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