Food chain & Food Web Flipbook PDF

Food chain & Food Web

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Subject - Botany

By- Dr. Deepti Sharma

Class - B.sc II

N.A.S ( P.G.) College, Meerut

Paper - II ( Cytology ,Genetics ,Evolution and Ecology) Unit- IV Topic - Ecosystem (Food Chain and Food Web)

Food chains In ecology, a food chain is a series of organisms that eat one another so that energy and nutrients flow from one to the next. Food chain, starting from the bottom—the producers—and moving upward. In a food chain, each organism occupies a different trophic level, defined by how many energy transfers separate it from the basic input of the chain.

Trophic Levels  The nutritive levels in a food chain are known as Trophic Levels.  The organisms in the trophic levels of the food chain are categorized based on their feeding patterns. Tertiary consumers (FOURTH LEVEL)

(Secondary Carnivores -Meat-eaters) ( Tiger, Lion)

Secondary consumers (THIRD LEVEL)

(Primary Carnivores -Meat-eaters ) (Fox , Wolf )

Primary consumers (SECOND LEVEL) Primary producers (FIRST LEVEL)

(Herbivores- Plant-eater) (Dear, Goat, Cattles) (Autotrophs - Plants ,Photosynthetic -organism)(Blue green Algae, Bacteria)

Decomposers Decomposers are sometimes considered their own trophic level. As a group, they eat dead matter and waste products that come from organisms at various other trophic levels. Fungi and bacteria are the key decomposers in many ecosystems; they use the chemical energy in dead matter and wastes to fuel their metabolic processes. Types of Food Chain 1. Grazing food chain: This type of food chain starts from the living green plants goes to grazing herbivores, and on to carnivores. Ecosystems with such type of food chain are directly dependent on an influx of solar radiation. (i) Predator food chain, where the sequence of organisms are generally from small to big. (ii) Parasitic food chain, where organisms tend to decrease in size as one goes higher up the food chain. Eg. Roots of vegetables nematodes → bacteria

Types of Food Chains Odum (1962-63) 1. Grazing food chain-

A. Grass land: Eg.- Grass→ Grass Hopper→ Frog→ Snake→ Peacock Eg.- Grass→ Rabbit→ Fox→ Wolf → Tiger B. Aquatic food chain: Eg. Pond : Phytoplanktons → Zooplanktons→ Small ( Diatoms, Hydrilla, Volvox) (Pramecium, Cyclops) Crustaceans → Predator Insect→ Small Fish→ Large Fish C. Forest Food chain: Eg: Tress→ Herbivores and Insects → Birds, Lizards→ Fox (Goat, Deer) (Aphids, Spiders)

2. Detritus food chain-

Eg. Dead organic matter or Fallen Leaves→ Fungi, Bacteria and Protozoans → (Insect larvae)

Figure-1, Food Chain (Thing link)

(Eschool)

(Embibe)

B. Detritus(Saprophytic) food chain: This type of food chain goes from dead organic matter into mi-croorganisms and then to organisms feeding on detritus (detrivores) and their predators. Such ecosystems are thus less dependent on direct solar energy. These depend chiefly on the influx of organic matter produced in another system. Significance of food chain: 1. The studies of food chain help understand the feeding relationship and the interaction between organisms in any ecosystem. 2. They also help us to appreciate the energy flow mechanism and matter circulation in ecosystem and understand the movement of toxic substances in the ecosystem. 3. The study of food chain helps us to understand the problems of bio-magnifications.

Types of Food Chains

FOOD CHAIN

GRAZING FOOD CHAIN

PREDATORY FOOD CHAIN

DETRITUS/SAPROPHYTIC FOOD CHAIN

PARASITIC FOOD CHAIN

Food Webs  A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. It includes many intersecting food chains. It demonstrates that most organisms eat, and are eaten, by more than one species. A food web represents multiple pathways through which energy and matter flow through an ecosystem.

Figure-2 : Food Web

(Biology CK12)

(Nature .com)

REFERENCES  Kumar Satish and Harjinder Singh ; Cytology Genetics Evolution and Ecology ,Pragati Prakashan, Meerut. Pandey , B. P ; College Botany , Volume : 3 ; S. Chand and company Pvt., Ltd. New Delhi. Sharma , P.D. : Ecology and Environment, Rastogi Publication, Meerut. Verma, P. S. and Agarwal, V.K. ; Cell Biology and Genetics , S. Chand and company Pvt., Ltd. New Delhi.