FEEDING RELATIONSHIP

Food chain is a series of steps in which organisms transfer energy by eating and being eaten.


Food chain show the one way flow of energy in an ecosystem.









Food web is the feeding relationship[s among the various organisms in an ecosystem which form a network of complex interactions. A food web links all the food chain in an ecosystem together.
Each step in a food chain or food web is called a trophic level. Producers make up the first trophic level, consumers make up the second, third, or higher trophic level. Each consumer depends on the trophic level below it for energy.

All organisms within a habitat play a certain role in the food chain; they are producers, consumers, or decomposers. A food chain is really an energy chain. Energy from the sun is captured by the producers and passed on to the consumers. A producer is a green plant able to make its own food by photosynthesis.

Plant and animals need energy. Plants use the energy in light from the sun. They trap energy using chlorophyll inside the chloroplast. Plants use the energy to make glucose, starch, fat and protein (food). That is why plants are called producers; they are the first organism in food chain. The organisms that can produce their own food are called autotrophs organisms.

A consumer is an organism that depends on producers or other consumers for its food needs. Consumers that eat plants (producers) are called herbivores. Consumers that eat animals (consumers) are called carnivores. Carnivores that eat dead animals are called scavengers and help keep an ecosystem clean. Consumers, like ourselves, that eat both plants and animals are called omnivores. Scavenger is an organism that eat cadaver.

Animals get their energy from other organisms, they cannot produce their own food, that’s why they are called heterotrophs organisms. Animals that eat the producers are called primary consumers (consumer I). Animals that eat the primary consumers are called secondary consumers (consumer II). Animals that eat the secondary consumers are called tertiary consumers (consumer III). Animals that eat the tertiary consumers are called quaternary consumers (consumer IV).
An additional component of food webs is the decomposers or detritivor. These organisms are bacteria, fungi, and small invertebrates that break down the remains of dead organisms into smaller molecules that are then available to plants and other organisms as nutrients. For example, fungi digest wood fibers into simple sugar as a food source. Nutrients and elements such as carbon and nitrogen recycled by decomposers are then available for the plant producers to turn back into food for themselves and the consumers. Without decomposers plant material such as logs and leaves would pile up and choke the habitat
Decay, or decomposition, in biology means the natural breakdown of complex organic compounds into simpler substances. Decay occurs in dead plant and animal tissue and is important to the Food Web.
The tissue of dead plants and animals is broken down by a combination of physical and chemical processes.
· Physical breakdown occurs when scavengers such as vultures, rats, and ants eat the flesh of dead animals. Beetles, termites, and their larvae eat the bark of fallen trees and the stems of other plants, and flatworms consume smaller bits of organic matter. Other organisms that participate in the physical decomposition process include mice, moles, earthworms, mites, maggots (fly larvae) and other larvae, and snails.
· The most important chemical decomposers are also the smallest—the bacteria and fungi. These microorganisms secrete digestive enzymes onto the organic compounds to break them down. A million bacteria can live in 1 gram (about 0.04 oz) of soil, where they break down organic compounds from dead tissue and use them for food. Fungi also break down organic compounds, including cellulose that other microorganisms avoid.


Glosary:
Absorb:menyerap
Avoid:hindari
Bark:batang
Bits:serpihan
Chemical:secara kimia
Completely:komplit, lengkap,sempurna
Compound:component, zat
Decay:pembusukan
Decomposition:penguraian
Digested:decerna
Enzymes: enzim, zat yang mempercepat reaksi kimia
Fallen:jatuh
Feces:feses
Flatworm:cacing pipih
Fly:lalat
Fungi:jamur
Important:penting
Include:termasuk
Larvae:larva
Maggot:belatung
Means:artinya
Mice:tikus
Mites:tungau, kutu, semacam serangga
Mole:tikus mondok
Molecules:molekul,zat
Occurs:muncul
Participate:berperan
Physical:fisik, secara fisika
Secrete:mengeluarkan
Simpler: lebih sederhana
Stem:batang

Reference:
Microsoft ® Encarta ® 2007. © 1993-2006
http://www.absc.usgs.gov/research/seabird_foragefish/marinehabitat/images/Food_Web3.gif
http://library.thinkquest.org/J0113170/forest/images/fodchain.jpg
www.borealforest.org