Evidence for Evolution Quiz #1

1. The picture for question 1 is evidence for evolution because it shows that species are always changing. The species evolved from a wolf/bear like creature to a whale life creature because the species needed to adapt to its changing environment. Many factors play into why the species needed to adapt. Either there was an abundance of food in the water, or the animals were trying to escape a predator. Through these factors, the species changes over time, such as new bone structures, and the species transforms into a whole new one.   2. Marsupials evolved from North America. Then they migrated to South America and then to Australia. The answer is E.  3. The Dragon fly, the bird, and bats are all animals from different lineages. But, they all have analogous structures that have similar functions. This is called convergent evolution. They have all evolved the capability of flight independently. They have all "converged" this trait. Their bone structures are different but it has similar uses. 

4. The Common Ancestry Lab shows evidence for evolution through the DNA of the common ancestor, gorillas  chimpanzees, and humans. They all have similarities, or matches, and differences. This shows us that gorillas, chimps, and humans are related. The gorilla is closely related to the chimp, and the human is closely related to the human. 

5. Homology is when animals have similar bones structures but different uses for them. For example from inner fish we can lear that humans, dogs, birds, and whales have similar bone structure in the are but we all use it for different reasons.  

After result of "cells" in distilled water

"Cells" immediately after put into distilled water

"Cells" in Osmosis Lab before put into distilled water

Class 4

For class 4, we did an osmosis lab. My lab partner, Alex, and I first created six "cells" using dialysis tubing and different color solutions. The we massed the cells. Then we placed them each into separate cups of 50ml of distilled water. After 30 minutes we re massed the cells and calculated the percent mass change. The clear cell had a mass change of 8.219% and a molarity of 0.2. The purple cell had mass change of 20.988% and 0.8M. The yellow had a mass change of 21.053% and 0.6M. The red cell had a mass change of 27.161% and 1.0M. The blue cell had a mass change of 0% and 0.0M. The green had a mass change of 13.514% and 0.4M. From the percent mass change, we can infer the molarity of the solutions. Osmosis is the net movement of the solvent molecules through a permeable membrane into a region of a higher solute concentration. A hypotonic solution is a solution that has a lower concentration of solutes and higher amount of water. A hypertonic solution is a solution that has a higher concentration of solutes and lower amount of water. The solutions want to reach a isotonic state, or equal state. This means that the water will move from the hypotonic solution to the hypertonic solution to try and balance out the solutions. In the lab, the mass changes meant if the solutions were hypotonic or hypertonic. If the result of the lab meant that the mass of the "cell" decreased, then that means that the cell was hypotonic because water transferred out of the cell. If the cell gained mass, then the cell was originally hypertonic because water went into the cell. My lab partner and I did part 4 of the lab next, which was with the rehydration drinks. We made six cells using the dialysis tubing and orange Powerade. We then put the new "cells" into six different cups containing six different color solutions. We originally massed the cells before putting them into the cups. Then, during the evening, we came back and massed the cells again. Every cell decreased in size except the cell in the blue solution. This means that all the cells, except the one in the blue solution, were hypotonic in relation to the Powerade. The blue solution was hypertonic to the Powerade. In the next class we did the diffusion part of the lab. 

Why water striders can stand on water

Why humans sweat and dogs pant

Class 3- 8/29/13 Water!

During class on 8/29/13, we learned about water, hydrogen bonding, and water's properties. But first, we took a quiz on basic chemistry. After the quiz we got into pairs. My partner was Alex. We then each received a question and had to present to the class what the answer was through the knowledge we gained from our homework on water. Alex and I got asked the question, " Why can a water strider stand on water?" The answer is that water has high surface tension and the water strider can stand on the hydrogen bonds without breaking them. The water strider can stand on them without breaking them because the water strider's legs are light and have large surface area. If the water strider had legs where the weight was not spread out (surface area) then the water strider would sink. Then after we all presented, we got into larger groups and answered the question "Why do humans sweat and why do dogs pant?" The answer is that our bodies need a way to cool off. Water has a high heat capacity of vaporization. So, when we sweat and our sweat (basically water) reaches a certain temperature, it evaporates, taking the heat away from our bodies. Dogs pant because they have fur so they cannot sweat. Their way of cooling off is by panting. Update of what we do next in honors biology coming soon!