PDS AP Environmental Science 8th Period 2010-11

Hey y’all-

So I saw in my notes that the higher the temperature, the higher the biodiversity. So that would mean that tropical biomes would have the most biodiversity which doesn’t make sense to me because only very specific types of organisms can live in these harsh climates. It makes sense to me to say that temperate climates have the most biodiversity since they have a very adaptable, non-extreme climate. Can someone clear this up for me? Thanks! Nat

Hey guys!

Could someone explain why the profundal part of a river is the most oxygenated? I would have thought it would be the top where plants are able to do photosynthesis, but that wasn’t the right answer on our test.

Thanks!

Hey guys- I’m still a little confused about climate.. I understand that uneven heating and water distribution were the two things we listed as “factors” to establish climate, but I thought that climate was more about precipitation. I know this sounds simple but I guess my real question is are climates and biomes the same? Or can one biome have multiple climates?

If so, check the box for “ALZ Biome Practice Test.” Download questions and a key to get you thinking…

For the global wind directions, I am confused as to why each “pair” of winds goes the direction they do. I understand that warm air rises and cool air falls and I understand that the rotation of the Earth causes winds to go East and West instead of just North and South but for example, why do the trade winds above the equator go the opposite direction of those below the equator? In other words, why do the pairs go in opposite directions? Also, why do the polar convection cells go the same direction as the hadley cells (tropic level) if the air temperature is significantly different?

Thanks!

What is the difference between an arctic grassland tundra and an alpine tundra? The textbook briefly mentions alpine and does  not specially mention arctic grassland. They seem to be grouped together for nearly everything. Is the alpine higher than the arctic grassland? There are abiotic and biotic factors nearly the same (as it would appear to me)? Lastly, is alpine the only one on the very top of a mountain?

Hey guys, this isn’t a question, but its something I asked Mr. Willard that I thought you guys may want to know too:

Dry vs. Rainy seasons only apply to deserts, grasslands, and chaparrals. This is why these 3 biomes can’t support big trees-they would die during a dry season.

All the other seasons have relatively constant precipitation so they can support big producers year round.

Also, in general,

any pole biome usually has two seasons, temperate biomes have four, and tropical biomes have one.. they vary because of the amount of solar radiation they receive.

I know that lakes and oceans share the name for the bottom most layer, but do they share a litoral zone. I know that some of the bigger lakes are affected by tides, so would that qualify the lake with an intertidal zone. And in rivers and streams, is there the same partition of zones as there are in lakes or rivers?

Climate is a very different concept then what we would call weather. While weather is a very local phenomenon, Climate is studied on a larger regional scale. Weather also changes and is studied on a hourly to weekly basis. Climate, on the other hand, needs to be studied on a much more long term scale that is usually based on decades. Weather and climate also differ in the specific areas of the atmosphere they occur. Weather is usually found in the lower troposphere, while climate is found in the lower stratosphere. Climate and weather are very different things, but they are related because the general “big picture” concept (climate) determines what is “normal” weather for a specific area.

We are now left with the question, “What drives and determines climate?” Through a couple of simple experiments we were able to answer this question. In the end there are three major factors that develop climate.

1. Uneven Heating of the Earth:

The tilt of Earth’s axis, its spherical shape, and its orbit are the primary reasons why some areas are heated more then others. The tilt of Earth’s axis (23.5 degrees) and its orbit work together to produce seasons. The the tilt never changes instead it is oriented differently depending on where the Earth is in its orbit. During its orbit, one hemisphere might be closer or further away from the sun then the other hemisphere. This creates seasons when a region will experience more heat then another.

Finally, the spherical shape of the Earth makes light hit the atmosphere at different angles. As light reaches the poles it has to go through more atmosphere then it would at the equator because of the angle it hits the atmosphere. One comparison can be the concept of sloped armor on vehicles (see picture). The fact that light cannot reach areas with higher or lower latitude further adds to the uneven heating of the earth. Our experiment in class involved a tilted globe with aquarium thermometers stuck on different latitudes and a lamp to heat the globe up. After a few minutes the poles where cooler then the areas closer to the equator.

2. Different Characteristics of Land and Water:

The most significant difference between land and water are their specific heats, or the amount of energy needed to heat something up one degree. Water has a very high specific heat and will be cooler then land during the day because in needs more energy to heat up to the same temperature, but the oceans will be warmer at night because they will retain this heat better than landmasses. This is why people call water a “heat sink”. Land and water are also not distributed equally on the globe, so there are always warmer regions and cooler regions at any given time. Air at the warmer areas will rise then move over a cooler region and fall. This action creates convection cycles which form the basis of global wind patterns. In class, we had two tubes that were connected to each other, and one tube had a beaker of hot water in it and the other a beaker of cold water. Mr. Willard then stuck a burned stick down the top of the cold tube. After a few minutes, the smoke fell to the bottom, shifted to the hot tube, and started to rise out of the top of the hot tube.

3. Rotation of the Earth:

Lastly, we discussed the effect the rotation of the planet has on climate. We watched a quick video on the Coriolis Effect, which described why winds can blow to the east and west rather then just north and south, due to convection cycles. The Coriolis Effect shows how things appear to curve when the move across a spinning object because the object moves under the traveling projectile. The move used the example of a carousel and throwing a ball to prove this point. When the carousel was not moving, it was easy for the boys on the carousel to throw and catch a ball. When the carousel started moving, the ball looked like it was curving because when the ball was thrown its target was moving from its past position as the ball continued going straight. The same thing happens to wind currents that “curve” around the planet as it moves which creates winds that can travel east or west.

Today in class we began our discussion on Earth’s atmosphere. Earth’s atmosphere is mainly comprised of nitrogen gas at 78%. N₂ is an inert gas (a gas that is non-reactive under normal situations) that does not natural affect humans. Decomposers put nitrogen gas into a useable form through the 3 reactions in the nitrogen cycle: nitrogen fixation, nitrification, and denitrification. The next gas that is in the atmosphere is oxygen, which makes up 21% of our air. O₂ is very different compared to N₂, because oxgyen is highly reactive. O₂ can be split by sunlight to make ozone, which is crucial for people on Earth. The last 1% of the atmosphere is made up primarily of Argon, and there are many other permanent gases (Ne, He, H₂, Xe) and variable gases (H2O, CO₂, CH₄, O₃) that can be found in very small percentages. The percentage of water vapor can vary between 0-4% depending on where it is (the desert would be closer to 0%, while the rainforest would be closer to 4%).

(top picture) http://www.asc-csa.gc.ca/eng/educators/resources/spacesuit/composition.asp

(bottom picture) http://www.aerospaceweb.org/question/atmosphere/atmosphere/layers.gif

The Earth’s atmosphere can be divided into 4 layers, but we will mainly focus on the troposphere and the stratosphere. The atmospheric layers are only about 1/100th of the Earth’s diameter. The first, bottommost layer is the troposphere; this is where weather and human life occur. A nickname for the troposphere is the “weather maker.” The tropopause marks the boundary between the troposphere and the stratosphere. The temperature also starts to raise again after this point until you reach the stratopause. The next layer, the stratosphere, is primarily made up of the ozone layer. The reason that the temperature begins to raise after the tropopause and until it reaches the stratopause, is because in the ozone layer scatters UV rays. Without the ozone layer scattering UV radiation, human life would cease to exist. A nickname for the ozone layer is  ”global sunscreen.”

As you go further up in the atmosphere, pressure decreases because there is less gravity to pull down the air molecules. The concentration of air molecules will increase as the altitude decreases. This is crucial when climbing mountains; if a person climbs too high, the air will get thinner, with less air molecules to breathe. If you were to climb to the top of  Mount Everest, you would be above 2/3 of the air molecules. 99% of the air molecules are below 50% of the atmospheric layers. The atmospheric pressure is 14.7 lb/in² at sea level.

Relative humidity is the ratio of the amount of water vapor actually in the air to the maximum amount of vapor required for saturation at the particular temperature. The relative humidity would be higher on a tropical island than at the desert. High humidity feels hotter to our bodies because it affects the ability of the air to evaporate our sweat. When the humidity is higher, there is more water vapor in the air. This means that it will take longer to evaporate sweat, which we need in order to cool our bodies.

http://en.wikivisual.com/index.php/Air