DSST Environment-Humanities DANTES II

Differences between food chains and food webs food

Info icon This preview shows pages 8–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Differences between food chains and food webs Food chains - Food chains are overly simplistic as representatives of the relationships of living organisms in nature. Most consumers feed on multiple species and in turn, are fed upon by multiple other species. The relationship is basically a line of predator-prey relationships. Food webs - A food web is a series of related food chains displaying the movement of energy and matter through an ecosystem. There are many food chains contained in these food webs Irrigation and Salinization Irrigation - is an artificial application of water to the soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall. Irrigation has a large impact on costs and energy since it affects downstream users, available land for use, and can affect soil salinity. Salinization – is the salt content in soil. Salinity from irrigation can occur over time wherever irrigation occurs, since almost all water (even natural rainfall) contains some dissolved salts. When the plants use the water, the salts are left behind in the soil and eventually begin to accumulate. Since soil salinity makes it more difficult for plants to absorb soil moisture, these salts must be leached out of the plant root zone by applying additional water. This water in excess of plant needs is called the leaching fraction.
Image of page 8

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Salination from irrigation water is also greatly increased by poor drainage and use of saline water for irrigating agricultural crops. Producers and consumers in an aquatic ecosystem (Question was like what is the primary producer in the oceans.) Autotrophs (producers)-are organisms that can manufacture the organic compounds they need as nutrients from simple inorganic compounds obtained from their environment. These are mainly phytoplankton. Heterotrophs(consumers)-are organisms which cannot synthesize the organic nutrients they need and get their organic nutrients by feeding on the tissues of producers or other consumers. There are several classes of consumers, depending on their food source. Trophic levels (food chain, food web, producers, consumers) (Know “How does a primary producer in a tropic level receive its energy from the sun..answer..as heat.) Producers (autotrophs) are typically plants or algae. Plants and algae do not usually eat other organisms, but pull nutrients from the soil or the ocean and manufacture their own food using photosynthesis. For this reason, they are called primary producers. In this way, it is energy from the sun that usually powers the base of the food chain. Consumers (heterotrophs) cannot manufacture their own food, and need to consume other organisms. They are usually animals. Animal that eat primary producers, such as plants, are called herbivores. Animals which eat other animals are called carnivores, and animals which eat both plant and other animals are called omnivores.
Image of page 9
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern