Got Fish?

I recently read a couple of articles online that fish may not be around too long. Because of negligence, over fishing, and pollution we are at risk of fish extinction. The next generation may not see the many beautiful creatures of the sea. The Marianas need to take some kind of action now to prevent fish scarcity so that many generations to come may have the same luxury we do today.

I love the ocean and the many creatures in it. Some of my favorite dishes include fish and seafood. At first, I didn’t grasp the concept of protecting some of the islands’ location from fishermen. I always believed that a fisherman was out fishing to feed his family and/or generate some income, which is an admirable thing to do considering the economic state we are in today. But after reading the articles, I now understand and appreciate why there are sanctuaries around the Mariana Islands. Unlike the many fisheries around the world, the local fishermen use spear, rods, nets, and boats for trolling for the fortunate ones. Major fisheries around the world use high-technology for detecting and capturing an abundance of fish and other sea life. This could be damaging because sometimes their intentions are to catch tuna, for example, but dolphins and many other sea creatures are caught in nets. In the Marianas, fishing is more of an essential part of a family’s life. Although it may not be as alarming to us as the rest of the world, we should be just as aware and careful about our surrounding waters. The sanctuaries being protected around our islands are a good way of being proactive. The opposition may say there’s a lot of fish to go around. But when the time comes when there’s no fish at all, we’ll regret and not forget that we were part of the problem. There’s never enough of anything in this world. We need to make the best of what we have and protect what’s left for us.

Questions? Comments? Send me one.

Squid

click on image to enlarge.CLASSIFICATION:
Squid are a large, diverse group of cephalopods. Squid are members of the class CEPHALOPODA, subclass COLEOIDEA, and the order TEUTHIDA. There are 2 suborders, MYOPSINA and OEGOPSINA. The order Teuthida is a member of the superorder DECAPODIFORMES.

HABITAT:
Squid are most commonly found between the ranges of Greenland and Florida. Abundance and distribution vary greatly, both seasonally and annually. Distribution between offshore and inshore are greatly influenced by environmental conditions, with water being the major factor. Evidence suggests that highest concentrations occur where bottom temperatures exceed 6 C. There seems little doubt that temperature at intermediate depths as well as other biological factors such as predator and prey abundance and their distribution also play an important role.

FOOD SOURCE:
Adults eat voraciously, consuming a variety of crustacea and fish. Smaller squid tend to feed more heavily on small crustacea such as euphasids, turning more to fish and fellow squid as they mature. The extent of cannibalism among squid is unclear, but it would appear that the larger specimens are the most inclined to eat their own species.

LIFE CYCLE:
Squid is believed to live no more than 12 to 18 months. Spawning females create large, clear, almost neutrally buoyant egg masses by releasing a gel-like substance with the fertilized eggs. The gel reacts with seawater to form a globular-shaped egg mass, up to I m in diameter, containing about 100,000 eggs of about I mm in diameter. After a period of growth and development, the larval squid becomes a juvenile about 6 mm in mantle length with adult features. By this time, the proboscis has split to form the two tentacles, and the other eight arms have grown larger.

UNIQUE CHARACTERISTICS:
The head end of the squid bears 8 arms and two tentacles, each a form of muscular hydrostat containing many suckers along the edge. These tentacles do not grow back if severed. In the mature male squid, one basal half of the left ventral tentacle is hectocotylised and ends in a copulatory pad rather than suckers. It is used for intercourse between mature males and females.
The mouth of the squid is equipped with a sharp horny beak mainly made of chitin and cross-linked proteins, and is used to kill and tear prey into manageable pieces. The beak is very robust, but does not contain any minerals, unlike the teeth and jaws of many other organisms, including marine species.

1. What is DNA?

DeoxyriboNucleic Acid.

2. What are the 4 bases?

Adenine, Thymine, Cytosine, and Guanine. (A, T, C, & G)

3. What 2 pieces of information did the scientists need to resolve the elusive structure of DNA?

One was that the phosphate backbone was on the outside with bases on the inside; another that the molecule was a double helix. It was also important to figure out that the two strands run in opposite directions and that the molecule had a specific base pairing.

4. What are the specific bases?

Adenine, thymine, guanine, and cytosine

5. How does the pairing rule effect the shape and structure of DNA?

the amount of adenine always equals the amount of thymine. The same goes for the pair guanine and cytosine. With this information at hand Watson was able to figure out the pairing rules. If the bases were paired in this way, each rung of the twisted ladder in the helix would be of equal length, and the sugar-phosphate backbone would be smooth.

6. What does the DNA do during cell division?

During cell division, the DNA molecule is able to "unzip" into two pieces. One new molecule is formed from each half-ladder, and due to the specific pairing this gives rise to two identical daughter copies from each parent molecule.

7. How many base pairs does E.Coli have? How long does it take to replicate? How is the DNA packaged in the cell?

E. coli bacteria is made up of 4 million base pairs. The single-cell bacterium can copy its genome and divide into two cells once every 20 minutes. In E. coli the single circular DNA molecule is curled up in a condensed fashion.

8. How many base pairs does the Human DNA have? How long does it take to replicate? How is the DNA packaged?

The DNA of humans is composed of approximately 3 billion base pairs, making up a total of almost a meter-long stretch of DNA in every cell in our bodies. The human DNA is packaged in 23 distinct chromosome pairs. Here the genetic material is tightly rolled up on structures called histones.

1. What is RNA? How different is it from DNA?

RiboNucleic Acid. Unlike the double stranded DNA, RNA is only made up of a single strand. Furthermore, the base T, thymine, is replaced by U, uracil in RNA. This RNA string is used by the organism as a template when it builds protein molecules, sometimes called the building blocks of the body. For example, your muscles and hair are mostly made up of proteins.

2. How are the RNA messages formed?

The alphabet in the RNA molecule contains 4 letters, i.e. A, U, C, G as previously mentioned. To construct a word in the RNA language, three of these letters are grouped together. This three-letter word are often referred to as a triplet or a codon. An example of such a codon is ACG. The letters don't have to be of different kinds, so UUU is also a valid codon. These codons are placed after each other in the RNA molecule, to construct a message, a RNA sequence.

3. How are the RNA messages interpreted?

Every organism has an almost identical system that is able to read the RNA, interpret the different codons and construct a protein with various combinations of the amino acids mentioned previously. In fact every RNA word or codon, corresponds to one single amino acid. These codons and their correlation with the amino acids in a protein sequence is what defines the genetic code.

Cell Cycle (Mitosis & Meiosis)

1. Describe cell cycle.

The cell cycle is the orderly sequence of events that occurs from the time a cell divides to form two daughter cells to the time those daughter cells divide again. The phases of the cell cycle occur in meiosis as well as mitosis.

2. What is nuclear division?

In nuclear division also known as, Karyokinesis, the nucleus divides during this process. Nuclear division includes several subphases. Prophase, Metaphase, Anaphase, and Telophase.

3. What is interphase?

During interphase the cell is growing and metabolic activity is very high. Toward the end of interphase, new DNA is synthesized and the chromosomes are replicated. Each chromosome of the homologous pair is then composed of two sister chromatids.

4. Cytokenises is the process in which the cytoplasm divides and two identical daughter cells are formed.

5. Homologous chromosomes: In diploid (2n) organisms, the genome is composed of homologous chromosomes. One chromosome of each homologous pair comes from the mother (called a maternal chromosome) and one comes from the father (paternal chromsosome).

6. Phases of mitosis:

Prophase, Interphase, Anaphase, Metaphase, and Telophase.

7. Phases of meiosis and how different from mitosis.

Prophase, Metaphase, Anaphase, and Telophase.

Meiosis follows phases similar to those in mitosis, but the outcome of the process is very different. The DNA of the parent cells is replicated in interphase preceding both mitosis and meiosis. However, in meiosis, replication is followed by two divisions.

Meiosis reduces the chromosome number of the parent cell so that four daughter cells are produced, each with one-half the chromosome number of the parent cell. Each daughter cell contains only one chromosome from each homologous pair.

8. Describe the process and purpose of crossing over.

Crossing over occurs during prophase I of meiosis. In prophase I of meiosis, the replicated homologous pair of chromosomes comes together in the process called synapsis, and sections of the chromosomes are exchanged. You can see that after crossing over, the resultant chromosomes are neither entirely maternal nor entirely paternal, but contain genes from both parents. Synapsis and crossing over occur only in meiosis