Heredity and evolution – Class III, chapter III

In this last class along with chapter III of the book, we were able to take a look at how the process of heredity started being studied as well as important names and people who helped come up with concepts of cell structure and division.

The book spends several pages explaining the cell, its functions, the DNA and how all of that connects with heredity and evolution. In class, on the other hand, we took a deeper look at Mendel’s work and some other important people who influenced the concept of evolution.

Firstly, I will approach the book and then introduce the content viewed in class.

It’s important to understand what a cell is in order to understand evolutionary principles.  Cells are the basic unit of life in all living things. We humans are multi-cellular, but some organisms could be unicellular. Here is a drawing that explains in detail each part of the cell and each function:

None of that would function if it wasn’t for the DNA. All the cellular functions are related to the DNA.

Here is a drawing of the structure of the DNA:

 

The DNA is important for manufacturing proteins. Proteins serve a variety of functions for the body, such as producing energy. Proteins are made of small molecules of amino acids.

A goes with T only and G goes with C. They are compatible and “attracted” to each other.

Cell Division:

To understand cell divisions, it is important to understand Chromosomes. They are small structures made of DNA and protein and they are located only in the nuclei of a cell. Each different type of species has a certain number of Chromosomes. We humans have 46 chromosomes, divided into 23 pairs.

Mitosis:

This type of cell division is somatic, it’s the same type that occurs to injured tissues in their healing processes. 

 

Meiosis:

This process can give origin to a new organism, while mitosis only produces new cells. Meiosis is a much more complex process, because it is based on two different stages, not only one.

Considering that fact, meiosis will produce four daughter cells containing only ½ of the original number of chromosomes. The final number is 23 for each gamete and they can get united to another gamete, if they do so, they will form a zygote or fertilized egg.  

DNA is found in each zygote and that will carry certain characteristics to the offspring. At this point we can introduce the content learned in during class. Mendel.

Mendel was known for discovering the mysteries of heredity. He worked with garden peas of seven different traits and crossed them to see what would be the results. During the crossings, he found out something very unique. The crossing of the wrinkled pea with the round pee would result in all round peas on the first generation, but on the second generation it would result in ¼ wrinkled and ¾ round. Given that fact, Mendel introduced the recessiveness  and dominance of the genes. He pointed out that the allele that determined that the pea would be round was dominant and the allele of the wrinkled pea kind, was recessive. This principle is the same for humans and other living things.

Besides that important discover, Mendel found out that different traits could be inherited at different times and this was called principle of independent assortment.

In humans, things like the blood type would fit into that system of dominance and recessiveness. 

It's important to understand that the whole evolutionary process happens because of mutations. Mutations are changes that happen in the genetic code. That also influences in creation of new species, but not alone. Genetic Drift and Speciation are also considered. 

Personal Input:

This chapter was both interesting and challenging to me.

I realized that everything I had learned in high school somehow disappeared of my brain, because I was a bit confused by the book and the class. Now that I went deeper on the subject writing the blog post, I feel like I understand everything pretty well and hopefully won’t forget it anymore. I also realized that the class lacked that visual part that I was able to find in the book and online, so me being a graphic designer feel the need to see visual inferences to be able to understand a certain subject. That will explain why my blog post today is full of images.

This was a great introductory subject for evolution, and it will certainly help understand humanity in depth as we go further into the anthropology subject.

I was particularly impressed with Gregor Mendel’s work. I took the time to go online and try to find more about him and his personality. He was a very wise man, but somehow failed a few times in the test to become a teacher. I also found interesting the fact that he took the time and the patient to observe his peas during the studies and was not content with only what he saw, he looked for answers, studied possibilities and took a tremendous amount of time, until he finally understood there were genetics involved. And that was just brilliant. I would never have come up with something so detailed and important. 

I also found it very challenging writing about this theme, because it's really not in my area of studies and all the names become very confusing at certain point. 

I liked the fact we watched a movie called " DNA obsession" because that movie helped understand the DNA principles and how it was mapped and "discovered".

Additional Information:

 My first very interesting additional information is about an artist in New York who went around the city and picked up random objects such as gum, cigarette butts and with the DNA present on these objects, she was able to recreate complete 3D faces out of it.

http://www.nydailynews.com/new-york/artist-creates-3d-models-faces-discarded-dna-article-1.1384149

Another fun  link is to an interactive explanation of what happens inside of a cell. As you click on each part of the cell an explanation of that part's function will come up. 

http://learn.genetics.utah.edu/content/begin/cells/insideacell/
 The last link is about human mutations. I chose this link because it showcases real peoples' stories about mutations in the genes providing some biological explanation in a very interesting way.  Mysteries of Mutation on Discovery Channel.
 http://dsc.discovery.com/tv-shows/discovery-presents/videos/human-mutants-mermaid-syndrome.htm