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ESO 4 B & G · 6 · Dynamics of Ecosystems

What to Learn

  • Ecosystems: concept, components. The Ecosphere.
  • Ecological factors; conditions and resources. Limiting factors. Tolerance curves. Ecological niche. Habitat.
  • Ecological factors in land ecosystems.
  • Ecological factors in aquatic ecosystems.
  • Ecological succession.
  • Biotic interactions: intraspecific and interspecific interactions.
  • Population growth. Positive and negative feedback in the interspecific interactions. Plagues and their control.
  • Feeding interactions: flow of energy and matter in the ecosystems; producers, consumers and decomposers; food chains and food webs; trophic pyramids.
  • Biogeochemical cycles.
  • Atmospheric pollution: the greenhouse effect and the global warming; the slimming of the ozone layer; acid precipitations.
  • Water consumption: water treatment and sewage treatment.
  • Water pollution: fertilisers, industrial pollutants, thermal pollution.
  • Other major human influences in the ecosystems.

Key Information

Mind Map: The Nitrogen cycle
[Source]
Presentation: We are eating up our world
[Source]

Movies, Animations and Audios

Global Warming
Global Warming

Global Warming

Global Warming is a hot topic. This video looks at the evidence and focuses on these two questions: "is the Earth getting warmer?" and "what are the effects of Carbon Dioxide in the atmosphere?"

Produced by Cassiopeia Project

The truth about global warming

The truth about global warming

A simple and effective way to see how human activity relates to global warming.

Climate Change 2013: The Physical Science Basis

Climate Change 2013: The Physical Science Basis

The IPCC has produced a video on its Fifth Assessment Report (AR5). The first part on the Working Group I contribution to AR5 is now available.

Produced by the Intergovernmental Panel on Climate Change

Ask for a better world

Ask for a better world

Global warming: when you feel it, it's already too late.

Produced by Ponto de Criação

Teens, frogs and climate change

Teens, frogs and climate change

With frogs and other amphibians already dying in large numbers, a group of teenagers is joining other amateur scientists to gather information on the problem.

Produced by ScienCentral

Early birds and springtime

Early birds and springtime

A growing body of evidence shows that birds are nesting earlier due to global warming, with potentially harmful consequences.

Produced by ScienCentral

Acid Rain
Coal combustion and acid rain

Coal combustion and acid rain

Watch how sulphur-rich coal is a major source of acid rain and what can be done to mitigate its damage.

Produced by Britannica.com

Analysing acid rain

Analysing acid rain

Visit this research station in the Black Forest, Germany, to watch rainwater being tested for acidity.

Produced by Britannica.com

Other Human Influences on the Ecosystems
The disappearing male

The disappearing male

Documentary about one of the most important, and least publicized, issues facing the human species: the toxic threat to the male reproductive system. The last few decades have seen steady and dramatic increases in the incidence of boys and young men suffering from genital deformities, low sperm count, sperm abnormalities and testicular cancer. At the same time, boys are now far more at risk of suffering from ADHD, autism, Tourette's syndrome, cerebral palsy, and dyslexia. The Disappearing Male takes a close and disturbing look at what many doctors and researchers now suspect are responsible for many of these problems: a class of common chemicals that are ubiquitous in our world. Found in everything from shampoo, sunglasses, meat and dairy products, carpet, cosmetics and baby bottles, they are called "hormone mimicking" or "endocrine disrupting" chemicals and they may be starting to damage the most basic building blocks of human development.

Produced by CBC

Podcasts

NPR Topics: Environment 
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Now in the News

Scientific American Topic - Biodiversity 
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Activities

Questions: Ecology
[Source lesson]
  1. (a) Which are the fossil fuels? (b) Where do we use them? (c) Why is their daily consumption a problem for the environment?
  2. Make a diagram showing how the greenhouse effect is produced.
  3. Why are plants important at alleviating the problem of the global warming?
  4. Methane has a greater heat-trapping power than CO2. How is it produced?
  5. Make a diagram showing how acid rain is produced.
  6. What are the main harmful effects of the acid rain?
  7. What are the main sources of water pollution?
  8. How can a lot of organic waste reduce the numbers of animal life in a river?
  9. How can phosphates or nitrates accumulate in your body?
  10. What is eutrophication and why is it a problem for both aquatic plants and animals?
  11. How can pests be controlled naturally? What risk do this techniques pose?
  12. Why is manure more eco-friendly than chemical fertilisers?
  13. Name five reasons by which the fish populations may be declining in many areas of the planet.
  14. Why is deforestation produced?
  15. Name six adverse effects of deforestation.
  16. Which three measures to conserve natural ecosystems do you find more necessary in your region?
  17. Why are fungi and bacteria so important for ecosystems?
  18. How would you slow down the rate of decay of dead organic matter?
  19. Why is carbon essential for all living beings?
  20. Make a diagram of the carbon cycle.
  21. Why is nitrogen essential for all living beings?
  22. Why do plants depend on soil's bacteria and algae for their nitrogen supply?
  23. Why is it good for farmers to grow a crop of leguminous plants from time to time?
  24. Make a diagram of the nitrogen cycle.
Questions: Populations
[Source lesson]
  1. What is the difference between an habitat and an ecosystem?
  2. What is the definition of population in Ecology?
  3. Name four factors that have contributed to the human population explosion in the past two centuries.
  4. What is the difference between measuring and estimating the size of a population?
  5. How would you use quadrats to estimate the amount of daisies in the school gardens?
  6. Quadrats can be used to estimate the size of the populations of which type of species?
  7. What are transects used for?
  8. How could you identify which animal species live in the foliage of a tree?
  9. How could you identify which animal species live crawling on the ground?
  10. How could you identify which animal species live in leaf litter?
  11. What technique could be used to estimate the size of an animal population in an area?
  12. What pattern does the growth of a population that arrives to an unoccupied area follow?
  13. There are two types of ecological factors: conditions (e.g. temperature) and resources (e.g. heat). Which are the ones likely to provoke competition among the living beings? Why?
  14. Which resources could trigger competition among plant species?
  15. Of all the resources necessary for photosynthesis, which one is the least likely to produce competition among plant species?
  16. What is a community or biocenosis?
  17. Give four examples of interactions between species of a same community and tell the balance of advantage of each one.
  18. Name two adaptations of polar bears to their environment.
  19. Name three adaptations of cacti to their environment.
  20. Write a land food chain of 3-4 links, naming the position of each species in the chain.
  21. Write an aquatic food chain of 3-4 links, naming the position of each species in the chain.
  22. How are primary consumers also called? Why?
  23. How are secondary and forth consumers also called? Why?
  24. Which are the decomposers? What do they feed on? What do they produce?
  25. How do the populations of herbivores in a savannah control the number of small birds? Why? Which type of birds are favoured with this situation? Why?
  26. How are pyramids of numbers useful?
  27. What do pyramids of biomass account for? Why are they always a pyramidal shape?
  28. Why food chains have rarely more than 4 levels?
  29. Why is a vegetarian diet more likely to feed a greater amount of people?