What Can Cause a Chance in Allele Frequency
1. Mutation: A mutation is a change in DNA sequence, that which can be cause by a mistake in the process of cell division, and exposure to radiation and infections caused by viruses. Though mutations must occur in the gamete. to be passed down to offspring. Mutations can not occur in any other body cell for it to be passed down. Across is a diagram of mutation, it shows the difference form of mutations and how it affects the DNA sequence.
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2. Migration: This is the transfer of genes or alleles from one population to anther population. Genes can be carried be migrated to other populations where the gene did not exist before. A diagram is shown across, keep note of the brown bug leaving tracks while migrating to the green bug population.
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3. Genetic Drift: The frequency in alleles can chance based of who is the "luckiest" individual, not the best individual in a population. Which animal is the luckiest is the one who will pass down the genes. The luckiest one can be determined by which organism survives a natural disaster. The diagram across shows genetic drift.
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Natural Selection
Natural selection is most described as "survival of the fittest." It is when a trait is either more or less common and becomes better adapted to fit an environment. This process usually starts with genetic variation. though a change in the environment does not support the changes in the gene. The stronger gene in this situation is the gene that would most likely reproduce. There are three types of selection: stabilizing, directional, and disruptive. Stabilizing selection is when the medium of a trait is the selective trait, and the extreme measures are not. Directional is when the extreme measure is more desirable in the environment, and the medium one is not. Disruptive is when both the extreme and medium are selective.
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Evidence of Evolution:
A major piece of evidence is homologous structures. This is when different species have the same structures. This can prove that different spices may share a common ancestor. Though when the same structures are variates, this can also show how the organism has adapted to is environment. Vestigial organs are organs that have no longer serve a purpose, but are still present. Vestigial organs help show the evolution of animals and how animals most likely have used these organs in the past. Convergent evolution is when two species are not related but have the same adaptations, due to similar living conditions. Embryology is also another major evidential part of evolution. When in the process of developing in the womb, at first all embryos are the same or look the same. All embryos have gills and a tail. Over time, the species either looses or keeps the tail or gill, depending on whether its need for living standards or not. This shows how animals have developed and evolved to achieve what they need to survive. Many scientists believe that we share a common ancestor, a primate. Fossils are another piece of evidence. Relative dating is a process that helps estimate the age of a fossil based on its level in a sedimentary rock. The placement of animals can also help prove evolution. Species are sometimes found in continents such as Africa, and another sub-species of the same ancestor was found in South America. This proves that species have common ancestors, and the species found on both continents show that they have adapted to their new environment.
A Prezi Presentation about the Organisms of The World:
Special Adaptations:
- The Emperor penguin has evolved to grow a thick layer of fur to help with stand temperatures as low as 100 below.
- It also grows a thick layer of fat beneath its skin to also help with the cold temperatures.
- A complex heat exchange systemallows 80% of heat in the breath to be recaptured in the nasal passages
- They can dive to a depth of 1,800 feet (550 meters) and hold their breath for up to 22 minutes, so are able to reach and exploit food resources that other birds can't reach
- The normal resting heart-beat is about 60-70 beats per minute (bpm), this goes up to 180-200 bpm before a dive as they load up with oxygen, as they hit the water, the rate drops to 100 bpm immediately slowing to 20 bpm for most of the dive
Evidence of Evolution in the Emperor Penguin:
DNA evidence and fossil evidence disagree on exactly where the basal lineage is. If the DNA evidence proves to be correct, then the Emperor Penguins common ancestor would have been around five feet tall. The skull of the penguin evolved more into a primitive configure later on in the penguins evolution. It is very likely that the modern form of penguins may have an origin in the tropical South America.
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Though recent studies conduct that fossils have been found that are over 60 million years old. The fossils even depict that the penguins wings had still not yet developed for diving. As of 36 million years ago, the penguins still had a reddish color to them, and had suggest that they lived in a temperate area in south america.
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