Current Events: Evolution in the Peppered Moth

Can you see the black moth?

          The peppered moth is one of the many examples of evolution in the wild.  Before the 19th century in Britain, the most commonly seen kind of moth was pale in color.  There was a very small percentage of dark or black moths, but almost all of them were lighter.  The pale moths were not very easily seen against pale backgrounds, whereas the dark ones stood out.  However, after the 19th century, Britain began producing more and more pollution, causing the death of pale lichens on trees where the moths lived and turning their bark black.  Consequently, the whiter moths showed up very well on the dark trees and became easy prey.  The black moths were not as easily spotted on the dark bark as the pale ones, and were not caught and eaten as often as the pale ones, and black soon grew to become the more common color of moths.  However, since the amount of pollution has decreased from the 19th century, the number of pale moths has risen again and the black moth population has gone down. 
          As you can see, these moths have evolved to fit their surroundings.  If they had all stayed white when the trees turned black, the entire moth population could have been wiped out by predators.  Because they evolved to become black to match the color of their habitats, the moths survived.  This is an example of evolution.

For more information, go to: http://www.truthinscience.org.uk/tis2/index.php/component/content/article/127.html

Reflection on Sex Eduation Unit

During this unit, I learned several things about sexual intercourse that I did not know before:
          -There are many many kinds of STDs that people do not know about, and the best way to protect yourself from them is ABSTINENCE!  (Not having sex.)
          -Many people around the world have a kind of STD that is a bacteria, but do not actually have any symptoms from them.
          -I learned all the parts of the reproductive organs in both male and female bodies.
          -You can get herpes by sharing a towel with someone else who has contracted it.
          -The menstruation cycle is a hormone-regulated cycle that is controlled by four hormones:  LSH, LH, Estrogen, and Projesterone.
          -There are gender stereotypes.
          -The differences between a healthy and an unhealthy relationship.
          -The different kinds of birth control, including condoms, birth control pills, the counting method, surgery, and ultimately abstinence.
          -The consequences of having unprotected sexual intercourse.
          -The process of a baby growing as a fetus inside their mother's uterus.
          -The treatment of STDs.
         
 

Healthy vs Unhealthy Relationships

This is a comparison of the aspects of healthy and unhealthy relationships:

Healthy:
-Trust and understanding between partners
-Both enjoy being with each other
-The two people can function normally apart
-The couple can argue without breaking up
-Respect
-The two people rely on each other

Unhealthy:
-The relationship is purely physical
-The two people in the relationship cannot function apart
-Lack of trust
-The couple is too afraid to argue or argues all the time
-Lack of respect

          As you can see, a healthy relationship will include trust, respect, and understanding whereas an unhealthy relationship will not.  It is important to have these things in a relationship, because without them, you and your partner cannot truly relate to each other in the intimate way you should.  Trust makes you capable to rely on your partner and "share the work".  However, if you end up relying too much on the other person, it becomes an unhealthy relationship because you cannot function without them.  It is also important that the relationship is not only physical, because that can end up leading to physical abuse.    

 

Science Gone Bad

          In 1939, Doctor Wendell Johnson decided to conduct an experiment on 22 orphans - ten of whom stuttered when they talked, and the rest with no speech impairments.  He divided up the ones that stuttered into two groups - one group that got negative reinforcement, and the other got positive reinforcement.  He also divided the children that spoke normally into two groups - one that was told they had good speech, and another that was told that they stuttered and that they needed to look out for errors all the time.  He wanted to make the group of stutterers with positive reinforcement stop stuttering and the group of children who were told they stuttered to stutter.  The children who were told that they had speech problems immediately began to think that they could not speak well, and many stopped talking completely.  After the experiment, they were told three times that they had no speech problems, but it did not work.  Even when they had grown up, although none of the children who had been experimented on stuttered, many had speech impairments and were reluctant to talk. 
          I think that this experiment was inhumane and that the doctor never should have gone through with it.

Resources:  http://www.neatorama.com/2011/03/23/5-science-experiments-gone-wrong/

Current Events: Brain Parasite affects Dopamine Levels in Brain

          New studies show that a parasite called Toxoplasmosis gondii that directly affects how much dopamine there is in the human brain.  It is transmitted to humans through cat faeces that ends up on the fruits and vegetables we eat.  The parasite gets to our brain, where it then infects it by making a cyst in it cells and creating an enzyme called tyrosine hydroxylase, which is a chemical used by our bodies to make dopamine.  Because of this, a carrier of toxoplasmosis gondii can have very high levels of dopamine.  These discoveries may help scientists explain or find cures for dopamine-related disorders such as schizofrenia or Parkinson's disease.  It is estimated that around 22% of Americans have the parasite in their bodies, and most of them live normally.  However, the parasite can be dangerous to those not immune to its affects - especially pregnant women. 

Resources: http://www.sciencedaily.com/releases/2011/11/111104102125.htm

Onion Mitosis Lab

Guiding Question:  Approximately how much time do cells spend in each phase of the cell cycle?
Cells spend approximately 56% of their time in interphase, about 28% of their time in prophase, 8%  of their time in metaphase, 5% in anaphase, and 3% of their time in telophase.  We figured this out by analyzing how many out of 36 cells were going through which phases of mitosis.  20/36 were going through interphase, 10/36 through prophase, 3/36 through metaphase, 2/36 through anaphase, and 1/36 through telophase.  We then turned those fractions into percents. 

Procedure:
Perform the onion root tip simulation and tabulate the number of cells in each phase. Construct an appropriate graph using your data to present the relative time a cell spends in each phase of the cell cycle.

Table:   

This graph shows the number of cells going through each phase of mitosis, and the approximate percentage of the time they spend going through them. 

Graphs:
These graphs are analyses of our tables.  They both show how much time a cell spends on each phase of mitosis.  The pie chart shows this in contrast to the whole time spent going through mitosis, whereas the bar graphs shows this in comparison to each phase. 

Conclusion:
In conclusion, we can tell that the interphase part of mitosis is the longest part of the process that a cell devotes its time to.  Second comes prophase, then metophase, and after that anaphase and telophase.  Notice that as the mitosis process progresses, each phase takes a shorter and shorter period of time.  This, however, may not be completely reliable, since the onion-root biology website may not be correct.  With this in mind, I looked up the stages of mitosis over the internet, and the data we received from the onion website appear to be correct. 

Current Events: A New Take on the Male Y Chromosome

        There is a theory that sooner or later, the male gender will become extinct.  This is because old research has said that the male Y chromosome is genetically decaying, which means that there will no longer be men on this planet in five million years.  However, that was the old research.  In 2005, scientists compared the human Y chromosome with those of chimpanzees, who evolved away from humans six million years ago.  Now, they have also compared human Y chromosomes with those of the rhesus monkey, which have been a separate species from humans for 25 million years.  These studies show that the Y chromosome has only lost one gene in the last 25 million years.  Its genetic decay is very, very slow, if it has not stopped yet.  Men will be on this planet for many more millions of years to come.

Resource:
http://www.bbc.co.uk/news/science-environment-17127617

Current Events: Global Warming Affects Chipmunk Genes

          According to the University of California Berkeley, global warming is causing chipmunks living in the High Sierra to move up to higher and cooler land.  They were originally found at altitudes of 7,800 feet, but have now moved up by as much as 1,640 feet.  Because of this, they are losing their available habitat and are forced to live in smaller and more isolated groups.  This could lead to genetic diseases caused by interbreeding that would not have been present in the chipmunks' lives before.  In order to figure out exactly how much of an impact this is having on the genetic diversity of alpine chipmunks, scientists compared 146 DNA samples from from of these organisms living today, to 88 samples from past chipmunks.  These experiments resulted in the fact that alpine chipmunks now have a much less rich allele diversity than they did back when the 88 older samples were alive.  At the same time, scientists completed the exact same experiment with lodgepole chipmunks (another species of chipmunk that thrived in lower elevations than alpine chipmunks).  They did not find any radical genetic differences in this species, because they lived lower down, and did not have to migrate to higher altitudes in order to survive Global Warming.  The alpine chipmunks could face becoming threatened or even extinct wildlife if this continues. 

Resource:  http://summitcountyvoice.com/2012/02/20/global-warming-sierra-chipmunks-take-genetic-hit/

Current Events: Possible New Cures

          Scientists may have made new breakthroughs with finding cures for previously incurable illnesses such as cancer and brain injuries.  They are trying to figure out how to develop and create real 3D stem cells that are very similar to those in a regular human body.  Stem cells are types of cells that can morph into other cells.  They have the potential to either stay in the form of stem cells or to change into red blood cells, brain cells, muscle cells, and other kinds of cells with specific purposes.  Stem cells can renew themselves, and the new stem cells also have the same properties as their "parents" where they can change into new cells.  Replicating these kinds of cells can help lead to new cures, and that is exactly what these scientists are trying to do.

Sources:
http://finance.yahoo.com/news/rbcc-explores-cures-cancer-brain-100000290.html
http://stemcells.nih.gov/info/basics/basics1.asp

Reflection - Cracking the Code of Life Part II

          We finished this movie in class today.  It showed more diseases that can be passed on through heredity like cancer.  One thing I really liked about this movie is that it showed a variety of things.  It hopped back and forth from showing us stories about people with disease caused by their genes, and the two competing teams of scientists trying to be the first ones to map someone´s entire DNA structure.  The movies made me more aware of the role genetics plays in our lives, and how there are some things we can´t escape because it´s in our DNA.  Something I found ironic was the fact that in my previous post, I had made connections between Cracking the Code of Life and Gattaca, and the documentary had clips of Gattaca in it, and talked about how our future might very well turn into one just like in the world of Gattaca.  All in all, I thought that Cracking the Code of Life was a good movie full of information for people who want to learn about genetics.

Reflection on Cracking the Code of Life Movie

          So far, this movie has taught me a lot about genetics, and since it's pretty interesting, what I learn sticks in my brain.  One really important thing that I learned from this movie is that even just one wrong letter in your DNA can decide whether you will grow up to have schizophrenia, a deathly disease, cancer, or some other horrible illness.  Just one out of all the millions of A's, C's, G's, and T's in your DNA can determine how your life will end.  One example of a rare but horrible disease that is caused by two parents passing two of the same recessive alleles to their child was showed in the movie.  One pair of parents each had the Tay-Sachs gene in their bodies.  Both of them passed this gene on into their child, and their child developed this disease.  The father's identical twin brother had just resolved that he had to be his brother's rock and support him, when he discovered that his child, too, had Tay-Sachs.  It was such a sad story because Tay-Sachs is such a rare disease.  Even if one parent has the allele for it, they won't be able to pass it on so that it harms their child, and if both parents have it, there is only a 25% chance of their kids getting the disease. 
          The movie then discussed how scientists may be able to map one person's entire DNA, and tell them which diseases they may develop, how long they may live...everything about their future.  Personally, I think this is a great idea if you are only doing it to stop yourself from passing illnesses on to future generations.  However, I feel that if we have this ability to map out peoples' lives in our hands, our world will become kind of like the one in the movie GATTACA.  You will only be able to do a certain job because of the DNA you have, and you won't be allowed to do other things because of your genes.  I don't think that this would be such a great thing, and I hope that if our planet does become like GATTACA, it doesn't happen in my lifetime.

Current Events: Twins and Heredity

          National Geographic is talking about studies on twins and how they can help scientists discover exactly how much of an influence heredity has on our lives.  One very interesting story featured in the article was about two twins who were separated at birth.  Coincidentally, both families who adopted each twin named their kids Jim.  The two twins were reunited when they were 39, and they realized that, even when they were separate, they had led similar lifestyles.  Both Jims had married and divorced women called Linda, and then remarried to women called Betty.  They had named their sons James Allan and James Alan, and they had both taken their families on vacation to the same beach in Florida.  Both men had had dogs named Toy, and each had been part-time sheriffs, dabbled in carpentry, smoked the same kinds of cigarettes, and drank the same kinds of beer.
          I thought that this section in the article was very interesting, because it helps show exactly what a strong pull genetics has in our lives.  When I read it, I was shocked that the two Jims even married wives with the same names.  How does liking different names have anything to do with genetics?  But how can it be a coincidence that so many of the names in the two Jims' lives were the same?  This article was also very thought provoking, because it also said that even though they had been raised in different families, both had similar IQ scores.  Later in the article, it stated that 75% of IQ differences was because of genes, and not the environment around the people.  I don't really like that idea, because they are trying to say that how smart you are depends on what you inherited from your parents.  I think that your surroundings and how hard you work also has an influence on your IQ, and I just don't really think it's fair that you inherit your smarts.

Resource:  National Geographic Magazine for January 2012, page 54

Mendel's Pea Experiment

         Gregor Mendel was a monk who lived in what we now know as Czech Republic.  He enjoyed gardening, and one day he became curious about the fact that some pea plants were tall and others were short; some were yellow, and some were green etc.  Mendel decided to check this out, so he forced a tall pea plant and a short pea plant to mate with each other by collecting the pollen from one and placing it in the pistil of the other.  He made sure that neither plant mated with its own type.  The pea plants produced from that experiment were tall - not of medium height like you would expect to get by mixing a tall and a short plant, but tall.  After many more experiments, Mendel then proceeded to mate the offspring of the original pea plants with each other.  Curiously, three out of four pea plants were tall, but one was short. 
          From these experiments, Mendel became the first investigator of genetics.  The parent plants were both purebred short and tall pea plants.  When they were mated to produce F1 offspring, each parent plant passed on one allele.  (An allele is a form of a gene that changes is in charge of changing only one aspect of a trait.)  The tall plant passed on an allele for being tall, and the short one passed on an allele for being short.  If the dominant or tall allele is represented by a capital T and the short or recessive allele is represented by a lowercase t, then the alleles for the F1 offspring looked like Tt.  What Mendel began to discover was that a recessive allele will only be visible in an organism if it is the only allele for that trait present.  If there is one tall and one short allele, then the plant will be tall.  If there are two tall alleles, then the plant will be tall.  The only way the plant will be tall is if it has two short alleles.  This is why none of the F1 offspring were able to be short, because they always had one short and one tall allele.  However, when Mendel mated F1 offspring with each other to make F2 offspring, he noticed something strange:  approximately 1 in every 4 pea plants created by two F1 offspring were short.  This was because, although all the F1 offspring were tall, they each had one short and one tall allele.  When two of them were mated, there was a small possibility that, out of Tt and Tt alleles, a seed would be generated that would be tt. 
          The experiment we did was that we had a bowl full of yellow and black balls to represent peas.  The ratio of yellow to black peas was uneven, and there were many more yellow peas than black ones.  We took turns pulling out four "peas" from the bowl and recorded our data.  We did this 20 times.  Each time, we wrote down how many yellow and how many black balls we pulled out of the bowl, and then we averaged our results.  In the end, we pulled out 2.85 yellow peas and 1.15 black peas, which averages down to three yellow and one black pea.  Mendel, on the other hand, would have had to do this experiment MANY more times, since he did not know any of the things we do now about genetics.  Mendel probably had to plant 50 to 100 pea plants to be sure of his data.

Reflection on Gattaca

          I really enjoyed this movie.  I thought that it was really interesting how everyone was chemically made to be immune to diseases, live long lives, and have overall good bodies physically.  Also, scientists were able to get rid of traits such as attention deficit disorders and anger management problems.  However, I thought it was really unfair that people who didn't have great genes were not allowed to do things like fly into space, but that others who were genetically modified could take good jobs just by giving in a urine sample.  Even if someone had a really good brain, they would not be permitted to do the really important stuff.  If you had not been made in a test tube, then you were not expected to be great physically, either.  No matter how hard you trained, everyone would expect you to lose in sports because of your genes.  I also thought that it was really interesting that scientists were able to figure out one person's whole life at birth.  The main character was told that he had a 99% chance of heart problems, an expected life span of 30.2 years, and many other things the second after he was born.  From then on, people could tell everything about you just by taking a urine, hair, blood, or skin sample from your body.  This whole idea of genetics and DNA was very, very interesting and overall, I enjoyed the movie.  Even though it's fictional, I learned a lot about how DNA is almost everything about you from the film.