Exploring Food Chains

Name: Lindsay Husta

Title of Lesson: Exploring Food Chains

Date of Lesson:

Length of Lesson: 55 minutes

Description of Class:

Name of Course: Biology

Grade Level: 9-12

Honors or Regular: Both

Source of the Lesson:

Riverdeep Website

http://www.riverdeep.net/science/biology_gateways/bg_activity_pages/catn.activityi_800022.jhtml

TEKS Addressed:

(2) Scientific processes. The student uses scientific inquiry methods during field and laboratory investigations. The student is expected to:

(C) organize, analyze, evaluate, make inferences, and predict trends from direct and indirect evidence;

(D) communicate valid conclusions; and

(9)  Science concepts. The student knows metabolic processes and energy transfers that occur in living organisms. The student is expected to:

(D)  analyze the flow of matter and energy through different trophic levels and between organisms and the physical environment.

(12)  Science concepts. The student knows that interdependence and interactions occur within an ecosystem. The student is expected to:

(A)  analyze the flow of energy through various cycles including the carbon, oxygen, nitrogen, and water cycles;

(B)  interpret interactions among organisms exhibiting predation, parasitism, commensalism, and mutualism;

(D)  identify and illustrate that long-term survival of species is dependent on a resource base that may be limited; and

(E)  investigate and explain the interactions in an ecosystem including food chains, food webs, and food pyramids.

The Lesson:

I. Overview:

In this activity students see how populations inside a community affect each other. They learn to describe these effects using a graph of population size vs. time.

II. Performance or Learner Objectives:

Students will be able to:

· Distinguish between the various feeding levels in a food chain.

· Compare and contrast a food chain and a food web.

· Define an organism as a producer or a consumer.

· Describe the relationships that exist among the various feeding levels in a food chain.

· Classify an organism as a herbivore or carnivore.

III. Resources, materials, and supplies needed:

· The Riverdeep Website: Biology Gateways: Exploring Populations

http://www.riverdeep.net/science/biology_gateways/bg_activity_pages/catn.activityi_800022.jhtml

PDF of simulation can be found here.

· Downloadable program to run simulation

http://www.riverdeep.net/support/downloads.jhtml#Online

·

IV. Safety considerations:

V. Supplementary materials, handouts:

· Worksheet

Teacher Says/Does	Student Says/Does
Engage: Have the students create a hypothetical food chain with themselves at the top using pictures from magazines or drawings of their own. Have students use any labels of which they know.	Students create a food chain.
Evaluate: Does the chain contain the sun, producers, consumers, and themselves? Are the students using trophic level, producers, consumers, and other types of words correctly or at all?
Explore: Students go through the activity: http://www.riverdeep.net/science/biology_gateways/bg_activity_pages/catn.activityi_800022.jhtml	Students complete the activity and the worksheet.
Evaluate: Are students on task in filling out the worksheets. Are they able to interpret the graphs correctly? Can they make predictions based on the graphs.
Explain: What is the ultimate source of energy? How is energy transferred to producers? What process do plants use? What energy transformations take place? How did having two primary consumers change things?	The sun. The plants use it. Photosynthesis Lightàchemicalàheat and mechanical energy There was competition for resources which decreased the number of both species.
Evaluate: Are students able to answer questions? Are students involved in the discussion.
Elaborate: Besides food what are the primary consumers competing for? How might having these resources change an organism’s fitness? What would happen if a primary producer was removed from the food web? What would happen if a primary consumer was removed from the food web? (ask about effects on other primary consumers) What would happen if a predator was removed from the food web? (Top vs subordinated predators, different lengths of food chains) Can you think of any examples of top predators that have been removed? What are the effects? Let’s think of aquatic systems now. What does the term aquatic mean? What is the base of the food web in aquatic systems? How big is phytoplankton? So, if it’s that tiny, how many phytoplanktons are there? How big are the things that eat phytoplankton? How big do creatures normally get in the ocean? What does that tell you about the length of the food chain? What happens if toxic chemicals (mercury, DDT) get into the bottom of a marine food chain?	Hiding places, nesting sites, places to store food… A good hiding place is protection from predators. The primary consumers would die of starvation. Then the predators would die of starvation. The food chain would collapse from the bottom up. The plants would increase in number until they because resource (space, nutrient…)limited. The predators would starve or rely more heavily on other food sources, which may decrease another species numbers. In a three level chain, the level primary consumers will grow in number and eat too many producers. The decreased number of producers will not be able to feed all the primary consumers, so some consumers will starve. If a predator is reintroduced, there may not be enough primary consumers to sustain it. This is top down-control. Water-fresh and marine systems Phytoplankton Tiny, microscopic Lots Pretty small Sharks, whales, dolphins, pretty large Its really long. It’s very concentrated by the time it get to a top predator like tuna or marlin.
Evaluate: Are students paying attention and engaged? Are students using appropriate terminology? Are students thinking about food webs rather than food chains? Can they use what they know about terrestrial systems to think about marine systems?