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Notes:Evolution NotesEvolution Jeopardy REview |
Evolution Overview
Evolution = change in the heritable characteristics of a population over time.
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While Darwin's view of the evolutionary tree is the most common theory of looking at evolution, there are some scientists who have been pushing back.
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See "Evaluating the Evidence" below for more specific articles and videos.
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Charles Darwin (1809- 1882)
Natural Selection
3 key principles must be in place for Natural selection to occur:
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Example: Pocket Mice video
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Evolution and Disease Project
Humans have been dealing with evolving diseases for 1000s of years. Paleontology and Archeology tell us that Tuberculosis was predominant in ancient Egypt, so disease is nothing new. What is new is how we have learned to fight these diseases. Vaccines, antibiotics, anti-virals, as well as social programs put in place all have helped but fight diseases.
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Diseases that cross from one species into another are called zoonoses. The 1918 Influenza Pandemic, Ebola, the Bubonic Plague, HIV/AIDS, Malaria, Dengue, SARS and most recently COVID-19 are all various types of zoonoses. They demonstrate the wide variety by which transmission can occur. COVID-19 is not the first nor will it be the last of these diseases’ humans face. Unfortunately, they are a rather deadly group of diseases because they are often novel, meaning never seen by a human immune system so we cannot defend ourselves). But our past experiences with other zoonoses have helped us immensely in dealing with our current pandemic.
Our understanding of Natural selection and evolution has enabled scientists to better fight many of these new novel diseases.
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1918 Influenza (Flu) |
Bubonic Plague |
'Wolf' to Whale Example
The small adaptive changes that occur within a population of organisms through natural selection is well documented science. But what is harder to verify and provide evidence for is the dramatic changes that would cause one form of organism (a wolf like creature) to change into a completely different form (a whale like creature).
To demonstrate Darwin’s Theory of Evolution as true, we must first be able to demonstrate that such a set of changes exist.
The primary pieces of evidence are presented by the above video clip to support this theory:
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Evaluating the Evidence
While the evidence seems compelling, there are holes that do not necessarily add up.
See a Student Google Document discussion for an activity
- The drastic amount of changes needed INTERNALLY and GENETICALLY to make this happen are astronomical. And currently (2020) we still have no mechanism to accomplish them.
- Natural selection has not been shown to be able to make such intense changes in such a short period of time. The question of Natural selection having limits is well researched.
- The time between Pakicetus to whale is very short, too short in fact to make the drastic leaps even by evolutionary timelines
- The skull they found with the inner ear of the whale was only a small fraction of the head, so knowing where the nostrils etc were requires some educated guess work
- Although other fossils have been found more complete, and the nostrils do not seem to be in the places originally indicated, therefore not demonstrating the slow migration of the nostrils to blowhole one would expect in this hypothesis.
- Also the bump found on the skull is not the same as a whales it is much more flat in comparison, indicating that it may not be the same structure after all.
- We know very little about whales in general in terms of their habits, mating, etc which means we do not know if the pelvis bones may have another entirely different purpose
See a Student Google Document discussion for an activity
The Fossil Record
What is a fossil? Definition:
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What are scientists looking for?
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The Geologic Column
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Interpreting the Geologic Column
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Layers are color coded and labeled (A-D) for your benefit.
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What are we looking for in the geologic Column?
Transitional Fossils
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Vestigal Organs
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Homology = Similarity due to a common ancestor
Bone Homology
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DNA Homology
DNA homology is aligning the sequences of DNA or proteins between various species to determine the number of similarities and differences between them.
Current research indicates that information is not just coded for in the sequence of DNA or protein, but also in 3D shapes of DNA, the chromosomes, and proteins themselves, as well as in the “tags” placed on the DNA from the environment.
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Evaluating the Evidence
Arguments always have strengths and weaknesses to them. The question is how strong these arguments are as evidence of macroevolution, being able to change entire forms of one organism to an form (example wolf to whale). The more we learn, the more some of these things are brought into question. The above information is some of the many arguments used for a Darwinian view of evolution.
Macro vs Micro |
Here are a few scientists arguing against Darwin's understanding of evolution, or at least calling into question the classic understanding of evolution.
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