Evolution Paper

                                                               
                                                     The Idea Of Evolution


         Evolution is the theory that states that species have descended from many ancient forms of life by living matter and structural modifications.“Organic life beneath the shoreless waves Was born and nurs'd in ocean's pearly caves; First forms minute, unseen by spheric glass, Move on the mud, or pierce the watery mass; These, as successive generations bloom, New powers acquire and larger limbs assume; Whence countless groups of vegetation spring, And breathing realms of fin and feet and wing”-Erasmus Darwin. There are many philosophers that contribute to evolution. One of the major philosophers was Charles Darwin’s grandfather Erasmus Darwin. He was a man of many incredible interests and pursuits of whom he was a physician, poet, philosopher, naturalist, and botanist, and was one of the greatest leaders of the eighteenth century in England. One of his first theories on evolution was in Zoonomia, or also known as The Laws of Organic Life. Erasmus did not come up with the idea of natural selection, but he presented his focus on how life evolved from one common ancestor forming “one living filament”. He believed that sexual selection and competition can cause changes in species. "The final course of this contest among males seems to be, that the strongest and most active animal should propogate the species which should thus be improved.” Erasmus reached his final conclusions by doing observations of the behaviour of wildlife, of domesticated animals, and by presenting his knowledge in many different fields. He wasn’t quite sure how species could evolve into another, so he really debated this question. Lamark’s scientific theories was quite ignored during his lifetime, he never received the acceptance of his colleagues Buffon and Cuvier. He believed something more complex than the other philosophers, he believed that organisms are not changed by their environment. His belief was that there is a change in the environment that changes the necessities of organisms living in that certain environment, which results in a change in their behavior. His theory of evolution is different from the modern evolutionary theory. Lamarck pictured evolution as a process of increasing density and perfection. He did not believe in extinction, however he did think that species disappeared because they developed into other species. This evolutionist published a series of books about paleontology and invertebrate zoology. Out of all the books that he published Philosophie zoologique, which was published in 1809 best explains his theories of evolution. Lamarck presented his ideas in two laws and the first law was in his book Philosophie Zoologique. The result of these two laws is that there is a change in all organisms as they adapt to their environments. Charles Darwin’s theory of evolution was presented in different characteristics such as size, tooth length, or the sense of smell of individual members of a species. Like, if you smell predators far away, you will have a greater chance of survival then others that don’t have a good sense of smell. He didn’t form his theory of evolution on the idea of evolution itself, but when he went to the Galapagos Islands in 1836 he had already made many observations and had a lot of questions. Darwin believed that the earth changes over time. He said that "The town of Concepcion is now nothing more than piles and lines of bricks, tiles and timbers-- it is absolutely true there is not one house left habitable.” Ideas that he knew was that he knew that plants and animals are different by location, organisms change over time; such as how fossils relating to armadillos and sloths were found in places that similar animals were still living, and how island animals are similar to mainland animals; like how the Falklands fox was found on the South Atlantic Islands that was like a fox on mainland. While sailing through the Pacific Ocean; he noticed different forms of mockingbirds, and of the Galapagos giant tortoises he had watched might have provided clues to evolution. So, Charles Darwin had a great reputation on evolutionist.

       Microevolution is evolution, but just on a smaller term within a single population. Which basically means narrowing our focus down to one simple aspect of life. It states that changes within a population of a single species occur over time. For example, if you selected the branch of beetles then you would notice another phylogeny relating all of the insect lineages. Macroevolution is evolution on a bigger term. It states that all life is descended from one common ancestor. Some microevolutionary mechanisms include natural selection in which it is a type of mechanism of evolution, and it is one of the most basic ones. In order to understand how natural selection works you can imagine a population of beetles. First of all there is variation in the traits, like how beetles are different colors because some of them are brown and others are green. Then there is different reproduction such as how not all individuals get to reproduce to their full capability. Like for example, if the green beetles got eaten by birds then they would reproduce less than the brown beetles. Then, this results in heredity and the surviving brown beetles have brown baby beetles because this trait has a genetic basis. The end result is that whichever trait has more advantage then it becomes more common in a population. Like, in this example if this process continues on then the population of beetles will be brown. So, in order to have evolution by natural selection then variation, different reproduction, and heredity will need to be present. Genetic Drift is also a basic mechanism in which in each generation some individuals may leave behind more genes and descendents than the other individuals. The genes of the next generation will not necessarily be the healthier ones. It affects the general outlook of a population , and it doesn’t produce adaptations because it is a different process than natural selection. Genetic Drift affects all populations in which there is no chance on avoiding it. Mutation can cause parents of genes for a certain color have offspring with a gene for a different color. Like, if a parent beetle with genes for green coloration has offspring with a gene for brown coloration then it would result in making the brown genes more common in the population. Migration is when individuals from a population join up with another population. Like, if a population of brown beetles join a population of green beetles then it would make it more common for there to be brown beetle genes in the green beetle population.

        A type of evidence of evolution is the fossil record. Scientists have had the capability of putting together a time scale for the history of life on earth by dating fossils. Fossil evidence states that over time organisms of increasing involvement appeared on earth. Blue and green bacteria are the first fossils that were maintained from the Precambrian era. Complex invertebrates controlled life in the oceans during the Paleozoic era. Plants and animals had inhabited the land surface of the earth at the end of the Paleozoic era. There are many examples on the fossil record that interpret that species have evolved from many ancient organisms, according to scientists. Embryology is the study of the formation, development, and growth of embryos. Embryos start off by looking alike in the early stages of development, and the evidence shows that organisms had a common ancestor. Biochemistry shows that there is a biochemical similarity in all living things. DNA is one of the mechanisms for gene activity and inheritance in all living organisms. So, the evidence shows that the structure of the genetic code is almost exactly the same in all living things. Comparative morphology is the analysis of the patterns of the locus of structures within the body plan of an organism, which shows similar patterns of the body plan of organisms. The only type of evidence that shows me that species have changed over time is the fossil record because it the most accurate out of the other types of evidence. There is a lot of examples on the fossil record that shows that species have changed over time. The time scale represents the history of life from long ago, and how species have changed. In conclusion, evolution is just another theory out there, and some of it is correct like how it proves adaptation but most of the facts that it proves to be true, are not true in my opinion.


                                                       Bibliography



"Erasmus Darwin (1731-1802)." Ucmp.berkeley.edu/. Web. 11 May 2011.

"Evidence for Evolution." Clifsnotes.com. Web. 14 May 2011.

"Evolution." Bioweb.cs.earlham.edu. Web. 14 May 2011.

"Evolution 101: Genetic Drift." Evolution.berkeley.edu/. Web. 12 May 2011.

"Evolution 101: How It Works." Evolution.berkeley.edu. Web. 14 May 2011.

"Evolution 101: Mechanisms of Change." Evolution.berkeley.edu/. Web. 12 May 2011.

"Jean-Baptiste Lamarck (1744-1829)." .ucmp.berkeley.edu/. Web. 11 May 2011.

"Treasures of Evolution I Evolve, You Evolve, They Evolve." The Why Files
           The Science Behind the News. The Why Files. Web. 11 May 2011.

pGLO Transformation Lab

 

Results from our lab. The four plates above are the +LB/amp,+ LB/amp/ara,-LB/amp, and the -LB.
The +LB/amp was the antibotic, the + LB/amp/ara was the arabinose sugar, and the negative plates were the plasmids.

 



This lab that we did in class was about how we collected information about the +pGLO cells with E coli grown on the plates. The plates that I would expect to find bacteria like the original non-transformed E.coli colonies that were intially observed would be on the LB plate because you can hopefully see everything growing because it is cabale of doing it. The LB/amp/ara plates would genetically have transformed bacterial cells because it would have had to take the DNA from the Amp in order to survive. The -pGLO and + pGLO plates should be compared to dertermine if any genetic transformation has occured because it would tell you if the plasmid transformed them. The negative plates were the control plates.

Observations that we collected was how there was alot of bacterial colonies on the + LB/amp, and there was around 35 colonies. The bacteria is a fluroscent green color. The bacteria in this plate didn't glow. On the + LB/amp/ara there was a less amount of bacterial colonies, and there was around 25 colonies. The bacteria was also a fluroscent green color. The spots on this plate glowed because it got a signal from the environment. The - LB/amp didn't have any spots, it was just a smear which was a fluroscent green color. Nothing occured on the - LB plate because there was just condensation on the plate. The traits that was originally observed for E.coli that was not altered was the colony shape and color. Traits that were different after performing the transformation procedure was the colony shape because there was a less amount of dots on the two positve plates, and on the -LB/amp the shape was totally different because there wasn't any dots. If the genetically transformed cells were acquired the ability to live in the presence of the antibiotic ampicillin then the other genes on the plasmid would have no bacteria growing. The changes that occured were due to the procedure that was performed because the + LB/amp didn't glow due to that glowing will only happen in the presence of arabinose. With the plasmid, the genes that code for the enzyme that digest arabinose are replaced with the GFP. So, without arabinose the gene is no longer working so that is why it didn't glow. In conclusion, I learned alot of neat information by doing this lab, and the transformation about pGLO cells with Ecoli grown on the plates.

Movie GATTACA

The movie GATTACA that we watched in class was a fascinating movie about a guy who posed as someone else to pursue a life long dream of going to space. I think vincent tore his photo out of the family photo after winning the swimming race against his brother because I think he wanted his family to appreciate what he did; and to prove to his brother that he could strive in life and that he could do whatever he wanted even though his DNA claimed he had a heart condition. Anton didn't have the drive in life, like Vincent did. The relationship between Vincent and Anton wasn't very good because they didn't talk to one another in years. My favorite character in this movie was Vincent because he did extraordinary things to pose as Jerome to go into space without getting caught. I would have wanted to be Vincent because I think that it would be really fun to pose as someone else, but I would be very worried about getting caught. Three ways that society portrayed in this movie that usually reads a person's genetic profile is by hair, saliva, blood, and urine.

I think that Vincent's world could eventually happen in America because I think that we will be able to have the technology to do it. If I was Anton in this film I would have had a better ambition in life, and would have strived harder then what he did. I would have had more confidence in Vincent then what he did. I would have told him that I knew he could make his dream come true. I think that the doctor went along with Vincent's fraud because he wanted him to be able to pursue his dream because he knew that it was very important to him. If I was the doctor I would have let him go to, so I would have done the same thing.  In conclusion, this movie was very interesting and I learned alot about DNA, and all of the great technology that will probably be available in America one day to pose as someone else.

DNA Sequence Comparisons Analysis

For the results of Abby there was a 97% similarity. There was one base change because there was a change between the A and the T because it should have been a GAG and instead the results was a GTG. This process is called point mutation. I don't think that she has a disease because most of her DNA was the same.

For the results of Bob there was a 97% similarity. There was not enough protein produced once it reached the STOP signal. He has a disease. This process is called truncation mutation.

For the results of Carol there was a 58% similarity. In the frame, she was only missing the T. So, only one changed out of the sequence. She has a disease. This process is called Frame Shift mutation.

DNA Lab



This is what the formation started to look like in the tube.

This is what DNA looks like from the results of the lab.



      DNA Is totally amazing!!! Well to start with, DNA is a polymer. The monomer units of DNA are called nucleotides. The polymer is called a polynucleotide. Each nucleotide consists of a 5-carbon sugar, a nitrogen containing a base that is attached to the sugar, and a phosphate group. There are four different types of nucleotides that are found in DNA which are A, G, C, and T. A is for adenine, G is for guanine, C is for cytosine, and T is for thymine. In purine bases which are adenine and guanine there are nine atoms that make up the fused rings, and all of the ring atoms lie in the same plane.

The lab that we did in class was DNA Extraction from Wheat Germ. The wheat germ soup looked like a watery brown color to begin with. Then the appearance changed as my group added detergent and swirl into it. It turned to a lime green color with brown speks. At this step it is getting into the process of creating DNA. The appearance of the mixture after the alcohol was added, was that there was five different layers and now it has created DNA. At this step DNA has been created because of the formation it has went through. At the water-alcohol interface it didn't mix and it was staying separated. At the end of this lab the DNA looked like a white clump, like a spider web. In Conclusion, I learned about the formation of DNA by doing this neat lab.

From DNA to Proteins Vocabulary Words

Anticodon - A sequence of three nucleotides in transfer RNA that binds to the complementary triplet in messenger RNA to specify an amino acid during protein synthesis.

Codon - A sequence of three adjacent nucleotides, which encode for a specific amino acid during protein synthesis, or translation.

Exon -A sequence of a gene's DNA that transcribes into protein structures.

Genetic Code -The ordering of nucleotides in DNA molecules that carries the genetic information in   living cells.

Intron - A sequence of a eukaryotic gene's DNA that is not translated into a protein.

Messenger RNA -The template for protein synthesis; the form of RNA that carries information from DNA in the nucleus to the ribosome sites of protein synthesis in the cell.

Promoter - A region of DNA that facilitates the transcription of a particular gene.

Protein-coding Gene -Consists of a promoter that is followed by the coding sequence for the protein and then a terminator.

Ribonucleic Acid (RNA) -A nucleic acid molecule that is similar to DNA, but it contains ribose rather than deoxyribose.

RNA polymerase - An enzyme that produces RNA.

Ribosomal ribonucleic acid (rRNA) -Is the central component of the ribosome, the protein manufacturing machinery of all living cells.

Transcription -Or RNA synthesis. It is the process of creating an equivalent RNA copy of a sequence of DNA.

Translation -The process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm.

Transfer RNA (tRNA) -A relatively small RNA that transfers a particular amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation.

In Sickness and in Health Genetic Counseling

The pedigree for Greg's Family 




This is an example of an autosomal dominant inheritance pattern.

 



The Pedigree for Olga's Family

        Many people wonder well could our kids develop the same diseases that run in our family? Greg and Olga were wondering the same thing. Well it's all genetics!!! For the Sickness and Health Genetic Counseling Greg and Olga went to the genetic's counselor because they were worried about having kids because they were concerned whether or not their kids will have myotonic dystrophy or factor VIII. Autosomal dominant disorders don't skip generations. So, Greg and his mother couldn't be factors of the gene that causes myotonic dystrophy. There is not a possibility that Greg's aunt or uncle could be homozygous for the myotonic dystrophy because they only got one copy. So, they are both heterozygous. There is not a possibility that Greg's cousin has inherited the myotonic dystrophy gene. Greg and Olga's children won't have myotonic dystrophy because Greg doesn't have the disease. The five hallmarks of autosomal recessive traits are females and males are equally likely to be affected, on average, the recurrence risk to the unborn sibling of an affected individual is one out of four, the trait is characteristically found in siblings, not parents of affected or the offspring of affected, and parents of affected children may be related. Autosomal recessive traits do skip generations.

      The rarer the trait in the general population, the more likely a consanguineous mating is involved, and the trait can appear as an isolated event in small sibships. Consaguinity is when there is a possibility of one parent being a carrier, with the recessive allele being passed through the carrier offspring and by producing an affected homozygous offspring generations later on. This is important when relating to autosomal recessive inheritance because in order for a child to be a carrier of a disease they must receive a recessive allele from both of his or her parents. The inheritance pattern of the factor VIII deficiency that is recognized in Olga's and Greg's pedigree shows that it is not an autosomal recessive trait because it is a sex-linked trait, because only guys get it. Greg's brother had it and Olga's brother had this disease. Some of the characteristics of X-linked recessive inheritance is that the disease is never passed from father to son, and this trait or disease is usually passed from an affected grandfather, through his carrier daughters, to half of his grandsons.  A son never inherits their father's defective X-chromosome, because they only inherit their father's Y-chromosome. When the mother is a carrier she will pass the affected X-chromosme to her son only one half of the time, and her daughters will not be affected because they always get a normal X-chromosome from their father.

                               

     There isn't a possibility that Greg carries the factor VIII gene, but if he did he couldn't be a carrier. There is a possibilty that Olga carriers the factor VIII gene, but it depends upon which of her mother's X chromosomes she inherited. So, her sons would be affected one half of the time but her daughters would not be affected. Olga has a one in twenty three chance of carrying the cystic fibrosis gene. Since, Greg is Asian American and within his population group the carrier frequency is 1 out of 180.  So, the possibility of producing a baby with cystic fibrosis would be 1 out of 16,560. So there chances are very slim of having a kid with that disease. The equation P+q=1 describes all of the alleles in the population. The percentage of the healthy people represents the p. The rest of the alleles must have the disease causing form which represents the q. If p is .65, then q is the other alleles that must be the disease causing form which is .35. Then, p+q=1. In all, I understand about the characteristics of autosomal dominant traits, autosomal recessive traits, and sex-linked traits.



The link to my paper about Eugenics

This is a link to my paper about Eugenics

Source: http://www.eugenicsarchive.org/eugenics/ - That is where I got my Information from.

Wonderful Genetics!!

This is a picture representing homozygous and heterozygous genes given off by the mom fish and the dad fish and the different gametes that are possible.

  













    
   The Idea of genetics is amazing!!! There is so many things that you can think of when you think about genetics. In class we have been learning about genetics, and we did a baby lab to represent the outcome of what you and yours partner's baby would look like. There are many different terms that is involved with genetics. When someone is Homozygous they have two of the same copies of a gene. For example, AA and HH. When someone is Heterozygous, it is the complete opposite they have two different copies. For example, Aa and Ff. Gametes are reproductive cells that have haploid chromosomes. A dominant trait is a trait that shows up in the offspring if one of the parents contributes it. A recessive gene is hidden, it has identical alleles for a single trait.  A gene is DNA region for one trait. An allele is a form of a certain gene. Phenotypes are visible traits, it's what the baby is going to look like. Genotypes are the genes that are present. A chromosome is an organized structure of DNA and protein that is found in cells. The difference between a diploid and a haploid is that a diploid are two copies of each chromosome and a haploid is one copy of each chromosome. In meiosis when mom and dad's chromosomes are separated this is called segregation. If a mom is homozygous for free earlobes and marries a man who doesn't have free earlobes,what are the possible genotypes and phenotypes of their children? Well, the genotypes would be Ff, and ff. The phenotypes would be free earlobes and not free earlobes.

Independent Assortment is when there are as many combinations as possible. According to Mendel's second law alleles of two or more different gene pairs inherit two different alleles. They assort independently of each other during meiosis. A random combination of the genes from each pair end up in the gametes. For example, Ss and Yy assort independently because when the S and s alleles segregate from each other during meiosis, each one is most likely to land in the same gamete with the big Y allele and with the little y allele. The reason why idependent assortment occurs is because there are many ways that chromosomes are placed in metaphase one of meiosis. Two genes must reside on different chromosomes or on the same chromosome in order to assort independently. They must be located far apart from each other along the chromosomes arms. Genetics is involved everywhere in our world, and it plays a major role. It determines what you look like, like if you get more traits from your mom or dad. Sometimes, you can look more like family members in your family's history from generations ago. I have a good understanding about genetics, and how we get the traits that we do.

Meiosis/Reproduction

This is a diagram of meiosis. 



The division of meiosis. 



























Meiosis is the type of cell division by which eggs and sperm are produced. In meiosis I, the chromosomes in a diploid cell resegregate, which produces four haploid daughter cells.  This step in meiosis generates genetic diversity. It occurs in humans, fungi, plants, and animals. Each human cell contains a full set of 46 chromosomes. When meiosis begins, each chromosome is attracted to its special homologous partner. The two number one chromosomes; one from the paternal set and one from the maternal set, wrap tightly with each other in a process called synapsis. Then, a tetrad of four chromosomes is created. Each homologous pair forms its own tetrad, which happens with the other chromosomes. All of the tetrads arrange themselves on the spindle. The chromosomes are pulled apart, and divisions happen. The four chromosomes are separated into two's and then into ones of each tetrad. 


Meiosis II is very similar to mitosis. However, there is no S phase. The chromatids of each chromosome are no longer identical because of recombination. Meiosis II separates the chromatids producing two daughter cells, each with 23 chromosomes and each chromosome has only one chromatid. Homologous chromosomes pair forming bivalents until anaphase I in chromosome behavior. In genetic identity of progeny during meiosis the chromatids are not identical. The daughter cells have a new assortment of parental chromosomes. Meiosis can only happen if the nucleus contains an even number of chromosomes. 


In class we watched the movie Life's Greatest Miracle in which it was about the long processes it takes to have a baby. It was interesting to learn about how a baby is formed by how the process has to be done  right on time. In which, there has to be enough sperm that is developed and the egg can't die. But, the process of having a baby is all about meiosis. This movie really taught me a lot of information about how meiosis is very important, it was gross though watching the live birth of a baby. Meiosis produces different sperm and egg.  In conclusion, I understand about the processes of meiosis and how it is different from mitosis. 

The Idea of Stem Cells

This is a diagram of Pluripotent Stem Cells. 

   Cells develop into many different cell types in our bodies during early life and growth. When a stem cell divides, each new cell has the capability to either remain a stem cell or become another type of cell with a more important function; such as a muscle cell, a red blood cell, or a brain cell. There are two important characteristics that stem cells are distinguished from other cells. The first characteristic is that  they are unspecialized cells that are capable of renewing themselves through cell division, sometimes after long periods of inactivity. Another characteristic is that under certain experimental conditions, the cells can become tissue or organ-specific cells with special functions. Stem cells regularly divide to repair and replace worn out or damaged tissues, in some organs such as the gut and bone marrow. Stem cells only divide under special conditions, in organs such as the pancreas and the heart.


  Scientists have worked with two kinds of stem cells from animals and humans which are embryonic stem cells and non-embryonic somatic stem cells. Scientists discovered ways to derive embryonic stem cells from early mouse embryos in 1981. Then in in 1998,  a method to derive stem cells from human embryos and grew the cells in the laboratory was developed. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through procedures called invitro fertilization. Stem cells are important to living organisms for a lot of reasons. The inner cells give rise to the entire body of the organism in a blastocyst embryo which is a 3- to 5-day-old embryo. It includes many specialized cell types and organs such as the heart, lung, skin, sperm, eggs, and many other tissues. Some tissues that are in adults such as bone marrow and muscle generate replacements for cells that are lost through injury, diseases, and normal wear and tear. Stem Cells offer new ways for treating diseases like heart and diabetes. Scientists use stem cells in labs to test new drugs and to find the reasons that causes birth effects. 


The research about stem cells continue to advance about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. All stem cells have three properties which are how they are unspecialized, capable of renewing and dividing themselves for a long period of time, and how they can give a rise to specialized cell types. Information is difficult for scientists to be able to grow a large number of unspecialized stem cells in the lab for further experimenting. One of the main properties of a stem cell is that it does not have any tissue-specific structures that allow it to perform specialized functions. Stem cells can't carry oxygen molecules through the bloodstream. But, when stem cells give a rise to specialized cells, this process is called differentiation. The cell usually goes through several stages, while differentiating. There are many questions about the process of stem cell differentiation that still remains. 


I understand about the capabilities and the unique features about stem cells. It's interesting about how stem cells develop into many different cell types in our bodies. 

The Cell Cycle of Mitosis

In Class, we have been learning about the different stages of mitosis. The different stages are Interphase, Prophase, Metaphase, Anaphase, and Telophase. The biggest percentage of what the cells mostly spend there time in is Interphase, which is about 90% of the time. Cells rarely spend there time in Telophase which is about 2.7% of the time.






 Interphase: 

                                                                                                       

      Interphase is the period of the cell cycle in which the nucleus does not undergo division. It mainly occurs between mitotic or meiotic divisions. Its the resting stage between all cell divisions. It usually lasts between twelve to twenty-four hours in mammalian tissue. The cell is always synthesizing RNA during this period. Interphase can be divided into four steps which are Gap 0, Gap 1, synthesis phase, and Gap 2. In Gap 0 there are times when the cell may quit dividing. An example would be a cell that has reached an end stage of development and will no longer be able to divide. In Gap 1 the cells increase in size, producing synthesize and RNA protein. A cell cycle control mechanism is activated during this period and it makes sure that everything is ready for DNA synthesis. During the synthesis phase DNA replication occurs. This happens in order to produce two similar daughter cells. During Gap 2 between DNA synthesis and mitosis, the cell will continue to grow and produce proteins. At the end of the cycle it determines if the cell can proceed to enter mitosis and divide. 

                

  Prophase:     

Prophase is the first stage of mitosis in which the chromosomes join together and become visible. The nuclear membrane breaks down and the spindle apparatus forms at opposite poles of the cell. Two centrosomes, in which replicate independently of mitosis have microtubule-activity increased due to the recruitment of the y-tubulin. The interesting feature of prophase is the setup of the mitotic spindle, in which is used to maneuver the chromosomes about the cell. The spindle is formed by extra parts from the cytoskeleton. The cell's centioles are duplicated to form two two pairs of centrioles. In which, each pair becomes the part of the mitotic center which forms the focus for an array of microtubules. This procees is called the aster. Two asters lie next to each other close to the nuclear envelope. Towards the end of prophase the asters pull apart and the spindle is formed. 

                                                                        

                                                    

                Metaphase:

                                                 Metaphase is the stage that follows prophase and preceeds anaphase, in which the chromosomes are aligned along the metaphase plate.  The genetic material is condensed into chromosomes. The chromosomes therefore become visible. The nuclear disappears and the chromosomes appear in the cytoplasm of the cell. As metaphase continues the cells break into two daughter cells.   

                                                                  

              Anaphase:
During anaphase two events occur. Anaphase begins when the duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell, due to the action of the spindle. The kinetochores begin to move towards the poles. Then the polar fibers elongate, which spreads the poles farther away from each other . Anaphase follows as the separated chromatids move toward opposite spindle poles. Wherever the centromere is located along the chromosome, a characteristic shape appears during chromosome movement. Then, at the end of anaphase a complete set of chromosomes is collected at each pole of the cell.

         Telophase:
                                           In the last stage of mitosis, which is telophase there are two separate groups of chromosomes at each pole.  A nuclear envelope begins to form around each set of chromosomes to form two nuclei. It is temporarily in one cell. When the envelope reassembles RNA synthesis that begins to break down the chromosomes. This causes the nucleolus to reappear. The chromosomes of daughter cells are basically grouped in new nuclei. There are many changes that occur in telophase. Some of the changes is that the polar fibers continue to lengthen, nuclei begins to form at opposite poles, and the nuclear envelopes of these nuclei are formed from pieces of the parent cell's nuclear envelope, and from pieces of the endomembrane system. Also, nucleoli also starts to reappear. After these changes, the genetic contents of one cell has been divided equally into two.
 
   By learning about the different types of stages in mitosis I now have a good understanding about how each stage works. I understand how to classify which cell is in what stage during mitosis.