From Atoms to Traits Q & A

1. Mendel conducted a breeding experiment with peas in 1850's and 1860's. The peas had obvious morphological differences and when the breeding of two plants crossed, their offspring resembled one of the two parents. Both traits would reappear in further generations. Mendel's experiments changed the general perception of that time that heritable variants from ephemeral and blendable to discreet entities passed from parents to offspring, present even though they are not always visible. Mendels findings were soon seen in the behavior of chromosomes in the cell nucleus.

2. James D Watson and Francis Crick had proposed a structure for the DNA molecule in 1953, that helped us understand hereditary and variation physically. It helped us sequence various organisms and their offspring, and look for any spontaneous changes in the long chain of DNA letters passed down from generation to generation.

3. Point mutation, insertion, gene copy number, duplication and regulatory changes are all examples of variations that occur to DNA. 

Point mutation: Or single base substation, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA. This also includes insertions or deletions of a single based pair. For example in whipped dogs, a single based pair change makes the difference between a slender silhouette and a hulking animal. The mutation inactivates the gene for a signaling molecule that regulates muscle growth is uncontrolled because there is no "stop" signal. 

Insertion: Is the addition of one or more nucleotide base pairs into a DNA sequence. For example, in pea plants, an 800 base pair sequence inserted into a gene produces wrinkled peas instead of smoothed ones. The intruding DNA element disables a gene necessary for starch synthesis, altering the peas sugar and water content. 

Gene Copy Number: Entire genes can be duplicated by copying errors during cell division, leading to differences between species and variation among the individuals of the same species. For example, the genome of chimpanzees, which have a diet consisting of mostly green plants, normally contains just a single gene for the starch-digesting enzyme salivary amylase, where as humans can carry up to 10 copies of that gene. 

Duplication: Sequences containing the same based pair copied and repeated eight or more times, known as homopolymers, are highly prone to copying errors. For example, in pigs, the gain of two additional C-G pairs in such as sequence inactivates a gene for a signal receptor in pigment cells, producing light colored coats. Copying mistakes in the individual cells can also cause the lose of bases which restores the gene's function and causes dark colored spots in the coats. 

Regulatory Changes: Mutations in the DNA that controls when and where genes are activated can produce profound trait changes by altering the formation of body parts during the development of the organism. For example, the shape difference between the bushy teosinte plant and its descendant the modern cornstalk are different because of the change in the regulatory regions of a single gene that controls patterns of cell division during stem development. 

4. Evo-devo is a subspecialty within evolutionary biology that concentrates on studying the effects of changes in important developmental genes and the role they play in evolution. It adresses the origin and evolution of embryonic development; how modifications of development and developmental processes lead to the production of novel features, such as feathers; the role of developmental plasticity in evolution; how ecology impacts development and evolutionary change; and the developmental basis of homology. 

5. In the case of some dietary adaptations, the changes enabled entire populations to migrate and take up new ways of life, such as herding and agriculture. An example of such as trait, the ability to digest milk into adulthood, is found to have risen independently in groups on different continents, attesting to the great nutritional advantage the variant provides and to the possibility of directly connecting simple DNA sequence changes to human cultural evolution. Lactose intolerant people cannot digest complex milk sugar lactose because of the lack of lactase produced. Its retention in milk dependent societies also illustrates how culture can reinforce the forces of evolution. 

Class 18

      Today we finished the movie "Journey of Man" and our worksheets. We learned about the importance of the Y chromosome as it is the best place to look for a genetic marker because it does not get recorded every time like the X chromosome, instead it gets passed down unchanged through generations. The narrator goes to an isolated village with indigenous people that have not had outside encounters so he could find the genetic marker. We learned that Africa had a drought were animals and resources were scarce so they migrated. The environment of different places changed the human race to either be lighter or darker complected. We learned that the first Americans arrived on the continent 13,000 to 11,000 years ago.  

Class 17

Today in class we watched "The Journey of Man," a documentary film about the evolution of the human species. We were given a worksheet of questions that we would answer while watching the film. I learned that we can trace back in history and find information from the past by examining blood and DNA samples of different people. I learned that 50,000 years ago our ancestors were still living in Africa. The Sanbushmen is the tribe of the first ancestors of mankind. I observed many different races in just one of their faces, from European to African to Asian features. A genetic marker is a mutation that occurs through generations of offspring. The Sanbushmen were very advance thinkers using bone as spears instead of stone and creating a language of their own. We learned about the routes that people took out of Africa such as the route to Austraila.

Test 2

Today in class we took our unit 2 test about evolution and the evidences for evolution. I first wrote an essay on population genetics and comparative anatomy and embryology to support the theory of evolution. I wrote about Darwins theories, his work and contribution to evolution. I explained overpopulation and effects of mutation. I also gave examples of population genetics and adaptive radiation. I compared homologous structures and explained their link to a common ancestor. Then we did 30 multiple choice and a few extra credit questions. We were free to leave once we finished the test.

Does Race Exist

Does Race Exist?

     People differentiate themselves based on their physical characteristics, traits and most importantly, their "race." What makes an individual a member of a particular race differs from region to region. Humans originated in Africa and then migrated over a vast period of time to all parts of the world. They learned to adapt to their different environmental changes and go through "survival of the fittest." These facial features and traits are influenced by natural selection and divide people into "races."Studies have shown that 90 percent of human genetic variation occurs within a population living on a given continent than whereas 10 percent of human variation distinguishes continental populations. Individuals from different populations, on average, are slightly more different from one another than individuals from the same population. Two groups that are genetically similar to each other might be exposed to different selective forces in their environments. Natural selection can define some of the differences between groups, making it easier to see the physical differences and harder to see the genetic similarities. In the "Journey of a Man" video, we were shown the tribe in Africa of the first ancestors of mankind called the Sanbushmen. Each individual face had physical characteristics that are seen in different areas of the world today. They had eyes and rounded foreheads of an Asian or Pacific Islander, lips and noses of an African or African American, and pointed chins and ears of a European. We could already see from the faces of the Sanbushmen that humans originated in Africa, having identical similarities, but through adaptation and mutation, have been modified.
     Genetic analysis can distinguish groups of people according to their geographic origin to a certain extent. Geneticists rely on polymorphisms in human's DNA to determine the degree of relatedness among groups. A study was done examining 100 different Alu polymorphisms in each of the 565 people born in sub-Saharan Africa, Europe and Asia. They sorted the people into groups only based on their genetic information, removing the identifying labels of origin. Once they placed the labels to the person accordingly, they realized that the groups correlated with origin and ethnicity, having one group of Europeans, one group of Asians and one group of Africans. The results of this study indicate that genetic analyses can distinguish groups according to their geographic origin. Populations have adapted to survive in their environment. They have also passed down mutations to their offspring which altered parts of their DNA. These different mutations alter health by preventing some diseases or influencing them. Several polymorphisms that differ in frequency from group to group affect health. Genetic variation plays a major role in individual susceptibility in diseases such as influencing AIDS because of the polymorphisms in CCR5 receptor gene found mostly in northeastern Europeans that increases HIV-1 infection leading to AIDS. Polymorphisms in genes might have an affect on one group and a different affect on another. Scientists can group individuals according to their probable ancestry by looking at their DNA and "genetic marker." Membership in geographically or culturally defined group can be correlated with health related genetic traits.  

class 16

   Today in class we learned about population genetics and evolution, the Hardy-Weinburg law of genetic equilibrium and the relationship between evolution and changes in allele frequency by using the class to represent a sample population. There are five conditions that have to be met in order for the populations allele and genotype frequencies will remain constant from generation to generation. These conditions are:
   1. The breeding population is large
   2. Mating is random
   3. There is no mutation of the alleles

   4. No differential migration occurs
   5. There is no selection

   We then tested allele frequencies for a specific trait within the population (class). We had to put PTC taste test papers in our mouths for 15 seconds and see if we tasted chemical or not. We recorded the number of people who tasted and did not taste and determined the frequencies of the two alleles using the Hardy Weinburg equation. We then did case studies where we are given 4 cards, two dominant and 2 recessive. We would then find a partner and then choose a card from them without looking at the card. We did this 5 times, each with a new person. Then we did Case IV about genetic drift where a river split the population so we had to trade cards 5 times to create 5 offspring babies with different traits. With this information we used the Hardy equation to find the frequencies. Then we took a quiz on Hardy Weinburg equations.

Class 14

 

   Today was parents day!!! We came into class and recorded data for the brine shrimp after 48 hours of being in the solutions. We wrote down our data of which ones survived and which ones died.

   We learned about Natural Selection in humans. We did an activity about femininity and masculinity attributes to a person that makes them more attractive to a male or female. We were shown 2 of the same face that had different features and had to circle the one that was more attractive. We were shown ten female faces and ten male faces, finding out that one of the faces was feminine and the other masculine. Both the parents and students were shocked that men and women find feminine faces much more attractive on both a male and female. My results were that I thought feminine features in girls and guys were more attractive than masculine faces. I learned that i like feminine faces in men because i feel like the man is loving, compassionate, caring and can protect me while I think feminine faces in girls are more attractive and try to compete with her because men like feminine faces. Studies show that the only time that a girl would usually find a feminine face more attractive is when she is ovulating.

Class 15

Today in class we discussed the brine shrimp lab and constructed graphs. We graphed the classes results to see which solution is the Brine Shrimp mostly adapted to. We determined the ideal salt concentration for brine shrimp survival was 0.5 from our data and graph.

We then moved on to an activity that shows how recessive traits lessen while dominant traits increase. We had 50 beads, 25 red and 25 green. These beads represented tigers with no hair and tigers with hair. My partner and I decided that the green ones were the tigers with hair and the red ones were the tigers without hair. We put all beads in a bag and shook it. Without looking we picked out two beads at a time. If it was green, green we put it in the HH container because it is dominant, if it was red red we would put it in the hh container because it is a recessive trait and if it was both we would put it in the Hh container. The ones that were recessive would die. We did this 10 times and recorded how many were in each container. There would always be one red bead present. We also talked about how migration played a role in populations, for example recessive traits such as the tigers with no hair can migrate into an area and then reproduce other tigers with no hair.

Class 13

   Today we started an exercise involving characteristic of sea shells. We separated the shells based on structure and size. We discussed their different traits and what kind of environments did they live in. We observed that some seashells had tiny little holes in them and tried to come up with a reason why. Mr Quick told us that these shells were once eaten by special types of shells that eat other shells by using a drill like mechanism on their tongue to poison its prey.

    We then started on the Brine Shrimp Lab in class. We put different concentrations of salt in five petri dishes (0, 0.5, 1, 1.5, 2). Then we put twenty to thirty eggs on half a cm of tape. We counted the eggs of each dish. We put the tape on a slide and placed it in the dishes. We would have to weight 24 hours to collect data for which ones survived and which ones did not.  

Class 12

    Today in class we took a quiz on constants, independent and dependent variables. I understood that the independent variable is the one changed on purpose and the dependent is the one changed because of the independent variable. I got a 1 on the quiz. We also went over our reading in Survival of the Sickest about fava beans, G6PD deficiency, malaria and defensive mechanisms in plants. Many people have G6PD, which is a hereditary abnormality in the activity of an erythocryte (red blood cell) enzyme. This enzyme is essential for assuring a normal life span for red blood cells, and for oxidizing processes.  This enzyme may be provoke the sudden destruction of blood cells and lead to hemolytic anemia with jaundice following the intake of fava beans. 

Then we started to work on our paleontology projects in class with our partners. My partner and I chose to create a transitional fossil between a mosasaur and a eupodophis. We worked on our outline of the project and left early for lunch. 

Evidence for Evolution Quiz

1. The picture shows evidence for evolution because it shows the transition from a land animal to a water animal. The land animal most likely had a change in environment living near water and adapted while giving offspring that transitioned to live in that atmosphere. The picture shows transitional fossils that have traits of a land and water animal. It is an incomplete fossil record, but gives evidence that things such as animals evolve through time.

2. E. North America

3. Dragonflies, birds and bats are all examples of evolution. They all have analogous functions, but they differ in appearance and structure because they all have different ancestor genes.

4. The Common Descent lab shows DNA evidence and ancestry as evidence for evolution. There is a common ancestor that branches to other organisms that are related but all are derived from the common ancestor. We compare DNA strands of apes, gorillas, humans, and chimpanzees to see which ones are closest in DNA. We realized the gorilla was closest related to the common ancestor and humans were closest related to chimpanzees. We drew a cladogram that showed the relationship of the organisms that  are all derived from the common ancestor. We can see that through time organisms evolve from a common ancestor.

5. Homology is the similarities in the structures, DNA and genes of an organism that is derived from a common ancestor. The structures change to adapt to their environment such as birds and bats (very similar organisms). A bird and a bat both have similar functions but their structure in their wings are different. The digits at the end of a bird wing are closer together while a bat wing's digits are far apart and separated. They have adapted to a different environment and evolved through time.

Class 11

     Today in class we had a choice between two worksheets about evolution. My partner and I chose the worksheet on "Investigating Common Descent with Molecular Biology using DNA Comparison." We were given four different colors of beads (red, white, green and blue). We compared the DNA of a common ancestor, chimpanzees, gorillas and humans. First we made hypothesis on how these organisms are related like how they have four limbs, give live birth, and have similar bone structures and hair. We made the DNA of the organisms by connecting the beads on strands in the proper sequence given. then we compared the DNA with the mammals and wrote the number of matched and unmatched bases. We then sketched a cladogram and realized the gorilla is mostly related to the common ancestor.

                            Top to bottom: Human, Chimpanzee, Gorilla, Common Ancestor

Class 10

We started Unit 2 on the theory of evolution. We discussed the evidences for evolution the earths shift through time and live in the different eras. We watched videos about the plates of the earth that moved the land through time until it formed what we have today. We learned about how fossils are formed and the rock layers that make a well preserved fossil. We also discussed transitional fossils that played a major role in the evidence for evolution. Transitional fossils are fossils found that are between two different species such as the eupodophis which is a transitional fossil between a monitor lizard and a snake. We looked at a particular transitional fossil called the Tiktaalik at the Webb Schools museum. The Tiktaalik displays a transition between a fish and a land animal. The changes in its bone structure, ribs, legs, arms eyes and tail shows the adaptation to land and water, It had a bone structure in its limbs close to a humans and had a push up motion to move through obstacles in mud and water. It lived in shallow waters and its eyes shifted to the top of its head to see in and out of the water. Its ribs are expanded so it could lay on land or move through obstacles in water. Its diet consisted of bugs and small fish as it could find food in and out of the water.

Class 9 - test day

Today in class we took the Unit 1 test. First we had to analyze data and make a graph for two different types of potatoes testing the molarity of sucrose and percent change in mass of potatoes. There was lower solute in Russet potato then sweet potato. We had to explain osmosis and diffusion in the potatoes on the graph. Then we had to answer multiple choice questions on basic chemistry, macromolecules, molecule structures, water properties and much more. We also had to answer free response on the cell membrane. After finishing the test we turned it in and were free to leave.

Class 8

     Today in class we had a review on important topics that will be in the test. We went over water and its properties discussing adhesion, cohesion, hydrogen bonds and surface tension.



We also went over basic chemistry and learned how to find the valence electrons of an element without looking at the periodic table for guidance. Using the atomic number, you find the valence electrons keeping note that there are two valence electrons in the first shell and eight after that(electron configuration - two eight rule). Then we went over macromolecules, their structures and properties. We discussed polymers, monosachrides, disacharides, polysacharides, amino acids, proteins, dehydration synthesis and polypeptides.


We also went over DNA and RNA differences. RNA is one stranded and forms protein from DNA. DNA lacks oxygen.

Class 7

   In class today we learned about lipids (proteins and fats) and carbohydrates (glucose). we also learned about condensation, hydration and dehydration. We had a choice between two different labs covering similar topics. My partner and I chose "Who took Jarell's iPod" lab. In this lab we had to test different food items to see who took Jarells Ipod. We first tested vegetable oil, starch and glucose from potatoes, powdered egg whites and water for starch, lipids, proteins and glucose. We then did similar testing but with pretzels, jelly, butter, fat free yogurt and beans to test for lipids, starch, proteins and glucose. After testing the foods, we chose a solid type of evidence and a liquid type of evidence to solve the mystery. We concluded that Kiara took Jarells iPod.

Class 6

   Today in class we discussed in depth the components, functions and parts of a cell(the semi permeable membrane). We learned about the phospholipid bilayer that only allows certain molecules to pass through. Proteins act as a "gate" that transport molecules through. There are different kinds of passing such as transport, enzymatic activity, signal transduction, and cell-cell recognition. There are Glycol proteins that are integral proteins which help with the cell membrane and cell-cell recognition. Cholesterol allows the membrane to be fluid. Water wants to reach the higher concentration so the concentration solute needs to be the same. Hydrophobic molecules can get across the bilayer but polar ones can't. We also talked about plant cells and their differences with human or animal cells. Plant cells contain rigid walls and do not burst as easily as animal cells. Mr. Quick explained the isotonic, hypertonic, and hypotonic variables in cells. We also talked about passive and active transport of molecules. Active uses energy (ATP energy) where as passive has channels and carriers. Size and polarity influence the transport in diffusion and osmosis.

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    Then we discussed the House Case #1 that was assigned to us for homework. The Case gave information on an 18 year old boy who is a cross country runner. one day after practice he started to have a severe headache followed by vomiting, fatigue and confusion. He was sent to the emergency room. We had to predict a possible diagnosis with the little information we had. I initially believed he had a heat stroke or dehydration. Mr Quick let the students ask questions about the boy so we could make an accurate diagnoses. We soon found out that the boy previously drank gallons of water before practice so he could not have dehydration.Then Mr. Quick gave us the test results of the boy when he was in the hospital. I found out that his sodium level was low so I concluded that it was overhydration. 

Class 5

              Today in class Mr. Quick went over and explained the diffusion and osmosis labs from last class as we drew graphs to better understand the lab. The potato is shown in the graph as hypertonic at first and the solution is hypotonic. When the line hits the x-axis, it is isotonic. Then the line shows that the potato becomes hypotonic and the solution becomes hypertonic, so the mass increased and the molarity in the solute decreased. We continued the osmosis and diffusion lab. We had permeable "cells"that contained starch and glucose. We predicted that the starch particles were too big to pass or enter the cell but that the glucose would pass through. We first added iodine to the solution and noticed the blue color  that showed an amount of starch. We put it in water for 15 minutes. When we heated the solution it turned an orange color showing that glucose had left the tubing. Then we cut up the cells into cubes, each a different size. We measured the size and volume of each cube before and after the experiment. We put them into the solution to see how much diffusion would occur and measure it. Then we put the semi permeable membrane "cell" into water with iodine in it to see if any starch would leave the cell. The cell turned black concluding that the starch had not left.

class 4

      In biology class, we discussed and observed diffusion and osmosis occurring in cells and water in an experiment. We learned that diffusion is the net movement of molecules down their concentration gradient while osmosis is the movement of water through a selectively permeable membrane from a region of its higher concentration to a region of its lower concentration. Molecules can move in both directions in and out of the membrane, as long as it is permeable to the molecule. Types of solution such as hypertonic, hypotonic, and isotonic have different affects to the membrane. A hypotonic solution has lower solute concentration, but hypertonic has higher solute concentration as water moves inside both the bag and beaker. On the other hand, isotonic solutions have equal solute concentrations. The class split into groups of four and started experimenting using "cell membranes", solute with different molarities, and water to find the molarity and any changes in the cells mass.We made six different cells filled with 7ml of solution, each with a different molarity, and measured them before we put each in a cup of water. Then after about 30 minutes we took the membrane out of the water, dried it and then massed it one more time to determine it's mass change and molarity. Our results for the molarities of the solutions were; Blue:0 Clear:0.2 Green:0.4 Yellow:0.6 Purple:0.8 Red:1.0
     Then we tested diffusion and osmosis with potatoes. First we skinned russet potato and then tested the amount of sugar the potato contained. We cut the potato into 24 pieces and put 6 in each cup filled with different solution. That night we recorded the change in size and mass of the potato to see if it got smaller or bigger.  The potatoes mass increased.

Class 3

      In Biology Class we learned about the properties of water and the way it reacts with other objects. We reviewed the properties of water, such as ability to moderate temperature, expansion upon freezing, versatility as a solvent and cohesive and adhesive behavior. For example, a water strider is able to walk or stride on water because of the hydrogen bonds and the surface tension that is created. Then we did a lab consisting of pennies, water and dishwater soap. I slowly count how many water drops (the dependent variable) I could put on the penny without it breaking.  Because of water's cohesive properties, the water is able to create a "bubble" affectThe class does it twice, but the third time we put a drop of dishwater soap in the water. The water spilled immediately after applying the soap. This experiment correlates with lab 1: milk and food coloring. The water in the milk reacted to the dishwater soap in lab 1. The lab shows that water molecules are attracted to other water molecules because of the charges of the oxygen(-) and hydrogen(+) charges that attract each other. The cohesion creates a surface tension in the water. Some substances can lower or change the surface tension (in this case the dishwater soap) of the water which makes it react and move.

Class 2

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              During class 2, we went over the layered assignments for unit 1 and the topics we would cover. There are A1 assignments that have the highest score of 1 and B2 assignments that have the highest score of 2 on the class rubric. We then looked at the different and required standards we would have to complete in each quarter. We were then given worksheets to complete about basic chemistry. We refreshed our brains with basic chemistry, learning the lewis dot structure and how to find the number of neutrons, protons and electrons in an element. We also relearned the number of valence electrons, the oxidation number and number of electrons to fill the outer shell of an element. We then took an oral quiz and soon after took a written quiz on basic chemistry.