ZOOLOGY FUNDAMENTALS

The prolific use of detailed artwork intro-
duces the many worlds of zoological
science and the classifications that syste-
matize its diversity. Discounts of 25% or
more on bundled sets.

NUTRIENT CYCLES, FOOD CHAINS & WEBS
The cycles by which energy and vital elements are transfered through various trophic levels. 5 programs. 120 slides. Detailed texts.
EPSS-0785X SLIDES
$199.95

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SAVE OVER $52.00 ON 5 SLIDE SET BUNDLE ORDER EP #SS-0785X.....$199.95
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FOOD CHAINS & FOOD WEBS Slides order #SS-0122X.......$72.50

An examination of these important concepts through live photographs and full
color artwork. Ecological interdependencies are focused upon in a pyramid approach,
leading to an understanding of food webs at the basic level. 4O frames, 2 guides.
(Filmstrips (2) order SS 0123X.......$25.00.)

CONTENT SAMPLE: 16. As a very basic statement, then, a food cycle includes
the sun for original energy, that energy being converted by producers to stored glucose (or
starch); the stored glucose may be obtained by first-order consumers, which in turn may by
eaten by higher-order consumers. When any of these components of the food cycle die, the
decomposers take over, eventually forming nutrients which nourish the plants (producers).
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MARINE FOOD WEBS Slides order #SS-0785S............$49.95

Provides a general summary of the trophic relationships in the marine
ecosystem. Discusses the importance of inorganic nitrates and phosphates to
production, and the roles of thermocline turnover, or water mixing in the aquatic energy
cycle. 20 frames, cassette and guide. (Filmstrip order SS-0785F.......$15.00.)

CONTENT SAMPLE: 3. The sunlit surface waters of the ocean where plants live
is called the photic zone. The lower boundary of the photic zone is the compensation level,
where sunlight is attenuated to the point that plant photosynthesis does not exceed plant
respiration. Below the compensation level there is no net photosynthesis, and the consumers in
this euphotic zone rely on organic materials that are produced in the sunlit waters above them.

The photic zone varies in depth according to the amount of incident sunlight and the
amount of suspended materials in the water. The compensation depth may be no lower than a
few meters in turbid coastal water, but may exceed 100 m in the clearest oceanic waters. This
is relatively shallow compared to the average 4,000 m depth of the ocean as a whole. Primary
production in the ocean is thus confined to a relatively narrow volume of surface water.
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MARINE NUTRIENT CYCLES Slides order #SS-0790S..........$49.95

Examines the chemical makeup of the oceans' productive waters, wherein
nearly every naturally-occurring element can be found, although most are not required by
marine organisms. Also illustrates primary productivity, its dependence on nitrates and
phosphates and the interaction of light and nutrient salts. 20 frames, cassette and guide.
(Filmstrip order SS-0790F......$15.00.)

CONTENT SAMPLE: 10. Vertical mixing can also be induced by wind-driven currents in
coastal waters. Wind stress drags the surface waters, but due to the rotation of the earth the net
transport of water is perpendicular to the direction of the wind: to the right in the northern hemi-
sphere and to the left in the southern hemisphere. Where the prevailing winds blow perpendicular
to a coastline and toward the equator the surface waters are transported offshore. In compen-
sation, subsurface waters then flow to the surface along the coast. As the surface waters are
driven offshore they are replaced by waters from 100-200 m deep.

These upwelling waters are relatively cool and rich in nutrients. Locations of such
upwelling enjoy high productivities as long as the prevailing winds maintain their direction and
intensity. Such productive waters are common along the western margins of continents, and it is
there that the world's most productive fisheries are located. Foremost among these are the
fishing grounds associated with the Humboldt Current off the coast of Peru. The productivity of
this fishery periodically crashes as the upwelling patterns are modified every seven years by
current changes, and more dramatically every thirty years or so when abnormally weak air
circulations fail to drive the surface waters offshore.
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NUTRIENT CYCLES: CARBON, NITROGEN, SULFUR, CALCIUM and PHOSPHOROUS
Slides order #SS-0912X..........$79.95

Green plants incorporate carbon atoms from atmospheric carbon dioxide into organic
compounds. Respiration by plants, animals and decomposers returns carbon to the atmosphere
and hydrosphere. The carbon cycle is not complete: minor leaks include fossil fuels derived from
ancient plants and the remains of animal skeletons in sedimentary rocks. The nitrogen cycle
traces the flow of nitrogen compounds through the biosphere, focusing on the microbial activities
of ammonification, nitrification, and nitrogen fixation that make nitrogen available to plants and
animals. Sulfur and calcium are minor components of plants and animals, yet they perform many
vital functions. Microorganisms in the soil and water make these nutrients available to plants.
Such microbial activities interrelate the sulfur, calcium and nitrogen cycles in interesting ways.
Unlike nitrogen and carbon, phosphorus has no atmospheric reservoir, although it is plentiful in the
lithosphere and hydrosphere. Lack of soluble phosphorus limits the growth of terrestrial and
aquatic plants, while agricultural and waste disposal practices accelerate the loss of this element.
40 slides, 4 guides.
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hydrocat_09.tif Nutrient cycling. graphic by Educational Images Ltd.

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