Chapter 54: Introduction to Ecology (Part 2, Week 3) Flashcards
[Start 54.4 Climate and its Relationship to Biological Communities]
What do you call the prevailing weather pattern in a given region?
Climate (temp, wind, precipitation, and light)
Explain how substantial differences in tempeture occur over the Earth
Mainly due to what?
Surface area example.
Greater distance traveled example.
- Mainly due to latitudinal variations of incoming solar radiation
- Increase of surface area of where sun’s rays hit (Canada and Russia) vs the equator (smaller surface area)
- More heat is also lost in the atmosphere of higher altitudes because the Sun’s rays travel a greater distance through the atmosphere (think layers of the earth), allowing more heat to be dissapted by cloud cover. Results in 40% less solar energy strikes polar latitudes than equatorial areas.
Where in the world does both cloudiness and rain reduce average temperature, so the temperatures do not continue to increase toward the equator?
The tropics. (there is a wide latitudinal range where temperature remains the same)
What are areas of high pressure that are the sites of the world’s tropical deserts because the subsiding air is relatively dry, having released all of its moisture over the equator?
Subsidence zones
What do you call the equatorial flow from oth hemispheres meeting near the equator in a region?
InterTropical Convergence Zone (ITCZ)
What is the Earth’s axis of rotation tilted in degrees?
23.5 from vertical.
The solar equator, the area receiving the most solar energy (which is North and South of the equator), varies seasonally and reaches 23.5 degrees north on June 21 and 23.5 degrees south on December 21.
This means that for half of the year the Northern Hemisphere receives more solar energy, and for the other half of the year the Southern Hemisphere recieves more solar energy.
In the Northern Hemisphere, these dates are called the summer and winter solstices.
On the dates of March 21 and September 22, the so-called spring and autumn equinoxes, what do all locations in the Northern and Southern hemispheres experience?
Equal amounts of solar radiation. The solar equator does not exist during these times.
At 60 degrees north, during the northern winter, temperatures in Siberia may average what temperature? What about summer?
-12 degrees celsius
16 degrees celsius (a difference of 28 degrees celsius.
In contrast, tropical temperatures vary relatively little, prehaps 2-3 degrees celsius year round.
Even though the Southern Hemisphere temperatures vary seasonally also, how does it moderate temperature extremes?
The large expanses of open water.
What is the Coriolis force? And why is it important for rockets and pilots?
Because of the Earth’s rotation, winds are deflected east and west, which gives spin to storm systems, and is a reason hurricanes spin counterclockwise in the Northern Hemisphere but clockwise in the Southern Hemisphere.
Pilots have to compensate… They cannot fly in a straight line since the earth is always rotating. If they flew straight from the north pole towards mexico, they would probably land in hawaii or thailand.
What is the process in which increasing elevation produces a decrease in air temperature due to lowered air pressure?
Adiabatic cooling
What happens to air as it is blwon across the Earth’s surface and up over mountains?
It expands because of the reduced pressure (less gas molecules meaning less dense air “thin air”) Earth’s gravity tries to keep gas molecules as close to the surface as possible.
Gravity also decreases with elevation.
What happens to air as it expands when it gets at higher elevation?
It cools at a rate of about 10 degrees Celsius for every 1,000 m in elevation, as long as no water vapor or cloud formation occurs.
Because there is less gas or air density at higher elevations, the molecules in the air do not bump into each other as often which reduces temperature.
Extra: What household appliance uses adiabatic cooling? How does it work?
This process is applied in the function of a refrigerator!
The refrigerant gas cools as it expands coming out of the compressor (mimics low altitude)
What amount of vertical ascent produces a temperature change roughly equivalent to that brought about by an increase in latitude of 1,000 km?
600 meters.
This explains why mountaintop vegetation, even in tropical areas, can have characteristics of a colder biome.
How do mountains influence patterns of precipitation?
When warm, moist air encouters the windward side of a mountain, it flows upward and cools, releasing precipitation in the form of rain or snow. (think the windward side in hawaii, it was very green).
On the side of the mountain sheltered from the wind (leeward side), drier air descends (because it rained or snowed all its moisture), producing what is called a rain shadow, an area where precipitation is noticeably less.
The western side of the Cascade Range in Washington State recieves more than 500 cm of annual precipitation, whereas the eastern side recieves only 50 cm!
What is the familiar onshore sea breezes in coastal areas an affect of?
- Land cools and heats more quickly than the sea does. Remember: the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius is called specific heat. It is much lower for land.
- When warm air rises and cooler air moves in to replace it.
- At night, the land cools quicker than the sea, and so the pattern is reversed, creating offshore breezes. The sea, therefore, has a moderating effect on the temperatures of coastal regions and especially islands.
What is created by wind that acts as pinwheels between continents running clockwise in the ocean basins of the Northern Hemisphere and counterclockwise in those of the Southern Hemisphere?
Ocean currents
