Sep 27 2011
Intro to Ecology
In class Monday, we discussed the importance and fundamental ideas of Ecology. Ecology, known as the interaction between biotic and abiotic components in an ecosystem, is one of the most important units in this course (pretty thrilled you missed the notes, right?). These interactions include how abiotic factors in an ecosystem like pH, temperature, salinity, and sunlight will affect certain communities and populations. However, the key in Ecology, and in this course, is to always look at the big picture and how individuals affect it. This is different from our previous science courses when we would analyze specific individual components like atoms and molecules in Chemistry, and cells, organs, and health systems in Biology. A perfect example of this is a pond. In Biology, we would examine only individual species or certain processes like photosynthesis and cell respiration in algae. Whereas in Environmental Science, we are going to study the pond ecosystem as a whole and issues a pond may face like algal blooms or pollution. Another important lesson we learned Monday was about the trophic levels in an ecosystem. A trophic system, more commonly known as a food chain, is a system that classifies and maps out a succession of organisms, what they eat, and what they are eaten by.
These trophic levels are (Starting at the top of the pyramid):
4.) Tertiary Consumers: Organisms in the quaternary level consume secondary consumers. E.g. Bald Eagle
3.) Secondary Consumers: Organisms classified at the tertiary level or above are carnivores or omnivores. Meaning that they, at least, consume other heterotrophs. E.g. lions, snakes
2.) Primary Consumers: All organisms classified in trophic levels above level one are known as heterotrophs. These organisms are incapable of photosynthesis and must obtain their energy through consuming other organisms. In the case of primary consumers, they eat only plants and are herbivores. E.g. most insects, tadpoles
1.) Producers: Also known as autotrophs, these organisms undergo photosynthesis and make their own energy. This means that they do not consume other organisms and are the bottom and base of the trophic system. E.g. plants or algae
Although these trophic levels help summarize a very intricate and complex natural process, there things that it fails to mention. The first point is that you are unable to see if an organism is an omnivore, both plant and meat eating, organism. Second, Food chains are unable to show the impact of decomposers or detritivores in an ecosystem. Decomposers, such as fungi or bacteria, break down the remains of organisms at any level. Meaning that they wouldn’t really fit in the pyramid and are given the title Trophic Level 0. Lastly, the food chain is unable to show the role of detritivores in an ecosystem. Detritivores feed on detritus, also known as nautre’s trash. Since they are not producing their own energy, but not eating any of the consumers, they don’t fit in the food chain either. So what can we do to properly show that decomposers and detritivores play a vital role in ecosystems? Food Webs. Shown in one of the pictures below, food webs accurately portray who eats who in an ecosystem. Although it may be harder to tell what trophic level they are on, it makes it much easier to see who are omnivores, decomposers, and scavengers.