Food Chains and Food Webs

Transcription

1 Name: Date: Period: Science ID#: Food Chains and Food Webs 1 Topic: Food Chains and Food Webs Energy: The most basic building block that all living organisms need. The ability to do work. 2 All of the energy for most life and human technology comes from the SUN. What does this chemical reaction represent? 6CO2 + 12H2O + sunlight ---> 6O2 + C6 C H12 12O6 + 6H2O or... carbon dioxide + water + sunlight ---> oxygen + carbohydrate + water 3 4 Photosynthesis The process where green plants trap the sun s energy and use it to make food. The process by which carbohydrates (glucose/sugar) are synthesized from carbon dioxide and water using light as an energy source. 5 6

2 Oxygen is released as a byproduct. 7 Organisms are classified as producers or consumers. a producer? An organism that can use the sun s energy to make its own food. The foundation of all ecosystems An autotrophic organism Constitutes the first trophic level in a food chain Green plants & algae 8 Why are producers vital to the ecosystem? *They make food for all other species. Use sunlight to create food molecules (sugar) from nonfood molecules (water and carbon dioxide). No animal can make food from nonfood a consumer? Organism that cannot make its own food. Depends upon producers A heterotrophic organism Constitutes the second, third, etc. trophic levels in a food chain substances List the 4 types of consumers: herbivores, carnivores, omnivores, decomposers 11 Herbivores Consumers that eat plants; plant eaters Range from insects to large mammals Grasshoppers, rabbits, koala bears, deer, cattle, elephants, etc. 12

3 Herbivores 13 Carnivores Consumers that feed on animals instead of plants; meat eaters Hawks, tigers, Venus-flytrap, sea lions, dogs, cats, Emperor penguins, snakes, sharks, spiders, etc. 14 carnivores 15 Omnivores Consumers that eat both plants and animals Bears, coyotes, red fox, pigs, rodents, raccoons, sea gulls, most primates, some fish, etc. 16 omnivores 17 Decomposers Consumers that feed on the waste products or bodies of other dead organisms. Recycle nutrients by breaking down dead organisms and animal waste Fungus, bacteria, a few flowering plants such as Indian pipes, maggots, dung beetles, earth 18 worms, sow bugs, etc.

4 Fungus Decomposers Sow Bug or Pill Bug Indian Pipes 19 a niche? An organism s role or job in the ecosystem. Describes the position of the organism in the food chain. 20 Some organisms have a specialized niche: Some organisms have a broader niche: Koala bears only eat shoots and leaves of the eucalyptus trees Panda bears eat mainly bamboo Brown bears eat both plants and All carnivores do not fill the same niche: Predators carnivores that feed on other animals (prey) animals Scavengers carnivores that feed on carrion: dead animal carcasses (ex: vultures, flies, crows) Parasites carnivores that feed on living organisms (mosquitoes, ticks, fleas, leaches) 23 24

5 Parasitic Carnivore Medicinal Leech 25 Not all parasites are considered carnivores: If their host is a plant, they are classified as herbivores. Mistletoe Toothwort 26 Parasitic Herbivore Purple Toothwort (Lathraea clandestina) grows on the roots of alder, poplar, and willow trees a food chain? A diagram that shows the flow of energy from green plants or algae to consumer organisms. Shows the niche of an organism Food Chain The arrows in a food chain show what eats what. The arrow replaces the phrase is eaten by. The direction of the arrow is very important. The arrow must point toward the eater. always the first step in a food chain? the producer Leaf Grasshopper Frog Heron Second step? the herbivore (sometimes it s an omnivore) 29 30

6 a primary consumer? An herbivore or first consumer in a food chain that is sometimes called the first-order consumer. 31 a secondary consumer? A carnivore or second consumer in a food chain that is sometimes called the second-order consumer. May be a predator, scavenger, or a parasite 32 the tertiary consumer? A third-order carnivore an apex predator? Predators that have no predators of their own, residing at the top of long food chains, where they play a crucial role in maintaining the health & balance of their ecosystems. In some food chains there is a fourthorder consumer Ecological role: Carnivore examples: the big cats, crocodilians, wolves Omnivore examples: grizzly bears & humans Apex predators affect prey species population dynamics. Removal of top-level predators can radically disrupt trophic levels (ex: the eradication of gray wolves from Yellowstone Where are decomposers located in the food chain? They may be at any step except the first, for like any other consumers, they depend upon producers. Decomposers eat everything! National Park) 35 36

7 What phrase is replaced by the arrow in a food chain? is eaten by 37 a food web? A diagram that shows the many possible food chains (different trophic levels) that exist in an ecosystem; it s more complex. For example: Grasshoppers eat other plants, not just grass. Frogs eat other invertebrates, 38 not just grasshoppers alone. Food Web A food web shows the many possible food chains that exist in an ecosystem. 39 Why are ecosystems with complex food webs more stable than ecosystems with simple food webs? Organisms have more choices of things to eat. If the population of one food source declines, animals can feed on other organisms. 40 Food Web Practice Creating a Food Web Poster Be sure to read ALL directions for #8. Refer to your notes that s why you took them! 41 Use your notes, the text, & all of your teammates before you get the teacher use your resources 1 st! You will have only 30 minutes to finish this next class! 42