Quiz for Evolution

Access the quiz at: https://docs.google.com/file/d/0B_nnOJLj_iJAaFVCUWxHelRvM1E/edit?usp=sharing

Question 1 Answer:

The whole picture shows the evolution of a species of whales.
Mesonychid: mammal that lived on land, with 4 limbs to move and search for food.
Ambulocetus: Evolved from Mesonychid. It has a flatter head with a slightly longer and more sharp-triangular mouth. Its limbs adapted to amphibian like arms and legs, allowing it to traverse both on land and water to search for food. A closer inspection also reveals that the Ambulocetus has eyes which are closer to the sides of its head, this allowed the species to have better vision in water.
Rodhocetus: Evolved from Ambulocetus. The most significant change was the whole structure of the Rodhocetus is more water dynamic, along with the change of limbs to fins (limbs were not needed in water), and the splitting of the tail into 2 (gives balance when swimming),
Basilosaurus: Evolved from Rodhocetus. The body evolved even more water dynamic, its fins grew smaller as it had a long and huge tail which would propel it through water.

Question 2 Answer:

E

Question 3 Answer:

All of the three animals have wings, and can fly. Bats are different in that they have finger bones; Birds have one single limb; whilst dragon flys have none. Birds also have strong feet, which allow them to stand. The dragonfly is the only animal out of the three that has a long tail, which it uses for balancing in flight. Birds and bats do not need a tail.

Question 4 Answer:

Differences between the strand of cytochrome C between different species show their similarity. As creatures mutate over time, the more different 2 creatures are from each other the more different their DNAs will change, thus the more differences there will be in the sequences of cytochrome C. Humans and chimpanzees have only 1 difference in their cytochrome C amino acid strands...they are very closely related.

Question 5 Answer:

Titaaliks and fishes, modern day whales and the Rodhocetus all share common ancestors. Homology shows the relationship between the 2 species' structures and genes.

Class 4 & 5: Diffusion and Osmosis

In classes 4 to 5 we did a large lab on demonstrating diffusion and osmosis. First we went through all of the important terms and background information.

Definitions:

Diffusion: Molecules travel from an area of high concentration to low concentration, such as perfume spreading through the air.

Osmosis: Transfer of water molecules from area of high concentration to low concentration through a semi-permeable membrane like a cell. Stopping when equilibrium is reached.

Hypertonic: A solution that where there are more solvent than solute

Hypotonic: Opposite of hypertonic, where a solution has more solute than solvent

Isotonic: Equal amount of solute and solvent

LAB:

Part 1: Starch diffusion through a cell (fake cell made with dialysis tubing)

Part 2: Osmosis of 6 different concentration fake cells

Part 3: Determining the solute % of 4 different potatoes through osmosis of its cells

Part 4: Determining the solute % of 4 different energy drinks (same as above basically)

Extra Part 5: Diffusion of benedict's solution into a NaCl cell. Calculate percent diffusion

For a complete formal lab report with data visit:

https://sites.google.com/site/seanyangworkhardlabharder/

Pictures of the lab:

Potatoes!

6 Different concentration solutions!

6 fake cells!

More potatoes!

Cell after osmosis

Class 3: Water, Surface Tension, and Coins

Class 3

Our homework before coming to class today was to listen to a slightly funny sounding video made by Mr. Quick on the properties of water. In class, we went over all the different characteristics of water, such as its molecular shape, polarity, cohesion/adhesion, and surface tension.
In order to demonstrate cohesion and adhesion, we did a small experiment involving coins.

We would slowly drip drops of water onto the coin so that it forms a groovy dome-like, hemispherical body of water over the coin. Mr. Quick told us that water forms a dome shape when its molecules cohere with each other because a water molecule's molecular shape is bent, therefore showing that when water is filled to the brim in a cup, there is a small smooth hump over the lip of the cup.

We then proceeded to dip a toothpick covered with dish soap into the water covered coin. The water spread itself out all over the table immediately. This phenomenon happens because dish soap breaks the surface tension of the water; the cohesion bonds between each molecule. From this experiment, we also learned why a water-strider can run across water; Their thin legs are light enough so that it does not break the bonds of the water.

Class 1 and 2: Milk Experiment and Molecular Structure Review

Class 1: Milk lab Experiment and Doing Labs In General

After watching a video showing whole milk, food coloring, and dish soap mix in a bizarre matter, we were tasked with forming a hypothesis about why such a phenomenon would happen and create a useful experiment in order to test our hypothesis.

Hypothesis: 

Dish soap has the ability to attract fat molecules and break them apart, thus creating a chaotic mess. The food coloring is in the mixture simply to show the dish soap breaking apart milk’s fat.

In order to test our hypothesis, we used the following equipment and decided to test many different solutions copying the same method used in the video.

Procedure:

1.     Pour whole milk into a circular dish

2.     Dab 2-3 drops of water coloring in the circular dish

3.     Dip toothpick into dish soap, and then dip toothpick into solution

4.     Observe chemical reaction of the solution

5.     Repeat above process with different solutions using same dish soap

Though our experiment is far from perfect and contained numerous human errors, we discovered that solutions that contained the most amounts of fat (whole milk) reacted most vigorously when dabbed with dish soap whilst solutions which had less fat (skim milk) or no fat at all (coffee/orange juice) did not react much at all.

Equipment used

Solutions

Important notes

After our first experiment, Mr. Quick went over some key aspects on doing effective experiments in general. Hopefully next time when my team and I are given an experiment, we can complete it in a more efficient and professional way.

Class 2

In our second class we simply went over some basic chemistry topics from Chem last year. We mainly focused on molecular shapes and did a worksheet on different molecules. We had a brief review of the octet rule and different bonds also.