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Ap biology evolution essay rubric ipgproje com
Although the overwhelming devastation of the Permian extinction seemed to play no favorites and whatever survived was the luck of the draw, recent research has demonstrated that even with such a catastrophe, certain life forms were more resilient than others, related to biological “buffers” in their life processes. In marine environments, the warming, anoxia, and acidification would have wiped out species vulnerable to them, and corals were and still are particularly susceptible to those changes. Those conditions wiped out the corals in the Permian extinction, and they are the first ecosystems being devastated today, with similar conditions of . Whether it was the ability to move to safer environs or the ability to buffer chemical changes, the more organisms had a better survival rate than others.
People and animals universally prefer the taste of cooked food over raw, except for fruit, which was designed by the plant to be eaten by animals; no other foods were designed to be eaten and digested (except nectar, blossoms, and mother’s milk). The toxins created by cooking, such as , can cause health problems in humans, including chronic diseases. But cooking also destroys some toxins, making otherwise inedible food palatable. Cooking also reduces , which makes meat tough, to gelatin (called the protein, when it falls apart), and converts raw starch to a far more digestible form. However, , humans only have to live long enough to produce offspring. The degenerative diseases (especially artery disease, cancer, and diabetes) that shorten human lives today would have been irrelevant in the ancient past, when virtually nobody lived long enough to die of old age and they could reproduce long before the deleterious effects of cooked food caught up with them. Many detriments of cooking and food processing have only become important to human welfare with the advent of civilization. Cooking would have been an undisputed advantage long ago.
AP Biology test essay rubric Biological molecules
During that “,” , , and the rise of grazing and predation had eonic significance. While many critical events in life’s history were unique, one that is not is multicellularity, , and some prokaryotes have multicellular structures, some even with specialized organisms forming colonies. There are , but the primary advantage was size, which would become important in the coming eon of complex life. The rise of complex life might have happened faster than the billion years or so after the basic foundation was set (the complex cell, oxygenic photosynthesis), but geophysical and geochemical processes had their impacts. Perhaps most importantly, the oceans probably did not get oxygenated until just before complex life appeared, as they were sulfidic from 1.8 bya to 700 mya. Atmospheric oxygen is currently thought to have remained at only a few percent at most until about 850 mya, although there are recent arguments that it remained low until only about 420 mya, when large animals began to appear and animals began to colonize land. Just as the atmospheric oxygen content began to rise, then came the biggest ice age in Earth’s history, which probably played a major role in the rise of complex life.
Canfield’s original hypothesis, which seems largely valid today, is that the deep oceans were not oxygenated until the Ediacaran Period, which followed the Cryogenian; the process did not begin until about 580 mya and first completed about 560 mya. The wildest swing in Earth’s entire geological record begins about 575 mya and ends about 550 mya, and is called the Shuram excursion. Explaining the Shuram excursion is one of the most controversial areas of geology today, with numerous proposed hypotheses. When the controversies are finally resolved, if they resolved, the Shuram and excursions, even though they go in opposite directions, I suspect will likely be both related to the dynamics of ice ages and the rise of oxygen levels. Ediacaran fauna, the first large, complex organisms to ever appear on Earth, also first appeared about 575 mya, when the Shuram excursion began. I strongly doubt that Earth’s first appearance of large complex life at the exact geological timescale moment of the wildest carbon-isotope swing in Earth’s history will prove to be a coincidence. The numerous competing hypotheses regarding the Shuram excursion include:
AP Biology Student Handbook PDF Oak Ridge AP Biology PBworks
Readers for the collective task that I have in mind need to become familiar with the scientific process, partly so they can develop a critical eye for the kinds of arguments and evidence that attend the pursuit of FE and other fringe science/technology efforts. For the remainder of this essay, I will attempt to refrain from referring to too many scientific papers and getting into too many details of the controversies. Following my references will help readers who want to go deeply into the issues, and many of them are as deep and controversial as the Snowball Earth hypothesis and aftermath has proven to be, or attempts to explain the . These are relatively new areas of scientific investigation, partly due to an improved scientific toolset and ingenious ways to use them. It is very possible that the controversies in those areas will diminish within the next generation as new hypotheses account for increasingly sophisticated data, and in the near future are nearly certain. But science is always subject to becoming dogmatic and hypotheses can prevail for reasons of wealth, power, rhetorical skill, and the like, not because they are valid. The history of science is plagued with that phenomenon, and probably will be as long as humanity lives in the era of scarcity.
are created by undisturbed organism remains that become saturated with various chemicals, which gradually replace the organic material with rock by . Few life forms ever become fossils but are instead consumed by other life. Rare dynamics lead to fossil formation, usually by anoxic conditions leading to undisturbed sediments that protect the evidence and fossilize it. Scientists estimate that only about 1%-2% of all species that ever existed have left behind fossils that have been recovered. Geological processes are continually creating new land, both on the continents and under the ocean. Seafloor strata do not provide much insight into life’s ancient past, particularly fossils, because the process in “mere” . The basic process is that, in the Atlantic and Pacific sea floors in particular, oceanic volcanic ridges spew out basalt and the plates flow toward the surrounding continents. When oceanic plates reach continental plates, the heavier (basaltic) oceanic plates are subducted below the lighter (granitic) continental plates. Parts of an oceanic plate were more than 100 mya and left behind plate fragments. On the continents, however, as they have floated on the heavier rocks, tectonic and erosional processes have not obliterated all ancient rocks and fossils. The oldest “indigenous” rocks yet found on Earth are . have been dated to 3.5 bya, and fossils of individual cyanobacteria have been dated to 1.5 bya. There are recent claims of finding . The oldest eukaryote fossils found so far are of . The first amoeba-like vase-shaped fossils date from about 750 mya, and there are recent claims of finding the first animal fossils in Namibia, of sponge-like creatures which are . Fossils from might be the first animal fossils, and some scientists think that animals may have first appeared about one bya. The first animals, or , probably descended from . The is a tail-like appendage that protists primarily used to move and it could also be used to create a current to capture food. Flagella were used to draw food into the first animals, which would have been sponge-like. When the first colonies developed in which unicellular organisms began to specialize and act in concert, animals were born, and it is currently thought that the evolution of animals probably only happened . In interpreting the fossil record, there are four general levels of confidence: inevitable conclusions (such as ichthyosaurs were marine reptiles), likely interpretations (ichthyosaurs appeared to give live birth instead of laying eggs), speculations (were ichthyosaurs warm-blooded?), and guesses (what color was an ichthyosaur?).
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Ap biology essay questions plants
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.
AP essay questions - Biology Junction
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.
Ap biology essay 1991 transpiration
A free radical is an atom, molecule, or ion with an unpaired valence electron or an unfilled shell, and thus seeks to capture an electron. The used to create ATP in a mitochondrion leaks electrons, which creates free radicals, which will take that electron from wherever they can get it. creates some of the most dangerous free radicals, particularly the . The more hydroxyl radicals created, the more damage inflicted on neighboring molecules. Another free radical created by that electron leakage is , which can be neutralized by , but there is no avoiding the damage produced by the hydroxyl radical. Those kinds of free radicals are called (“ROS”). ROS are not universally deleterious to life processes, but if their production spins out of control, the oxidative stress inflicted by the ROS can cripple biological structures. ROS damage can cause programmed cell death, called , which is a maintenance process for complex life. Antioxidants are one way that organisms defend against oxidative stress, and is a standard antioxidant. Antioxidants usually serve multiple purposes in cellular chemistry, and antioxidant supplements generally do not work as advertised. They not only do not target the reactions that might be beneficial to prevent, but they can interfere with reactions that are necessary for life processes. Antioxidant supplements are blunt instruments that can cause more harm than good.
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