Friday, March 2, 2012

Genome - Entry 5

Chapter 12 - Self Assembly

Ridley starts off the chapter talking about the analogies that we use like how our eyes are considered as a camera, and how our heart is like a pump. Two scientists working in Germany named Jani Nusslein-Volhard and Eric Wieschaus that tried to find as many mutant flies as possible. They would dose their flies with chemicals that would cause mutation and bred them. The mutated flies came out in separate groups with some only having wings, or only limbs. If you move a hedgehog-expressing piece of tissue int the anterior half of the wing, the fly would come out as if it has mirrored the front to the back. Hox and hedgehog genes aren't the only genes that can control development, in fact, there are many more genes that can do the same.

Citation:

Ridley, Matt. Genome: The Autobiography of a Species in 23 Chapters. New York: HarperCollins, 1999. Print.

Genome - Entry 4

Chapter 15 - Sex

Ridley introduces this chapter by mentioning a five-year-old girl who has a rare inherited disease called Prader-Willi syndrome. The Prader-Willi syndrome has many symptoms like having small hands and feel or mildly mentally retarded. In the late 1980s there were two scientists who tried to have a mouse with only one parent, but failed because the method they used did not help develop the embryo. Ridley mentions that diseases " do not always result from a mutation in one of these genes but from an accident of a different kind." The placenta is an organ that a father's gene would not trust the mother's genes t make and then the cerebral cortex is the organ that is the other way around. Ridley then continued to talk about a boy who got a circumcision, but went wrong and changed the boy into a girl by castration. The boy grew up thinking he was a girl until his parents told him the truth.

Citation:

Ridley, Matt. Genome: The Autobiography of a Species in 23 Chapters. New York: HarperCollins, 1999. Print.

Genome - Entry 3

Chapter 6 - Intelligence

Ridley introduces the chapter by first mentioning that "GENES ARE NOT THERE TO CAUSE DISEASES" and then eventually talking about how a gene for intelligence has been found. Robert Plomin has been researching, and found a group of gifted teenagers. It was proven that the smarter teenagers have a different DNA sequence than a normal teenager. There are two sides on where intelligence comes from, either nature or nurture. I go on the nature side because i believe that people are born with intelligence inside them, they grow up to learn how to use intelligence, but they are born with it. The intelligence gene they found is very big, it contains 7,473 in total and the sense-containing message spreads over 98,000 letters of the genome.

Citation:

Ridley, Matt. Genome: The Autobiography of a Species in 23 Chapters. New York: HarperCollins, 1999. Print.

Genome - Entry 2

Chapter 9 - Disease


Ridley introduces this chapter by mentioning the different blood types like A, B, AB, and O. He explains how A and B can provide blood for AB, but AB cannot provide blood for A or B. He also mentions that O is a universal donor for any blood type. A and B type of bloods have difference in their genes, where the letters are ordered differently. Ridley explains how the people who have AB blood type are more healthy and to be AB, they have to be offspring of A and B bloody type. So it is suggested for an AA to mate with a BB to have AB healthy children. Ridley talks about a experiment with wearing and smelling a t-shirt with no perfume or deodorant for 2 days, and ranking them by the attractiveness of the smell. There will always be change, and nothing stays the same.

Citation:

Ridley, Matt. Genome: The Autobiography of a Species in 23 Chapters. New York: HarperCollins, 1999. Print.

Thursday, March 1, 2012

Genome - Entry 1

Chapter 7 - Instinct

Ridley describes some examples of how instinct is like for animals, and how humans don't NEED to rely on instincts, but instead we learn. Chomsky studied the way human beings spoke, and came to a conclusion that there are similarities to all languages that bore witness to a universal human grammar. Ridley discusses how we can change a statement in English by just changing one word to the front, making it a question. There are particular parts in the brain that can cause one to lose the knowledge of how to use sentences that are grammatically correct. English is something we can learn by reading books, but the environment allows us to improve our English. All human beings have instinct, but that doesn't mean that it is developed equally. There are many people who are more advanced than others who could just be slower in learning grammar.

Citation:

Ridley, Matt. Genome: The Autobiography of a Species in 23 Chapters. New York: HarperCollins, 1999. Print.

Describe a starfish in terms of symmetry, germ cell layers, coelem, Circulatory system, reproduction, feeding, excretion and nervous system. Find picture examples of each living class Crinoidea, Ophiocistioidea, Astroidea, Echinoiudea and Holothuidea.

The starfish has 5 rays or arms, most of the space in the ray is covered up by the starfishes branched digestive glands. The food that goes through the starfish's is partially digested through the anus of the starfish. The anus of a starfish is where the waste products are released to the outside. There are two rectal pouches near the anus, which functions as a temporary storage for the waste products before being released. the male and female gonads look very alike to the point where it has to be microscopically examined to tell the difference. The ovaries of a starfish are considered to be larger than the sperm, and the testes have flagellated sperm. The water vascular system consists of seawater filled ducts that help the starfish feed and move around.

Crinoidea


Ophiocistioidea


Astroidea


Echinoiudea


Holothuidea


Sources: The little booklet from Starfish Dissection and google images.

Describe double fertilization

Double Fertilization occurs when a female gametophyte is joined with 2 male gamete. This happens in angiosperm plants, which is capable of having asexual or sexual reproduction. A diploid zygote and triploid endosperm form during Double Fertilization. When the haploid sperm cell joins with a haploid egg cell in order to try and form a diploid zygote, which allows the outcome to develop into a embryo. The ovary develops into a fruin in order to protect the seeds that may help distribute.

Describe how a nephron works. How is this similar to counter currents or hydrostatic skeletons?

Some of the nephron functions are the secretion of some solutes, or re-absorption of various solutes. The nephron has cells with different properties, it also helps the kidney regulate blood because it has a unique blood supply. Parts of the nephron like the Bowman's capsule helps filter and removes all the organic wastes, and water.

Counter Currents: Creates concentrated urine based on what the body needs or wants. Loop of Henle's length is based on the amount of water that goes through, it allows the absorption of water to go back into a body.

Hydro-static Skeletons: Found in many cold-blooded organisms, and surrounded with muscles. Hydro-static skeletons play a role in how sea creatures move in the water.