Ch 6 Survival of the Sickest Summary

In chapter 6 of Survival of the Sickest, it talks about how scientists have  realized that DNA can be modified by other factors, and not just random mutations. Lamarckism or, the  inheritance of acquired traits, seems to be superseding the original theory of Darwin that is mentioned in his book Origin of the Species. Barbara McClintock provided evidence in the 1950's for traits caused by jumping genes. Jumping genes are whole sequences of DNA that has been prompted to move from one place to another, by stress in the environment. Occasionally, jumping genes, or transposons, preform a "cut and paste" process, or a "copy and paste" process. Cut and paste is when whole sequences are removed and relocated, and copy and paste is when sequences are duplicated first, and then relocated. Jumping genes are what make up large portions of our junk DNA, or DNA that does not code for proteins.

This chapter also talked about the relationship of viruses, DNA, and RNA. Retroviruses are made up of RNA and can be inserted into, or written into, DNA. HIV is an example of a retrovirus, and is combated by the drug "cocktail" therapy. Cocktail therapy targets the enzyme that helps RNA become apart of DNA, in the hopes of slowing the process. Retroviruses that are already a part of DNA are called HERV's, also known as Human Endogenous Retroviruses. Some HERV's have a positive effect on DNA and are known for playing a number of roles such as producing a healthy placenta.

Bio Class 19

Today in class we took a quiz on "The Journey of Man" and then turned to the whiteboard for an activity. We discussed DNA and its properties such as: nucleotides: phosphate+sugar+base 

Adenine, thymine, guanine, cytosine: makes up DNA. Hydrogen bonds connect base pair.

Phosphate diester bond: through dehydration synthesis

Purines and Puyrimidines: 1 group vs 2 groups

3' base and 5' base: 

3 prime base has an OH group.

Special enzymes help to unzip DNA when mitosis in a cell occurs or there is a need for replication: 

Form atoms to traits

1.) Mendel was important because he helped adjust and prove Darwin's theory. By crossbreeding pea plants, he was able to prove that the offspring did indeed share similar traits. He also proved that heritable variations are their own separate entities that are always passed on but not always present.

2.) DNA:

Discovered by James D. Watson and Francis Crick. 

3.) 1. Copying errors during DNA replication such as copying the wrong letter of skipping a letter.

2. Substitution of different strands of DNA can cause mutations, and can change the variation.

3. Point mutation is when a single base pair changes for example muscle growth in dogs such as the whippet.

4. Insertion is when a base pair sequence is inserted into a gene that can cause different traits to become present. For example wether pea plant seeds are wrinkled or not.

5. Gene copy number is when duplicating errors occur in cell division leading to variations in a species. For example, humans look very different from each other but we are all the same species.

4.) evo-devo is the study of the effects of changes in important developmental genes and the role they play in evolution.

5.) lactose intolerance into adult hood can be traced back to the genes of our ancestors. In Africa the ability to digest milk was useless because of milks lack of abundance. However, when our ancestors reached Europe, they began to herd milk producing animals that made the gene of lactose tolerance more prominent.

Honors Bio Class 18

Today in class we finished watching a movie about the origin of man, and how we were able to populate the entire planet. Last class we left off at Australia, the place where man supposedly traveled to after leaving Africa. However, the narrator found proof in India that our ancient ancestors had indeed passed through India to get to Australia. He found this proof in a man among a remote village on the outskirts of India that had a similar mutation in his DNA in relation to our ancestors DNA. The reason why the narrator was only testing men was because of the Y chromosome. The Y chromosome is special because it does not change when it is transferred to offspring and would provide untainted proof. 

After Australia, the narrator studied the movement of the second group of ancestors that instead moved through Central Asia and Europe. We see proof that our ancestors moved through Pakistan, and Afghanistan through the study of one mans blood, Niazov. 

This man had DNA that could be traced back to the original group of ancestors that had made the trek from Africa to Afghanistan. from this point on, it took humans 10,000 years longer to get to Europe because of the drought caused by the ice age. However once they reached Europe and the Arctic Circle many physical changes took place. One of the most noticeable changes was the color of skin. Dark skin was for people that lived in an environment that had constant sunlight where dark skin could offer protection. Light skin on the other hand, was for places with less sunlight so that the skin could pick up as much sunlight as possible in order to receive nutrients. 

Honors Bio Class 17

Today in class we discussed the readings from homework that set up an overview of the trek our first ancestors took. The readings also questioned what enabled humans to populate most of the world in such a short expanse of time. The first traces of our ancestors can be found in Africa, dated back to 50,000 years ago. However, evidence of their existence was also found in Australia, implying that our ancestors had somehow traveled from Africa to Australia. one theory is this:

Long before the continents had fully separated, there was a land bridge that had connected Africa to Australia. This land bridge would have offered an acceptable route to reach our ancestors destination.
After discussing this possibility in groups, we watched a video that went into depth on the mindset of our ancestors, and what may have prompted them to leave Africa.

In Africa, there is a tribe called the San Bushman tribe, that is supposedly the closest living relatives to our ancestors. When studying their features we noticed that they shared characteristics from people all over the world; Asian eyes, European cheek bones, and African mouth shape and skin color. These traits imply that every single human may have possibly originated from these people, and through natural selection, different traits became more prominent. But why did our ancestors leave? Scientists have found evidence of an massive ice age that had taken place around  the same time we were evolving. The ice age greatly effected the climate, resulting in fluctuations of food availability. Also, our ancestors had begun to develop their own language and a more sophisticated way of thinking. this also resulted in advancements of technology, which may have also helped prompt the immigration.

Does Race Exist?

After reading the article “Does Race Exist” and analyzing the data collected through lessons in class on evolution and on the origin of man, one question stood out from the rest: Can race be used as a genetic identifier for different ethnic groups?. My answer to this question is no. Classifying people based on their physical characteristics varies among individuals because they are based on their personal opinions of what is required to be a part of a certain race. Although you can argue that obvious characteristics such as skin color, and hair color, should enable people to come to similar conclusions, scientists debate that categorizing is not that simple. The reason for this can date back to the origins of man, and its immigration throughout the world.

           The first evidence of man can be found in Africa, the proposed birth place of the first human, before it began its great trek around the world. By implying that this theory is true, it suggests that all humans have an ancestral line that can be traced back to Africa. This concept contradicts the generalization that all “African-Americans” are black, since there is a possibility that “Europeans” share the same ancestor. Also, traits such as skin color and facial features are greatly influenced by natural selection. Different groups of people may be exposed to many variations of selective forces, causing their physical traits to be greatly modified. Although two different groups may appear to be different physically, it does not mean that they aren’t similar genetically. This can be further proved through the study of DNA and its many variations of polymorphisms (mutations). Polymorphisms are what can be used to help identify and group the differences between people. However, they do not always dictate a characteristic that can be physically seen or identified. Most Polymorphisms dictate subtle differences such as resistance to a certain disease or an allergy to a certain drug. For this reason, using traits such as skin color and hair color to genetically classify people will most likely result in incorrect data; possibly leading to harmful repercussions.

quiz!!

Answers

1.) The picture above shows evidence for evolution because it depicts the similar characteristics of a whale throughout its lifetime. All the animals appear to have distinct characteristics that are carried through the timeline. It also depicts a common ancestor for all the different animals that have seemingly evolved from the mesonychid.

 

2.) E, North America

 

3.) a dragonfly, bird, and bat are all forms of analogous structures that serve as evidence for convergent evolution. this means that their are many similarities, but the underlying structure is completely different.

 

4.) The  Common Decent Lab shows evidence through DNA by depicting different animals with minimal differences in their DNA. This shows evidence for a common ancestor, therefore supporting the theory of evolution. One is the difference between a human and a Chimpanzee. Scientists have found there to be only a 2.5% difference in the DNA. Another example is the DNA of a human and an Old World Monkey. Their difference is only 9%!!! Proving that humans are really not  that different from primates.

 

5.) Homology is the when structures have enough similarities to prove they descended from a common ancestor. One example is the many similarities between the wing of a bat and a bird, both structures are used for flying and are shaped similarly. Another example is a human and an orangutan, both have five fingers used for grasping, and the structure of the arm bones are also very similar.





Honors Bio class 16

Today in class we discussed how to solve for allele frequency based on population and genes. we used the equation p^2 + 2(pq) + q^2 = 1, and p + q = 1. p^2 = AA, q^2 = aa, 2pq = Aa.

We also mentioned the Hardy-Weinberg ideals for a population so that nothing influences the result:

We applied this in the activity we did using sex gamies: 

After we collected our data we put them I to columns and analyzed it. We found that the majority would always be the dominant trait, and therefore the recessive gene would on be present in those with heterozygous genes. For the recessive gene to appear, we would have to mate with a Heterozygous + Heterozygous, or introduce hh back into the gene pool. However, through natural selection, the recessive gene hinders those who carry it (sometimes), and can cause them to have a shorter life expectancy,

We then took a really hard quiz on what we had learned (calculating frequencies).

Honors Bio class 15

Today in class we reviewed our results on the brine shrimp lab and graphed it on a whiteboard: 

Next we discussed the significance of these numbers:

We concluded that because none of them were at 0% viability besides the 0% NaCl concentrated water, that at least a few had adapted to that specific concentration through mutation in their parents DNA (osmosis).

Next we began an activity with red and green beads where we threw in 25 of each color and drew them at random in pairs. The read beads represented the dominant allele (H) while the green beads represented the recessive alleles (h). The dominant alleles represent the tigers with fur (good), while the recessive alleles represented tigers with no fur (lethal). If we pulled a green and a green those would immediately die and not get put back into the bag. We recorded our data by ten generations (10 pulls). Each time the population would get smaller and change the frequency. 

We concluded that the recessive allele frequency decreased but the allele would not disappear.

Parents day class 14

Today we had a short amount of time where we discussed the attractiveness of male-female, male-male, female-female. To help is with this discussion, we were assigned with some reading for the night before. One of the readings was on the symmetry of the face, and how people were more attracted to people with symmetrical faces. The other reading explained why certain people were attracted to others, based off their feminine/masculine characteristics. 

Next we did an activity where Mr. Quick showed us a slide show with men and women that had very similar faces. He would switch from male to female as he went through the slides, and asked us to circle which one we thought was more attractive on our sheet: 

Once we had finished the slide show, he told us which one was more feminine and  which was more masculine. We labeled what we got according to which person you circled. After, we concluded men usually found the more feminine one attractive because they liked to feel dominant over them. Women were more complicated though. Women can prefer feminine men because the want their husband to be nurturing. However if the women is ovulating, she may want a man with more masculine features because she wants strength and protectiveness. 

Honors Bio Class 13

Today in class we categorized shells based on their different characteristics such as shape, size, texture, and color. We reviewed what may have caused these species of snails to die, and found that predators may have been the main reason. As we studied the shells closely we noticed little holes in the shells that had been drilled by a special type of snail that fed on other snails. 

This special type of snail has adapted it's tongue to have a drill at the tip. This allows it to drill holes into the shells of others and inject poison. This characteristic was was passed down from parent to baby through a mutation in the DNA.

After the lesson, we began the brine shrimp lab, where we would discover what percentage of NaCl in water suited the shrimp best. First we had to calculate how many grams of NaCl we would need to get the percentage of 0%, 0.5%, 1.0%, 1.5%, and 2.0% in 30 mL of water. After this we poured the different solutions into five different petri dishes and labels them. The next step was to collect the brine shrimp eggs. We did this  by brushing the eggs on to a piece of tape stuck on a glass slide. Before we could place the slides into the solutions we had to record the amount of eggs. After this was finished we placed them into the solutions and would check on them in 24 hours. 

These are some of our different slides

This is a close up

This is what some of the brine shrimp look like

And finally the results after two days:).

Honors Bio class 12

Today in class we went over what independent variables, dependent variables, constants, and controls. After that, we took a quiz on these concepts. Next we talked about the importance of fava beans and how favism is an enzyme deficiency that is found in both humans and fava beans. This shows evidence for the possibility of fava beans having similar traits as humans. Once we had concluded the discussion, we chose our animal to research for the paleo project which required us to create a transition fossil. My partner and I chose to do the the Eupodophis (early snake). While researching we found this: 

This is in fact a Eupodophis, which was a snake with two limbs. It lived in the late Cretaceous period, and enjoyed itself in large bodys of water. 

In this photo, one can see more clearly what kind of transition was taking place while the Eupodophis was alive. We also found that it was related to the Mosasaur; a large aquatic dinosaur with four flippers: