Is Sexual Reproduction Important?

          In the selected reading, Dr. Tatiana's Sex Advice to All Creation by Olivia Judson, animals were invited to a talk show about the benefits and costs of sexual and asexual reproduction. The sexually reproducing animals, like the rams, pigeons, mice, and armadillos as depicted in this reading, argue that sexual reproduction is the best way to reproduce and that asexually reproducing organisms will become extinct. The asexually reproducing organism that was interviewed in the story was a rotifer called Philodina. The Philodina argued that its species is an asexually reproducing species and that organisms can survive using asexual reproduction for a long time, unlike what the sexually reproducing organisms argued about.
         Sex is important because it causes more genetic variation which can lead to an organism to adapt better to its environment. "Sex, they insist, is essential. And ancient asexuals -- creatures such as the bdelloid rotifers that have lived without sex for millions of years -- should not exist" (Judson 216). Reproduction does not cause genetic variation by itself, it needs genetic mutation alone to create genetic variation which is rare and unreliable. This is the reason why most asexual species go extinct. "But although asexuality often evolves -- it pops up in groups from jellyfish to dandelions, from lizards to lichens -- it rarely persists for long" (Judson 216). The main benefits of sexual reproduction is the genetic variation created when the sperm and egg fuse together to form a genetically unique zygote which grows into a genetically unique organism. "In eukaryotic sex, you get half your genes from your mother and half from your father.... Thus, at the end of meiosis, each sperm and egg carries one complete but unique mixture of genes -- a complete but shuffled deck" (Judson 219). The costs of sexual reproduction is the dangers of STDs and parasites and that it takes up a lot of energy. The benefits of asexual reproduction is that the genes stay relatively the same, so organisms can become extremely adapted to their environment. The costs are also that genes stay the same. "[Philodina's] proof rests on the fact that cloning for millions of years has dramatic effects on the way genes evolve. 'Being asexual for generations leaves an unmistakable mark, a molecular tattoo on your genes,' she said smugly, ' If you always clone, there's only one source of genetic novelty, only one thing that could cause my genes from to differ from my mother's, grandmother's, or great-great-grandmother's: mutation" (Judson 222).
          Some things that are confusing to me are that how mutations occur, why they occur, and how they impact the organism with them.

Unit 3 Reflection

          This unit was about cells, their functions, and their structures. The themes and essential understandings were that cells are the basic unit of life and they carry out all life processes that are needed to survive. Also, we learned about the cell itself and the different organelles and the processes that occur inside the cell as it adapts to the environment and what it does to keep itself alive. My strengths were that I knew most of the content from previous classes. I knew what most of the organelles and their functions. I also knew what cellular respiration and photosynthesis were generally, so that helped me understand the specifics when we learned that. My weaknesses were understanding the concepts of osmosis and hypotonic and hypertonic solutions. Also, I had trouble with understanding the very specific processes that occur in photosynthesis and cellular respiration, although I had a basic understanding about the two processes. 
          What I learned from this unit and its experiences were that I learned how our cells function and how organisms live on the microscopic level. I also learned many things that I already knew, but more in depth, such as photosynthesis, cellular respiration, and the origins of cells and organelles. This makes me a better student that before because I know more content and I understand how cells live and how they function to keep organisms alive and how they react to their environments. I want to learn more about the fine details of photosynthesis and cellular respiration and the evolution of the modern-day eukaryotic cell. 

Photosynthesis Virtual Lab

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 plants absorb mostly blue and/or red light, then it will produce the most plant growth.

If plants absorb mostly green and/or yellow light, then it will produce the least 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 used the virtual lab to test my hypothesis. The variables I controlled were type of plant, amount of light, and soil. The variable I changed in order to compare my growth results was the wavelength or color of light.

Results:

Filter Color	Spinach Avg. Height (cm)	Radish Avg. Height (cm)	Lettuce Avg. Height (cm)
Red	18	13	11
Orange	14	8	7
Green	3	1	3
Blue	19	14	13
Violet	16	10	8

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.

Yes. The differences between other seeds is the type of plant and how much it grew. The similarities were that they all reacted to the light relatively the same.

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

I can conclude that blue and red light causes the most plant growth.

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

I would expect the plant to grow to be the average of all of the individual colors.

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 increasing the amount of CO2 cause more photosynthesis to occur?

Hypothesis:

If CO2 is used for photosynthesis, then a greater amount of CO2 will cause the plant to do more photosynthesis and produce more oxygen.

Experimental Parameters:

Dependent Variable: Rate of photosynthesis

Independent Variable: Amount of C

Control: 0 CO2

Constants: Water temperature (10 ⁰C), light intensity (100%), light wavelength (white), water, plant

Data Table:

Amount of CO2	None	All
O2 bubbles/ 15 sec	3	6

Conclusion:

In this virtual lab, I asked the question, will increasing the amount of CO2 cause more photosynthesis to occur? I found that increasing the amount of CO2 increases the production of oxygen in photosynthesis. When I increased the amount of CO2, more oxygen bubbles came out of the plant compared to no CO2. This data supports my claim because the higher amount of CO2 caused the plant to photosynthesize more and produce more oxygen.

This lab was done to demonstrate the effects of CO2 on photosynthesis. From this lab, I learned that increasing the amount of CO2 increases the rate of photosynthesis and produces more oxygen, which helps me understand the concept of the role of CO2 in photosynthesis. Based on my experience from this lab, I could apply this knowledge to another situation by helping stop global warming by planting more plants, which will suck CO2 out of the air and reduce the amount of global warming.

Microscope Lab

          In this lab, we asked the question, "What are the key features of autotrophs, heterotrophs, eukaryotes, and protists?" The key features we found were different among the different cells that we observed. In the amoeba, I was able to observe the nucleus, cell membrane, and the pseudopods. In the euglena, I was able to observe the nucleus and the chloroplasts. In the bacteria, I was able to observe the different types of bacteria. In the cyanobacteria, I was able to observe a single cell. In the spirogyra, I was able to observe the cell wall, chloroplasts, and cytoplasm. In the muscle cell, I was able to observe the nucleus, muscle fibers, and striations. In the ligustrum, I was able to observe the cell walls, cell membrane, veins, xylem, and phloem. Here are the pictures of all the organisms that we studied in this lab. The characteristics of autotrophs are that they are usually green and have chloroplasts. The characteristics of heterotrophs are they have a nucleus. The characteristics of eukaryotes are that they have nuclei. The characteristics of prokaryotes are that they don't have nuclei.

Amoeba
High power, black, odd shape, many black blobs inside, black blobs may be organelles, eukaryotic, heterotrophic

Euglena
High power, thin, dark nucleus, blue, green, eukaryote, autotroph and heterotroph

Bacteria Cells: General Shapes
Very small, different shapes, prokaryotes, autotroph or heterotroph

Cyanobacteria
High power, ancestor of chloroplast, small blue balls in a string, prokaryote, autotroph

Spirogyra
High power, cells are stacked on top of each other, fits together in boxes, eukaryote, autotroph

Muscle Cell
High power, pink and long, big cell, eukaryote, heterotroph

Ligustrum
High power, red and blue cells, cell walls, eukaryote, autotroph

Egg Diffusion Lab

          In this lab we asked the question, how and why does a cell's internal environment change, as its external environment changes? We found that when the egg is placed in sugar water, it shrunk both in circumference and mass. The solution that the egg was in was hypertonic, meaning that there was a greater concentration of solute outside the egg than inside, so water left the egg to the outside solution to balance the concentration and reach equilibrium.

Class Data: Sugar Water                                                     Percent Change

Group #	3	5	6	Average
% Change in Mass	-48.4	-35.8	-43.12	-42.17
% Change in Circumference	-18.75	-30.5	-9.8	-19.6

We also found that when the egg is placed in deionized water, it grew both in circumference and mass, except for one group. The solution that the egg was in was hypotonic, meaning that there was a lesser concentration of solute outside the egg than inside, so water went into the egg to balance the concentration and reach equilibrium.

Class Data: Control (Deionized Water)                               Percent Change

Group #	2	4	7	Average
% Change in Mass	1.1	0.69	1.74	1.18
% Change in Circumference	6.1	-8.3	8.82	2.21

       
          One group had data that contradicted our hypothesis because, their egg was placed in deionized water, but it shrunk in circumference. Our hypothesis was that the egg would increase in mass and circumference. The egg grew in mass, but its circumference shrunk. This affected the results by changing the average. Also, some possible errors could be that people could have measured the circumference the long way first, then the short way after the experiment. That would have changed the results by making it seem like the egg shrunk in circumference or grew in circumference. Due to this error, in future experiments I would recommend keeping track of which way the egg is measured initially to keep the data accurate.

            This lab was done to demonstrate our understanding of osmosis and diffusion in cells. From this lab I learned the difference between hypertonic solutions and hypotonic solutions and their effects on a cell, which helps me understand the concept of how cells grow and shrink. Based on my experience on this lab, I could apply this knowledge to figure out how to quickly hydrate someone's cells when they are dehydrated. 

          When the sugar concentration increased, the mass and the circumference shrunk because the cell has to take out more water from itself, through the membrane to achieve equilibrium. The cell's internal environment changes as its external environment changes because it has to adapt in order to survive in changing external environment. This lab demonstrates a biological principal I've learned in class by showing that organisms adapt to their surroundings. Water is added to plants in markets to keep them moist. Salt is sprinkled on icy roads to cause the ice to diffuse away and melt into water. Based off of this experiment, I would want to test the affects of salt on ice. 

Egg Macromolecules Lab

         In this lab, we asked the question, can macromolecules be identified in an egg cell? Looking at our results, we found that different parts of the egg have different macromolecules in them. The egg membrane tested positive for lipids. When the egg membrane solution was mixed with Sudan III, it produced an orange color, indicating that lipids were present in the egg membrane solution. Sudan III is an indicator that changes color to orange when a lipid is present in a solution. The egg white tested positive for proteins. When the egg white solution was mixed with a combination of copper sulfate (CuSO₄) and sodium hydroxide (NaOH), the solution turned into a purple color, showing that proteins were present in the egg white solution. The egg yolk tested positive for carbohydrates and more specifically, polysaccharides. When the egg yolk solution was mixed with iodine, it turned yellow-brown, showing that polysaccharides were in the egg yolk.

         Our data contradicts our initial hypothesis on what macromolecules are going to be in each part of the egg. For the egg yolk, we predicted that it will be mostly protein, but it tested for more polysaccharides than proteins. Also, for the egg white, we predicted that it will mostly be carbohydrates, but it tested for more proteins than monosaccharides and polysaccharides. While our hypothesis for the egg membrane having mostly lipids was supported by our data, there could have been errors due to contamination of pipets or not measuring the right amount of egg membrane or Sudan III. These errors would have affected this lab by giving results for other macromolecules and making our data false and inaccurate, or by causing the macromolecule to give wrong information when testing if the right amount of the substance is not used. Because of these potential errors, in future experiments I would recommend that the substances be measured correctly and as accurately as possible and try to keep things neat and organized while doing the experiment.

         This lab was done to demonstrate the roles and functions of macromolecules in eggs. From this lab I learned that membranes usually contain lipids, egg whites usually contain proteins and egg yolks usually contain polysaccharides which helps me understand the concept of each macromolecules' function and role in a cell. Based on my experience from this lab, I could apply this knowledge and skills to test different substances for macromolecules.