DNA Lab

We did the DNA lab in class today.
What you do is to put different colored beads onto a string according to human, chimpanzee, gorilla and common ancestor's DNA pattern and compare these four different patterns. We find out that human, chimpanzee and gorilla's DNA all share some similarities with the common ancestor's DNA, which proves that human, chimpanzee and gorilla are evolved from a common ancestor. However, human DNA has more similarities with chimpanzee DNA than with gorilla DNA. This shows that human and chimpanzee are more closely related.

We made a cladogram according to the relationship between human, chimpanzee, gorilla and common ancestor. Human, chimpanzee and gorilla all branch out form the common ancestor, gorilla has more similarities with the common ancestor, so it is the closest to the common ancestor. The next one is chimpanzee and after that is human. Human and chimpanzee do not have too much space between them because they are more closely related.
we also talked about convergence and divergence. For convergence, it means that animals with different ancestors evolved body structures with similar functions. And for divergence, it means animals with a common ancestor evolved body structures with different functions.

Evidence of Evolution Quiz

1. These animals share similar morphological feature. For example, their head adopt similar shapes and their teeth look similar. One can also see the gradual change in their feet. At first, webs grow out, and then they evolved into fin like structures. They don't need hind legs anymore since they swim in water, so the hind legs gradually shrank.

2. E

3. They show the convergent evolution because they evolved from different species but they all developed body structures with similar functions that enable them to fly. Although these body structures have different internals, they provide the same function.

4. The more similar the two DNA patterns are, the more likely evolution process is involved between the two species. For example, chimpanzee DNA and human DNA share more than 97% similarity; therefore, chimpanzee and human are very likely to share the same common ancestor.
 
5. Homology means the body structure of animals are similar. For example, a lot of animals share the same arm structures. These animals that share homologous body structures most likely evolved from a common ancestor.

IMMA FISH!!!!!!!!

If I was originally a fish, how can I be so bad at swimming...?

How did fossils form?
Fossils usually form in sedimentary stone because the temperature and pressure are mild enough for fossils to preserve. Say if a fish died in water, it would fall to the river bed and decay. The bone will be covered by dirt and particles. After a period of time, the bones were fossilized and covered in deeper layers. Fossils are exposed because of wind, rain or earthquakes.

Homology

Homology means the resemblances between animals' body structures. If animals have similar body structures, they probably evolved from the same animal and are classified in the same group. For example, most land animals have the same "one, two and a bunch" arm structure, which was seen in Tiktaalik's fossil.

Macromolecules Lab

If you put benedict into substance that contains glucose and heat the substance up, the initially blue substance will turn orange. If you put iodine into substance that contains carbohydrates, the substance will turn blue. If you put biuret into substance that contains protein, the substance will turn purple. if you put Sudan III into substance that contains lipid, the color of the substance will turn into a shiny red. We applied these different solutions to 10 different substances and found out that:
A: protein + oil
B: glucose
C: starch
D: starch+protein+lipid
E: glucose+starch
F: starch+lipid
G: glucose+starch+protein
H: glucose+protein
I: protein+lipid
J: glucose+lipid

House Case and Cell Membrane

I don't really remember if we did these two in the same class, but anyways...

For the House Case:
There's one dude with a cool hair style. He is a senior cross country runner. One day, he felt dizzy and nauseous, and he lost consciousness after practice. I thought he might have dehydration or hypoxia or hypoglycemia, but Mr. Quick said that was wrong.

For the cell membrane lecture:
The function of the cell membrane is transportation, enzyme activity, signal transduction and cell-cell recognition.

More Diffusion and Osmosis

Yay! More diffusion and osmosis labs!

For the first part, we put "cells" of different sizes into colored solution and then take them out after a certain amount of time. We measured the volume of which the solution diffused into, and found out that the bigger and thicker the cell is, the slower the solution diffuses.

For the second part of the lab, we put a "cell" that contains glucose and starch solution into water. After a while, we took it out, and tested if there was starch or glucose in the "water." The result is that there was glucose in it, but there wasn't any starch in it. It is because starch is too big to get through the cell membrane.

Diffusion and Osmosis

I really have no idea why I got 64 page views. I mean who would read this perhaps THE most boring blog in the world except maybe my mom... and certainly Mr. Quick but I doubt if he has figured out my link yet...

Anyways, in the class before last class (interesting phrase...) we studied about diffusion and Osmosis.

Diffusion:

Say if you drop food coloring into water, it would diffuse because of the constant molecular movement.

Osmosis:

Water molecules would get through cell membrane and move to the other side if the other side has a higher molarity of the solute or lower molarity of water. 

To prove the concepts, we did an osmosis lab.

In the first part, we put "cells" that contain different molarities of solution into water, and measure their changes of mass. The more the mass increased, the more water went into the cell, and the bigger the molarity was.

In the second part of the lab, my group put equal amount of yam into solutions with different molarities and measured the change of mass of yam. If the mass increased, it means the molarity of the yam was bigger than the molarity of the solution. If the mass decreased, it means the molarity of the yam was smaller than the molarity of the solution.

Water

We did a lab in class. So what we did was to put water onto a coin drop by drop until the surface of the coin could not hold more water. When the water was about to "collapse," it was in the shape of an arch, like this:

The reason why water can stay on the coin is because the water molecules are sticked together by hydrogen bonds(cohesion). It has the shape of an arch because each water molecule has the shape of an arch, and when they stick together, they make archs, too. If you poke the arch made by water with a toothpick, you will find out that instead of bending in, the water arch "climbs" up the toothpick. This is caused by the adhesion of water. Because of the difference of charges, water molecules are attracted to the toothpick, therefore, "climbs" up. This is also how plants absorb water. When water evaporates from leaves, more water will be pulled up by adhesion.

Water has a higher heat capacity, which means that a certain amount of water can absorb or release more heat in a certain amount of time than most other matters. This is why the climate is milder at seaside.
The evaporation of water absorbs heat, so human and animals sweat when they feel hot.
Water evaporates faster when there's lower pressure, higher temperature and bigger area exposed to air.

I think that's all...