As we can see from the word equations respiration and photosynthesis are opposites. Respiration uses oxygen and produces carbon dioxide. Photosynthesis uses carbon dioxide and produces oxygen.
Because they interact with light to absorb only certain wavelengths, pigments are useful to plants and other autotrophs--organisms which make their own food using photosynthesis.
An ecosystem consists of the whole community of living organisms (biocenosis), the abioticcomponent of a certain environment (biotope) and their relationships.
The relationships essentially consist in a flux of substances which pass from thenon-living components to living ones and in a flux of energy which passes from thephotosynthetic organisms (plants) to the herbivorous animals, then to carnivores. Thewastes and the dead organisms are then decomposed by the micro-organisms which brake downthe substances back to simple components, in a full cycle.
1 - With a shovel in a field or in a wood, dig a square hole of about half a meter (1 1/2feet) square and about 40 cm (18") deep. Describe the non-living components of thesoil and all forms of life you find: roots, earthworms, snails, centipedes, spiders,crickets, etc. To complete the description of the ecosystem of the soil, look forinformation on the role of each of these organisms and the relationships with the otherforms of life of this environment.
2 - In similar way you have studied the soil ecosystem, you can analyze other ecosystemssuch as the ones in a forest, pond, shore, or desert.
G. and L. Durrell (2) can be useful, or there are many other books on this matter.
An Illustration of a Soil Ecosystem
Protocols for a Soil Ecosystem Approach for Characterizing Soil Biodiversity
Internet keywords: soil ecosystem.
Making an aquarium or a terrarium is not a complicated thing. Learning to build them isvery useful for those who are fond of breeding animals, observing them, taking picturesand movies. You can use an aquarium to breed fish, amphibians, protists, algae, artemia,shrimps, etc. You can use a terrarium to breed many species of animals, but avoid raisingspecies which suffer in captivity. Aquaria and terrariums can be used also to take picturesof animals temporarily taken from their environment.
In their simpler form, acquaria and terrariums are simple glass boxes enclosed on 5 sidesand which can be provided with a lid. This simple container is suitable to breedamphibians and as a terrarium. Aquaria for fish require a compartment for a filter, a pumpfor water circulation, another pump for air, a thermostat, lighting, etc. We'll deal ofthe simplest aquaria.
How you can build an aquarium? In first you have to make a drawing. The bottom glass hasto be surrounded by the other four walls and it has to be the thickest. The thickness ofthe plates has to be proportioned to the size of the aquarium. Avoid building too wide,and more importantly, too high an aquarium. The pressure of the water increases and couldunglue the plates. After having drawn the acquarium you have to cut the glass plates bymeans of a glasscutter. To do this keep the glasscutter vertical and push down with forcewhile you move it along a ruler. This operation require practice, so use some scrap piecesuntil you have the necessary manual ability. It is important you use a sharp glasscutter,kept in oil to avoid rust. Before gluing the slabs, you have to round off the edges withsandpaper in order to remove their sharp edges. With some acetone, clean the slabs wherethe silicone rubber will be deposited. As the acetone is toxic, work outdoor or in a wellventilate piece. Use high quality transparent silicone. To keep the internal walls free ofexcessive glue, on the slabs and near the gluing positions, place stripes of sticking tape(figure 6). When the silicone is cured, remove these stripes and the excess glue.
: handling and cutting glass is a dangerousoperation which has to be made only by adult people wearing gloves and a heavy apron. Away to elegantly solve this problem is to order plates. A hardware or building supplystore can help. Never move aquaria and terrariums containing water or stones, move them onlywhen they are empty. Do not place aquaria in positions where a water leak could damagesomething below them, for example over electrical devices or sockets, and books. Onlyadults should handle glass-made aquaria or terrariums. Give children transparent plastictanks. Do not keep dangerous or rare organisms. Do not breed and most important, do notfree species which do not belong to your environment! Do not free sick animals or plants.
Reef Aquarium Guide
CyberAqua (list of links)
Internet keywords: aquarium glass homemade.
Hydroponics is a method of growing plants without soil. Plants are simply placed in water with the necessary chemicals. As plants are deprived of support from the ground, they will fall down. To support the plants, an inert material like expanded clay pebbles is used in a pot in the tank (figure 5). Before inserting a plant in a hydroponic system, you must carefully remove all soil from the roots otherwise bacteria will putrefy them.
For many houseplants you can use tap water. Though, particularly for vegetables, it is advised to add appropriate nutrients. This cultivation method has the advantages of both requiring less frequent waterings and using very little water. With this system you can grow nearly any houseplant or vegetable. Hydroponics is useful also to show what nutrition plants need.
1 - Place some houseplants in hydroponics.
2 - Try hydroponics with vegetables and find the suitable nutrients.
Hydroponics in the Classroom
Growing plants without soil
To teach orphaned children how to grow their own food with hydroponics (gardening that uses very little water).
Organic Greenhouse Vegetable Production
Internet keywords: hydroponics classroom.
The figure illustrates how closely photosynthesis and respiration are linked. As you can see, thanks to these two life-sustaining processes, plants and animals depend on each other to survive.
Only plants can photosynthesize, but both plants and animals depend on respiration to release the chemical potential energy originally captured through photosynthesis.
Photosynthesis is the first stage of energy flow through an ecosystem. You and all other animals on earth rely on the energy that plants store for life. But animals aren’t the only organisms that burn energy. Plants burn energy as they grow, too. In both plants and animals, the process of — which releases stored energy for use — occurs in the mitochondria inside each cell.
Environmental scientists recognize that the fundamental source of energy for most life on earth is the sun. Through photosynthesis, plants capture the light and convert it into chemical potential energy. Plants then store the potential energy in the form of (biological matter that fuels nearly every animal on earth).
It should be emphasized that plants respire just like any other higher organism, and that during the day this respiration is masked by a higher rate of photosynthesis.
Plants that lose their leaves in winter store food produced during the summer by photosynthesis. They store enough food to last them over winter, and to provide energy reserves for new growth in the spring.
Photosynthesis usually results in a net food gain (net glucose gain), once respiration has been accounted for. This means that there is an increase in the biomass of the plant.
Green plants absorb light energy using chlorophyll in their leaves. They use it to react carbon dioxide with water to make a sugar called glucose. The glucose is used in respiration, or converted into starch and stored. Oxygen is produced as a by-product.
A lot of organisms emit light. Of course you know fireflies, but there are also otherluminescent organisms such as some fishes, mushrooms, bacteria, dinoflagellates, andshellfishes. The culture of luminescent bacteria is not difficult. What you have to do isto get a strain of luminescent and harmless bacteria and raise it in a suitable culturemedium. A bacterium widely cultured and used also for lessons in schools is the Photobacteriumphosphoreum, now renamed: Vibrio phosphoreum.
Search for information about the mechanism of the bioluminescence. You can findinformation for this culture and general information on the Internet at sites listedlater. There is a lot of information on bioluminescence on the Internet. There are evenamateur sites devoted to this topic. You can buy the Vibrio phosphoreum at commercially,such as the ATCC (American Type Culture Collection) .You can find other firms of this type on the Internet, using the keywords: culturecollection. Also try the links for the protists experiment. These companies also supplythe culture media and in their sites you can often read their composition.
: In these experiments, need thehelp of a biologist to avoid culturing dangerous microorganisms. Even with help, keep thecultures only for a short time, wash your hands, wash and disinfect all tools which havebeen in contact with the cultures.
Utilisation Pedagogique de Bacteries Luminescentes (in French)
Bioluminescence in Plankton and Nekton (there is a list of luminescent organisms)
Flash! Bacterial illumination
Isolation of Pure Cultures Of Bacteria (Please, read the safety warnings present inthis website)
Bioluminescence Web sites
Internet Keyword: luminous bacteria luminescent bioluminescence luciferin luciferase.
To find companies which sell strains of microorganisms use the keywords: culturecollection.
Are the insects which fly around lamps at night attracted by light or heat? To find out,use a clothing iron and an electric lamp. The electric lamp produces light with a littleheat, the iron produces only heat. Put both on a table. Keep them at least a meter (abouta yard) apart and with the emitting surfaces turned away from you. Note the differentbehavior of insects. Mask the lamp with plastic sheets of different colors and verify ifbugs are more attracted to a particular color. This is also a method to capture nighttimeinsects, particularly moths, so you can observe them with a lens or a stereoscopicmicroscope.