According to , oxygen levels rose in the Cretaceous and reached nearly modern levels by the end. But anoxic events also dotted the Cretaceous, probably related to rising sea levels. The lived in the Cretaceous and reached three meters in length. It was a deep-water species that probably formed symbiotic relationships with chemosynthetic organisms, along with those other low-oxygen Mesozoic bivalves, and it went extinct as oxygen levels rose in the atmosphere and probably also in the seas.
While oxygen level changes of the model show early fluctuations that the model does not, both models agree on a huge rise in oxygen levels in the late Devonian and Carboniferous, in tandem with collapsing carbon dioxide levels. There is also virtually universal agreement that that situation is due to rainforest development. Rainforests dominated the Carboniferous Period. If the Devonian could be considered terrestrial life’s , then the Carboniferous was its . In the Devonian, plants developed vascular systems, photosynthetic foliage, seeds, roots, and bark, and true forests first appeared. Those basics remain unchanged to this day, but in the Carboniferous there was great diversification within those body plans, and Carboniferous plants formed the foundation for the first complex land-based ecosystems. Ever since the episodes, there has , and the that have prominently shaped Earth’s eon of complex life probably always began with ice sheets at the South Pole, and the current ice age arguably is the only partial exception, but today’s cold period really began about 35 mya, .
As with enzymes, the molecules used in biological processes are often huge and complex, but ATP energy drives all processes and that energy came from either potential chemical energy in Earth’s interior or sunlight, but even chemosynthetic organisms rely on sunlight to provide their energy. The Sun thus powers all life on Earth. The cycles that capture energy (photosynthesis or chemosynthesis) or produce it (fermentation or respiration) generally have many steps in them, and some cycles can run backwards, such as the . Below is a diagram of the citric acid (Krebs) cycle. (Source: Wikimedia Commons)
As with other early life processes, the first photosynthetic process was different from today’s, but the important result – capturing sunlight to power biological processes – was the same. The scientific consensus today is that a respiration cycle was modified, and a in a was used for capturing sunlight. Intermediate stages have been hypothesized, including the cytochrome using a pigment to create a shield to absorb ultraviolet light, or that the pigment was part of an infrared sensor (for locating volcanic vents). But whatever the case was, the conversion of a respiration system into a photosynthetic system is considered to have only happened , and all photosynthesizers descended from that original innovation.
Those molecules initiate photosynthesis by trapping photons. Chlorophyll is called a and, as it sits in its “,” it only absorbs wavelengths of light that . The wavelengths that plant chlorophyll does absorb well are in the green range, which is why plants are green. Some photosynthetic bacteria absorb green light, so , and there are many similar variations among bacteria. Those initial higher electron orbits from photon capture are not stable and would soon collapse back to their lower levels and emit light again, defeating the process, but in the electron is stripped from the capturing molecule and put into another molecule with a more stable orbit. That pathway of carrying the electron that got “excited” by the captured photon is called an . Separating protons from electrons via chemical reactions, and then using their resultant electrical potential to drive mechanical processes, is how life works.
Synthesis of bioactive molecule fluoro benzothiazole comprising potent hetrocyclic moieties for biological and pharmacological screening, Res Rev Biomed Biotech1(1),issue (1);2010,24-30
Synthesis of bioactive molecule fluoro substituted benzothiazole comprising sulphonamide quinazolinyl imidazole for biological and pharmacological screening, Ultra science vol.20(2),281-296 (2008)
Subra Suresh, MIT Professor of Biological Engineering in the Department of Materials Science & Engineering of the Biological Engineering Division, gives a video talk on "". The potentially low cost fluidic measurement of nanonewton forces can analyse the mechanical properties of deformation and mass of red blood cells- erythrocytes. Diagnostic aids and new approaches to treatment for diseases such as malaria, hereditary spherocytosis and pancreatic cancer are suggested. The Gobal Enterprise for Micro-Mechanics and Molecular Medicine- supports this development.
Marburger III, Director of the White House's Office of Science and Technology Policy, in The NY Times, 8/03/2005"We believe that intelligent design is neither sound science nor good theology."
— The International Society for Science and Religion"There is absolutely no scientific basis or evidence for 'intelligent design.' It is simply a religious assertion, and it has no place in a science course."
— biologist David Hillis, University of Texas"The theory of natural selection is the centerpiece of and of evolutionary theory.
Raup, "Conflicts between Darwin and Paleontology" (1979)"Nothing in biology makes sense except in the light of evolution."
— Theodosius Dobzhansky, a Christian who was one of the founders of the modern synthesis of evolutionary theory"To teach kids that creationism explains something about the world is no different than teaching them that the earth is flat."
— Alan Wolfe, director of the Boisi Center for Religion and Public Life at Boston College"The breathtaking inanity of the [school] Board’s decision is evident when considered against the factual backdrop which has now been fully revealed through this trial."
— Judge John Jones III, G.W.
[New] data belie the common idea that animal species can't hybridize or, if they do, will produce inferior or infertile offspring — think mules. Such reproductive isolation is part of the classic definition of a species. But many animals, it is now clear, violate that rule: Not only do they mate with related species, but hybrid descendants are fertile enough to contribute DNA back to a parental species — a process called introgression. . . . Biologists long ago accepted that microbes can swap DNA, and they are now coming to terms with rampant gene flow among more complex creatures. "A large percent of the genome is free to move around," notes Chris Jiggins, an evolutionary biologist at the University of Cambridge in the United Kingdom. This "really challenges our concept of what a species is."
In the earliest days of life on Earth, it had to solve the problems of how to reproduce, how to separate itself from its environment, how to acquire raw materials, and how to make the chemical reactions that it needed. But it was confined to those areas where it could take advantage of briefly available potential energy as . The earliest process of skimming energy from energy gradients to power life is called respiration. That earliest respiration is today called because there was virtually no free oxygen in the atmosphere or ocean in those early days. Respiration was life’s first energy cycle. A biological energy cycle begins by harvesting an energy gradient (usually by a proton crossing a membrane or, in photosynthesis, directly capturing photon energy), and the acquired energy powered chemical reactions. The cycle then proceeds in steps, and the reaction products of each step sequentially use a little more energy from the initial capture until the initial energy has been depleted and the cycle’s molecules are returned to their starting point and ready for a fresh influx of energy to repeat the cycle.