How to make Handouts?

Partido State University

Goa Camarines Sur

College of Education

A/Y: 2012-2013

“How to Prepare Handouts”

BY: Kisha Leonie Ababa

akishalheonnie@gmail.com

akishalheonnie@yahoo.com

Food Chain and Food Web

“All living things need food to give them the energy to grow and move.”

FOOD CHAIN

• Is a food networks describe the feeding relationships between species in a biotic community.

• A linear sequence of links in a food web, starting from a trophic species that eats no other species in the web and ends at a tropic species that is eaten by no other species in the web.

• Path of food consumption.

• In other words, they show the transfer of material and energy from one species to another within an ecosystem. As usually put, an organism is connected to another organism for which it is a source of food energy and material by an arrow representing the direction of biomass transfer.

BRIEF HISTORY OF FOOD CHAIN:

Al-Jahiz

• Al-Jahiz is an African-Arab scientist and philosopher, the one who first commenced in the 9th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept.  

  
  

• Introduced the concept of food chains and also proposed a scheme of animal evolution that entailed natural selection, environmental determinism and possibly the inheritance of acquired characteristics. 

Food Chain

Ocean Food Chain

simple illustration of food chain

TROPHIC LEVEL

- Level of consumption in a food chain.

TROPHIC (NUTRITIONAL) LEVELS:

1. Green plants (PRIMARY PRODUCER)

     - Manufacture food from inorganic raw materials or utilizes solar energy or

       heat energy to synthesize starch.

     - All food chains must start with a producer.

     - Belong to the FIRST TROPHIC LEVEL.

2. Herbivores (PRIMARY CONSUMERS)

     - Consumers of green plants.

     - Belong to the SECOND TROPHIC LEVEL.

Giraffe is an example of herbivore animal. because Giraffe eats only green plants.

3. Carnivores (SECONDARY CONSUMERS)

     - Organisms that eat other organisms.

     - Predators feeding upon the herbivores.

     - All organisms in a food chain, except the first organism, are consumers.

     - Belong to THIRD TROPHIC LEVEL.

Crocodile is an of the carnivore animal.

4. Omnivores (TERTIARY CONSUMERS)

     - Consumers of both plants and animals

     - Belong to the SECOND AND THIRD TROPHIC LEVEL.

5. Decomposers (QUARTERLY CONSUMERS)

     - Fungi and bacteria.

     - Break down organic matter from a complex to a simpler form.

     - Belongs to SECOND AND HIGHER TROPHIC LEVEL.

Mushrooms are the best example of decomposer. they decompose the dead organisms.

• The table below gives one example of a food chain and the trophic levels represented in it.

 

Grass →	Grasshopper →	Toad →	Snake →	Hawk →	Bacteria of decay
In general,
Autotrophs (Producers)→	Herbivores (Primary Consumers)→	Carnivores (Secondary, tertiary, etc. consumers)→			Decomposer

      

      trophic pyramid (a) and a simplified community food web (b) illustrating ecological relations among creatures.

                                                                

TWO CATEGORIES CALLED TROPHIC LEVELS:

          1. Autotrophs

• - Green plants, those are capable of making nutrients or organic matter from inorganic materials including both minerals and gases such as carbon dioxide.

• - Source of all food.

          2. Heterotrophs

• - Obtaining nourishment by digesting plant or animal matter, as animals do, as opposed to photosynthesizing food, as plants do.

• - The linkages in a food web illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs.

• - The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange.

FOOD WEBS (food cycle)            Most food chains are interconnected. Animals typically consume a varied diet and,  in turn, serve as food for a variety of other creatures that prey on them.      Interconnections of food chain.     Depicts feeding connections (what-eats-what) in an ecological and hence is also referred to as a CONSUMER-RESOURCE SYSTEM.    This food web of different living organisms is a network of food chains.       BRIEF HISTORY:            Charles Elton pioneered the concept of food cycles, food chains, and food size in his classical 1927 book "Animal Ecology";        Elton's 'food cycle' was replaced by 'food web' in a subsequent  ecological text.       Elton organized species into functional groups, which was the  basis for Raymond Lindeman's classic and landmark paper in 1942 on trophic dynamics.      Lindeman emphasized the important role of decomposer organisms in a trophic system of classification.        The notion of a food web has a historical foothold in the writings of Charles Darwin and his terminology, including an "entangled bank", "web of life", "web of complex relations", and in reference to the decomposition actions of earthworms he talked about "the continued movement of the particles of earth".      Even earlier, in 1768 John Bruckner described nature as "one continued web of life". DIFFERENT KINDS OR CATEGORIES OF FOOD WEBS:     SOURCE WEB             -  One or more node(s), all of their predators, all the food these               predators eat, and so on.     SINK WEB            - One or more node(s), all of their prey, all the food that these prey eat, and so on.     COMMUNITY (OR CONNECTEDNESS) WEB            - group of nodes and all the connections of who eats whom.     ENERGY FLOW WEB           - Quantified fluxes of energy between nodes along links between a             resource and a consumer.     PALEOECOLOGICAL WEB           - A web that reconstructs ecosystems from the fossil record.     FUNCTIONAL WEB         - Emphasizes the functional significance of certain connections having strong            interaction strength and greater bearing on community organization, more           so than energy flow pathways. REFERENCE:      http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/F/FoodChains.html      http://en.wikipedia.org/wiki/Food_web      http://en.wikipedia.org/wiki/Foodchain      http://www.sciencedaily.com/articles/e/ecosystem.htm      Microsoft® Encarta® 2009. © 1993-2008 Microsoft Corporation.

Grass
→

Grasshopper
→

Toad
→

Snake
→

Hawk
→

Bacteria of decay

In general,

Autotrophs
(Producers)→

Herbivores
(Primary Consumers)→

Carnivores
(Secondary, tertiary, etc. consumers)→

Decomposer   

      FOOD WEBS (food cycle)

•            Most food chains are interconnected. Animals typically consume a varied diet and,  in turn, serve as food for a variety of other creatures that prey on them.

•      Interconnections of food chain.

•     Depicts feeding connections (what-eats-what) in an ecological and hence is also referred to as a CONSUMER-RESOURCE SYSTEM.

  

This food web of different living organisms is a network of food chains.

      BRIEF HISTORY:

  

•         Charles Elton pioneered the concept of food cycles, food chains, and food size in his classical 1927 book "Animal Ecology";
• 
  
•        Elton's 'food cycle' was replaced by 'food web' in a subsequent  ecological text.
• 
  
•       Elton organized species into functional groups, which was the  basis for Raymond Lindeman's classic and landmark paper in 1942 on trophic dynamics.
• 
  
•      Lindeman emphasized the important role of decomposer organisms in a trophic system of classification.

•        The notion of a food web has a historical foothold in the writings of Charles Darwin and his terminology, including an "entangled bank", "web of life", "web of complex relations", and in reference to the decomposition actions of earthworms he talked about "the continued movement of the particles of earth".

•      Even earlier, in 1768 John Bruckner described nature as "one continued web of life".

DIFFERENT KINDS OR CATEGORIES OF FOOD WEBS:

•     SOURCE WEB  

          -  One or more node(s), all of their predators, all the food these 

             predators eat, and so on.

•     SINK WEB 

          - One or more node(s), all of their prey, all the food that these prey eat, and so on.

•     COMMUNITY (OR CONNECTEDNESS) WEB 

          - group of nodes and all the connections of who eats whom.

•     ENERGY FLOW WEB

          - Quantified fluxes of energy between nodes along links between a

            resource and a consumer.

•     PALEOECOLOGICAL WEB

          - A web that reconstructs ecosystems from the fossil record^.

•     FUNCTIONAL WEB

        - Emphasizes the functional significance of certain connections having strong 
          interaction strength and greater bearing on community organization, more
          so than energy flow pathways.

REFERENCE:

•      http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/F/FoodChains.html
•      http://en.wikipedia.org/wiki/Food_web
•      http://en.wikipedia.org/wiki/Foodchain
•      http://www.sciencedaily.com/articles/e/ecosystem.htm
•      Microsoft® Encarta® 2009. © 1993-2008 Microsoft Corporation.