Chapter+Six


 * Ecological Succession, Communities and Biomes** Chapter Six

The following is an online activity I would like for all of you to do. Click on the following link to learn about succession. Please complete the following worksheet.

media type="youtube" key="O8-LZdIyUQg" height="315" width="560" Do some research and find out how the US Forest Service and US Park Service has changed their policies about stopping wild fires in past 50 years. While you are researching this issues be sure to review the plot (especially the ending) of Bambi. That movie certainly impacted a generation of the US public.

Nick: It was around the 1960's when the US Forest Service had found that certain species of trees hadn't grown in quite some time. Upon further research of the issue, it was found that trees such as the Giant Sequoia could not reproduce without the presence of fire, a key element of their lifestyle. The Service thus changed their policy on forest fires to allow natural fires to run their course, along with prescription fires, as long as they didn't get too out of control. over the years since, the policy regardin forest fires has changed regarding how the fires are to be regulated, and to what extent they should be allowed to occur, but for the most part the base of the policy has stayed relatively the same.

Here is one more site for you to check out how policy changes over time.

Here is your chance to do some written debate with each other. The way I want you to approach this is .. who ever makes it to this answer first can choose their opinion to write about. Then ...the next person to hit this question needs to take the opposite point of view, and then have that discussion go back and forth.

If you review the Issues & Analysis: Ecosystem Loss in North America (p. 137 12th edition)., you will find that in the United States, 99 percent of tall grass prairie has been transformed, 95 % of the original forest is gone, 50% of the wetlands have been drained and filled. Much of this has occurred because people  used the resources or converted them to farmland. Many people and conservation agencies in economically advanced countries feel that poor countries should preserve their natural ecosystem (particularly in tropical rain forests  ) rather than use them for economic development. Many people in these developing countries feel they have a right to use their own resources the way people in other countries have.

** Choose to support either preservation or development of these resources, and prepare arguments to support your position. **

Nick: Though it may seem unfair to the developing countries, and hypocritical of more advanced countries, natural ecosystems in these rising countries must be preserved. Much of the prosperity gained by advanced countries we know today, such as Japan and the United States, has been obtained by the unwise usage of resources drawn from natural ecosystems. It is the responsibility of these advanced nations to preserve what little natural environments they have, and find ways to prosper without harming the environment. Based on the way the world is currently living, it is predicted that by 2030 the people of Earth will need the resources of two Earths to sustain their way of living. If these developing countries are allowed to become countries which will contribute to the usage of resources Earth is simply running out of, it could mean chaos for the near future. The development of these countries must be watched carefully, as it can certainly be done but not by the same means current advanced nations have risen to their status.

Go to this textbook [|website's animation] about biomes to review what you learned as a freshman.

List one biome and a challenge faced by organisms in that biome. Each of you should do one biome a piece. Kelcie: Aquatic Freshwater Biome- The freshwater biome often faces the issue of pollution. Runoff containing fertilizer and other wastes enter into rivers, ponds, and lakes and promote abnormally rapid algae growth. When these algae die, dead organic matter accumulates in the water. This makes the water unusable and it kills many of the organisms living in the habitat.

Catie : **Tundra**: The tundra is located in the Northern hemisphere, and is a windswept, open, grassland biome where very few trees grow. There is not a lot of pressure from human populations in the tundra because not very many people live in this cold, barren environment, but organisms due face challenges. For areas where humans do live, air pollutants are affecting organisms and killing them. Lichen becomes contaminated with these pollutants, and then the organisms that eat the lichen are also affected. Global climate change, however, has become a great problem for the tundra. Scientists are beginning to worry that global warming could eliminate the tundra forever. The warming of the planet has begun to cause the tundra's winters to be shortened and has caused the permafrost to melt. This causes plants to die and animal's migrant patterns to change. The tundra has become a fragile biome due to the warming of the earth.

Max: **Savanna**: A savanna is a grassland ecosystem, characterized by an open canopy with sparse trees and plentiful grass. They cover 20% of the Earth's land and are usually transition zones between Deserts and Forests. Organisms in Savannas often struggle to find water, as they are known for only one season of rainfall. Savannas can be found in Africa, South America, and Australia.

Alex: ** Desert: ** Desert biomes average less than less than 10 inches per year, making a lack of water the primary problem in these regions. Organisms in these areas must adapt to survive with very little water. Some plants have small leaves to help prevent water from evaporating, and others store water in their roots or bodies. Animals become primarily active at night, the coolest part of the day, and receive most of their water from what they eat.

Charles: **Tropical Rainforest:** The main challenge faced by organisms in this biome is loss of habitats due to logging. This problem affects all of the organisms found in this biome equally. However, many species of algae face natural environmental pressures in rainforests due to the shape and lack of adhesiveness of leaves that grow in rainforests. Algae faces these pressures because they block the organisms path to sunlight.

What do you think about restoring ecosystems that have been degraded by human activity? Should it be done or not? Why? Who should pay> Alex: I don't think that we should physically restore ecosystems that have been degraded by human activity, because we as people cannot truely resore those ecosystems. Instead, if we wanted to help and contribute to those ecosystems, we should back out of them and stop degrading them. That way, those ecosystems can go through a sort of 'succession' and restore themselves over time.

Max: I agree with Alex that some ecosystems are better left to restore themselves, yet human interaction is needed in some cases. Intervention can help set the restoration of these ecosystems in progress, and in some cases it is crucial to ensure restoration occurs. We do need to back out of ecosystems foremost in order to stop the harm we are causing.