PDS APES 8th Period 2009-10

I wasn’t here in class when we learned about these. This is what I know about Soil Horizons; if someone can add/clarify, that would be GREAT.

A Horizon: topsoil/vegetation

B Horizon: subsoil/inorganic material and broken down rock

C Horizon: parent material/bedrock

O Horizon: ?

Hey, Guys!

Sorry if y’all answered this question in class today, but I was having trouble differentiating between rocky and sandy beaches.  My understanding is that they are both located in the intertidal zone, and that species in both areas must adapt to fluctuating water levels, salinity levels, and temperatures.  There does not seem to be a striking difference between the two besides the obvious fact that one is rocky and one is sandy?!?  Did y’all go into greater depth in regards to the differences between these two zones in class today?

Thanks!  -Molly (P.S. Sorry this post is so late!  I just got back from a visit at Emory)

Hi guys, Im confused about why deserts are found on the tropic latitudes and not the actual equator… I think it has something to do with the heating and cooling of the air? I thought the equator got the most direct sunlight, so shouldnt all the water be evaporating away more quickly? Instead there are tropical rainforests on the equator… Im hoping someone can explain how temperature/air/water make this happen.

I looked thoroughly in the book about watersheds, and it says it is the “land area that delivers runoff, sediment, and dissolved substances to a stream.” Maybe what confuses me about this definitition is that it makes watersheds sound active rather than a passive location. Is a watershed just a buffer?

My second question might confuse people, but I will try my best not to mess up your understanding. : ) If the NPP is higher when water is more penetrable, then a lake with a lot of phytoplankton on its surface blocking light would not be very productive, correct? That seems contrary to the picture of the green lake in the book which claims to have an excess of plant nutrients and thus be eutrophic. Maybe it is a cycle: First, the lake is full of plant nutrients, so it has high NPP and grows a lot of algae and cyanobacteria; Next, there are too many plants for light to penetrate the water and the nutrients run out, so the lake has a much lower NPP.

Is this cyclical perspective completely wrong…someone save me if it is!

Thanks!!

So, how do you work to build memory? Many times, when asked, seniors tell me “I read over my notes.”  Isn’t that called reading?  While repetition does help build memory, there are other ways to practice analysis.  One easy (and free) way is to use interactive quizzes found online.  You at least know immediately if you have reasoned poorly, and you might be able to go back to the book or notes and look up why.  Here are a few sets of practice problems:

1.  Your online text resource website–always listed on the main page of the blog.  Go to Chp. 5, and take the quiz (menu on the left). There are usually 10-15 multiple choice questions.

2.  Not sure who made this one, but here is another small set of multiple choice questions to get you thinking.

3.  Here is another “quiz” based on flashcards.  First, you can click “study” and do the flashcard bit.  Then, click quiz. Click your choice for each question and once at the bottom, hit “score this quiz.”

These were easy to find with a Google search….just an idea.

Good Luck,

W

I know in class today i asked about this when Sydney was giving her presentation, but it still isn’t clear for me.  When you are getting closer to the shore it makes more sense, at least in my head, that the salinity would become higher because there is less water to dilute it.  When you get deeper out into the ocean there would be a better balance and so the salinity would decrease.  I am a little confused on how it works in the opposite way.  Maybe i am looking at it in the wrong way but something is not clicking for me.  If someone could clear this up that would be great! thanks

Last week during class, I tried to note general trends found in biomes all across the globe.  Here is a brief list that I came up with:

• Increased rainfall = increased plant height
• Increased rainfall = increased biodiversity
• The Tropics contain broadleaf evergreen trees
• The Temperate zones contain broadleaf deciduous trees
• The Poles contain coniferous evergreen tress
• Land Ecosystems- rank of NPP: 1)forests  2)grasslands  3)deserts
• Water Ecosystems- rank of NPP: 1)estuaries  2)swamps/marshes  3)lakes

First:  What other major trends am I missing?!  Second:  In class, we talked about how swamps and marshes have a much higher NPP than do lakes for multiple reasons including shallow water… but I’m a little confused on why this makes such a huge difference.  If anyone could help me out that would be great! Thanks!

On Friday, we talked about why there is uneven heating on the earth and what affects wind. There are 3 main reasons that the earth is heated unevenly:

1. The rotation of the earth

• The earth rotates around an axis, and it completes one full rotation each day.  At different times of the day, different areas of the earth receive sunlight, which actually brings me to the next factor:

2. The earth’s tilt

• The uneven heating of the earth’s surface also has a lot to do with the tilt of the earth’s axis.
• Since the axis is tilted, different parts of the earth are facing the sun more directly at different times, depending on where the earth is in its rotation around the sun.
• During our summer, the earth is tilted so that the northern hemisphere gets more heat because the sun hits the hemisphere more directly. The southern hemisphere isn’t facing the sun as directly, so it is colder down there…and visa versa for our winter.

http://www.nationsonline.org/bilder/earth_rotation_axis.jpg

The picture above shows how the earth’s rotation and the tilt work in conjunction with each other to cause uneven heating on the earth’s surface.

REMEMBER: DISTANCE DOES NOT AFFECT HEATING!!! The distances are not shown in the diagram; however, during our summer, the earth is actually further away from the sun than in our winter. The distance has nothing to do with how much heat the surface actually gets though; it just depends on the tilt and rotation of the earth.

3. The other factor that causes uneven heating is the difference in heating between land and water. The land heats up quickly and stores heat for a shorter amount of time, while the water takes a longer time to heat up but stores the heat for a much longer period of time.

In class, we demonstrated all 3 factors by putting two beakers with a globe behind them on the counter with a huge lamp shining on them. One beaker had water, and one had soil, and the globe had three temp. readings on it: one at the equator, one at the temperate zone, and one at the polar zone. Everything started out at room temperature. We left them out for the whole class, and at the end of the period, we found that the soil was warmer than the water, and the three zones on the globe all had different temperatures. The equator was 84 degrees Fahrenheit, the temperate was 74 degrees, and the polar was 70 degrees.

The picture is pretty blurry, but you can see how the equator would get the most direct sunlight, and the polar area would get the least direct sunlight. Also, the beakers are a little difficult to see, but they are in front of the globe.

After talking about uneven heating, we moved on to CONVECTION and wind.

In the atmosphere, hot air rises because the heat causes the volume to increase, which makes the density decrease, and the air therefore rises.  Cold air does the opposite: the volume decreases because there is less heat, causing the density to increase, and the air sinks.  The lateral movement between the hot and cold air is wind, and the entire unit is called a convection cell.  We demonstrated this in class by putting a candle under one tube and ice under another tube, and when we connected the two tubes and put the lit stick down the cold air tube, the air sank and moved through the connecting tube into the hot air tube, where the air rose again.

There are 3 main types of convection cells that govern the earth’s wind:

1. Hadley Cells–these control the tropics–move counter-clockwise
2. Ferrell Cells–control the temperate zones–move clockwise
3. Polar Cells–control the polar zones–move counter-clockwise

http://www.windows.ucar.edu/earth/Atmosphere/images/mesosphere_diagram_sm.jpg

Next, we talked about global winds that occur in the upper troposphere/ lower stratosphere.  (These winds are part of what we call the Jet Stream).  Global winds are created by “global air circulation,” which is determined by (1) uneven heating of earth’s surface by the sun, (2) rotation of the earth on its axis, and (3) properties of air, water, and land.  We watched a short video called The Unchained Goddess, which taught us about wind.  First, the ultimate cause of wind is the sun.  The sun heats the equator more directly and intensely than the poles, so warm air is constantly rising and moves towards the poles. The poles, have cooler air, which is constantly falling and moving towards the equator.  This creates the movement of North and South winds; however, wind also moves East and West.  The earth is curved and is always rotating on its axis- because of this, the big loop of the winds moving North to South and South to North, is broken up into three small loops that circulate in different directions.  Wind is given direction by the Coriolis Effect.

The Coriolis Effect is essentially what makes the winds “curve.”  For example, think about two children on a carrousel throwing a ball; both children are moving with the carrousel.  When one child throws the ball, the other child doesn’t catch it because it appears as if the ball is moving on a curved path; however, this is not the case.  The ball is thrown straight, but it is the catcher that is moving away from the original target of the ball.  Click on the link to see an animation of the Coriolis Effect.  http://www.mhhe.com/biosci/genbio/tlw3/eBridge/Chp29/animations/ch29/global_wind_circulation.swf