior to our own
- Flamboyant cuttlefish are the only posionous cuttlefish and 1 out of 3 of posionous cephlapods,
- Flamboyant cuttlefish mostly crawl along the sea floor because their cuttlebones are smaller than most cuttlefish.
- They are very smart and they have one of the best brain to body ratio.