Learning About Food Webs and Energy Pyramids Summary

There are various types of organisms, all of which belong to ecosystems. Within an ecosystem,food chains, food webs, and energy pyramids are used to show how organisms interact/depend on each other to obtain nutrients. They show who eats who or who eats what through the study of trophic levels (relationships) that are put in order.Organisms are divided into two groups, autotrophs (producers) and heterotrophs (consumers). Producers are organisms that have the ability to make their own food by using energy from the sun (photosynthesis), carbon from CO2 in the air, and H2O from soil. Consumers are organisms that get their food (energy) from consuming those producers. Consumers are narrowed down into specific trophic levels such as primary consumers, secondary consumers, tertiary consumers and so on. Those trophic levels form a food chain, which leads us to a food web. Food webs show how members in a range of food chains may interact with one another. With food chains and food webs comes the flow of energy. "Most of the food that is produced by photosynthesis is used to run all of the activities and processes going on in the plant's cells, including energy for growth and reproduction...in fact, most of the sun's energy either doesn't reach Earth's surface or doesn't fall on areas where plants live. When a primary consumer eats a plant, it only gets a small fraction of the original sunlight energy that made it to earth."("Unit 3 | Lab 9: Learning About Food Webs and Energy Pyramids Student Guide") When a primary consumer eats a producer, the primary consumer retains only 10% of the producer's energy. A secondary consumer ingests a primary consumer and once again retains only 10% of the primary consumer's energy. As this process continues, the amount of energy eventually reaches the point where no more energy can be transferred.

Photo: A food web representing some of the numerous creatures that lie in the aquatic biome of planet earth.

In my group's food web, the organisms all connect in some way. The order of the trophic levels in the picture (from top to bottom) are scavengers(organisms that consume dead animals), tertiary consumer, secondary consumers, primary consumers, and producers. In the second row (from top to bottom) a sea cucumber, sea turtle, sea star, oithona, and diatoms are shown. Diatoms use photosynthesis to get their energy. The oithona then feed on the diatoms and energy is transferred. Later, a sea star consumes the oithona. This flow of energy is continued as a sea turtle starts hunting for food and finds the star fish. Lastly, when the sea turtle inevitably dies, sea cucumbers feed on the decaying body of the turtle.

"Earth is divided into major divisions called biomes." ("Unit 3 | Lab 9: Learning About Food Webs and Energy Pyramids Student Guide") The type of food web my group's food web represents is the aquatic. The aquatic biome may be broken down into two basic regions, freshwater(streams and rivers, wetlands), and marine regions (oceans).("The Aquatic Biome") Our food web revolves more around the ocean which contains a great diversity of species. The organisms displayed in the photo come from three of the four zones of the the ocean regions. These zones are the intertidal zone, the pelagic zone, and the benthic zone.

                       

                                                                          Works Cited

"Unit 3 | Lab 9: Learning About Food Webs and Energy Pyramids Student Guide"

"The Aquatic Zone." Link: http://www.ucmp.berkeley.edu/glossary/gloss5/biome/aquatic.html