AP Bio: Genome Chromosome 5: Environment

In "Chromosome 5: Environment," Ridley begins the fifth chapter of Genome by saying that he has been misleading the readers because he talked about genetics as if it was words written in a simple language when it is actually "a world of greys, of nuances, of qualifiers, of 'it depends'" (65).  With that, Ridley presents Chromosome 5, a more complicated gene that is called the 'asthma gene.'  There are many theories about asthma, including one theory that claims that people who wash themselves more or encounter less mud have a higher chance of becoming asthmatics.  To make it more complicated, most people with asthma are also allergic to something else, such as allergies to bee stings or peanuts. As a result, there is no clear cause for the wide range of responses from asthmatics and Ridley concludes that "grey indeterminacy, variable causality and vague predisposition are the hallmarks" (75) of genetics.


Source: Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley

AP Bio: Understanding Intelligence

In Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley, the sixth chapter "Chromosome 6: Intelligence" presents that a person's IQ is determined both by 1) their genes and the environment of the womb, and 2) the things they learn after birth and the outside environment.  It is important of define and debate our understanding of intelligence and its origins because then we can know which is the best way for us to learn.  It also provides insight into who we are and our origins.

This relates to us because as the book Genome discussed, someone who may have top grades in school and is book-smart may not be streetwise, whereas someone who may have low grades in school would most likely be streetwise.  This implies that there are different types of intelligence: natural intelligence, mathematical/logical intelligence, spatial intelligence, interpersonal intelligence, intrapersonal intelligence, linguistic intelligence, kinesthetic intelligence, musical intelligence, and existential/spiritual intelligence.  Different people are more intelligent in different areas, and not all of these intelligences are valued in school.  School mostly tests your mathematical and linguistic intelligence.

Depending on which area you are more intelligent in, you could use it to help you in school if you are a student.  For example, if you are interpersonally intelligent, you can study in a group and will be able to absorb information faster that way.  If you are intrapersonally intelligent, it is best for you to study on your own and ask yourself how the things you are learning can apply to you.  If you are spatially intelligent, you can draw diagrams to let you see the big picture/concept of things.  If you know that you are more intelligent in one area, use strategies that match that area to help you.

Source: Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley

Anatomy and Physiology: Brain Plasticity

Brain plasticity is important because then it means that the brain can undergo changes that would cause a difference in their behavior or how they sense things, even as an adult.  This means that the brain has the lifelong ability to make neural pathways based on new experiences, in other words, the ability to learn.  New knowledge and skills are gained through experience or instruction.

A representation of the body surface on the surface of the brain.

The brain is mapped so that it has different regions that are responsible for certain behaviours.  In Phantoms of the Brain by V.S Ramachandran, M.D., Ph.D. and Sandra Blakeslee, they provide a diagram of a representation of the body surface on the surface of the brain.  The foot comes after the genitals, followed by the trunk, hand, thumb, face, lips, and pharynx.  Based on this, various fetishes, or nongential regions of the brain that causes a habitual erotic response, can be explained.  For example, a graduate student who had a phantom leg after losing it in an accident said that whenever she had sex, there were strange sensations in her phantom leg.  This would be explained by the foot being next to the genitals in the brain.  When she still had her foot, it kept the genital region in the brain from taking over, but now that her foot is gone, the genital region encroaches on the foot region, resulting in her feeling her phantom foot whenever she had sexual activity.

Source:

information from: Phantoms of the Brain by V.S Ramachandran, M.D., Ph.D. and Sandra Blakeslee

brain picture from: 

Phantoms of the Brain picture from: http://michael5000.blogspot.com/2011/11/reading-list-phantoms-in-brain.html

AP Biology: Nephron

The nephron is the basic, functional unit of the kidney.  Each kidney has 1 million nephrons packed into the cortex.  It has three main parts: the glomerulus, the Bowman's Capsule, and the tubule (divided into the proximal tubule, distal tubule, the Loop of Henle).  The nephron restores essential nutrients and water into the bloodstream, and removes waste products from the blood through tubular reabsorption and tubular secretion.  In tubular reabsorption, proximal tubule cells remove water and nutrients from the filtrate and they are returned to the bolood while wastes are kept in the tubule.  IN tubular secretion, wastes not filtered in the Bowman's Capsule are removed from the blood by the distal tubule.  The filtrate flows through the proximal tubule to the Loop of Henle, which concentrates the flitrate by removing more water from it, and the concentrated filtrate then flows through the distal tubule to the collecting duct.  The filtrate is now called urine and the collecting duct prepares the urine for transport.  Afterwards, it is collected in the renal pelvis and goes through the ureter to the bladder.

The way the nephron works is similar to countercurrent exchange.  Solutes are exchanged as the nephron returns nutrients to the blood and removes wastes from the blood.  The kidney has a countercurrent multiplier system where it allows the kidney to maintain high concentrations of solutes, which is essential to the kidney's function of removing wastes from the blood.

Hydrostatic skeletons are water-based and muscles surround fluid-filled body cavities.  The nephron is similar to hydrostatic skeletons because both of their function in removing wastes.  Also, in animals such as worms, their hydrostatic skeletons allow them to move when contractions squeeze their internal fluid in the body cavities.








Below is a mind map on kidney function:

Sources:
information from: Campbell and Reece's Biology, Sixth Edition

nephron picture from: http://www.irvingcrowley.com/cls/nephron.htm

countercurrent picture from: http://en.wikipedia.org/wiki/Countercurrent_exchange

hydrostatic skeleton picture from: http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookmusskel.html

AP Bio: Genome Chromosome 4: Fate

In the "Chromosome 4: Fate," Matt Ridley begins the fourth chapter of Genome by talking about how most genes are named and identified with the diseases they cause.  He introduces Chromosome 4 as "the most famous of all the 'disease' genes" (55), as it is associated with the disease Huntington's chorea, which is caused by the mutated version of the gene.  If this gene is not present, it causes Wolf-Hirschhorn syndrome.  The gene repeats the "word" CAG over and over again.  If it is repeated thirty-nine times or more, in mid-life, you will lose your balance, have jerking limbs, deep depression, hallucination, and delusions for about 25 years and eventually die.  There is no cure for the disease and being diagnosed with the disease and waiting for it to strike is likely worse than just being ignorant about it.  When the scientist Nanacy Wexler was deciding whether to take the test to see if she had the disease, she compares science to Tiresias, the blind seer of Thebes, who had the gift of foresight but could not change the future, implying that for people like her who have a high chance of having the disease, "[their] fate is in [their] genes."


Source: Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley

Anatomy and Physiology: Sense of Taste

The typical map of an "average" person's tongue.

For your sense of taste, there are taste bus, which are specific receptors that are scattered in the mouth.  Most are on the tongue, but there are some on the soft palate and inner surface of the cheeks.  There are five basic taste sensations and five major types of taste buds, which match each other.  There are sweet receptors believed by some to respond to the hydroxyl (OH-) group, sour receptors to respond to hydrogen ions (H+), bitter receptors to respond to alkaloids, salty receptor to respond to metal ions in solution, and umami (discovered by the Japanese) appearing to respond to the "beef taste" (292) of meat and the food additive monosodium glutamate.  The tongue tip is usually sensitive to sweet and salty substances, the sides to sour, the back to bitter, and the pharynx to umami.


Taste is affected is heavily affected by olfactory (smell) receptors, which stimulate our sense of taste.  This is why food tastes bland when you have a cold and your nasal passages are congested.  Also, the temperature and texture of food can affect taste of food.  For instance some people do not eat foods with a pasty texture or hot, spicy foods that stimulate the mouth's pain receptors.


Sources:
information from: Essentials of Human Anatomy & Physiology, Eighth Edition by Elaine N. Marieb
tongue mapping picture from: http://misconceptions.us/taste-buds-and-the-tongue/

AP Bio: Genome Chromsome 3: History

In the third chapter of Genome, "Chromosome 3: History," Ridley beings by by talking about what happened historically in genetics and the researcher Archibald Garrod's conclusion that "what we inherit from our parents is a gigantic list of recipes for making proteins and for making protein-making machines" (40).  Through evolution, which was "the accumulation of slight and random changes through selection" (44-45), in other words, mutations, different species emerge.  At the end of the chapter, Ridley explain how Chromosome three was discovered by two Spaniards using the fungus Aspergillus, making a defective form of the protein homogentisate dioxygenase.  Ridley goes on to say that this third chromosome is "the epitome of a boring gene" and that there's nothing special about it and it does not tell us anything important about the origin of life.


Source: Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley

AP Bio: Starfish

An Echinoderm.

Starfish are in the phylum of Echinodermata.  They have 5-rayed symmetry, usually radial but sometimes bilateral.  Their bodies have two cell layers of tissues and organs and the body cavity has a true coelom.  They do not have gills and instead have a open circulatory system.  They also have a water vascular system, operated by tube feet or feeding tentacles.  They normally reproduce sexually and are gonochoristic.  Starfish do not have excretory organs, but most have an anus.  Their nervous system includes a circum-oesophageal ring.  They feed through a mouth near the center of their body and feed on particles, detritus, or other animals.


These pictures below are examples of the living classes of Crinoidea, Ophiocistioidea, Astroidea, Echinoiudea, and Holothuoidea.


Crinoidea

This class includes sea lilies and feather stars.

Ophiocistioidea

A brittle star, this class is now extinct.

Astroidea

A sand dollar; this class includes sea stars, starfish, and sand dollars.

Echinoiudea

Sea urchins; this class includes sea urchins, sea biscuits, and sand dollars.

Holothuoidea

This class includes sea cucumbers, such as this one.

Sources:
information and Echinoderm picture from: http://www.earthlife.net/inverts/echinodermata.html
Crinoidea picture from: http://www.ucmp.berkeley.edu/echinodermata/crinoidea.html
Ophoicistiodea picture from: http://www.okc.cc.ok.us/biologylabs/documents/Echinodermata/Class_Ophiuroidiea.htm
Astroidea picture from: http://jbournesblog.wordpress.com/2011/12/13/the-gift-of-the-sand-dollar/
Echinoiudea picture from: http://ocean.nationalgeographic.com/ocean/photos/sea-urchins/
Holothuoidea picture from: http://animals.nationalgeographic.com/animals/invertebrates/sea-cucumber/

Anatomy and Physiology: Tricks Your Eyes and Brain Can Play on You

The visual virtual lab project begins with asking whether a horizontal table or vertical table is longer.  It turns out that preceptual clues make us think that the vertical table is longer, but they are actually the same size.  As a result there is a difference between reality and what our eyes perceive.

This is known as the Rubin vase illusion, made by psychologist Edgar Rubin.  Because of figure-ground segregation, we either see two faces on a white background or a vase on a gray or black background.


As the visual project continues, it discusses how our brain is sensitive to contrasts.  It gives us two circles, one light gray, and one black.  Each has a smaller gray circle in the middle.  Although both of these smaller gray circles are the same brightness, we think that the one in the larger light gray circle is lighter because of the color around it is lighter.

This is the Thatcher illusion.  When the images are upside down, it looks like both of them are smiling.  However, when they are flipped right-side up, one is smiling and the other is frowning.  This is because we draw familiarity from experience.  We process the image and fill the rest in based on experience, even though both images are not smiling.








Sources:
rubin vase illusion picture from: http://www.lifeisanillusion.info/the-rubin-vase-illusion/
thatcher illusion picture from: http://scienceblogs.com/mixingmemory/2006/09/cool_visual_illusions_the_marg.php
information from: http://virtuallabs.stanford.edu/demo/

AP Bio: Genome Chromosome 2: Species

The evolution of man.

In "Species," the second chapter of Genome, Matt Ridley discusses how the species of humans came about.  Chromosome 2 is actually the second biggest human chromosome and is formed by two medium-sized ape chromosomes fusing together.  Ridley mentions that it is surprising that humans don't have twenty0four pairs of chromosomes because chimpanzees and other monkeys have twenty-four pairs and according to the theory of evolution, we are closely related to them.  He goes on to say that although "the human species has shown a remarkable capacity for colonising different habitats" (25), "the remarkable truth is that we come from a long line of failures."  Humans were once apes that almost became extinct fifteen million years ago when we were in competition with better-adapted monkeys.  He mentions that we are descended from synapsid tetrapods, limbed fishes, and chordates, then goes on to describe our journey to existence through natural selection and evolution.  Ridley ends with concluding that it is crazy that small differences in the genes of different species result in large differences in behavior and that  "genes are recipes for both anatomy and behaviour" (37).


Source: 
Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley
picture from: http://www.dailymail.co.uk/sciencetech/article-1070671/Evolution-stops-Future-Man-look-says-scientist.html

AP Bio: Genome Chromosome 1: Life

In "Life," the first chapter of Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley, the author describes life as "a slippery thing to define, but it consists of two very different skills: the ability to replicate, and the ability to create order" (12).  He talks about how information is the key to these two conditions of life, and that DNA is that information, "written in a code of chemicals" (13).  He also talks about how life began: Chromosome I, the largest chromosome, is called the "ur-gene" (18) and was a "combined replicater-catalyst" which may have caused the chemicals around it to replicate itself.  He compares about the genes being a language of itself in a book.




Source:
Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley
picture of Genome book from: http://vanlagerstatten.blogspot.com/

AP Bio: Double Fertilization

Double fertilization is the unusual reproductive process that flowering plants go through and there are two fertilization events, not one.  The ovule (female reproductive part of plant) has a megaspore (mother) that is diplod (2n) but undergo meiosis to produce four haploid cells (n).  Three of these degenerate and one megaspore is left.  This remaining megaspore undergo mitosis to produce eight haploid nuclei, making a multinucleate structure called an embryo sac.  Three antipodal cells form at the opposite side of the microphyle opening.  Two synergids and the egg form near the microphyle opening and two polar nuclei remain together as a central cell.  Before fertilizing, a pollen grain lands on the stigma and germinates to send a pollen tube down the style and the ovary.  A haploid/generative cell travels down the tube and divides to produce two haploid sperm cells.  The pollen tube digests through one of the synergids, the synergid degenerates, and one of the sperm cells fertilizes the egg.  The second sperm fuses with both polar nuclei to make a triploid (3n) cell that later becomes the endosperm, the embryo's food supply.


Source:
information from: http://bcs.whfreeman.com/thelifewire/content/chp39/3902001.html
picture from: http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookflowersii.html