Energy in Food Chains

B. ENERGY: THERMODYNAMICS 1st Law energy can neither be created nor destroyed it merely changes form solar  chemical  mechanical  heat 2nd Law every time energy changes form some energy is lost as “waste” or useless energy in the form of heat (less energy at the end of the transfer than at the beginning) Living things and the cells that make them up must follow the laws of thermodynamics. Cells take energy and convert it into different forms.Important principles in biology that govern the chemical process of metabolism

ENERGY: THE SUN source of all energy for living organisms absorbed or reflected by: gases in the air water (clouds, ice, lakes, etc…)‏ rocks and soil living organisms photosynthesis collect solar energy convert to chemical energy (food)‏

ENERGY: PHOTOSYNTHESIS green plants (some single celled organisms)‏ collect sunlight using a green pigment called chlorophyll plants convert light, CO 2 and water to glucose (sugar)‏ plants serves as the origin of food for all other organisms: directly from herbivores eating green plants indirectly from other animals (carnivores) eating the herbivores

ENERGY IN FOOD CHAINS producerprimary (1 o ) consumer secondary (2 o ) consumer 10% 90% energy used to live energy passed to consumer 10% Rule: only 10% of the energy in an organism is stored and passed on to the next trophic level (90% of the energy is used to live). 10%

ENERGY IN ECOSYSTEMS & TROPHIC LEVELS The term trophic level describes the place in a food chain that an organism feeds 1 st TROPHIC LEVEL producers or autotrophs that feed themselves

2 nd TROPHIC LEVEL herbivores or primary [1 o ] consumers that eat producers 3 rd TROPHIC LEVEL carnivores or secondary [2 o ] consumers that eat herbivores

4th TROPHIC LEVEL carnivore or tertiary [3 o ] consumers that generally eat other carnivores

All consumers are called heterotrophs. All producers are called autotrophs

A food web is a series of interconnected food chains HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Identify an autotroph Identify a primary consumer produces its own food eats a producer (herbivore) BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Identify a secondary consumer a carnivore that eats other herbivores producer 1 o consumer 2 o consumer BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Identify an organism at the fourth trophic level BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Identify a decomposersomething that eats dead things Identify an omnivoresomething that eats plants & animals BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Explain what would be the effect on voles of fewer hawks  hawks =  weasels and  mice  mice & weasels =  grasshoppers  grasshoppers =  grass  grass =  food for voles =  voles BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Explain what would be the effect on bobcats of fewer grasshoppers OVER THE SHORT TERM  grasshoppers =  grass & seeds =  food for frog, weasels & mice  food for frogs means frogs leave or die  frogs means less food for bobcats =   bobcats OVER THE LONG TERM  grass = more food for voles =  voles  voles = more food for bobcats =  bobcats BACTERIA

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Explain, what would be the effect on grasshoppers of fewer leaves  fallen leaves =  food for voles voles now eat more grass  grass for grasshoppers =  grasshoppers (they die off/ or leave area as less food)  food means some voles leave  voles =  food for bobcat bobcats now eat more frogs  frogs = weasels eat more grasshoppers  fewer grasshoppers BACTERIA OVER THE SHORT TERM OVER THE LONG TERM

HAWK WEASEL BOBCAT MOUSE GRASSHOPPER FROG SEEDS GRASS VOLE FALLEN LEAVES Explain what would be the effect on hawk of fewer bobcats.  bobcats =  voles and frogs  frogs =  food for weasels some weasels leave or die off =  food for hawks = fewer hawks OVER THE LONG TERM  voles eat more grass =  grass  grass for grasshoppers & mice  grasshoppers & mice =  food for hawks  fewer hawks BACTERIA OVER THE SHORT TERM