Shared Flashcard Set


ISSL Physical Geography U7 final
as an aid to the online course
11th Grade

Additional Geography Flashcards




Explain the Big Bang Theory of the creation of the universe?

beginning with a singularity

the beginning with a point of singularity is now questioned because of the "uncertainty principle" in quantum Mechanics  , which say one can not measure accurately both the speed and position of a quantum of energy. thus if we know the speed the Universe was expanding we can not be sure of its position)

there was an explosion

expanding gas nebula left all stars, galaxies we see in all directions were formed

still expanding

The understanding of what will eventually happen is divided into three groups:

1.) if there is enough m,ass gravity will take over and the universe will collapse again.

2.) if there is not enough mass the Universe will keep expanding, slow down, stop, freeze, and parts will collapse into "black holes"  Most scientist are in this group they only differ in the rate and change of slow down.

3.) there are some who talk about the pressure of expansion becoming too great and the Universe splitting or ripping.

Explain the formation of the earth by accretion and differentiation

accretion = parts joining, example planetesimals smashed  into each other, stuck, heated up in the collision, the result is earth has a hot core.

differentiation (things separating - becoming different) occurs in four ways:

1.) heat - light elements rise in a hot liquid - heavier sink.

2.) gravity - light hings are not pulled towards the centre of the earth as rapidly as heavier elements, thus the core of the iron, a heavy metal

3.) chemically - example the earth has formed different rocks  through cooling they have chemically crystallized or through heat and pressure chemically formed metamorphic rocks.

The earth is still in a proce\ss of both accretion - things sticking together (volcanic islands forming) and differentiation - things separating (the air forming into pockets of high or low pressure; warm or cold fronts).

[image]Given the topographical map of Fundy Park, New Br; give the 6 figure reference for the most southerly tip of the lake.

First you go in from left to right = 37.9

then you go up from the bottom = 54.2




[image] Part of the Fundy Park topographic map 


Given the topographical map of Fund Park, New Br.; it measures 13 cm from the southern tip of Bennett lake TO THE PICNIC IN 4452. HOW MANY KILOMETEERS ON THE GROUND IS IT BETWEEN THE TWO POINTS? SHOW ALL YOUR WORK INCLUDING THE COVERSION OF THE SCALE INTO CM TO KM. 


1 to 50,000 means

1 cm measured on the map = 50,000 cm measured on the ground

thus 13 cm times 50,000 = 650,000 cm on the ground

i km = 100,000 cm 

thus 650,000 divided by 100,000 = 6.5 km between the two points

[image]given Fundy park topographical map. What is the direction of the marked picnic ground from Bennet Lake?
south east
[image]Given Fundy Park topographic map. The highest point on Dickson Hill is

1000 ft

on the map in reddish brown are the heights of 750 feet and 1,000 with five space marked by green lines. The difference between 750 and 1,000 is 250 ft. thus divide 250 by 5 each green line = 50 ft.

Counting up from the 750 reddish brown line on Dickson Hill we get 5 space because there is a small circle just under the name = 1,000 ft 

[image]which of these profiles most closely resembles the shape of the land between Dickson Hill and the marked picnic ground on the Fundy Park map.
[image]Given the air photo of entrance to Fundy National Park What are the light areas in the water in the upper right corner of the photo
[image]Given the air photo of entrance to Fundy National Park what are the smooth green areas under, for example, C, E, G, and L
grass lawns
[image]Given the air photo of entrance to Fundy National Park  what is the black area at J
[image]Given the air photo of entrance to Fundy National Park  what is the blue rectangle at A
swimming pool
[image]Given the air photo of entrance to Fundy National Park  how can you tell the light blue object at A is man made?

It is a rectangle and very regular

no organic shape to it

[image]Match the name of the atmosphere with the number indication its correct location on the diagram. Troposphere is number ...
[image]Match the name of the atmosphere with the number indication its correct location on the diagram.  Mesosphere is number .... 
[image]Match the name of the atmosphere with the number indication its correct location on the diagram. Thermosphere or Ionosphere is number ...
[image]Match the name of the atmosphere with the number indication its correct location on the diagram.  Stratosphere is number ....
[image]Match the name of the atmosphere with the number indication its correct location on the diagram. Exosphere is number ...

Briefly describe the main characteristics of each layer of the atmosphere. 



14-18 km high
all weather happens here
almost all water vapour is in this layer
0° to -90°C
at top of pressure drops to 1/10 sea level pressure

the lowest layer of the atmosphere. This is the layer where most weather takes place. Most thunderstorms don't go much above the top of the troposphere (about 10 km) . In this layer, pressure and density rapidly decrease with height, and temperature generally decreases with height at a constant rate. The change of temperature with height is known as the lapse rate. The standard lapse rate for the troposphere is a decrease of about 6.5 degrees Celsius (C) per kilometer (km) (or about 12 degrees F). Near the surface, the lapse rate changes dramatically from hour to hour on clear days and nights.Sometimes the temperature does not decrease with height, but increases. Such a situation is known as a temperature inversion. Persistent temperature inversion conditions, which represent a stable layer, can lead to air pollution episodes...

The other main characteristic of the troposphere is that it is well-mixed. The name troposphere is derived from the Greek tropein, which means to turn or change. Air molecules can travel to the top of the troposphere (about 10 km up) and back down again in a just a few days. This mixing encourages changing weather.

The troposphere is bounded above by the tropopause, a boundary marked as the point where the temperature stops decreasing with height and becomes constant with height. Any layer where temperature is constant with height is called isothermal. The tropopause has an average height of about 10 km (it is higher in equatorial regions and lower in polar regions). This height corresponds to about 7 miles, or at approximately the 200 mb (20.0 kPa) pressure level. Above the troposphere is the stratosphere.


What is the greenhouse effect
The Earth is wrapped in a blanket of air called the 'atmosphere', which is made up of several layers of gases. The sun is much hotter than the Earth and it gives off rays of heat (radiation) that travel through the atmosphere and reach the Earth. The rays of the sun warm the Earth, and heat from the Earth then travels back into the atmosphere. The gases in the atmosphere stop some of the heat from escaping into space.These gases are called greenhouse gases and the natural process between the sun, the atmosphere and the Earth is called the 'Greenhouse Effect', because it works the same way as a greenhouse. The windows of a greenhouse play the same role as the gases in the atmosphere, keeping some of the heat inside the greenhouse.
How can the problem of global warming and the greenhouse effect be corrected over time


By some stroke of providence, every step we need to take to reverse the greenhouse effect is worth doing anyway. Every step is technically possible. Most of them will even save money. Unfortunately for our sense of drama, preventing global climate change need not be a great, grim sacrifice. We are not called upon to save the world. Instead we have an opportunity to build a better one.

Here's a list a list of anti-greenhouse measures, in order of effectiveness, as I heard them presented to an international meeting last month:

- Use energy much more efficiently (which would also cut fuel bills, urban smog, acid rain, oil spills, toxic wastes, and oil imports),

- Phase out chlorofluorocarbons (CFCs) completely and quickly (an international treaty has already mandated a partial phase-out, in order to repair the "ozone hole"),

- Accelerate the transition to solar, wind, hydro, and biomass energy sources (which would have all the beneficial effects of energy efficiency and ensure an inexhaustible energy supply),

- Shift fossil fuel use away from coal and oil and toward natural gas (an interim measure until solar sources are tapped -- it would also reduce many air pollutants),

- Stop deforestation and accelerate reforestation (thereby sustaining the supply of forest products, reducing soil erosion, flood, and drought, moderating temperatures, and preserving endangered species),

- Increase use-efficiency and recycling of all materials and of water (which would save money, reduce energy needs, extend the lives of mines and groundwaters, and reduce municipal solid waste, toxic waste, mine waste, and water pollution),

- Practice low-input agriculture (reducing farm costs, increasing energy efficiency, restoring soils and wildlife, reducing water pollution, improving health).

- Slow population growth in poor countries, where 90% of population growth takes place. Slow wasteful consumption in rich countries. (These two measures would ease every environmental problem and most economic ones -- and without them the other steps listed here would just be stop-gaps.)

Some people find this list an exciting challenge. Others think it sounds like Exercise Properly, Get Enough Sleep, Floss Your Teeth. We know our lives would be better if we did these things, but somehow there's a barrier of habit to get over -- we'd really rather not think about it.

People will never change their comfortable little self-destructive habits, some say. Let's talk about adapting to climate change; we'll never prevent it.

I'm not willing to be that fatalistic. I believe in good old self-serving human rationality. I think that anyone, however lazy or greedy, who looks at the full costs and benefits of preventing climate change, as opposed to enduring it, will see that there is no better payoff on the planet than greenhouse prevention.

At least the first few steps could be trivially easy. If West Germany put a speed limit on its Autobahns, it would reduce its greenhouse gas emissions by 26 million tons per year. By buying efficient refrigerators, Americans have already cut electricity use enough to avoid building 80 coal-fired power plants (and saved $5 for every $1 spent on the refrigerators). We could save more money and reduce refrigeration energy by another 2/3 by installing the most efficient models now on the market.

WHO should lead the way? Governments? Individuals? The only possible answer is both, with the realization that in democracies the people are always out in front. And there's plenty we can do. The Greenhouse Crisis Foundation has come out with a list of 101 things YOU can do to stop global climate change. You can imagine what's on it.

Buy energy efficient appliances and a car with the highest possible gas mileage. Insulate your home, caulk and weatherstrip your doors and windows, turn off lights when you're not using them. On nice days use the sun, not the clothes dryer. Reuse, repair, recycle everything you can. Don't buy stuff you don't need. Shop with a re-usable canvas bag; turn down BOTH paper and plastic bags from the stores. Shun overpackaged products and bug manufacturers about them. Don't take unnecessary car trips. Don't speed. Buy organic food, not junk food. Plant trees. Plant a garden and don't use chemical fertilizers or pesticides on it, or on your lawn. Write to Congress and the President.

It may sound like Eat Balanced Meals, Don't Smoke, and Balance Your Checkbook, and in a way it is -- it's what adult people need to do, as an unremarkable matter of habit, to make their lives and their planet work. As Winston Churchill once said, "Sometimes you have to do what is required."

Or as Buckminster Fuller used to say, it's time to grow up. The human race has been like a bird in the egg, supplied with an abundance of nutrient, and an unpolluted space into which to develop -- to a certain point. We've exhausted the nutrient and the space. "We are going to have to spread our wings of intellect and fly, or perish."


give two examples of the albedo effect

 is the percentage of incoming radiation reflected off a surface. An albedo of 1 means that 100% of incoming radiation is reflected (no radiation is absorbed); an albedo of 0 means that 0% of incoming radiation is reflected (all radiation is absorbed).

Why is the Albedo effect important?
The more radiation reflected the less global warming that occurs. You have probably heard how the ice caps reflect solar radiation and hence why their melting is such a big issue. Fresh snow has an albedo of approximately 0.9.

The tropics

Although the albedo-temperature effect is best known in colder regions on Earth, because more snow falls there, it is actually much stronger in tropical regions which receive consistently more sunlight.

]Small scale effects  Albedo works on a smaller scale, too. People who wear dark clothes in the summertime put themselves at a greater risk of heatstroke than those who wear lighter color clothes]


Because trees tend to have a low albedo, removing forests would tend to increase albedo and thereby could produce localized climate cooling (ignoring the lost evaporative cooling effect of trees). Cloud feedbacks further complicate the issue. In seasonally snow-covered zones, winter albedos of treeless areas are 10% to 50% higher than nearby forested areas because snow does not cover the trees as readily. Deciduous trees have an albedo value of about 0.15 to 0.18 while coniferous trees have a value of about 0.09 to 0.15.[4]

Studies by the Hadley Centre have investigated the relative (generally warming) effect of albedo change and (cooling) effect of carbon sequestration on planting forests. They found that new forests in tropical and midlatitude areas tended to cool; new forests in high latitudes (e.g. Siberia) were neutral or perhaps warming.


Snow albedos can be as high as 0.9; this, however, is for the ideal example: fresh deep snow over a featureless landscape. Over Antarctica they average a little more than 0.8. If a marginally snow-covered area warms, snow tends to melt, lowering the albedo, and hence leading to more snowmelt (the ice-albedo positive feedback). Cryoconite, powdery windblown dust containing soot, sometimes reduces albedo on glaciers and ice sheets.


Water reflects light very differently from typical terrestrial materials. The reflectivity of a water surfaces depend upon, the wavelength of light even wavy water is always smooth so the light is reflected in a locally specular manner (not diffusely). The glint of light off water is a commonplace effect of this. At small angles of incident light, waviness results in reduced reflectivity because of the steepness of the reflectivity-vs.-incident-angle curve and a locally increased average incident angle.

Although the reflectivity of water is very low at low and medium angles of incident light, it increases tremendously at high angles of incident light such as occur on the illuminated side of the Earth near the terminator (early morning, late afternoon and near the poles). However, as mentioned above, waviness causes an appreciable reduction. Since the light specularly reflected from water does not usually reach the viewer, water is usually considered to have a very low albedo in spite of its high reflectivity at high angles of incident light.

Note that white caps on waves look white (and have high albedo) because the water is foamed up, so there are many superimposed bubble surfaces which reflect, adding up their reflectivity.


Cloud albedo is an important factor in the global warming effect. Different types of clouds exhibit different reflectivity, theoretically ranging in albedo from a minimum of near 0 to a maximum approaching 0.8. "On any given day, about half of Earth is covered by clouds, which reflect more sunlight than land and water. Clouds keep Earth cool by reflecting sunlight, but they can also serve as blankets to trap warmth."

Albedo and climate in some areas are affected by artificial clouds, such as those created by the contrails of heavy commercial airliner traffic. A study following the burning of the Kuwaiti oil fields during Iraqi occupation showed that temperatures under the burning oil fires were as much as 10oC colder than temperatures several miles away under clear skies.

]Aerosol effects

Aerosols (very fine particles/droplets in the atmosphere) have both direct and indirect effects on the Earth’s radiative balance. The direct (albedo) effect is generally to cool the planet; the indirect effect (the particles act as cloud condensation nuclei and thereby change cloud properties) is less certain. the effects are:

  • Aerosol direct effect. Aerosols directly scatter and absorb radiation. The scattering of radiation causes atmospheric cooling, whereas absorption can cause atmospheric warming.
  • Aerosol indirect effect. Aerosols modify the properties of clouds through a subset of the aerosol population called cloud condensation nuclei. Increased nuclei concentrations lead to increased cloud droplet number concentrations, which in turn leads to increased cloud albedo, increased light scattering and radiative cooling (first indirect effect), but also leads to reduced precipitation efficiency and increased lifetime of the cloud (second indirect effect).

]Black carbon

Another albedo-related effect on the climate is from black carbon particles. The size of this effect is difficult to quantify: the Intergovernmental Panel on Climate Change estimates that the global mean radiative forcing for black carbon aerosols from fossil fuels is +0.2 


Explain how pressure systems  affect climate
Pressure systems have a direct impact on the precipitation characteristics of different climate regions. In general, places dominated by low pressure tend to be moist, while those dominated by high pressure are dry. The seasonality of precipitation is affected by the seasonal movement of global and regional pressure systems. Climates located at 10oto 15o of latitude experience a significant wet period when dominated by the Intertropical Convergence Zone and a dry period when the Subtropical High moves into this region. Likewise, the climate of Asia is impacted by the annual fluctuation of wind direction due to the monsoon. Pressure dominance also affects the receipt of solar radiation. Places dominated by high pressure tend to lack cloud cover and hence receive significant amounts of sunshine, especially in the low latitudes. 


Explain how large lakes  affect climate



The oceans aren't alone in affecting climate. The Great Lakes, for example, have a decided affect on regional weather conditions. "Acting as a giant heat sink, the lakes moderate the temperatures of the surrounding land, cooling the summers and warming the winters,"

"This results in a milder climate in portions of the basin compared to other locations of similar latitude." The Great Lakes also increase the moisture content of air throughout the year, acting like a "giant humidifier," . In fact, the lakes are responsible for "snow belts" on their downwind shores, caused in the winter when this moisture condenses as snow. According to Great Lakes Net, the coast of Lake Superior is particularly affected by this and have recorded "up to 350 inches of snow in a single year."



Explain how urban centres affect climate



n urban climatologist studies the climate in and around cities. Urban areas are both affected by weather and climate, and exert an influence on the local scale weather and climate. The climate in and around cities and other built up areas is altered in part due to modifications humans make to the surface of the Earth during urbanization. The surface is typically rougher and often drier in cities, as naturally vegetated surfaces are replaced by buildings and paved streets. Buildings along streets form urban street "canyons" that cause the urban surface to take on a distinctly three-dimensional character. These changes affect the absorption of solar radiation, the surface temperature, evaporation rates, storage of heat and the turbulence and wind climates of cities and can drastically alter the conditions of the near-surface atmosphere. Human activities in cities also produce emissions of heat, water vapour and pollutants that directly impact the temperature, humidity, visibility and air quality in the atmosphere above cities. On slightly larger scales, urbanization can also lead to changes in precipitation above and downwind of urban areas. In fact, urbanization alters just about every element of climate and weather in the atmosphere above the city, and sometimes downwind of the city.

Although cities themselves form a very small fraction of the Earth's surface area, the world's population has become increasingly urbanized and is now affected by urban climates. Cities too, are important sites for greenhouse gas emissions because of the high energy demands by urban residents and activities. These emissions extend the (indirect) influence of cities on climate to much larger scales. Locally altered urban climates that have existed for many years may provide us with some insight into how to respond to large scale climate change and this makes the study of urban climates increasingly important.




Explain how altitude affect climate




Relief of the land affects climate


The higher you go the colder it gets.

Climate can be affected by mountains.


Mountains receive more rainfall than low lying areas because the temperature on top of mountains is  lower than the temperature at sea level.  That is why you often see snow on the top of mountains all year round.  The higher the place is above sea level the colder it will be.  This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat


[image]Given the climagraph is this place in the northern or southern hemisphere? Why do you think so?
It is probably in the northern hemisphere because it is hotter in summer and the temp on graph rise and peek during the northern hemisphere summer period -June, July, and August
[image] Given the climograph Is the place illustrated nearer to the pole or the equator? Why?

This place would not be on the equator because the temp goes to minus five ( -5 ) Centigrade in December, January, and February.

Although it is unlikely to be at the poles because the temp also rises to  twenty (20 ) Centigrade in summer.

Thus it is most likely at a moderate latitude

[image] Given the classification system illustrated in the diagram, which climate type does the place in the graph fall into?

the grey area represents a moderate climate

with temp between 15 and -3

with precipitation between 600 to 1,400 mm

The place in the earlier climagraph also falls within this ranges of temp. -10 to 20 (slightly colder and slightly warmer)


within the same precipitation range

with precipitation of 1,100 mm per year

Which air masses affect Atlantic Canada in summer? Where do they originate from?  What type of weather conditions do they bring?

Four of the six basic air masses types affect weather in Atlantic Canada. They can bring anything from scorching heat to bone-chilling cold depending on the type of air mass and time of year. The most violent weather usually occurs during Spring when cold, dry continental polar air clashes with hot, humid maritime tropical air.

Arctic (A): Extremely cold temperatures and very little moisture typify Arctic air masses. They usually originate north of the Arctic Circle, .... are rarely seen at lower latitudes during the summer because the 24-hour sun warms the Arctic region considerably and the polar front and accompanying jet stream generally remains at higher latitudes. So during summer this air mass would rarely affect the weather in Atlantic Canada

Continental polar (cP): Cold and dry, Continental polar masses are not as cold as Arctic air masses. These usually form further south in the sub-polar Canadian North and Alaska and ... do form during the summer, but mostly influence only Canada and therefore Atlantic Canada. These air masses are usually responsible for bringing clear and pleasant weather during the summer.

Maritime polar (mP): Cool and moist conditions characterize Maritime polar air masses. They usually bring cloudy, damp weather. Maritime polar air masses form over the northern Pacific (and would never affect Atlantic Canada) and the northern Atlantic Oceans (which do affect Atlantic Canada). These generally influence the Pacific Northwest and the Northeast, respectively. Maritime polar air masses can form any time of the year, thus during summer would bring cooling storms


Maritime tropical (mT):
 Warm temperatures with copious moisture typify Maritime tropical air masses. They are most common across the eastern US and southeastern Canada (which would include Atlantic Canada) originating over the warm waters of the southern Atlantic Ocean, Caribbean Sea and the Gulf of Mexico. These air masses can form year round, but they are most prevalent during summer. Maritime tropical air masses are responsible for the hot, humid days of summer across much of the eastern half of the continent. Such air masses are often called the Bermuda High because of their birthplace within the subtropical zone around and east of Bermuda.



[image] Using the weather map. Considering the direction of the movement for weather systems in Canada, what may Sept Isle's weather be like in 24 hours? Why?

given that air masses move from west to east in Canada and North America

The cold front over north-westerrn Ontario will continue to move east as all of the arrow indicators on the weather stations also indicate.

The grey area in front of it is probably snow storms as the temp of those weather stations are -2 to -3

Also the cloud cover symbols are all solid in those areas (withing the grey mass in front of the cold front) where-as Sept Isl right now is clear 

It is more than likely a snow storm will hit Set Isl in the next twenty four hours bringing freezing temp as Sept Isl is right now 5

Explain how thunderstorms form. When are they most likely to occur in New Brunswick, Canada?

Lightning is the key ingredient that defines a thunderstorms since lightning is needed to create thunder.

Thunderstorms come in all shapes and sizes with some cells only a few miles in diameter and some clusters of storms, known as mesoscale convective complexes, that span hundreds of miles.

A typical thunderstorm produces a brief period of heavy rain and lasts anywhere from 30 minutes to an hour.

Warm, humid conditions are very favorable for thunderstorm development. This helps create the strong updrafts that feed warm, moist air into thunderstorms.

If the air is very unstable, severe thunderstorms with damaging winds, large hail, and sometimes tornadoes erupt.


Cold fronts, dry lines, or afternoon heating, which causes warm air to rise, can trigger thunderstorms. Finally, you need lift. This can form from fronts, sea breezes or mountains.Thunderstorms can occur year-round and at all hours. But they are most likely to happen in the spring and summer months and during the afternoon and evening hours.

How are soil, vegetation and climate dependent on each other?

Retrogression and degradation are two regressive evolution processes associated with the loss of equilibrium of a stable soil.
The retrogression is primarily due to erosion and corresponds to a phenomenon where succession reverts back to pioneer conditions (such as bare ground).
Degradation is an evolution, different of natural evolution, related to the locale climate and vegetation. It is due to the replacement of the primitive vegetation (known as climax) by a secondary vegetation. This replacement modifies the humus composition and amount, and impacts the formation of the soil. It is directly related to human activity.

Soil evolution cycle

The soil represents the surface layer, of the earth's crust, resulting from the transformation of the bare rock, enriched by organic input. 
At the beginning of a soil formation, only the bare rock outcrops. It is gradually colonized by pioneer species (lichens and mosses), then herbaceous vegetation, shrubs and finally forest. In parallel a first humus-bearing horizon is formed (the A horizon [the top soil]), followed by some mineral horizons (B horizons[the sub soils]). Each successive stage is characterized by a certain association of soil/vegetation and environment, which defines an ecosystem.
After a certain time of parallel evolution between the ground and the vegetation, a state of steady balance is reached; this stage of development is called climax by some ecologists and "natural potential" by others. Succession is the evolution towards climax.
Regardless of its name, the equilibrium stage of primary succession is the highest natural form of development that the environmental factors are capable of producing.

The cycles of evolution of soils have very variable durations, between a thousand-year-old for soils of quick evolution (A horizon only) to more than a million of years for soils of slow development.

Ecological factors influencing soil formation

There are two types of ecological factors influencing the evolution of a soil (through alteration[?] and humidification). These two factors are extremely significant to explain the evolution of soils of short development.

  • A first type of factor is the average climate of an area and the vegetation which is associated (biome). This factor allows to define the world major areas of vegetation and soils.
  • A second type of factor is more local, and is related to the original rockand local drainage. This type of factor explains appearance of specialized associations (ex peat bogs).

The destruction of the vegetation implies the destruction of evoluted soils, or a regressive evolution. Cycles of succession-regression of soils follow one another within short intervals of time (human actions) or long intervals of time (climate variations).
The climate role in the deterioration of the rocks and the formation of soils lead to the formulation of the theory of the biorhexistasy (Erhart[?]).
In wet climate, the conditions are favorable to the deterioration of the rocks (mostly chemically), the development of the vegetation and the formation of soils; this period favorable to life is called biostasy.
In dry climate, the rocks exposed are mostly subjected to mechanical disintegration which produces coarse detrital materials : this is referred to as rhexistasy.

Why is it important to realize the connections between the various parts of the physical environment, like soil, vegetation.., and climate.


Perturbations of the balance of a soil

When the state of balance, characterized by the ecosystem climax is reached, it tends to be maintained stable in the course of time. The vegetation installed on the ground provides the humus and ensures the ascending circulation of the matters. It protects the ground from erosion by playing the role of barrier (for example, protection from water and wind). Plants can also reduce erosion by binding the particles of the ground to their roots.
A disturbance of climax will cause retrogression, but, if given the opportunity, nature will make every effort to restore the damage via secondary succession. Secondary succession is much faster than primary because the soil is already formed, although deteriorated and needing restoration as well.

However, when a significant destruction of the vegetation takes place (of natural origin such as an avalanche or human origin), the disturbance undergone by the ecosystem is too important.
In this latter case, erosion is responsible for the destruction of the upper horizons of the ground, and is at the origin of a phenomenon of reversion to pioneer conditions. The phenomenon is called retrogressionand can be partial or total (in this case, nothing remains beside bare rock). For example, the clearing of an inclined ground, subjected to violent rains, can lead to the complete destruction of the soil.
Man can deeply modify the evolution of the sols by direct and brutal action, such as clearing, abusive cuts, forest pasture, litters raking.
The climax vegetation is gradually replaced and the soil modified (example: replacement of leafy tree forests by moors or pines plantations). Retrogression is often related to very old human practices.


Influence of human activity;

Erosion is the main factor for soil degradation and is due to several mechanisms : water erosion, wind erosion, chemical degradation and physical degradation.

Erosion is strongly related to human activity. 
For example, roads which increase impermeable surfaces lead to streaming and ground loss. Agriculture also accelerates soil erosion (increase of field size, correlated to hedges and ditches removal). Meadows are in regression to the profit of plowed lands. Spring cultures (sunflower, corn, beet) surfaces are increasing and leave the ground naked in winter. Sloping grounds are gradually colonized by vine. Lastly, use of herbicides leaves the ground naked between each crop. New cultural practices, such as mechanization also increases the risks of erosion. Fertilization by mineral manures rather than organic manure gradually destruct the soil. Many scientists observed a gradual decrease of soil organic matter[?] content in soils, as well as a decrease of soil biological activity[?] (in particular, in relation to chemical uses).
Lastly, deforestation, in particular, is responsible for degradation of forest soils[?].

Agriculture increases the risk of erosion through its disturbance of vegetation by way of :

  • overgrazing of animals
  • planting of a monoculture
  • row cropping
  • tilling or plowing
  • crop removal
  • land-use conversion

Consequences of soil regression and degradation


  • yields[?] impact : Recent increases in the human population have placed a great strain on the world's soil systems. More that 5.5 billion people are now using about 10 % of the land area of the Earth to raise crops and livestock. Many soils suffer from various type of degradation, that can ultimately reduce their ability to produce food resources. Slight degradation refers to land where yield potential has been reduced by 10%, moderate degradation refers to a yield decrease from 10-50 %. Severely degraded soils have lost more than 50% of their potential. Most severely degraded soils are located in developing countries such as Asia and Africa.


  • natural disasters : mud flows, floods... responsible for the death of many living beings each year


  • deterioration of the water quality : the increase in the turbidity of water and the contribution of nitrogen and of phosphorus can result in eutrophication. Soils particles in surface waters are also accompanied by agricultural inputs and by some pollutants of industrial, urban and road origin (such as heavy metals). The ecological impact of agricultural inputs (such as weed killer) is known but difficult to evaluate because of the multiplicity of the products and their broad spectrum of action.


  • biological diversity : soil degradation may involve the disappearance of the climax vegetation, the decrease in animal habitat, thus leading to a biodiversity loss and animal extinction...


Soil enhancement and rebuilding

Problems of soil erosion can be fought, and certain practices can lead to soil enhancement and rebuilding. Even though simple, methods for reducing erosion are often not chosen because these practices outweigh the short-term benefits. Rebuilding is especially possible through the improvement of soil structure, addition of organic matter and limitation of runoff. However, these techniques will never totally succeed to restore a soil (and the fauna and flora associated to it) that took more than 1000 years to build up.


What is the significance of the hydrological and biochemical cycles for plant growth and food production?


The inorganic nutrients (the minerals) cycle through more than the organisms (plants and animals of the world), however, they also enter into the atmosphere, the oceans, and even rocks. Since these chemicals cycle through both the biological and the geological world, we call the overall cycles biogeochemical cycles. Each chemical has its own unique cycle, but all of the cycles do have some things in common. Reservoirs are those parts of the cycle where the chemical is held in large quantities for long periods of time. In exchange pools, on the other hand, the chemical is held for only a short time. The length of time a chemical is held in an exchange pool or a reservoir is termed its residence time. The oceans are a reservoir for water, while a cloud is an exchange pool. Water may reside in an ocean for thousands of years, but in a cloud for a few days at best. The biotic community includes all living organisms. This community may serve as an exchange pool (although for some chemicals like carbon, bound in a sequoia (a tree) for a thousand years, it may seem more like a reservoir), and also serve to move chemicals from one stage of the cycle to another. For instance, the trees of the tropical rain forest bring water up from the forest floor to be evaporated into the atmosphere. Likewise, coral endosymbionts take carbon from the water and turn it into limestone rock. The energy for most of the transportation of chemicals from one place to another is provided either by the sun or by the heat released from the mantle and core of the Earth.

While all inorganic nutrients cycle, 4 of the most important cycles - water, carbon (and oxygen), nitrogen, and phosphorous in the plants and animals we eat.

The Water Cycle:In the water cycle, energy is supplied by the sun, which drives evaporation whether it be from ocean surfaces or from treetops. The sun also provides the energy which drives the weather systems which move the water vapor (clouds) from one place to another (otherwise, it would only rain over the oceans). Precipitation occurs when water condenses from a gaseous state in the atmosphere and falls to earth. Evaporation is the reverse process in which liquid water becomes gaseous. Once water condenses, gravity takes over and the water is pulled to the ground. Gravity continues to operate, either pulling the water underground (groundwater) or across the surface (runoff). In either event, gravity continues to pull water lower and lower until it reaches the oceans (in most cases; the Great Salt Lake, Dead Sea, Caspian Sea, and other such depressions may also serve as the lowest basin into which water can be drawn). Frozen water may be trapped in cooler regions of the Earth (the poles, glaciers on mountaintops, etc.) as snow or ice, and may remain as such for very long periods of time. Lakes, ponds, and wetlands form where water is temporarily trapped. The oceans are salty because any weathering of minerals that occurs as the water runs to the ocean will add to the mineral content of the water, but water cannot leave the oceans except by evaporation, and evaporation leaves the minerals behind. Thus, rainfall and snowfall are comprised of relatively clean water, with the exception of pollutants (such as acids) picked up as the waster falls through the atmosphere. Organisms play an important role in the water cycle. As you know, most organisms contain a significant amount of water (up to 90% of their body weight). This water is not held for any length of time and moves out of the organism rather quickly in most cases. Animals and plants lose water through evaporation from the body surfaces, and through evaporation from the gas exchange structures (such as lungs). In plants, water is drawn in at the roots and moves to the gas exchange organs, the leaves, where it evaporates quickly. This special case is called transpiration because it is responsible for so much of the water that enters the atmosphere. In both plants and animals, the breakdown of carbohydrates (sugars) to produce energy (respiration) produces both carbon dioxide and water as waste products. Photosynthesis reverses this reaction, and water and carbon dioxide are combined to form carbohydrates. Now you understand the relevance of the term carbohydrate; it refers to the combination of carbon and water in the sugars we call carbohydrates.


Human civilization is dependent on agriculture. Only with agriculture can a few people feed the rest of the population; the part of the population freed from raising food can then go on to do all the things we associate with civilization. Agriculture means manipulating the environment to favor plant species that we can eat. In essence, humans manipulate competition, allowing favored species (crops) to thrive and thwarting species which might otherwise crowd them out (weeds). In essence, with agriculture we are creating a very simple ecosystem. At most, it has only three levels - producers (crops), primary consumers (livestock, humans) and secondary consumers (humans). This means that little energy is lost between tropic levels, since there are fewer trophic levels present.

This is good for humans, but what type of "ecosystem" have we created? Agricultural ecosystems have several problems. First, we create monocultures, or fields with only one crop. This is simplest for planting, weeding, and harvesting, but it also packs many similar plants into a small area, creating a situation ideal for disease and insect pests. In natural ecosystems, plants of one species are often scattered. Insects, which often specialize on feeding on a particular plant species, have a hard time finding the scattered plants. Without food, the insect populations are kept in check. In a field of corn however, even the most inept insect can find a new host plant with a jump in any direction. Likewise, disease is more easily spread if the plants are in close proximity. It takes lots of chemicals (pesticides) to keep a monoculture going.

Another problem with human agriculture is that we rely on relatively few plants for food. If the corn and rice crops failed worldwide in the same year, we would be hard-pressed to feed everyone (not that we're doing a great job of it now). Natural ecosystems usually have alternate sources of food available if one fails.

A final problem associated with agroecosystems is the problem of inorganic nutrient recycling. In a natural ecosystem, when a plant dies it fall to the ground and rots, and its inorganic nutrients are returned to the soil from which they were taken. In human agriculture, however, we harvest the crop, truck it away, and flush it down the toilet to be run off in the rivers to the ocean. Aside from the water pollution problems this causes, it should be obvious to you that the nutrients are not returned to the fields. They have to be replaced with chemical fertilizers, and that means mining, transportation, electricity, etc. Also, the chemical fertilizers tend to run off the fields (along with soil disrupted by cultivation) and further pollute the water.

Some solutions are at hand, but they bring on new problems, too. No-till farming uses herbicides to kill plants in a field; the crop is then planted through the dead plants without plowing up the soil. This reduced soil and fertilizer erosion, but the herbicides themselves may damage ecosystems. In many areas, sewage sludge is returned to fields to act as a fertilizer. This reduces the need for chemical fertilizers, but still requires a lot of energy to haul the sludge around. Further, if one is not careful, things such as household chemicals and heavy metals may contaminate the sewage sludge and biomagnify in the crops which we would then eat.




Briefly describe the main characteristics of each layer of the atmosphere. 



extends from 14-18 km to circa 50km
jet stream is here
ozone layer is here
-90° to 0°C
pressure drops to 1/100 sea level pressure

the layer above the troposphere, characterized primarily as a stable, stratified layer (hence, stratosphere) with a large temperature inversion throughout. The main impact the stratosphere has on weather is that its stable air prevents large storms from extending much beyond the tropopause.

The other main impact important to life deals with ozone. Ozone is the triatomic form of oxygen that absorbs ultraviolet(UV) light and prevents it from reaching the earth's surface at dangerous levels. The stratosphere contains the ozone layer that has been such a hot topic as of late. The maximum concentrations of ozone are at about 25 km (15 miles) above the surface, or near the middle of the stratosphere. The interaction between UV light, ozone, and the atmosphere at that level releases heat, warming the atmosphere and helping to create the temperature inversion in this layer.

The stratosphere is bounded above by the stratopause, where the atmosphere again becomes isothermal. The average height of the stratopause is about 50 km, or 31 miles. This is about the 1 mb (0.1 kPa) pressure level. The layer above the stratosphere is the mesosphere.



Briefly describe the main characteristics of each layer of the atmosphere. 



 the middle layer in the atmosphere (hence, mesosphere). There are two key points about the mesosphere. First, temperature in the mesosphere decreases with height. At the top of the mesosphere, air temperature reaches its coldest value, around -90 degrees Celsius (or -130 degrees Fahrenheit). The second point is that the air is extremely thin at this level. Over 99.9 percent of the atmosphere's mass lies below the mesosphere. However, the proportion of nitrogen and oxygen at these levels is about the same as at sea level.

The mesosphere is bounded above by the mesopause. The average height of the mesopause is about 85 km (53 miles), where the atmosphere again becomes isothermal. This is around the 0.005 mb (0.0005 kPa) pressure level. Above the mesosphere is the thermosphere.



Briefly describe the main characteristics of each layer of the atmosphere. 

Thermosphereionosphere or thermosphere


extends from crica 90 km to 350 km
-90°C to well in excess of 100°C, perhaps as high as 1000°C
pressure drops to .00001 of sea level pressure.
Most meteors burn up in this zone.
electrically charged ions produce the auroras here.

is a warm layer above the mesosphere. In this layer, there is a significant temperature inversion. The few molecules that are present in the thermosphere receive extraordinary amounts of energy from the sun, causing the layer to warm. Though the measured temperature is very hot, if you exposed your skin to the thermosphere, the perceived temperature would be very cold. Because there are so few molecules present, there would not be enough molecules bombarding your body to transfer heat to your skin. Temperature is a measurement of the mean kinetic energy , or average speed of motion, of a molecule. So although there are only a few molecules, each has a huge amount of kinetic energy.

Above the thermosphere is the exosphere. Unlike the layers discussed previously, there is no well defined boundary between the thermosphere and the exosphere (i.e., there is no boundary layer called the thermopause).



Briefly describe the main characteristics of each layer of the atmosphere. 



extends from the ionsphere out into space
pressure drops to that of interplanetary space by 10-13,000 km out

 the region where molecules from the atmosphere can overcome the pull of gravity and escape into outer space. The atmosphere slowly diffuses into the void of space. The exosphere usually begins about 500 km up, but there is no definable boundary to mark as the end of the thermosphere and the beginning of the exosphere. Even at heights of 800 km, the atmosphere is still measurable. However, molecule concentrations are very small and considered negligible.



The atmosphere has a number of gases, often in tiny amounts, which naturally traps the heat given out by the Earth.

To make sure that the Earth's temperature remains constant, the balance of these gases in the atmosphere must not be upset.





  • water vapour
    occurs naturally in the atmosphere.


  • carbon dioxide
    produced naturally when people and animals breathe. Plants and trees absorb carbon dioxide to live. Volcanoes also produce this gas. Carbon dioxide is not the same as carbon monoxide 


  • methane
    comes from cattle as they digest their food. The gas also comes from fields where rice is grown in paddy fields.


  • nitrous oxide
    when plants die and rot, nitrous oxide is produced.


  • ozone
    occurs naturally in the atmosphere.

    Some of the activities of man also produce greenhouse gases. These gases keep increasing in the atmosphere. The balance of the greenhouse gases changes and this has effects on the whole of the planet.Burning fossil fuels - coal, oil and natural gas - releases carbon dioxide into the atmosphere. Cutting down and burning trees also produces a lot of carbon dioxide.A group of greenhouse gases called the chlorofluorocarbons, - which are usually called CFCs, because the other word is much too long! - have been used in aerosols, such as hairspray cans, fridges and in making foam plastics. They are found in small amounts in the atmosphere. They are dangerous greenhouse gases because small amounts can trap large amounts of heat.Because there are more and more greenhouse gases in the atmosphere, more heat is trapped which makes the Earth warmer. This is known as GLOBAL WARMING.A lot of scientists agree that man's activities are making the natural greenhouse effect stronger. If we carry on polluting the atmosphere with greenhouse gases, it will have very dangerous effects on the Earth.


    With more heat trapped on Earth, the planet will become warmer, which means the weather all over Earth will change. For example, summers will get hotter, and winters too. This may seem a good idea, but the conditions we are living in are perfect for life, and a large rise in temperature could be terrible for us and for any other living thing on Earth.

    At the moment, it is difficult for scientists to say how big the changes will be and where the worse effects will occur.

    The Weather

    the effects on the weather will be different all over the world, some places will become drier and others will be wetter. Although most areas will be warmer, some areas will become cooler. There may be many storms, floods and drought, but we do not know which areas of the world will be affected.All over the world, these weather changes will affect the kind of crop that can be grown. Plants, animals and even people may find it difficult to survive in different conditions.

    Sea Levels

    Higher temperatures will make the water of the seas and oceans expand. Ice melting in the Antarctic and Greenland will flow into the sea.

    All over the world, sea levels may rise, perhaps by as much as 20 to 40 cm, by the beginning of the next century Higher sea levels will threaten the low-lying coastal areas of the world, such as the Netherlands and Bangladesh. Throughout the world, millions of people and areas of land will be at danger from flooding. Many people will have to leave their homes and large areas of farmland will be ruined because of floods.


    The changes in the weather will affect the types of crops grown in different parts of the world. Some crops, such as wheat and rice grow better in higher temperatures, but other plants, such as maize and sugarcane do not. Changes in the amount of rainfall will also affect how many plants grow.The effect of a change in the weather on plant growth may lead to some countries not having enough food. Brazil, parts of Africa, south-east Asia and China will be affected the most and many people could suffer from hunger.


    Everywhere in the world, there is a big demand for water and in many regions, such as the Sahara in Africa, there is not enough water for the people. Changes in the weather will bring more rain in some countries, but others will have less rain.

    In Britain, the Southeast will be at risk from drought.


    Plants & Animals

    It has taken million of years for life to become used to the conditions on Earth. As weather and temperature changes, the homes of plants and animals will be affected all over the world.For example, polar bears and seals, will have to find new land for hunting and living, if the ice in the Arctic melts.Many animals and plants may not be able to cope with these changes and could die. This could cause the loss of some animal and plant species in certain areas of the world or everywhere on Earth.

    People in danger

    The changes in climate will affect everyone, but some populations will be at greater risk. For example, countries whose coastal regions have a large population, such as Egypt and China, may see whole populations move inland to avoid flood risk areas. The effect on people will depend on how well we can adapt to the changes and how much we can do to reduce climate change in the world.





    Explain how ocean currents  affect climate




    ocean currents act as one of the most important factors that influence the climate. And the reason why is because a current is water that travels. With that traveling water comes heat.

    The best example of a current is the Gulf Stream. This is a current of water that originates in the Gulf of Mexico[image]and heads north in the Atlantic toward Western Europe and The United Kingdom. It then circles around and goes back to the Gulf. A current, therefore, is water that goes in a cycle. It goes north and then loops around and goes south and then loops around and goes north again.

    When the current heads north from the Gulf of Mexico, the water is typically very warm because of how near it is to the equator. However, more than just the water being warm, the air that goes with the warm water is also warm. So, warm water and water air are moving north into a region that is farther from the equator. It’s like having the heat on in one room of the house and then opening all the doors so that the heat can flow into them.

    When the warm air and water get north–toward the United Kingdom, Portugal, France and Spain–the water mixes with the slightly cooler water in this northern region and warms. However, the air is what is most important. The warm air typically is very moist. It carries a lot of water because it is coming from a very wet place. Because of the warmth, evaporation occurs thus hydrating the air.

    It is because of this that in the United Kingdom, it rains a lot. The warm air flows over Britain and as the cold air of Britain mixes with the warm air that came from the Gulf Stream, the water condenses and it rains. However, the Gulf Stream is also to blame for there being very little, if any, ice in Western Europe, but when summer comes along, it’s very warm. In other words, the Gulf Stream allows for a temperate climate year round for Western Europe.


    Explain how mountains affect climate


    The temperature on mountains becomes colder the higher the altitude gets.

    Mountains tend to have much wetter climates than the surrounding flat land.


    Mountain weather conditions can change dramatically from one hour to the next. For example, in just a few minutes a thunder storm can roll in when the sky was perfectly clear, and in just a few hours the temperatures can drop from extremely hot temperatures to temperatures that are below freezing.


    They receive more rainfall than low lying areas because the temperature on top of mountains is lower than the temperature at sea level. 

    Winds carry moist air over the land. When air reaches the mountain, it rises because the mountains are in the way. As the air rises, it cools, and because cool air can carry less moisture than warm air, there is usually precipitation (rain).


    The climate on a mountain varies depending on what altitude (how high) you are up a mountain. At the foothills (near the bottom) there may be a tropical climate, whilst the peaks (the very top of mountains) may be covered in ice. The uppermost level of mountains is often bare rock and snow. Tibet and the Himalayas and other mountain ranges such as the Rocky Mountains or the Andes are good examples of this.


    You can often see snow on the top of mountains all year round, because the temperature at the top of mountains is lower than at the bottom. The higher the place is above sea level the colder it will be.

    Some mountains reach higher than the clouds. At this altitude the extreme cold and high winds cause blizzards.

    Mountains make it possible for snow to be found at the equator.  


    Generally the climate on mountains get progressively colder with increased altitude (the higher up you go). This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. The cooler the temperature the less evaporation there is, meaning that there is more moisture in the air.

    Air pressure decreases with altitude. As a result of the reduced air pressure, rising air expands and cools.


    Because of the rapid changes in altitude and temperature along a mountain slope, multiple ecological zones are “stacked” upon one another sometimes ranging from dense tropical jungles to glacial ice within a few kilometres.


    Mountains can affect the climate of nearby lands. In some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert.

    Rain Shadow
    Much of airborne moisture falls as rain on the windward side of mountains. This often means that the land on the other side of the mountain (the leeward side) gets far less rain—an effect called a "rain shadow"—which often produces a desert.

    The higher the mountain, the more pronounced the rain shadow effect is and the less likely rain will fall on the leeward side.By the time the air gets to the leeward side of the mountain it has already lost some of its moisture.

    Many of the deserts of the world are formed because of the lack of moisture blocked by the mountains. The Gabi desert is located behind the Himalaya mountain range in Asia.




    Pick one of the world's biomes (natural vegetation regions) and describe it as full as you can. Include location, climate, and soil characteristics as well as vegetation.





    The Earth has many different environments, varying in temperature, moisture, light, and many other factors. Each of these habitats has distinct life forms living in it, forming complex communities of interdependent organisms. A complex community of plants and animals in a region and a climate is called a biome. 


    Tropical rain forest


    very wet


    always warm


    poor, thin soil


    many plants


    many animals


    Tropical rain-forests are found in Asia, Africa, South America, Central America, and on many of the Pacific islands. They are often found along the equator. Almost half of the world's tropical rain-forests are in the South American country Brazil.

    There are other types of rain-forests around the world, too. For example, northern Australia has a “dry rain-forest” that experiences a dry season each year, and the rainy Pacific Northwest in the United States has a “temperate rain-forest” that is made up of evergreen trees.

    Tropical rain-forests have hot climate and it rains throughout the year there. The season does not change. This is conducive for plant growth. It has enormous biodiversity. The heat and moisture causes dead plants to decay. This provides nutrients to the other plants. Water evaporates and forms clouds above the canopy.

    Where Rain Is Always in the Forecast

    Tropical rain-forests are warm, wet forests with many tall trees. In most tropical rain-forests, it rains every day. Tropical rain-forests grow in a narrow zone near the equator. They are found in Africa, Asia, Australia, and South and Central America. The largest rain-forest in the world is the Amazon rain-forest in South America. Tropical rain-forests are home to a huge number of different plants and animals. All tropical rain-forests are endangered.

    Rainforests need lots of water and most of it comes pouring down as rain - at least 200 cm per year. Some tropical rain-forests get more than 3 cm per day! When it is not raining, the leaves are dripping and steam is rising. This keeps the whole rain-forest constantly wet and steamy.


    Rain-forest trees are always “sweating” water. One tree might release over 755 L of water every year. This makes rain-forestclimates very different from other environments. In other climates, the water vapor blows away and later falls as rain in far off areas. But in rain-forests half the precipitation comes from the forests’ ownevaporation. Much of the rain that falls on the rain-forest never reaches the ground. It stays on the trees because the leaves act as umbrellas.

    Tropical rain-forests are important to everyone, not just to the plants and animals living there. For example, scientists are always discovering new plants. Some of these plants contain substances that can be made into medicines. In addition, tropical rain-forests store huge quantities of carbon, while producing much of the world's oxygen. Some people call tropical rain-forests the lungs of the planet because they make so much of the oxygen that animals breathe. Another important role tropical rain-forests play is in regulating global weather. They maintain regular rainfall. They also help prevent floods, droughts, and erosion.

    ·         Climate: Tropical rain-forests receive almost 12 hours of sunlight every day. This sunlight is converted to energy by plants through the process of photosynthesis. Since there is a lot of sunlight, there is a lot of energy locked up in the rain-forest. This energy is stored in plants that are eaten by animals. Because there is a lot of food, there are many species of plants and animals.

    Rich Biodiversity, Poor Soil

    When explorers first entered the world’s rain-forests, they were amazed by the rich growth of plants, giant trees, dangling vines, and epiphytes. They thought the soil of a rain-forest must be very rich. They tried cutting the forest and turning it into farmland. It didn’t work. When a rain-forest is burned or cut down, the soil can only be used for a very short time before it runs out of nutrients. Afterward, biodiversity suffers.

    Today, we know that the soil of the tropical rain-forests is thin and very low in nutrients. De-composers like leaf-cutter ants, termites, bacteria, and fungi quickly turn falling leaves and dead organisms into nutrients. Plants take up these nutrients the moment they are available, so they don’t get a chance to enrich the soil.

    Keeping Tropical Rain-forests Healthy

    Conservation of tropical rain-forests should be easy. They have survived for millions of years. The trick to keeping them healthy is to not take too much too fast. This gives the rain-forests time to recover from human activities like logging. But many countries that have tropical rain-forests are poor. They can make money by cutting down and developing the rain-forests. But uncontrolled development results in deforestation, erosion, and loss of biodiversity.



    A Sampling of Tropical Rainforest Animals

    Rain-forests are very dense, warm, wet forests. They are havens for millions of plants and animals. Rain-forests are extremely important in the ecology of the Earth. The plants of the rain-forest generate much of the Earth's oxygen. These plants are also very important to people in other ways; many are used in new drugs that fight disease and illness.

    Where are Rain-forests? Tropical rainforests are located in a band around the equator, mostly in the area between the Tropic of Cancer (23.5° N latitude) and the Tropic of Capricorn (23.5° S latitude). This 3,000 mile (4800 km) wide band is called the "tropics." Tropical rain-forests are found in South America, West Africa, Australia, southern India, and Southeast Asia. 

    Strata of the Rain-forest
    Different animals and plants live in different parts of the rain-forest. Scientists divide the rain-forest into strata (zones) based on the living environment. Starting at the top, the strata are:

    • EMERGENTS: Giant trees that are much higher than the average canopy height. It houses many birds and insects.
    • CANOPY: The upper parts of the trees. This leafy environment is full of life in a tropical rain-forest and includes: insects, birds, reptiles, mammals, and more.
    • UNDERSTORY: A dark, cool environment under the leaves but over the ground.
    • FOREST FLOOR: Teeming with animal life, especially insects. The largest animals in the rain-forest generally live here.

    Animals that Live in Rain-forests: Ridiculously huge numbers of animals live in rain-forests, including microscopic animals, invertebrates (like insects and worms), fish, reptiles, amphibians, birds, and mammals. The different rain-forests of the world support different populations of animals. A few animals from each rain-forest are listed below:

    • South America -

      • insects (morpho butterfly, Julia butterfly, Monarch butterfly, and millions of other insects)
      • mammals (jaguar, ocelot, didelphid opossums, sloth, howler monkey, spider monkey, capybara, many bats, marmosets, procyonids, peccaries)
      • birds (quetzal, macaw, tinamous, curassows, hoatzins, hummingbirds, eagles, ovenbirds, antbirds, flycatchers, puffbirds, toucans, jacamars, tanagers, tapirs, troupials, honeycreepers, cardinal grosbeaks, xenops)
      • reptiles (anaconda, caiman, iguanas, lizards, microteiid lizards, boas, and coral snakes), amphibians (poison arrow frog, etc.)
      • fish (electric eel, piranha), and millions of other animals.
    • Australia -
      • mammals (tree kangaroo, rat kangaroo, yellow-footed Antechinus, Giant White-tailed Uromys, opossums, bandicoot, echidna, duck-billed platypus, sugar glider, red legged pademelon)
      • birds (cassowary, brolga, emerald dove, orange-footed scrubfowl, Australian brush-turkey, sarus crane, gray goshawk, wompoo fruit dove, topknot pigeon, Australian king parrot, laughing kookaburra, lesser sooty owl, fernwren, barred cuckoo-shrike, golden whistler, etc.)
      • reptiles (frilled lizard, carpet python, Green Tree Snake, Spotted Tree Monitor, Eastern Water Dragon, Boyd's Forest Dragon, Northern Leaf Tailed Gecko)
      • insects (Ulysses butterfly, Zodiac Moth, Union Jack butterfly, Regent skipper, Birdwing Butterfly)
      • amphibians (Giant Tree frog, Striped marsh frog, Northern Barred frog, Dainty Green Tree frog), and millions of other animals.
    • Southeast Asia -
      • mammals (tarsiers, orangutans, Siamangs, gibbons, colobine monkeys, tigers, tree shrews, binturong, moonrats, most flying foxes, colugos, bamboo rats, Oriental dormice)
      • birds (tree swifts, leafbirds, fairy bluebirds, fantails, whistlers, flowerpeckers, wood swallows)
      • insects (Queen Alexandra's Birdwing butterfly, Goliath Birdwing butterfly, Saturn Butterfly), and millions of other animals.
    • West Africa -
      • mammals (antelopes, bonobo, chimpanzee, gorilla, Mandrill, scaly-tailed squirrels, otter shrews, duikers, okapi, hippopotamus, Cercopithecus monkeys, bushbabies, pygmy hippo, duiker)
      • birds (Congo peafowl, African Gray Parrot) and millions of other animals.

    People have lived in and around tropical rain-forests for many thousands of years. During most of that time, the relationship worked well. Forest people cut small amounts of the rain-forest to build their homes and to burn as firewood. They used plants as medicine and food. These indigenous people were semi-nomadic, which means they moved their villages when they needed to find new food supplies or to find higher ground during floods.

    Vanishing Rain-forest Cultures

    Today, a few of these rain-forest cultures still live in West Africa,Borneo, and the Amazon. Life is changing very rapidly for rain-forest people. Roads are often built through the rain-forest for oil and gas exploration, logging, and mining. These roads and development often chop up the traditional homelands of the local cultures. Outside people also bring diseases like colds, pneumonia, and measles. All these things are endangering the culture of the rain-forest peoples.


    Carving up the Forests


    One of the most damaging effects of development has been dividing the rain-forest habitat into little patches of forest. This is called fragmentation. Today, many species are isolated in these small areas of forest because they will not or cannot enter open habitats. The result is that species such as orangutans cannot connect with one another to mate and have babies.

    Conservations Efforts

    More research and strong conservation are the best tools for protecting the tropical rain-forest. Instead of cutting the forests, some people take visitors on hikes in the forests, which is part of a conservation effort known as ecotourism. People also are trying to help wildlife survive by creating protected areas and rehabilitation centers.

    Tropical Trivia

    ·         Rain-forests have 170,000 of the world's 400,000 known plant species.

    ·         The United States has 81 species of frogs, while Madagascar (which is smaller than Texas) may have 300 species.

    ·         Europe has 321 butterfly species, while Manu National Park in the tropical rain-forest of Peru has 1,300 species!

    ·         The world’s only species of flying snake and lizard live in the Borneo rain-forest.

    ·         The largest catfish in the world lives in a tropical rain-forest river in Vietnam. It weighs over 300 kg.

    ·         About one-quarter of all the medicines we use come from rain-forest plants.

    o    Curare comes from a tropical vine. It is used as an anesthetic .,and to relax muscles during heart surgery.

    o    Quinine, from the cinchona tree, is used to treat malaria.

    o    A person with leukemia has a 99% chance that the disease will go into remission because of the rosy periwinkle.

    o    More than 1,400 varieties of tropical plants might be potential cures for cancer.



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