FOOD CHAINS & WEBS
sun eclipse with palm the ultimate energy source
Energy Flow in Ecosystems Energy flows from where into the biological world?
Energy Flow • How does the sun’s energy enter the biological world? • What is photosynthesis?
consumer 2 sunlight producer consumer 1 Energy Flow • The sun’s energy flows into organisms that can change the sunlight into food then into organisms that eat them. • What are producers? • This flow is:
Energy Flow consumer omnivore producer detritivore herbivore decomposer carnivore heterotroph autotroph
consumer 2 sunlight producer consumer 1 PRODUCERS • Autotrophs that trap solar energy into organic molecules during photosynthesis; can produce their own food • Ex. Plants, algae and some bacteria
consumer 2 sunlight producer consumer 1 CONSUMERS What are consumers? • Heterotrophs that eat other organisms to obtain energy • Examples: deer, rabbits, cows, mice, lions, humans, hawks, snakes
consumer 2 sunlight producer consumer 1 HERBIVORES What are herbivores? • Organisms that eat plants • Primary Consumers • Ex. Cows, caterpillars, bunnies
consumer 2 sunlight producer consumer 1 CARNIVORES What are carnivores? • Organisms that eat meat (other animals/consumers) • Secondary Consumers • Ex. tigers, wolves, snakes, hawks
consumer 2 sunlight producer consumer 3 consumer 1 TOP CARNIVORES What is a “top” carnivore? • “Top” carnivores eat secondary consumers; usually nothing feeds on them • Ex. killer whale eating a sea lion or hawk eating a snake.
What are omnivores? Consumers that eat both plants and animals Secondary Consumers Ex. bears and humans OMNIVORES
Where do allthe dead things go? • They are eaten. YUMMMM! • They decay. SMELLY! decomposer detritivore What’s the difference?Is it just a matter of taste?
Detritivore vs Decomposers • Detritivores and decomposers both feed on the remains of dead plants and animals and other dead matter (detritus) • They rely on dead tissues for nutrients. decomposer detritivore
Detritivore vs Decomposers • Detritivores eat the remains of dead plants and animals • Decomposers breakdown (decay) organic matter and feed on it Crabs, mites, earthworms, snails Bacteria & fungi
Detritivores and Decomposers What is a scavenger? • A scavengers is a type of detritivore that feeds on carrion (dead animal remains). Ex. vultures, sharks, maggots, hyenas
Ding Beetle Biology by Peg Wallace http://www.esb.utexas.edu/nrm2001/dogdoo/dbbiology/Default.htm dung beetles on dog poop Detritivores and Decomposers • On what do detritivores and decomposers feed?
decomposer consumer 3 consumer 2 sunlight producer consumer 1 Detritivores and Decomposers Why would they be called the environmental “recyclers”? • They decompose excrement, dead bodies and leaf litter, returning nutrients to the physical environment.
consumer 2 sunlight producer consumer 1 Energy Flow • The series of steps in which organisms transfer energy by eating and being eaten is called a Food Chain
consumer 3 consumer 2 producer consumer 1 Food Chains & Food Webs • The steps in the transfer energy from organism to organism in feeding relationships are called Trophic Levels. • How does a food chain describe this path of energy? (arrows)
consumer 3 consumer 2 producer consumer 1 Food Chains & Food Webs • Name the number of the trophic levels in the food chain below. • How do the trophic level numbers correspond with the “eating terms”? Trophic Level 1 2 3 4
consumer 3 consumer 2 producer consumer 1 Food Chains & Food Webs • What important energy transfer is not shown in a food chain? • Why is it that some energy is lost from one level to the next level? • How much energy is actually passed on to the next level? (rule of thumb)
decomposer consumer 3 consumer 2 producer consumer 1 Food Chains & Food Webs • What vital “recycler” is not shown in this food chain? • Upon which organism(s) would it feed?
decomposer consumer 3 consumer 2 producer consumer 1 Food Chains & Food Webs • If all of the snakes in this chain died, what would happen to the hawk? • To the decomposers?
Food Chains & Food Webs • Most organisms feed on more than one trophic level and feed on several different species at each trophic level. This is a food web.
Arctic Food Web http://www.arctic.noaa.gov/essay_krembsdeming.html
Making a Food Web • Use these organisms for the lab in Part B of the Energy Flow Through Ecosystems worksheet.