Surivival of the Sickest

Today, we reviewed topics learned from reading "Survival of the Sickest " by Dr. Sharon Moalem.

Specifically we focused on how specific traits of organisms allow them to be more likely to survive or more likely to die. For example fruits that produce a poison when eaten are more likely to survive and reproduce than one that tastes pleasant. As shown in Fava Beans some traits that produce unfavorable reactions at the time can also be favorable in another area. Fava Beans can cause anemia, but they also help fight malaria.

Evidence for Evolution Quiz

1) Evolution occurs through small changes in a population over a long period of time. Thus organisms of different kinds can by traced to a common ancestor. For example, modern whales can be traced back to their common ancestor, the Mesonychid. Over time, the Mesonychid went through a series of gradual changes. It is closely related to the Ambulocetus, which is closely related to Rodhocetus, which is most closely related to the modern whale.

2) Marsupials originated in North America.

3) Dragonflies, birds, and bats are examples of convergent evolution, because all these are parts of different species that evolved to have some of the same characteristics because of their environment: air.

4) In the Common Descent Lab, we showed how similarities in DNA are evidence for evolution.  For example, from the hemoglobin strands we showed that gorillas are most closely related to chimpanzees, which are closely related to humans. We also found that all these share a common ancestor.  It is important to note that humans did not directly evolve from chimpanzees, they just share a common ancestor.

5) Homology refers to similarities between structures due to common ancestry. For example, the common structure for limbs is 1 bone --> 2 bones --> blob of bones --> fingers/toes.

Evidence for Evolution: LABS

Today we not only reviewed information that provides "evidence for evolution," but we also did labs that supported evolution. First, here's a list of all the topics we reviewed:

In the lab, we modeled hemoglobin strands from humans, chimpanzees, gorillas, and their common ancestor. We then analyzed them to see how much each one differed from the others. Here are our hemoglobin strands and the resulting cladogram we made form our data.

Intro to Evolution

Fun fact: My favorite scientist is Charles Darwin. I've read many books about him...not just his scientific theories, but also about his life. -- So naturally when I found out the next unit was about evolution, I became majorly excited (that's an understatement).

For homework, we read chapters 1, 2, and 11 of Your Inner Fish by Neil Shubin. These chapters talked about fossils and how they are formed, homology, and provided basic information and theories about evolution. It was interesting to read a book by Neil Shubin, because he found the fossil for the Tiktaalik (the transition fossil between water and land organisms) and I studied about the Tiktaalik last year in Honors Paleo.  Here's a picture of the Tiktaalik model in our very own Raymond M. Alf Museum of Paleontology:

As you can see, it has a flat head and wrist-like structures of an amphibian, but fins and scales like that of a fish.

Test Day!!!!

Me before the test:

Me after the test:

REVIEW DAY!!

Today in bio, we reviewed BIOCHEMISTRY!!  Here's a list of everything we covered:

After a reviewing of all of this, we studied for about 5 minutes with our partners, and then took a formative biochem quiz.











That pretty much took up the entire class period, but then my partner and I stayed after class to finish our Macromole "mystery compound" lab. My biology website will go up tomorrow with our results from the entire lab, but for now here are a couple pictures:

I'll give you a hint: the results have something to do with Mexican food..... hmmmmm....

Now it's time to put all of my lab results together and S.T.U.D.Y!!

Day 7: Organic Compound Mystery??!!

Today, we began my discussing the topics we took notes on for homework - mainly carbohydrates, monosaccharides, disaccharides, and polysaccharides.
 Then we were able to chose between two different labs, and I chose the "Who took Jerell's iPod? --An Organic Compound Mystery." First, we tests for the presence of glucose, starch, and lipids in vegetable oil, glucose, starch from corn/potatoes, powdered egg whites, and water.

Then, we tested for the presence of glucose, starch, and lipids in pretzels, butter, jelly, fat-free yogurt, and the dry and liquid part of Jerell's evidence.

We have not finished the lab yet, so I'll post the results and conclusion in a later blog post, but for now here are some pictures!

Day 6: Lab review and House Case introduction

In this class, we began with a quiz that asked review questions from our previous Osmosis/Diffusion lab and how to graph the data to find molarity.

We began discussing our first "House Case."  In this case, a 18 year old senior who runs cross country begins to feel a headache after practice. He feels tired, confused, and starts vomiting.  After further questioning, we further determined that he had chicken for lunch and had two glasses of water with lunch. He didn't take any medicine and only ran for about 7 miles. However, while he was running cross country, it was 104 degrees F outside, humid, and he drank 3 gallons of water while running.

These are results of his medical tests:

Most of the class thought that the diagnosis was overhydration, because of the abnormally high amount of water that the senior drank while running. However, this isn't correct, so I will have to further analyze the test results to solve this mystery..........

Day 5: Finishing Difussion/Osmosis Lab

On day 5, we finished up the final parts of he diffusion/osmosis lab. But first, we reviewed general graphing skills and how to apply those to find molarity.

For Part 1 of the lab, we recorded the original volume and surface area of a "cell" (we used agar). We cut two sets of small cubes, middle-size cubes, and large cubes. Then, we added KI to some and NaOH to the rest. After letting them sit for about 15 min, we again calculated the volume and surface area. The purpose of his experiment was to observe the time rate of diffusion of different substances and how it is affected by volume and surface. Here are the results:

For Part 2 of the lab, we tested how glucose and starch would diffuse through a semipermeable membrane.  Here was my group's hypothesis:

We filled a diffusion tube with a solution of glucose and starch and tested for glucose with a test strip. We placed the tube in boiling water, and after we let it set, we took a pipette full of the water and add it to a test tube. We then added a benedict solution (to test for glucose) and put it back in the boiling water. The solution in the tube turned orange, which indicates that there was glucose in the solution. Then we added iodine to the water and the solution inside the cell turned dark blue/purple which means that the starch diffused into the cell  From this we can see that our hypothesis was supported, because only the glucose molecule diffused through the cell into the beaker because it is a smaller molecule than the starch.

Day 4: Diffusion and Osmosis Lab

We started the class by taking a short, easy quiz on the properties of water that we had previously discussed.

We then reviewed the information about diffusion, osmosis, and the lab that we had learned from our homework.

Then, we started work on our lab.

First, we used diffusion membrane to form "cells" with 6 different types of liquid in them. We massed each cell, placed water over each one, and then let them set for 30 minutes. Finally, we massed each cell and calculated the % mass change to see how much water had diffused into the cell.  From this information, we were then able to calculate the molarity of each solution.

Next, my section of the group did section #3 of the lab, in which we tried to determine the molarity of a sweet potato. We first massed pieces of potatoes and put 4 pieces each in 6 cups. We covered the potatoes in each cup with water and let them sit (covered to prevent evaporation) for around 9-10 hours. We once again massed the potatoes and calculated the % mass change  and used the information from the first section determine the molarity of the potatoes.