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mahq58 mahq58
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9 years ago
As an investigator, you are studying the changes in structure of plains dwelling, bovine-like mammals based on fossil skeletons found in sedimentary rocks.  These images show an artist’s rendering of the animals based on reconstructed skeletons.  The image on the left shows the animals based on skeletons on the top layers of the rock, on the right is an image of it’s ancestor based on fossil skeletons found in deeper strata of the sedimentary rocks.  It is apparent that in the deeper sedimentary strata, the length of the horns are longer and their body mass was greater.  The more current fossil evidence of the animals shows shorter horns and smaller body mass.


1.Describe the evolution of these animals using an explanation based on inheritance of acquired characteristics.  You need to provide a mechanism of how the change occurred – not just a definition.
 2.Describe the evolution of these animals using an explanation based on natural selection by descent with modification.  You need to provide a mechanism of how the change occurred – not just a definition.
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9 years ago
1.Describe the evolution of these animals using an explanation based on inheritance of acquired characteristics.  You need to provide a mechanism of how the change occurred – not just a definition.

The inheritance of acquired characteristics is a hypothesis that physiological changes acquired over the life of an organism (such as the enlargement of a muscle through repeated use) may be transmitted to offspring.

So, an explanation for the smaller horns would be that over several generations, predators living in the same community decreased in numbers, so buffalo stopped investing the energy to grow longer horns. This treat was subsequently passed on to its offspring. For the change in body mass, you could hypothesize something about smaller body mass contributing to greater running distances in warm, humid conditions.

2.Describe the evolution of these animals using an explanation based on natural selection by descent with modification.  You need to provide a mechanism of how the change occurred – not just a definition.

According to natural selection, the population always contained large and small buffaloes. However, those shorter horns and smaller body mass were more likely to survive because they possessed the phenotype that would allow them to escape predation and rising temperatures over time. Those that were too large eventually decreased in numbers.
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