Activity 8: Stomach Content Analysis

OBJECTIVES

•Examine a frog’s stomach

•Identify the food items in it

•Determine the food item’s frequency of occurrence

•Create a typical food chain where the frog lives

Stomach Content Analysis

•A method of determining food habits of a species

•Disclose presence of species not obtained by ordinary collecting methods

Data and ResultsFrog #1 Frog #5

Frog #2 Frog #6

Frog #3 Frog #7

Frog #4

Data and ResultsTable 1Animal

No. Food Item % in Stomach

Frequency in

Occurrence

1 Darkling Beetle 100 4

2 Hair 10 1

3 Clear Fluid 100 1

4 Corn Seed 45 5

5 None _ 0

6 Clear Fluid 100 1

7 None _ 0

Data and ResultsTable 2

Organism Trophic Classification

Darkling Beetle Primary Consumer

Corn Producer

Data and ResultsFigure A. Typical food chain where the frog lives

Question and Answer Portion

Question

1 Of the organisms found in the frog gut,

which of these are considered, herbivore, carnivore, and parasite? Discuss briefly their position in the

pyramid of productivity.

Answer

1Darkling Beetles are herbivores. The position of darkling beetles in the pyramid of productivity is on the second base.

Question

2 The transfer of energy in a given

ecosystem is not 100 % efficient. Why are food chains limited only to about 4-5

trophic levels?

Answers

2Pyramid of productivity assumes only 10% efficiency of energy transfer across all trophic levels because:

1) not everything in the lower levels gets eaten2) not everything that is eaten is digested3) energy is always being lost as heat

•Food chains tend to have 4-5 trophic levels because sufficient energy is unavailable to support a large enough breeding population at trophic levels higher than these.

Question

3Does the type of food they eat have to do with the type of habitat they live? Can you relate the productivity of the ecosystem with the data you have?

Answer

3The type of food the frogs eat depends on the habitat they live in. This is because if the type of food items available in the habitat are only secondary consumers then these frogs would most likely be carnivorous instead of herbivorous or both.

We can relate our data with the productivity of the ecosystem by inferring that the number of beetles found inside the frogs’ stomach is directly proportional to the number of plants available for them to consume. In other words more plants, more beetles then more beetles, more frogs.

Conclusion

Frogs are organism that can either be classified as a secondary or tertiary

consumer. Their presence infers that there is high species diversity and

productivity in a certain ecosystem.

Documentary

Documentary

References

http://w3.marietta.edu/~biol/biomes/ecosystems.htmhttp://www.4sg.com.ua/pictures/board/44134.jpghttps://www.cals.ncsu.edu/course/ent425/spotID/Coleoptera/darkling.jpgwww.ask.com/pets-animals/beetles-herbivores-8085abb254660fa2http://cdn.lolwot.com/wp-content/uploads/2015/08/20-popular-myths-about-animals-that-people-truly-believe-18.jpg