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Food chains and food webs - Coggle Diagram
Food chains and food webs
Food chain
Shows feeding relationships between org. Each org is called a link. No. of links varies
Links in a food chain: 1st; producers (green plants) --> 2nd; primary consumers (animals that eat only plants; includes herbivores and omnivores) --> 3rd or more; secondary consumers (animals that eat other animals; carnivores and omnivores)
Food web
Network of interconnected food chains (formed when animals eat more than one type of food; each animal or plant is also eaten by more than one type of animal)
Upsetting the balance
In a balanced ecosystem, no. of organisms remain almost constant. Enough producers to provide food for the consumers and each consumer has enough to eat. If. balance is upset, no.s of organisms change in a way that may harm the ecosystem. Can be upset by natural forces, such as. weather or disease. Or human activities, such as use of poisons, over hunting and pollution
E.g. if a disease kills many caterpillars. Plants will increase --> fewer caterpillars due to disease --> lizards decrease as not enough caterpillars to eat --> snakes decrease as less lizards to eat
Energy flow
All org need energy to live and carry out activities. Source of energy is thus sun. Flow of energy within an ecosystem is shown by food chains and food webs.
Energy comes from the sun via phot. energy is transferred through the food chain. Thus energy transmitted from one trophic level to another comes directly/indirectly from the sun.
Energy is lost to the env at each link in the food chain. Is lost as faeces (some of the grass is not digested, but is passed out of sheep, along with energy stored in it). Also lost during respiration (energy is used for life processes and activities such as moving and breathing). The rest is lost as thermal energy to the surroundings. Remaining energy is stored in org to be used for growth. It is this energy that is passed to next consumer.
Only about 10 percent of energy available at any link is p[assed on to next link. The other 90 percent is lost. As energy passes. along a food chain, the amount of energy trasnferred gradually decreases. Energy loss:
http://lattestcurrentaffairsandgk.blogspot.com/2013/07/ten-percent-law-by-lindeman.html
Energy and nutrient flow
Trophic level: Each level or organism in a food chain. Usually don't have more than 4
Energy loss
Energy is lost to the env as food is transferred from one trophic level to another
Lost to the. environment as thermal energy during respiration, in uneaten body parts, thru undigested matter egested by consumers, through waste products excreted by consumers
About 90% of energy is lost when it is transferred from one. trophic level to another