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