Is Sex Important?

Sex is important in order for a species to stay alive, and reproduce successfully. There are 2 main different of sex, asexual and sexual.  For each type of sex there are it's benefits and costs.
In the book, the author tells us about the advantages and disadvantages of different types of  sex by writing in the form of various species. For an example the bdelloid rotifer  (or Mrs. Philodina) produces asexually by cloning. She says that this has been a big advantage for her species, "Sex may be fun, but cloning is much more efficient...In an asexual population, however, each female needs to have only one child for the population to remain the same size." Another asexual reproducer the E.Coli bacteria states that asexual reproduction is good for them because, " sex- by which I mean that acquisition of extra genes - is something we reap the benefits throughout their lives. If humans could do this, which they can't, it would be like suddenly adding a few genes for longer legs or bluer eyes."

However, sexual reproduction has it's advantages as well. For an example according to Muller's ratchet and Kondrasov's hatchet, " asexuals are driven extinct by the accumulation of harmful mutations- in other words, asexuals eventually die of genetic diseases." So being a sexual reproducer can ultimately keep your species alive for a much longer time, which is the ultimate goal. Another benefit of sexual reproduction is that they can avoid parasites unlike asexuals. "Since asexuals keep the same genes (give or take a mutation or two) from one generation to the next, parasites can easily evolve to infiltrate their defenses, annihilating clones.

In the end sexual reproduction is the best way of reproducing. This is because although it has it's own costs and benefits, the benefits outweigh the costs.

            

Unit 3 Reflection

Unit 3 was all about cells and how they function. Chapter 7 was mainly about the cell's structure and how it functions. We learned about the different parts of the cell, how they function, how they were discovered and about things like osmosis and diffusion. We learned about the 4 macromolecules of the cell, carbohydrates, proteins, lipids, and nucleic acid and what they do. Some parts of the cell are the nucleus, ribosomes, vacuole, mitochondria, and endoplasmic reticulum. We also learned about the 4 main types of cells prokaryotes who don't have a nucleus, eukaryotes who have a nucleus, autotrophs who make their own food, and heterotrophs who don't. Chapter 8 expanded and went into great depth about the process of photosynthesis which we touched on in middle and elementary school. We learned that photosynthesis which occurs inside chloroplasts is the process of taking water, carbon dioxide, and light energy to make glucose and oxygen. This occurs in 2 main parts the light dependent reactions and the light independent reactions (the Calvin Cycle). We also learned about the very important concept of ATP which and energy carrying molecule which is vital for the cell to function. The last chapter we learned about, Chapter 9 was all about cellular respiration. Cellular respiration is the exact opposite of photosynthesis, taking glucose and oxygen and turning it into water, carbon dioxide and ATP. Cellular respiration occurs in 3 different stages, glycolysis which takes place in the cytoplasm, Krebs Cycle which takes place in the mitochondria, and the electron transport chain which takes place in the inner membrane of the mitochondria.

Definitely one of the most challenging parts of this Unit was fully understanding the processes involved in both photosynthesis and cellular respiration. Cellular Respiration and Photosynthesis are both extremely complex processes so it was difficult for me to grasp what was going on in each individual part, and how that related to each other. However labs were really helpful in expanding my knowledge of different concepts such as the different cell types. With the microscope lab I was able too look at real cells with my own eyes and see how different types of cells are structured. For an example, after the lab i was able to easily recognize which cells were eukaryotic, prokaryotic, autotrophic, and heterotrophic.

What I have learned from this Unit is that making sure I go over the vodcasts a second time really helps. I realized during this Unit that with watching it one time I don't fully grasp the concept, leaving me confused for the next few days. However when I did take the time to watch it twice, I ended up with a pretty good understanding of what was taught.  Overall I think this Unit has taught me a lot only about cells, good studying habits that I should keep up with, and has made me a better student. 

Photosynthesis Virtual Lab

Photosynthesis Virtual Labs.

Lab 1: Glencoe Photosynthesis Lab

http://www.glencoe.com/sites/common_assets/science/virtual_labs/LS12/LS12.html

Analysis Questions

1. Make a hypothesis about which color in the visible spectrum causes the most plant growth and which color in the visible spectrum causes the least plant growth?

If blue light shines on the plants, then there will be more plant growth. If green light shines on the plant, then there will be less plant growth.

2. How did you test your hypothesis? Which variables did you control in your experiment and which variable did you change in order to compare your growth results?

I tested my hypothesis by putting each type of plant under each color of light to test what the effects were. The control variables in this experiment were the amount of water, soil, and the viability of each seed. The variables I changed in this experiment were the colors of light.

Results:

Filter Color	Spinach Avg. Height (cm)	Radish Avg. Height (cm)	Lettuce Avg. Height (cm)
Red	18.33	13	11
Orange	15	8.33	6
Green	3	1.66	3
Blue	19	14	12.5
Violet	16	30	8.33

3. Analyze the results of your experiment. Did your data support your hypothesis? Explain. If you conducted tests with more than one type of seed, explain any differences or similarities you found among types of seeds.

My data supported my hypothesis because as I suspected, blue was the color that produced the most plant growth and green was the color that created the least. I conducted tests with 3 different plants, radish, spinach, and lettuce. Across all of them green had the lowest height and blue the tallest. However there were some difference between the plants, for an example the lettuce did not grow as tall as the radish or spinach did.

4. What conclusions can you draw about which color in the visible spectrum causes the most plant growth?

I can conclude that the color green produces the least amount of plant growth, and blue light produces the most.

5. Given that white light contains all colors of the spectrum, what growth results would you expect under white light?

I expect an average of all the colors put together to be the effect of white light on a plant. Since, white light contains all of the colors, it makes sense to me that white light should be not as good as blue but not as bad as green.

Site 2: Photolab

http://www.kscience.co.uk/animations/photolab.swf

This simulation allows you to manipulate many variables. You already observed how light colors will affect the growth of a plant, in this simulation you can directly measure the rate of photosynthesis by counting the number of bubbles of oxygen that are released.

There are 3 other potential variables you could test with this simulation: amount of carbon dioxide, light intensity, and temperature.

Choose one variable and design and experiment that would test how this factor affects the rate of photosynthesis. Remember, that when designing an experiment, you need to keep all variables constant except the one you are testing. Collect data and write a lab report of your findings that includes:

• Question
• Hypothesis
• Experimental parameters (in other words, what is the dependent variable, independent variable, constants, and control?)
• Data table
• Conclusion (Just 1st and 3rd paragraphs since there's no way to make errors in a virtual lab)

*Type your question, hypothesis, etc. below.  When done, submit this document via Canvas.  You may also copy and paste it into your blog.

Question: Will increased amounts of carbon dioxide increase the rate of photosynthesis?

Hypothesis: If the level of carbon dioxide surrounding the plant is increased, photosynthesis will take place more rapidly.

Independent Variable: Amount of carbon dioxide

Dependent Variable: Number of bubble produced

Control: Plant

Data Table:

	Water	Carbon dioxide + water
Amount of bubbles in 1 min.	0	0

Conclusion:

In this lab we asked the question, will an increased amount of carbon dioxide added to the plant’s surroundings make photosynthesis occur more rapidly? Before performing the experiment I thought that it would increase the rate of photosynthesis, however after conducting the experiment I found that an added amount of CO2 does not have any affect on the plant. In one minute without adding any water, the amount of bubbles produced was 0 and with the carbon dioxide, the amount of bubbles was also 0.

This lab was done to demonstrate how changes in a plant’s environment affects how much oxygen it produces. From this lab I learned that even if more carbon is added to the atmosphere (something plants need) it doesn't necessarily mean that the plant will thrive. This lab deepened my understanding of photosynthesis because previous to this lab, I thought more carbon dioxide meant more photosynthesis. Based on my experience from this lab, if I ever decide to grow a garden I know the proper conditions to have a healthy plant.

Microscope Organism Lab

In this lab, we looked at different cells under the microscope and observed their characteristics. We learned how to properly use a microscope in this lab, and we got a hands on view of what real cells look like. 

After observing different cells under the microscope, I was able to find the differences and similarities between different types of cells. For an example, I found that all autotrophic cells (Spirogyra, Cynaobacteria, and Euglena) had a blue-green tint in them. Autotrophs are organisms  that make their own food, or producers. The reason why they all have a green tint on them is from the chlorophyll which is used to soak up light energy in order to make food. 
Heterotrophic cells (Animal Cell and Amoeba)  are cells that get their food and energy by consuming other cells. I classified that the muscle cells were heterotrophic since they had multiple nuclei and I classified amoebas as heterotrophic because they had pseudopods to consume other cells. 
The defining characteristic of a eukaryotic cells is that they contain a nucleus. Using this characteristic I classified the Animal cell, ligustrum, Spirogyra, Euglena, and Amoeba to be eukaryotic. In all of these cells I identified a nucleus which made me absolutely certain that it was a eukaryote cell. 
Prokaryote cells are single celled and without a nucleus. In this lab I found that the bacteria cells (Coccus, Bacillus, and Spirillum), and the cyanobacteria are all prokaryotic. Generally, almost all bacteria are classified as prokaryotic which was one of the reasons it let me to believe these cells were prokaryotes too. The other reason was that there was no identifiable nucleus. 

Spirogyra at 100X                    
Organelles Identified: Cell wall, Chloroplasts, Cytoplasm
Unique: Visible spirals in individual strands
Observation: Green streaks are formed by chloroplasts
Eukaryotic and Autotrophic

Ligusgtrum at 400X
Organelles Identified: Chloroplast, Epidermis cell, vein
Unique: Chlorplasts are extremely visible 
Observation: Visible holes within the individual circles
Eukaryotic and Autotrophic

Animal Cell at 400X
Organelles Identified: Nucleus, Muscle Fiber
Unique: Many nuclei visible as black dots
Observations: Individual striations are visible 
Eukaryotic and Heterotrophic

Cyanobacteria at 400X
Organelles Identified: One single cell
Unique: Individual cells are visible
Observations: Colors are various shades of blue green and purple
Prokaryotic and Autotrophic

Euglena at 400X
Organelles identified: Chloropast, Nucleus
Unique: Oval shaped cell is very clearly visible
Observations: Has a teal-blue pigment
Eukaryotic and Autotrophic

Ameoba at 400X
Organelles identified: Cell Membrane, Pseudopods
Unique: Many food vacuoles can be seen
Observations: Can see the pseudopods where the amoeba captures it's food
Eukaryotic and Heterotrophic

Bacteria Cells: General Shapes
Identified: Bacillus, Spirillum, Coccus
Unique: Bacteria are exteremely tiny compared to the rest of the cells
Observation: Compared to the other bacteria, coccus is the smallest
Prokaryotic and Heterotrophic

Egg Diffusion Lab

The question that was asked in the egg diffusion lab was why does a cell's internal environment change as it's external environment changes? To test this, we soaked to eggs in vinegar water for a few days and then placed one in sugar water and the other one in plain water for 2 days. When we collected the data after those 2 days, we discovered that the circumference of the egg in sugar water had gone down by 17.65% and it's mass had gone down by 48% and the one in water had expanded. The reason the egg in the sugar water deflated was because of diffusion. The solution was hypertonic: there was more solute outside of the cell, which caused water(solvent) to exit the egg to balance out the solution. When the water started to exit the egg, the egg lost mass which caused it to deflate.

As we have seen in the egg lab, when we placed the egg in sugar water, the water left the egg to balance out the solution surrounding it. This shows that when a cell's internal environment changes so does it's outside environment, because when the cell lost water, the environment around it gained water.

This lab demonstrates the biological principle of diffusion when the solvent spreads around to the environment around them. In the case with the sugar water solvent moved out of the cell (hypertonic), but there are other types of diffusion as well such as hypotonic and isotonic. Hypotonic is when solvent moves into the cell and isotonic is when the cell is already in balance. The principle of diffusion can be applied to real life as well. For an example when it snows, salt is poured on the road to melt the ice, however when the salt lands on plants it  can kill it. This is because the solvent (water) from inside the plant comes outside in order to balance the level of salt around it, which dehydrates the plant.

After doing this lab, I would like to do some further testing. For an example, I have wondered if the egg was put in a highly hypotonic solution, would it cause the egg to burst? When a solution is hypotonic, solvent goes into the cell to achieve equilibrium, so I want to test if there is a breaking point of the cell that causes it to rupture. 

Egg Macromolecules Lab

In this lab we asked the question, can macromolecules be identified in an egg cell? We made 3 different claims, one for each part of the egg. For the egg yolk we said, If lipids and proteins make up egg yolks, their respective solutions will change color from red to orange for lipids and from blue to purple for proteins. For the egg membrane we said, If lipids and proteins make up the egg membrane, their respective solutions will change  from red to orange for lipid, and blue to purple for protein. Lastly for the egg white we said, If proteins and monosaccharides make up the egg white, their respective solutions will change color from blue to purple for proteins and from blue to green to orange for monosaccharides. However, when we did the experiment, we found that some of our hypothesis were wrong. In the egg yolk, we found that in addition to lipids and proteins, it contained monosaccharides as well because the solution turned completely green (rate 10/10), signifying there definitely were monosaccharides. Additionally, in the membrane we found that in addition to lipids and proteins, there are monosaccharides in there as well as the solution turned a blueish purple which signified that there was not an overwhelming amount of monosaccharides in the membrane ut still some. Lastly, our hypothesis for egg whites proved itself to be true. 

There could have been some errors that affected the outcome of our data. For an example, in the lipid test, the egg white was not mixed with the Sudan III solution, and our data came out as no lipids in the egg white. However if the solution had been thoroughly mixed, our data could have came out differently. Another possible error in this lab is that polysaccharides tested as being nowhere in the egg. This might be true, or there might have been an error in our lab. We might not have put enough iodine into the solution for the results to show up clearly, because in all four test tubes nothing changed color.

This lab was done to demonstrate the different macromolecules and where they can be found. In this lab I learned where different macromolecules are found in a cell, which helps me understand the cell as a whole and it's functions. For an example, lipids and proteins and monosacharides and usually found in cell walls and membranes, which is why they are in the egg membrane to protect the chick. Based on my experience in this lab, I now know where the different macromolecules are in a cell and most importantly why they are there. This can help expand my knowledge later on when we dive in deep about cells and their functions.