Woodrow Wilson 2002 Commuter Institute/ American Museum of Natural History on

Biodiversity and Biocomplexity

August 2002

Agwu Justina

Walton High School

2780 Reservoir Avenue

Bronx, New York 10468

Investigation of different aquatic ecosystems

Aim: How does an ecosystem function as a living system?

Objectives:

The student will:

- Describe an ecosystem as a basic unit of an environment,

- Know the role of plants and animals in the web of life,

- Explain the role the organisms the cannot see with their eyes play in the web of life,

- Experiment on the samples using various microbiological techniques,

- Describe how energy flows from the producers to the consumers,

- Count the biomasses of the macro and the microorganisms,

- Establish mathematical relationships between the different ecosystems, and organisms using graphical methods,

- Understand the need of conserving the natural resources in the environment.

New York City Performance Standard

Science:

The student produces evidence that addresses the understanding of:

S2c: Biodiversity of organism,

S2d: Interdependence of organism such as ecosystem, and the human effect on the environment,

S2e: Energy and organization in the living system.

Mathematics:

S2b: Work with two- and three-dimensional figures

such as polygon like a square, and

S4a: Organizes, analyses, and display variable data using graphs.

Material: Nutrient agar, nutrient broth, safranine, iodine decolorizer, crystal violet, calcium chloride, E. coli, E. aerogenes disinfectant, soap, optical lens wipe, coins, salt, alcohol, marsh samples and egg.

Test book: Upco’s Biology course

Equipment: Microscope, petri dishes, incubator, computer, digital camera, disk, and the Internet.

Internet sites: www.amnh.org and www.prenticehall.com

Resources: Printed resources from the Museum of Natural History

Introduction:

I teach science and mathematics in the special education department.

This project is designed for the students in the tenth grade.

Three different ecosystems are to be covered by this investigation, which include a Museum trip to the New York State Environment Hall to observe the – From Field to Lake exhibit, Constitution Marsh at Philip town Putnam County, and the Central Park Lake. The students will observe and count the macro organism biomasses such as the turtles, cattails, arrow plants of a square meter of the of the constitution marsh, and the central park lake, and take some samples, which they will use to observe and count for different microbial biomasses and examine how they react to various microbiological tests such as gram stains, antibiotics sensitivity/susceptibity test, and to different enrichment tests. While in the field the students will count, measure, and record the number of each species of the square meter.

In the lab the students will culture, gram stain, do a wet mount from berlese funnel, experiment to see if crytozoa can be found from leaf mold, subject the organisms identified from pure culture to American and Canadian coins, made before 1965, to test for ant-microbial effects on heavy metal, and the other enrichment tests.

The students will follow up their experience with a trip to the Museum of Natural History to observe an exhibit on – From field to lake which addresses the content area of biodiversity, classification, habitats, succession, food webs, adaptations, reproduction and the human impact. In the Museum the students will be given worksheet based on objective and subjective observations they are making such as describe how ecological succession takes in the exhibit of – From Field to lake and how they feel about it.

After the Museum trip, the student will do a project based on the experience they have acquired from the three ecosystems.

I will assess the students’ work by using peer assessment, and the teacher-made test.

Procedure:

Pre-Visit Preparation:

The first thing I will do to prepare the students for the trip is help the students make connection between their prior knowledge and the content area of ecological systems such as lawn, garden, marsh by acting as a facilitator.

The students, through instruction will become familiar with the vocabularies such as ecosystem, population, community, niche, biomes, biomass, abiotic, biotic, conservation of natural resources, food chain, food web, producers, consumers, and decomposers, pyramids of numbers and trophic levels.

Then I will take the students to trips natural environments such as, the constitution marsh and the central park lake and have them count the species of different organisms they will see in one square meter of each. The students will use the data they collected to make pyramids of numbers of the constitution marsh and that of the Central Park Lake. The students will compare the data they collected graphically and arithmetically. From the counting the students would have done, they will use the data to make pyramids of numbers for both constitution marsh and the central park lake. At the base of the pyramid are the autotrophs such the algae, plants, cyanobacteria or the chemosynthnthic producing bacteria like hydrogen sulphide bacteria; while organisms in the middle are mostly herbivores, and the omnivores; organism at he top are the predators such as hawks. As the energy flows upward from the base of the pyramid to the top, the energy becomes less.

Table showing the Biotic Factors of the Constitution Marsh versus the Central Park Lake

Biotic Factor	Constitution Marsh	Central Park Lake
Autotrophs (cattail and arrow plants)	8000	2000
Herbivores (grasshoppers)	6000	1500
Omnivores (mouse)	4800	1200
Predators (hawks)	400	100

The student will compare each organism in both ecosystems by using arithmetic ratio.

The ratio of constitution marsh (CM) autotrophs to central park (CP):

8000:2000 that is 8000/2000, which is 4/1. This means, that for every four autotrophs at the constitution marsh there is an equivalent of one of such autotrophs at he Central Park Lake. The same goes for the herbivores, omnivores, and the predators.

Can any one wonder why this so? One of the reasons why the constitution marsh has more organisms than the central park lake is because organisms just like the video we watched about the chimpanzees survive better in their native environment than environment constructed by humans such as the central Park Lake.

In the lab, the students work with the samples collected from the constitution marsh and the Central Park Lake. The kind of microbiological tests include the culturing the samples collected, gram staining, serial dilution, ant- microbial sensitivity/susceptility test, and other enrichment media tests and the result recorded. The tests conducted with samples from the constitution marsh sample is summarized as:

Microbiological Tests

Test	Result
Nature of the organism in the nutrient broth	Turbid
Nature of the organism in nutrient agar	Many colonies were observed, some were mostly milky in color, and with different rounded in shape, small, large, elevated tops
Gram stain	Gram negative, positive rods, and gram negative cocci
High concentration of salt and gram stain	Gram negative cocci
Extreme temperature	Gram positive rods
Effect on the heavy metals	Zone of inhibition seen the coins made before 1965

I will also show the students video that is related to the aquatic ecosystem such as the video on the deep-ocean volcano and have them write what they learned from the expedition, and explain how chemosynthesis takes place. I will give the students articles from the Museum such as Biodiversity.

I will tell the students to focus their attention more on the New York State Environment Hall especially on the exhibit about –From Field to Lake and explain their observations. The students will also compare the different parts of this exhibit.

Worksheet

Write two sentences about the organisms in this ecosystem

Draw and label any plant of their choice

Draw and label any animal of their choice

Museum Visit:

I will maximize both the mental and the physical resources to the best of my ability and strength to ensure that the trip is a success. Last May, when I took thirty-five students to the Museum with the help of another teacher it was a huge success, and as such if I have another opportunity of doing so, it may be better because of what I know now, which I never knew before such as taking them to a natural environment such as 79^th Street Hudson River Boat parking first before taking them to a make-believe environment like the Museum.

Post- Visit:

I will ask the students to compare and contrast the three ecosystems they visited using graphics, drawings, computation and the problem solving skills of arithmetic’s to explain the food chain, food web, and to write an essay on human can improve and preserve the environment.