Climate and Life Distribution

Lecture: The Logic of Science

Prof. Stephen C. Stearns

OPEN YALE COURSE EEB 122: Principles of Evolution, Ecology and Behavior

Yale Univeristy

This lecture provides an overview of the physical aspects of earth’s biomes. Temperature, water, latitude, and altitude all come into play. Regions with similar levels of these climatic features tend to have similar life-forms living there. These same climatic features can also affect weather patterns, which in turn affect life by altering habitats and ecosystems. On a large enough scale, such as El Niño, these weather patterns can affect life all over the earth.

Part I

Part II

(Video source:

http://open.163.com)

Climate and the Distribution of Life on Earth (Part 1)

Prof.Stephen C.Stearns

(Source:http://open.163.com)

(Chinese and English subtitles:易仁知)

We are now going to show Block of the course. This is our ecology and these are the titles of the upcoming lectures. You can think of Ecology as providing the theater in the evolutionary play occurs. That's a metapher from the Evelpe Hutchinson.and I'm doing a top down and then going back. Going from the top down and then going from the bottom back of the top. So I'm going to start a to stay by taking about the climate and the planet and how life is distributed on the planet,And then move from that into the biology,So looking at Physiological ecology. And interaction. With the physical environment leading from the population growth、Competition, predation and parasitism up to vommunity.So this is sort of a way of doing a Cartesion bottom up construction of communities. And then dealing with some of the largest scale issues in ecology.  These will involve islands and collective populations as well as systems ecology, energy and material flows. The last section will cover both the role of biodiversity in ecology and the value of biodiversity. The last lecture in ecology will cover biodiversity from an economic perspective. Does biodiversity and biodiversity help ecosystems function better from an evolutionary perspective? This is our overall plan.

Today we are talking about the climate on earth, how the earth can be seen as a set of climate machines, and how climate gives birth to biological communities on earth. If we watch the world climate, we should be familiar with this knowledge. The world's climate is of course polar, tropical, but it contains a lot of details. The west of the Northern Hemisphere will be warmer and wetter, and the east will be cooler and drier. The effect of the Gulf Stream on Europe is obvious, because the warm current from the Gulf of Mexico pushes a large amount of warm water north and right. If it continues eastward into the Eurasian plate, it will be far away from the effects of the ocean, bringing the temperature to the lowest in the world, at least to record the lowest temperature in the northern hemisphere, or minus 127 degrees Fahrenheit is really sharp cold. Climate in similar areas has many very interesting similarities. Take a look at the coast of south america and the western part of north america, where the equator is the same, where temperate rainforests extend from northern california to alaska in north america or from south america to the coast of chile. these similar climates create similar biomes and selection pressures and also cause community convergence in these regions. So if you really want to figure out why I was in parts of new zealand in chile or british columbia in canada they always gave me a similar feeling? Although their vegetation is not related to each other, it looks just the same. It feels very similar. Even the forest is the same. This makes us understand why the Earth as a whole can construct similar climates in those places.

From a local perspective, the formation of rainforests in Chile or in British Columbia is partly related to the way mountains interact with the atmosphere. In both environments, clouds from the ocean are blocked up by mountains, and when they are forced to climb up, there are simple physicochemical reactions that result from the condensation of rising air that begins to cool, condenses all the time to form thick clouds, and then rains, after which the wind pushes them to the summit of the mountains. Basically all the moisture is blown away. Rainforests are formed because cold air can not hold as much water as warm air. A temperature drop cools at about six ℃ per 1000 m rise. Air temperatures from the ocean are 20℃, and the peak is about four ℃. Think of the mountain as the Sierra Nevada or the Karst Mountains in Oregon and Washington. On the other side of the mountain range, the air began to sink and become dry. The whole process is that moist air rises to form rainfall, moisture disappears, becomes dry, and the air begins to sink. And after such a wet air rising rainfall, dry air down warming process, leeward slope at the same height of the temperature is 4℃ higher than the upwind slope. Because the rain released the condensation heat, this is what we need to understand. As long as there is a larger flow of air on earth, this pattern is global. So where dry air drops, desert forms. where warm air rises forms rainforests. No matter the mountains or not, this pattern will change. This will be used soon, so I'd like to speak about it in advance. Warm air falls and is called burning wind in Switzerland. Swiss also often complain about the name, making them feel headache. It's called Santa Ana in Los Angeles. And in the valley of la haina town on Maui. The wind is so special that it can reach 140 mph. It's also hot, so it's important to keep these areas warm. That is why wildfires are blowing back in malibu.

Okay, now look at the global situation. If the earth is a still large ball, sitting quietly in space undisturbed, only the equatorial region is heated, it will form two convective monomers, one in each hemisphere. Then the cold air will begin to fall from the poles to the surface of the earth, in the process of absorbing water rising, forming a tropical rain forest near the equator, forming a slope vegetation zone in the middle of the desert in the polar earth. This is the case if the earth does not rotate, but the earth is constantly spinning, precisely because it is constantly rotating, the ideal earth will form three Hadley circulation circles. From the equator, the north and south three circulation circles. Because rising air condenses rapidly and loses its ability to control water to form rainfall, warm air rises in the equatorial region to form rainfall. Warm air moves north from the equator and drops 30 degrees north latitude, okay? At 30 degrees north, it interacts with another similar cyclophore, which carries warm air north to 60 degrees north. It is recalled that the tropical rainforests of Chile and British Columbia are located in these two regions, which are the desert zones of the earth, about 30 degrees north and south latitude.

Just about the idealized flow pattern. Incidentally, a polar peak is formed on their dividing line at the point where the polar pressure meets the Hadley Circles in the Northern Hemisphere. This is also the region of jet flow formation, in the northern hemisphere this region around the earth, in the southern hemisphere as well. This is where the jet stream is located. It contributes to most of the weather we encounter. It can almost be said that most of the polar peaks formed in Canadian weather are produced by jet flow structures, but this structure is unstable. These are very smooth and smooth in the idealized earth. These lines are very smooth, but in fact the earth's surface is not, the earth's surface will have continents and oceans. They also move in their own circulation patterns, both in the north and south. In the northern hemisphere, it moves from west to east, and the air flow is wobbly because the direction of the air flow is disturbed by the mountains and oceans of the earth's surface. Again, this picture is the actual model of the wind direction.

Wind affects not only the weather, but also history. To understand the history of the past 8,000 to 10,000 years, one must first understand the fact that people used to use climate phenomena in shipping trade. Westerly winds can be used at 35 and 40 degrees north latitude, and letter winds at 20 degrees north latitude, as in the southern hemisphere. In fact, these trade in the Indian Ocean, which promoted trade between India and the Roman Empire, so the letter wind between the Indian Ocean is also called the trade wind. So the earth's surface covered with these circulating cells is really very thin, such as the current observation distance, about three or four thousand miles about four or five thousand kilometers. while the depth of the circulating cell is only five to ten kilometers. So it's really very thin covering that keeps spinning. If there is no continent on earth, it will become like Jupiter. Jupiter has very clear partitions that are spinning. The Hadley Loop is seen as smooth, but the partitions are already very compact and clear. These are the rotating cyclophores. Jupiter's gyro cells are larger and larger than Earth's. Look for the earth's location on this map, so much larger, so Jupiter is going to be much bigger. Because the earth has continents and oceans, looking down from space at the photos taken by the clouds, it is not so smooth and smooth, you can see a lot of whirlpools. these eddies are caused by local airflow disturbances. This is the African continent and this is Antarctica. Between 40 and 60 south latitudes, the ocean is ° vast expanse, the sea breeze is moving in this direction, the whole ocean wind blowing unobstructed, almost all the way smooth, only at a small tip in South America will be subjected to resistance. The waves are as high as 100 feet and 30 meters, which is the starting point of the Volvo Global Sailing Race. Contestants can quickly move around the globe in a storm and life is in their own hands.

So there's no such perfect climate model on earth that I just showed you. The actual situation will be more chaotic, but there are still patterns, and then focus on a few patterns, of course, heat is still moving. The basic thing is that heat moves from the equator to the poles. This movement is driven solely by physicochemical dynamics to balance the heat gradient from the sun. This is done mainly by wind and water, and with the constant movement of air and water towards the poles, its radial speed is also getting faster and faster, because the earth rotates in different diameters at the equator and at the poles. The earth at the equator is 8000 feet in diameter and about 4000 miles in radius. As air and water release move towards several points, but eventually reach the pole, the moving diameter becomes zero. So we can use the trigonometric function to calculate the diameter of the circle of the rotating object in the process of moving north. If I start walking north from the equator, the ground at my feet is larger than my angular momentum, and the ground moves eastward slower than me. If I go south from the extreme and the ground under my feet starts moving outward, my angular momentum decreases. As a result, a stream of air and water moving toward the equator will be taken away, and its radial velocity will weaken, starting to accelerate westward. It is concluded that in the northern hemisphere to the north to the east and south to the west, this is the earth's rotation deflection force. Defines the direction of major ocean currents and climate such as winds, and shapes the way hurricanes rotate. So I want to make sure that everyone has this part, so give you a minute to think and answer. Now we can try to explain to our table how the earth's self-rotating deflection force moves. This is a three-dimensional geometric problem. The main principle is that the earth moves around the earth's axis, and the object moves south to north under the earth's surface, understand?

One or two minutes of discussion. how does the coriolis "force" work?: Cut a section along the equator, a circle with a radius of 4000 miles. If the cut is a little higher, it has a radius of 2,000 miles. A very rapid rotation of air or moisture moving north within 24 hours. The angular velocity here can reach 1000 miles per hour, then go up, let me calculate. 1200 miles in diameter. Instead of 2400 miles, he's here at 500 miles an hour. The object moves at an angular velocity of 1000 mph to a ground where the angular velocity is only 500 mph, so it moves in this direction. OK, this is the earth, this is the north-south axis of the earth. It is about 24000 miles long at the equator. The earth rotates once a day, and air and water on the equator move eastward at a speed of 1000 miles per hour. We have to move him north to bring heat to the poles. We pick a spot on the net and cut it off. The earth's circumference is 12000 miles, and the area rotates 500 miles per hour as the air moves northwards. When he reached the area, the land was 500 miles slow to the east, so the air speed exceeded the rotation speed of the land under it and moved eastward. can go from north to south, as in the southern hemisphere, but in the opposite direction. To figure this out, you have to separate the motion of the earth in your head and imagine yourself as an object moving south or north. Then on the ground either you rotate faster than the ground under your feet or the ground rotates outward as you move further south.

I had to speak these things in German, when I was learning German, I wanted to express the meaning of the earth's rotation, and it turned out that die erde spinnt( the world was crazy) The students were so happy that although the content was completely wrong, they were very happy. Well, if that happens, the result is that the earth's rotation bias affects the black tide, pushing it eastward during its northward shift, then southward into the california current in the west bank of the united states, then bent westward. In both northern and southern hemispheres, a pattern of ocean rotation such as this can be established, with ocean currents moving northward in the southern hemisphere bending westward; ocean currents moving southwards bending eastward. So the Northern Hemisphere bends clockwise and the Southern Hemisphere bends counterclockwise.

In addition, just as there are three cyclists in the atmosphere in the Hadley Loop, the ocean has a three-dimensional structure, where the cold Antarctic surface waters of the northern Antarctic continent sink, that is, the Antarctic band is about here, and then forms a cyclophore crawling against the bottom of the main ocean before rising to the surface. Here is a very important point where the waters from the Arctic Ocean sink undercurrent in Greenland to the Gulf Stream. This involves a very real problem in global warming. This is not really a point, but whether the sinking water can continue to stabilize, if the cyclists can not maintain a steady southward movement of the Gulf Stream will be blocked, the British, French and Spanish climate will soon become like the climate of northern Canada, if there is a mutation may occur within a few years, so it is important to understand the movement of these currents. has a great impact on society and the hundreds of billions of residents living there. I have two things to say about this general model. This picture is about to tell the overall pattern of the earth, the first division of the hurricane. This phenomenon exists in both the north and south, and there will be El Niño in the equatorial region of the Pacific Ocean. I would like to discuss the hurricane and El Niño phenomenon a little, because these are two large-scale weather patterns on Earth.