Just as with or the , there are plenty of scientists and scholars who argue that human-agency is not responsible for the decline and collapse of civilizations, question , assert that climate change did it, or invasion did it, and so on. The battle of competing hypotheses is part of the process of science, but all scientists whose hypotheses deflect responsibility from humanity (their ) have an inherent conflict of interest, and their work should be examined with that in mind. In the historical era, particularly when Europe conquered the world, the rapid deforestation and desertification of newly conquered lands was evident. Within a century of the Spanish conquest of the Aztecs, a valley of verdant forests and fertile farmland was . That valley is known as the today, because the desert-dwelling mesquite is the dominant tree in that semi-desert. British invaders of Australia did the same thing to within 50 years, via deforestation and sheep grazing. Streams quickly dried up, but flooded when it rained, as the “sponge” of the forest ecosystem was removed, so flood drought accompanied deforestation. Atlantic islands were by invading Spaniards and Portuguese.
Other than humans, rhesus macaques are Earth’s most widespread primates, and both species are generalists whose ability to adapt has been responsible for their success. Rhesus macaques are , about twice that of dogs and cats, and nearly as much as chimpanzees. Rhesus macaques have what is called Machiavellian social organization, in which everybody is continually vying for rank and power is everything. Those with rhesus power get the most and best food, the best and safest sleeping places, mating privileges, the nicest environments to live in, and endless grooming by subordinates, whom the dominants can beat and harass whenever they want, while those low in the hierarchies get the scraps and are usually the first to succumb to the vagaries of rhesus life, including predation. It is the . But even the lowliest macaque will become patriotic cannon fodder if his society faces an external threat, as even a macaque knows that a miserable life is better than no life at all. The violence inflicted seems economically optimized; within a society the violence is mostly harassment, but when rival societies first come in contact, the violence is often lethal, as the initially established dominance can last for lifetimes. Within a society, killing a subordinate does not make economic sense, as that subordinate supports the hierarchy. Potentates rely on slaves. The human smile evolved from the teeth-baring display of monkeys that connotes fear or submission.
Answer to are responsible for photosynthesis
When investigating how ice ages begin and end, and feedbacks are considered. A positive feedback will accentuate a dynamic and a negative feedback will mute it. In the 1970s, and the author of today’s , , , which posits that Earth has provided feedbacks that maintain environmental . Under that hypothesis, environmental variables such as atmospheric and levels, levels, and Earth’s surface temperature have been kept relatively constant by a combination of geophysical, geochemical, and life processes, which have maintained Earth’s inhabitability. The homeostatic dynamics were mainly negative feedbacks. If positive feedbacks dominate, then “runaway” conditions happen. In astrophysics, are responsible for a wide range of phenomena. A runaway greenhouse effect may be responsible for . Climate scientists today are concerned that burning the hydrocarbons that fuel the industrial age . Mass extinctions are the result of Earth's becoming largely uninhabitable by the organisms existing during the extinction event. The ecosystems then collapse Mass extinction specialist recently proposed his as a direct challenge to the Gaia hypothesis.
The organelle responsible for doing photosynthesis is ..
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.