Components of an ecosystem
By Marjorie Henry, Contributor

Manning Cup football action between St. Jago High School and Spanish Town High, in September. Spanish Town won 3-1. - Ian Allen/Staff Photographer

In today's lesson, my focus will be on the components of an ecosystem, as indicated in the lesson last week. Before I do that, however, I do trust that you have attempted the questions I gave you at the end of the lesson introducing this somewhat 'new' topic on ecosystem. Here are the expected responses: -

1. Ecosystem is a contraction of 'ecology' and 'system'.

2. The term 'ecology' refers to 'the study of where organisms live'.

3. The different ecological units in order of scale are microhabitat, habitat, zones, biomes.

4. Environment is a collective term to include all the conditions in which an organism lives.

5. The two divisions of environment are (i) the physical, non-living or abiotic environment and (ii) the living or biotic environment.

6. Ecosystem is a natural unit in which the life cycles of plants, animals and other organisms are linked to each other and to the non-living constituents of the environment to form a natural system.

The information on today's topic comes from the new edition of The Caribbean Environment for CXC Geography written by Mark Wilson. As I had mentioned in an earlier lesson, this text is highly recommended as it has been revised to be aligned with the new syllabus. It informs us that the different plants and animals of a forest, a grassland, or any other area, relate to each other in an ecosystem:

• Inputs add nutrients, water or energy to the system. The main ones are rainwater, sunshine, and minerals.
  
  
• Two of these inputs, rainwater and nutrients, can be stored in the soil.
  
  
• The producers are the green plants. They grow through photosynthesis. They make direct use of rainwater, sunshine, and minerals.
  
  
• The primary consumers are animals which feed directly off the plants, such as parrots, tapirs, bees, and monkeys. They are known as herbivores.
  
  
• The secondary consumers feed off the primary consumers and off each other. They include lizards, jaguars, spiders, and birds of prey.
  
  
• The decomposers feed off dead organic matter. They include fungi, termites, earthworms, and bacteria.

When organic matter has been broken down into humus by the decomposers, it is stored in the soil until the nutrients it contains are used again by the producers.

Marjorie Henry teaches at Glenmuir High School.