AP Bio: Review of the Semester

What was your favorite topic this semester? Why?
My favorite topic of the semester was animals because many of the dissections we did was able to help us to remember things about the animals.  I especially liked the shark and the starfish.

What was your least favorite?
My least favorite topic was genetics.  Although it is interesting, I found some of it hard to understand and absorb, probably because it was taught more quickly than usual at the end of the year.

What would you change about this class if you could?
Like in anatomy, I would like a whole list of assignments and its due dates at the beginning of the semester so that I would know exactly how the semester would be like.


What do you feel is your biggest accomplishment in biology this year?
Like in anatomy, I feel that my biggest accomplishment in biology this year is being able to appreciate how everything in the body is so complicated yet it works out just in the right way to support life.  (I am also very proud of that big, huge, fat notebook I built up during the whole course of the year). [:

AP Bio: Examples of Invertebrates

jellyfish

geographic cone snail

white-lipped cone snail

worm


Sources:
golden jellyfish picture and information from: http://animals.nationalgeographic.com/animals/invertebrates/golden-jellyfish/
geographic cone snail picture and information from:
http://animals.nationalgeographic.com/animals/invertebrates/geographers-cone-snail/?source=A-to-Z
white-lipped grove snail from: http://animals.nationalgeographic.com/animals/invertebrates/earthworm/?source=A-to-Z
earthworm information from: http://animals.nationalgeographic.com/animals/invertebrates/earthworm/?source=A-to-Z

Anatomy and Physiology: Review of Semester

What was your favorite topic this semester? Why?
My favorite topic this semester was the immune system because I find the process of how the human body is able to fight off and prevent us from getting sick very amazing.

What was your least favorite?
My least favorite topic was the urinary system because I had learned much of the information beforehand and was not as interesting to me.

What would you change about this class if you could?
I would like a whole list of assignments and due dates at the beginning of the semester so that I would know exactly how the semester would look like.

What do you feel is your biggest accomplishment in biology this year?
I feel that my biggest accomplishment in biology this year is being able to appreciate how everything in the body is complicated yet it works out just in the right way to support life.

AP Bio: Genome Blog 10, Chromosome 11: Personality

In "Chromosome 11: Personality," Ridley begins the twelfth chapter of Genome by quoting Heraclitus, who says, "A man's character is his fate" (161).  Afterward, he begins talking about a gene on chromosome 11 called D4DR.  He explains that "a 'long' D4DR gene implies a low responsiveness to dopamine in certain parts of the brain, whereas a 'short' D4DR gene implies a high responsiveness" (163).  In an experiment, he found that people with the long gene were more novelty-seeking than people with short genes.  For example, long-gened people had more sexual partners than short-gened people.  Ridley mentions that dopamine and norepinephrine are monoamines, as is serotonin.  He describes serotonin as another "chemical manifestation of personality" (167) and that it is "the brain's punishment chemical" (168) because it "abets...anxiety and depression" (168).  However, Ridley ends the chapter on a note that "social influences upon behaviours work through the switching on and off of genes" (172).

AP Bio: Genome Blog 9, Chromosome 10: Stress

In "Chromosome 10: Stress," the eleventh chapter of Genome, Ridley writes about a gene on chromosome 10 called CYP17.  It is used to produce a hormone called cortisol, which Ridley claims is "virtually synonymous" (149) with stress.  Ridley determines that "stress is caused by the outside world" (149) and "prepare[s] the body for 'fight or flight' in an emergency" (149).  He then goes on to say that people tend to get sick after an exam (when they're stressed out).  At the end of the chapter, he says that scientists are trying to find a good explanation for the link between stress and the immune system - "that stress inevitably depresses the immune system" (160).  There are two explanations, one that says that "it is all a mistake" (159) and was purely accidental while the other one says that "modern life produces prolonged and unnatural stresses" (159).  Whatever the true explanation is, this is an issue that still baffles scientists today.

AP Bio: Genome Blog 8, Chromosome 9: Disease

In "Chromosome 9: Disease," Ridley begins the tenth chapter of Genome with a discussion of the ABO blood groups, including which blood group could donate to the other blood groups. He goes on to explain why a blood group only donates to certain other blood groups: When a blood group (O blood group) "lack[s] just one letter fairly early in the message, the whole subsequent message says something completely different.  A different protein is made with different properties.  The chemical reaction is not catalysed (139).  Also, people with a certain blood type can be more susceptible to one disease, but more resistant to another disease. For example, the A gene gives better cholera resistance but the B gene gives better resistance to malaria.  Ridley ends the chapter by reminding the readers that "nobody can say that the blood group A is 'normal' adn O, B and AB are 'abnormal' (141) because "variation is an inherent and integral part of the human - or indeed any - genome" (141).

AP Bio: Genome Blog 7, Chromosome 8: Self-Interest

In "Chromosome 8: Self-Interest," Ridley begins the ninth chapter of Genome by quoting Richard Dawkins' The Selfish Gene, which says, "We are survival machines - robot vehicles blindly programmed to preserve the selfish molecules known as genes.  This is a truth that still fills me with astonishment" (122).  Ridley goes on to explain that 97% of the human genome are not true genes but are junk or selfish DNA, which is "not just a passenger, whose presence adds to the size of the genome and therefore to the energy cost of copying the genome" (128).  Also, selfish DNA threatens "the integrity of genes" (128) through mutation.  Ridley ends the chapter with an account of the Pitchfork case - where two identical samples of semen from the bodies of two girls who had been raped and killed helped to find and convict the murderer, proving the value of genetic fingerprinting.

AP Bio: Genome Blog 6, Chromosome 7: Instinct

In "Chromosome 7: Instinct," Ridley begins the seventh chapter of Genome by saying that there is a gene on chromosome 7 that "pays an important part in equipping human beings with an instinct...that lies at the heart of all human culture" (91).  He goes on to explain that instinct is a word used to describe animals whereas humans don't rely on instinct and that "everything they do is the product of free will, giant brains and brainwashing parents" (91).  Ridley establishes that although society thinks that "to believe in innate human behaviour, is to fall into the trap of determinism, and to condemn individual people to a heartless fate written in their genes before they were born" (91-92), practically everything is determined by genes, including language.  Ridley argues that there is "a set of innate mental rules" (95) in a child that allows the sentences of a four-year-old to be organized in a logical way.  Also, Ridley goes on to conclude that the instinct for language is an evolutionary adaptation for "clear and sophisticated communication between individuals" (104).

Anatomy and Physiology: Sense Challenges

Anatomy and Physiology: Action Potential vs. Cardiac Potential

Anatomy and Physiology: Different Pathogens

A cholera bacterium.

Bacteria

Bacteria can adapt very well to environment that change constantly because they have short generation spans.  During these short generation spans, they can undergo genetic recombination.  This way, so when they reproduce through various ways such as transformation, transduction, and conjugation, the new DNA will replicate along with their own original DNA.  These new, foreign DNA are expressed in the new strains of transformed bacteria.  This also lets each bacterium adapt their metabolic processes with the changes of their environment.

The structure of the HIV virus.

Virus

Unlike bacteria, virus are not actually alive because they cannot survive outside a host.  They are basically just genes in a protective coat.  The parts of a virus includes its capsid, protein coat, viral envelope, and nucleic acid.  Bacteriophages are the group of viruses that can infect bacteria.  They reproduce through the lytic and lysogenic cycles.  In the lytic cycle, they attack the host cell and when the cell bursts, the new viruses move on to destroy other host cells.  In the lysogenic cycle, the virus may lie in wait in the host cell for a long time before the lytic cycle is activated and it destroys the host cell.

The structure of a prion.

Prion

Prions are simple infectious agents.  They are protein that is misfolded but have no genetic material.  Although they are proteins, they can reproduce on their own and become infectious agents.  In humans, they may have been linked with the Creutzfeldt-Jakob Disease (CJD) and the Gerstmann-Straussler-Scheinker Syndrome.

Symptoms of hemophilia, a genetic disorder

Genetic


Genetic diseases are caused by an abnormality in person's genome.  This could result from a small mutation (ex: single base in DNA of a single gene) to a large mutation (ex: addition or deletion of entire chromosome).  Some genetic disorders are inherited from the parents but some are also caused by acquired changes and mutations in the genes.  An example of a genetic disease is hemophilia, which is sex-linked.

Lung infected with black lung disease.

Environmental


Environmental diseases are caused by factors in the environments, such as pesticides, chemicals, radiation, and pollution.The chance of a person developing a environmental disease depends on the dangers of their environment and their genetic susceptibility to certain dangers.  For example, coal miners are more susceptible to black lung due to the inhalation of dust.  Proper safeguard can prevent environmental disease.

Rash caused by Lyme disease.

Invertebrates


Some diseases are caused by invertebrates.  Many invertebrates carry diseases; for example, mosquitoes often carry and spread yellow fever and malaria.  Some of these disease-causing invertebrates are parasitic.  One example are ticks, which can cause Lyme disease.

Sources:
http://www.trupela.com/wp-content/uploads/2009/09/cholera-bacteria.jpg
http://www.scientificamerican.com/media/inline/F1C30FB9-F95F-8B4E-9FAF03A0503D1ABA_1.jpg
http://www.flickr.com/photos/ajc1/464066753/
http://www.doctortipster.com/wp-content/uploads/2011/11/Hemophilia-Symptoms.jpg
http://images.paraorkut.com/img/health/images/b/black_lung-580.jpg
http://images.paraorkut.com/img/health/images/l/lyme_disease_rash-55.jpg
http://www.medicinenet.com/genetic_disease/article.htm
http://www.humanillnesses.com/original/E-Ga/Environmental-Diseases.html#b

Anatomy and Physiology: Disease Awareness

During class, I have become more aware of salmonella.  Before taking this class, I did not exactly know what salmonella is.  Salmonella are bacteria that can cause food poisoning.  It can also cause diarrhea and typhoid fever.  Salmonella infections are most commonly caused by contaminated food.  After learning this, I started to eat less medium-rare cooked meat and more well-cooked meat.  By cooking meat for a longer time, it kills off more of the bacteria and contaminants in the meat and greatly reduces the chances of being infected with salmonella.

Anatomy and Physiology: The Humoral and Cell Mediated Immune Responses

Humoral (Antibody-Mediated) Immune Response


When there is a first exposure to an antigen, these free antigens activates B cells.  The lymphocyte "switches on" and undergoes clonal selection, which is when the lymphocyte grow and multiplies rapidly to form many identical cells called clones.  This clone formation is the primary humoral response.  Most of the B cell clone members become plasma cells, which produce the same highly specific antibodies.  The plasma cells die off after 4-5 days and the antibody level in the blood goes down.  There are some B cell clone members that don't become plasma cells but instead, become memory cells that can respond to the same antigen later.  As a result, in later immune responses or secondary humoral responses, the response to the presence of the antigen is more faster, prolonged, and effective.


Cellular (Cell-Mediated) Immune Response


In the cellular immune response, T cells are sensitized by binding to an antigen and a self-protein on the macrophage surface.  After clonal selection, clone members differentiate into memory T cells and effector T cells.  There are several different classes of T cells: cytotoxic (killer) T cells, helper T cells, memory T cells, and suppressor T cells.


Cytotoxic (killer) T cells: directly attack and kill infected and cancerous cells


Helper T cells: binds with specific antigen presented by a macrophage; stimulates production of other immune cells (cytotoxic T cells and B cells); acts directly and indirectly by releasing lymphokines


Memory T cells: descendant of a T cell; forms during initial immune response (primary response); may exist in the body for years to allow it to respond more quickly to later infections by the same antigens


Suppressor T cells: slows or stops activity of B and T cells when the infection or attack has been conquered




Sources:
Elaine N. Marieb's Essentials of Human Anatomy and Physiology, Eighth Edition

Anatomy and Physiology: Rickets - A Nutritional Disease

X-ray of the legs of a two-year old ricket sufferer.  Notice that the legs are bowed.

Cause


Rickets is a nutritional disease that is caused by a deficiency in vitamin D, calcium, or phosphate, leading to the softening or weakening of bones.  It is more common among children.


Symptoms


Symptoms of rickets include bone tenderness or pain, especially in the arms, legs, pelvis, and spine; impaired growth; increased bone fractures, muscle cramps; dental deformities, such as delayed formation of teeth, increased cavities, or holes in the enamel; skeletal deformities, such as an oddly shaped skull, bowlegs, bumps in the ribcage, or scoliosis; and short stature, when the adults are less than five feet tall.


Treatment


In order to eliminate the cause of the disease, the vitamin D, calcium, or phosphorus that is lacking is replaced.  This is usually done with a change in diet so that sources of vitamin D, such as liver, fish, or milk, are included in the diet.  Exposure to moderate amounts of sunlight is also needed.  In some cases in which rickets is caused by a metabolic problem, vitamin D supplements may be prescribed.  Position or bracing may be needed to reduce deformities.  For some skeletal deformities, corrective surgery may be necessary.


Sources:

information from: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001384/

picture from: http://en.wikipedia.org/wiki/Rickets

Anatomy and Physiology: Different Thinkers and the Nervous System

Part 1: Different Thinkers
The test that I did showed that I am a music thinker. When I study, it is probably better to study to music in the background to help me remember the information I studied.  I sometimes also put the information I am studying into a tune of a song to remember it better, (especially when it is with numbers).  By appealing to my musical ability/intelligence, it will make it easier for me to study.  For potential careers, I can possibly be a composer, musician, or sound engineer.


Part 2: The Nervous System
In this game, I learned that nerve impulses can travel from the cranial and cervical regions, or the spinal cord (which is made of the thoracic, lumbar, and sacral regions.)  Below are examples of parts of the body that are wired to each of these different regions:
cranial: liver
cervical: hand, diaphargm
thoracic region of spinal cord: rectus abdominis ("six-pack"), armpit
lumbar region of spinal cord: foot
sacral region of spinal cord: gluteus maximus (muscle that allows the leg to straighten out)

Sources:

part 1: http://www.bbc.co.uk/science/leonardo/thinker_quiz/

part 2: http://www.bbc.co.uk/science/humanbody/body/index_interactivebody.shtml

Anatomy and Physiology: A Disease of the Senses

Macular degneration is the degeneration of the macula, which is responsible for sharp, central vision.  It is often caused by aging and is usually genetic.  When it is age-related, it usually results in a slow but painless loss of vision.  Symptoms include shadowy areas in central vision or fuzzy and distorted objects in your vision.


A macular degeneration test can diagnose whether you have the disease.  This is done by looking at the Amsler grid, a chart of black lines organized in a graph pattern.  To a person with normal vision, the Amsler grid will look like this:

However, to a person with macular degeneration, the Amsler grid might look something like this:

There are two forms of age-related macular degeneration, the dry form and the wet form. No definite treatment or cure has been found for the dry form, but it can be prevented by consuming antioxidants, especially zinc and vitamins A, C, and E, selenium, and copper.  For the wet form, laser treatment can be used to stop or lessen vision loss by destroying some blood vessels to prevent the spread of vision loss.  However, laser treatment only works in about half of the cases.

Sources:

Amsler grid pictures from: http://en.wikipedia.org/wiki/Amsler_grid

information from: http://www.emedicinehealth.com/macular_degeneration/page2_em.htm#Macular Degeneration Causes
http://www.emedicinehealth.com/macular_degeneration/page3_em.htm#Macular Degeneration Symptoms
http://www.emedicinehealth.com/macular_degeneration/page7_em.htm#Macular Degeneration Treatment
http://www.emedicinehealth.com/macular_degeneration/page8_em.htm#Medical Treatment

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

Anatomy and Physiology: Control Systems

The human body has two control systems: the nervous system and the endocrine system.  The nervous system is faster and more complicated.  It sends electrochemical signals which stimulate immediate responses.  When electrochemical signals is being transferred, it goes down the axon of a nerve cell and is transmitted across the synapse (gap between nerve cells) to the next neuron.

The endocrine system works more slowly.  Hormones are released into the bloodstream, which then transports them to their target cells.  The hormones then act on their target cells to regulate their activity.  Unlike the nervous system, which causes a fast, specific response, the one hormone can affect the activity of many cells at the same time.


It is important for the body to have these two control systems because the nervous system is responsible mainly for rapid, immediate movement, such as skeletal muscle movement while the endocrine system is responsible for regulating a lot of the metabolic processes in the body, including cellular respiration.


Sources:
neuron picture from:
http://science.howstuffworks.com/environmental/life/human-biology/brain1.htm
endocrine system picture from: 
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_mckinley/endocrine%20system.htm
information from:
Elaine N. Marieb's Essentials of Human Anatomy & Physiology, Eighth Edition
https://docs.google.com/viewer?a=v&q=cache:pLygcenOGmsJ:www.angelo.edu/faculty/cadkins/Chp%252011%2520Control%2520Systems%2520of%2520the%2520Body.doc+control+systems+of+the+body&hl=en&gl=us&pid=bl&srcid=ADGEESjnS4rDPRFota_fUK0IVxBfnxaAhxkM67A8zn6hQAvTQanM0JGUS7BZEL72iuxRJ_lkw3cu_lRywmMN0KsoW6dzgfzoiDdKUPzh_6IRXLs7uMUZOfpm0lNiQKajteuzrfxf4jJ4&sig=AHIEtbRkIj6WxLjs0RmupHze3J-lSe08vQ&pli=1