Learn all about Ecology and Ecological Processes
Learn all about the living world and how organisms interact with one another. In this course you will cover a wide range of ecological concepts such as ecosystems, natural selection, competition, symbiotic relationships, the formation of rivers and mountains and how humans effect ecological processes.
Career Tips for Working with the Environment
- ensure your skills are up to date, by pursuing further studies or attending professional development activities.
- Keep up to date with what's happening in the field of Ecology. What are the most pressing issues and where is there likely to be more work?
- Join a networking group to meet ecologists who are working in the field.
- Get some experience. Whether paid or unpaid, experience will always make your CV look more impressive and give you some practical knowledge to apply in your interview.
This subject has 7 lessons as follows:
1. Ecosystems & Populations
Components of an ecosystem, Biomes, Detrital and grazing webs, trophic levels, energy flows etc
2. The Development Of Life
Lifespans, Natural selection, Genetics, Understanding arguments for and against theory of evolution, etc
3. Animals, Parasites & Endangered Species
Comparative anatomy, how animals fit in ecosystems, animals in the human community, parasites, etc
4. Fungi, Tundra, Rainforests & Marshlands
Physiology, anatomy, classification and ecology of fungi; Location, the climate, the plant and animal life
related to different systems including tundra, marshes and rainforests.
5. Mountains, Rivers & Deserts
Formation ecology and importance of mountains (including erosion, volcanoes etc), formation & types of rivers, catchments, dams, deserts and their ecology, etc.
6. Shallow Waters
Shore lines, coral reefs, intermediate reefs, estuaries, sandy shores, etc.
7. Ecological Problems
The Greenhouse Effect, The Ozone Layer, Poisons & Waste Materials
COURSE DURATION 100 Hours
EXAMPLES OF WHAT YOU MAY DO IN THIS COURSE
- Observe an ecosystem in your local area. Identify the inhabitants of the ecosystem and their location in the food web of that system.
- Compare the similarities and differences between the detrital web and the grazing web
- Discuss what scientific discoveries the Theory of Evolution, both past and present, is based on.
- List and explain the four arguments of evolution.
- Define Natural Selection.
- Discuss how genetics are related to evolution.
- Go to an ecological environment (as natural and un-human interfered as possible) and observe the plants and relationships that exist.
- Visit a local stream or river. Observe the condition of the stream, particularly the presence of indigenous vegetation and its affect on stream bank condition. Also look for evidence of human activity on the condition of the stream or river
- Discuss, in your own words, the theories which have been advanced in the past regarding the formation of coral reefs.
LEARNING TO UNDERSTAND ALL SORTS OF ENVIRONMENTS
The world is made up of many different types of environments; some wet, others dry; some hot and others cold.
As you progress through this course, you will learn to better understand the features that drive each of these different types of ecosystems and the interplay between living and non living components of those different systems.
Deserts are regions in which few forms of life can exist because of the exceptional drought or exceptional cold conditions. The term "desert" is applied to regions of the earth that:
- Are characterised by less than 254 mm (10 inches) of rainfall on average per year.
- An evaporation rate that exceeds the rate of rainfall.
- A high average temperature.
Because of the lack of moisture in the soil and a low humidity in the atmosphere most of the sunlight penetrates to the ground, where daytime temperatures can reach 55 degrees Celsius in the shade.
At night the desert floor radiates heat back to the atmosphere, and the temperature can drop to near freezing point.
Deserts are caused by a combination of climate patterns and geological features. It is noteworthy that the great hot deserts of the world are all on the west of the continents:
- West Australian
Other deserts are situated either in the interior, for example, the Gobi Desert in Asia, or in Arctic or Antarctic latitudes, where the intense cold checks precipitation and makes life difficult. The above mentioned regions are deserts, not because the never get any rain, but because the supply is deficient.
Most desert regions have been formed by movements of air masses over the planet. As the earth turns on its axis, it produces gigantic air swirls. Hot air rising over the equator flows northwards and southwards. The air currents cool in the upper regions and descend as high pressure systems in two subtropical zones. North and south of these zones there are two more areas of ascending air and low pressure. Still further north and south are the two polar regions of descending air. As the air rises, it cools and loses its moisture. As the air descends it warms and picks up moisture drying the land.
These downwards movements of warm air masses over the earth have produced two belts of deserts. One of these belts is along the tropic of Cancer, in the Northern Hemisphere, and the other belt is along the Tropic of Capricorn, in the Southern Hemisphere. Among the deserts in the northern region are:
- The Gobi Desert, in China
- The deserts of south-western North America
- The Sahara in North Africa
- The Arabian and Iranian deserts in the Middle-East.
The deserts along the southern belt are:
- Patagonia, in Argentina
- The Kalahari Desert, in Southern Africa.
- The Great Victoria and the Great Sandy Deserts of Australia.
Other deserts result from the influence of ocean currents on land masses. As cold waters move from the Arctic and Antarctic regions towards the equator and meet the edges of the continents, they are augmented by upwelling of cold water from the depths of the oceans. Air currents cool as they move across the cool water. These air currents carry mist or fog, but little rain. Such currents flow across:
- Southern California
- The south-west of Southern Africa.
Although these coasts are often shrouded in mists, they are deserts.
Mountain ranges influence the development of deserts by creating rain shadows. As moisture laden winds flow upwards over the windward slopes of mountain ranges, they cool and lose their moisture as rain and snow. The dry air descending over the leeward sides of the mountain ranges evaporate moisture from the soil.
The Great Basin, a desert of North America, results from the rain shadow produced by the Sierra Nevada range. Other deserts in the interiors of some continents have come about because the prevailing winds in these areas are far removed from any large bodies of water, and by the time that they reach these regions they have lost most of their moisture. Such deserts are the Gobi, and the Turkestan of Eurasia.
The landscape of a desert is stark. It is shaped by wind and, paradoxically, by water. When the rains do come to the desert, the soil, unprotected by vegetation, quickly erodes. This forms canyons where the water rushes down from the hills.
From the eroded angular peaks composed of harder resistant rocks, alluvial fans lead away to deposit large slopes of debris at the base. These slopes level off to form basins. During the infrequent rains, these basins fill with water. The rainfall then evaporates leaving behind, on the surface, a layer of glistening salt dissolved from the ground. Such salt lakes are a common feature of some deserts, for example, the salt pans of Namibia, and the Great Salt Lake of Utah in the United States of America.
The winds literally sand blast rocks to unusual shapes and build up the dunes. In sandy deserts such as the Sahara, parts of the North American desert and the Simpson Desert in Australia, sand dunes are typical features.
Wind built mounds of sand can reach heights of up to 200 metres or more in the Sahara, Arabian and Iranian deserts.
In those deserts where the prevailing winds are strong and sand is scarce, such as the coastal deserts of Peru, the dunes may take on a regular crescent shape. These shapes move continuously across the desert floor.
Dunes may be longitudinal ridges resulting from winds blowing strongly in only one direction, as in the Simpson Desert in Australia, or they may be star-shaped in regions where the wind blows from all directions.
Plant Adaptations to the Desert
All but the most arid of deserts support life in some form. This life is frequently abundant and is well adapted to the scarcity of water and the high daytime temperatures and the cold of the night.
Desert plants have evolved methods of conserving and efficiently using the water available to them. Some desert plants only live for a few days or weeks. These are known as ephemeral plants. Their seeds lie dormant in the sand, sometimes for many years. When a soaking rain comes along the seeds germinate and very quickly bloom and produce seed.
Woody desert plants either have long root systems that reach deep down to find water sources, or they have spreading, shallow roots that can take up the surface moisture from heavy dews and occasional rains.
Normally desert plants have small leaves. This conserves water by reducing the surface area from which transpiration can take place. Other plants shed their leaves during the dry periods.
Many also have waxy cuticles or fine hairs on their leaves, or modified leaf shapes (e.g. rounded or needle-like) to reduce transpiration losses.
The process of photosynthesis, by which sunlight is converted into energy by the green leaves, is taken over in the desert plants by the stems.
Many desert plants are succulents. They store water in their leaves, stems and roots. Thorns on the plants, which are commonly modified leaves, serve to guard the water from animal invaders.
Desert plants may take in and store carbon dioxide for use in photosynthesis only at night. During the day their pores are closed to prevent evaporation. Those desert plants that grow on saline soils may have a concentrate of soil in their sap. This salt is secreted out through their leaves or stems.
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