Watch this demonstration to see how to make the leaf disks sink.

Oxygen is one of 2 products of the green-plant process photosynthesis, the other being glucose.
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Photosynthesis Demonstration - Oxygen Production - …

For this essay’s purposes, the most important ecological understanding is that the Sun provides all of earthly life’s energy, either (all except nuclear-powered electric lights driving photosynthesis in greenhouses, as that energy came from dead stars). Today’s hydrocarbon energy that powers our industrial world comes from captured sunlight. Exciting electrons with photon energy, then stripping off electrons and protons and using their electric potential to power biochemical reactions, is what makes Earth’s ecosystems possible. Too little energy, and reactions will not happen (such as ice ages, enzyme poisoning, the darkness of night, food shortages, and lack of key nutrients that support biological reactions), and too much (such as , ionizing radiation, temperatures too high for enzyme activity), and life is damaged or destroyed. The journey of life on Earth has primarily been about adapting to varying energy conditions and finding levels where life can survive. For the many hypotheses about those ancient events and what really happened, the answers are always primarily in energy terms, such as how it was obtained, how it was preserved, and how it was used. For life scientists, that is always the framework, and they devote themselves to discovering how the energy game was played.

During this process of sugar production, carbon dioxide combines with water to form glucose and oxygen is released.
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Demonstrating Oxygen Evolution During Photosynthesis …

Plants have no use for oxygen.
The process of photosynthesis does not use oxygen, rather oxygen is produced as a bye product during photosynthesis.
In cellular respiration, cells use oxygen to break the sugar molecule.

How to Show Oxygen Is a By Product of Photosynthesis
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As with those small worms that crawled along and burrowed into the newly oxygenated seafloor (or helped oxygenate it), many small animals with shells and mineralized parts appeared in the late Ediacaran, and a misnomer was coined to account for them termed . Those small animals also , and many of them were ancestors to their larger descendants, which showed more intermediate steps in the “explosion.”

15/09/2017 · How to Show Oxygen Is a By Product of Photosynthesis
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Photosynthesis Demonstration - YouTube

Peter Ward led an effort to catalog the fossil record before and after Romer’s Gap, which found a dramatic that did not resume until about 340-330 mya. Romer’s Gap seems to have coincided with low-oxygen levels of the late Devonian and early Carboniferous. If coincided with a halt in colonization, just as the adaptation to breathing air was beginning, the obvious implication is that low oxygen levels hampered early land animals. Not just the lung had to evolve for the up-and-coming amphibians, but the entire chest cavity had to evolve to expand and contract while also allowing for a new mode of locomotion. When amphibians and splay-footed reptiles run, they cannot breathe, as their mechanics of locomotion prevent running and breathing at the same time. Even walking and breathing is generally difficult. This means that they cannot perform any endurance locomotion but have to move in short spurts. This is why today’s predatory amphibians and reptiles are ambush predators. They can only move in short bursts, and then have to stop, breathe, and recover their oxygen deficit. In short, they have no stamina. This limitation is called . The below image shows the evolutionary adaptations that led to overcoming Carrier's Constraint. Dinosaurs overcame it first, and it probably was related to their dominance and the extinction or marginalization of their competitors. (Source: Wikimedia Commons)

28/11/2011 · Photosynthesis Demonstration ..

What was most relevant to humans, however, was the almost-complete extinction during the Kellwasser event of the tetrapods that had come ashore. Tetrapods did not reappear in the fossil record until several million years after the Kellwasser event, and has even been referred to as the Fammenian Gap (the is the Devonian’s last age). The Kellwasser event also appeared to be a period of low atmospheric oxygen content, and some evidence is the lack of charcoal in fossil deposits. Recent research has demonstrated that getting wood to burn at oxygen levels of less than 13-15% may be impossible. Because all periods of complex land life show evidence of forest fires, it is today thought that oxygen levels have not dropped below 13-15% since the Devonian, but during the “charcoal gap” of the late Devonian, when the first landlubbing tetrapods went extinct, oxygen levels reached their lowest levels since the , which must have impacted the first animals trying to breathe air instead of water. During the , there is no charcoal evidence at all, which leads to the notion that oxygen levels may have even dropped below 13%. This drop may be related to severe climatic stresses on the new forests, which are probably related to the ice age that the forests helped bring about due to their carbon sequestering. That is an attractively explanatory scenario, but the continues. The first seed plants probably appeared before the Kellwasser event, but it was not until after the Fammenian Gap that seed plants began to proliferate.