Temperate grassland9 150-1500 500 4.5
An optimum temperature ranging from 25 o C to 35 o C is required for a good rate
Free rate of photosynthesis papers, essays, and research papers.
Prepare a graph of the collected data and analyze it.
(For each group of four students)
elodea (water plant) lamp (40 watt)
test tube razor blade (single-edge)
dechlorinated water (room temperature) tape
sodium bicarbonate powder (baking soda) clock or timer
metal stand with rod or test tube rack metric ruler
concentration, and soil water deficit affect stomatalresponse, gas exchange and photosynthesis (Mooney and Harrison, 1970; Berryand Bjorkman, 1980; Lieth and Pasian, 1990; Xie et al., 1996; Moriana et al.,2002). Based on changes during the day or between days, Heinicke and Childers(1937) concluded that light was the major factor affecting whole-canopy NCERof apple trees, and temperature was second most important, although Sirois andCooper (1964) concluded CO2 was second. A recent study(Corelli-Grappadelli and Magnanini, 1993) reported short-term whole-canopyNCER measurements declined with gradually declining light levels for one appletree. Photosynthesis and transpiration were greatly influenced by stomatalbehavior. Stomatal opening is affected by CO2 concentration, vaporpressure gradient (VPG), light, turgor pressure caused by change in potassiumand organic acids, and by abscisic acid (ABA) (Raschke, 1970; Schulze andHall, 1982). Berry and Bjorkman (1980) found light intensity, CO2concentration, temperature, and soil water deficit may have affected gasexchange of plants in a greenhouse. Bunce (1984) reported photosynthesisincreased when humidity was increased in the environment. Transpiration atnoon under a high temperature after 48 h of acclimation was 400% higher thanunder a moderate temperature. Stomatal resistance reached a minimum at noon,in accordance with the transpiration rate. Leaf wa
IB Biology Notes - 8.2 Photosynthesis
This process is also affected by the temperature surrounding the plant (the species of plant we experimented with, pond weed, photosynthesised best at around 20 degrees centigrade.) Light, temperature & CO2 are known as limiting factors, and each is as important as the next in photosynthes...
Until the end of the 17th century, people believed that little animals like flies andworms could spontaneously be born from substances in decomposition or from mud. FrancescoRedi, Lazzaro Spallanzani and Louis Pasteur made experiments which proved the idea of thespontaneous generation was wrong. At your home or in your school you can made suchexperiments too.
1 - Take two glass jars with a screw top. Put in each a little piece of cooked apple and aspoon of vinegar. For a night, leave one of these jars opened so it can be visited byvinegar (fruit) flies. Close the other jar with the lid and sterilize it by placing it inboiling water in a pressure cooker for a half an hour. After removing it from the cooker,let it cool, leaving it closed. The morning after, let the possible bugs present into thefirst jar leave and then close it with a fine gauze or a plastic sheet on which you willmake some pinholes to allow oxygen to enter. After a few days, you should see some bugs inthe first jar, and none in the second one. What has happened in the first jar which hasnot happened in the second? Some vinegar flies laid eggs in the first jar and from themsome new flies are born. In the second jar, even if there had been eggs, these are deadbecause of high temperature in the pressure cooker. More eggs were not laid because thejar was kept closed. With experiments like this one, you can realize that living beingscannot born from nothing, but they are born from other organisms like them. Fall is themore suited season to do this experiment because vinegar flies are particularly active.
2 - Anyway you can try to adapt this experiment to organisms present at other times of theyear. For example, if you place some dry grass in a water glass, in few days a deal ofprotists will appear. If instead you will put the same material in a close glass pot andif you boil it, nothing will be born. Only some rare thermoresistant microorganisms,bacteria which resist the high temperature of boiling water.
... Uhm, and still there is something which is not working: if any living being comes fromanother living being, from where has come the first living being from which all others arederived? Can we consider completely falsified the theory of the spontaneous generationwith these experiments? Is it possible to assert that, even if the spontaneous generationis not the usual way with which living creatures are born, at least at one time duringbillions of years it has happened on the Earth or another place in the Universe? It is noaccident that there are scientists who study how life began in the first place.
Internet keywords: spontaneous generation.
Climate Change Catastrophes in Critical Thinking
Let us see now how protists and other little animals of ponds react to alteration to theirenvironment.
1 - Some microscopic algae, like the euglena, search out light (phototaxis) and to do thisthey use an organelle sensible to the light, named stigma. With a dark paper, cover thebottom part of a test tube holding a culture of euglena. The part of the test tube exposedto light should become green, rich with algae. Make the same experiment with othermicroscopic algae and with protozoa.
2 - Add two or three drop of distilled water to a little water drop collected in a pondand watch what happens to the protists. Very probably you will see them inflate and thenexplode. This occurs because of the different saline concentration inside and outside theprotists and the osmotic pressure which is produced inside their cells.
3 - Protists are sensitive to most chemicals and generally they react by running away; insome cases instead they approach them (chemotaxis). Prepare some microscope slides withprotists and observe through the microscope their behavior when you add acidic substances(i.e.: vinegar), basic substances (i.e.: backing soda), glucose, salt, sparkling water(rich of CO2), broth, milk, tiny grain of cheese, dyes, etc. At thebeginning use very low amounts of these substances, then increase their concentration.
4 - From a pond or an aquarium, collect a hydra and place it on a microscope slide with apair of water drops. Observing this tiny polyp through the microscope, probably you willsee some sucker shaped microorganisms (trichodina) moving on its body. Watch what happensafter adding a little drop of vinegar to their water! Trichodina will escape from thehydra and probably die. Hydra itself will have launched many of its harmful paralyzingdarts.
5 - Submit protists to different stimulus such as light, temperature, electric field(about 5 V in DC). In this last case, some protists will gather on the cathode (thenegative - pole). Also amebas are inclined to move towards the cathode. Change thepolarity of the current and observe the behavior of the protists.
Internet Keyword: phototaxis chemotaxis protists.
Photosynthesis kit - Welcome to the NCBE
Geologic temperature record - Wikipedia
by Theresa Knapp Holtzclaw
A technically complete science fair project in ONE …
Science Experiments on Environmental Education and Biology
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