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4.) What sounds more logical?
a.) God created life.
b.) Although Earth was created around 4.5 billion years ago, life began to exist not long after. Due to the huge timescales involved, there is inconclusive evidence for exact dates, but nonetheless, the eagerness of life to exist was apparent from the beginning. Our Solar System was still young, and the Sun was still cooling down after its creation billions of years beforehand. The unique circumstances of our Solar System and our planet gave rise to life. This was due to a number of characteristics that are exhibited by our ecosphere, the area of a planet capable of sustaining life. Venus, one of our planetary neighbors, is closer to the sun, with the planet exhibiting characteristics that would not be able to support life. On the other hand, Mars is further away from the Sun, and too cold to naturally support life. However, with manipulation by man, via terraforming, Mars could indeed support life in its present state. However, Earth, for billions of years, has possessed all the materials and suitable conditions for supporting life. All living things possess the element carbon within them. In light of this, Earth had to have rich supply of carbon to support a rich diversity of life. This carbon was made available by the volatile nature of the Earth in the beginning, where volcanoes spewed various elements into the Earth's atmosphere. While other elements were present, various chemical reactions began to take place which would result in the creation of new compounds and elements. One of the family of compounds created over time were the amino acids, the building blocks of protein. Amino acids are the building blocks of protein, and thus the building blocks of life. The complex organisms of today harness the biological power of proteins in a variety of ways, such as the use of enzymes as a catalyst. In general, organisms over time in the evolutionary chain have grown and become more complex in their nature, i.e. the first origins of life were likely small, simple and not diversified. One understanding of the origins of life is that it would have been very unlikely that parasites were the beginnings of life. As parasites require biological hosts to reproduce and thus survive as a species, they would have been unable to successfully continue their species during this time period. In light of this, viruses and other parasites would have developed later on in the evolutionary chain. It is believed that heterotrophs were the first beginnings of life on Earth, inhabiting the sea and absorbing the organic material that was being created by the reactions of Earth at the time (i.e. the creation of amino acids). The building blocks of life created these organisms and also acted as a food source. This is where the idea of a food chain becomes relevant. When these first autotrophs died, the organic material that they consist of would break down and add to the 'organic soup' that was feeding these organisms at the time. Alias, it is believed that heterotrophic bacteria was the first signs of life on Earth
A component of all existing life is that it adapts to survive. You either adapt or you already have adapted. If species did not have this instinctive nature via their genetic information, then they would have no desire to continue living as a species. Although the beginnings of life above were successfully reproducing, an economy of scale involving the organisms would point out that their food source (the organic soup) would not be able to sustain all life. In light of this, the organisms on Earth at the time would have to diversify over the long term to survive. It is suggested that around three billion years ago, autotrophic animals had diversified from previous species. These autotrophs are capable of synthesizing energy from inorganic material, i.e. via the sun and elements on the Earth. This had allowed life on Earth to tap into a whole new energy resource, one that was literally inexhaustible - the Sun. Life began to flourish, and the autotrophic organisms had tapped a new niche allowing the biomass of Earth at the time to dramatically increase. The autotrophs en masse were absorbing carbon and light. The light invariably would always be an available source for synthesizing energy, while the carbon was not. CO2 was constantly being absorbed by these organisms, and after the biological reactions responsible for creating energy in them, oxygen would be released as a by-product. This meant that oxygen began to accumulate in the oceans where life existed. This new material would in turn be taken advantage of by the adapting organisms, alias, leading to the creation of aerobic organisms, who used oxygen as a component of their energy creation. This is another example of life diversifying to adapt to its environment and exploit the niches that it could occupy. This type of evolution continued, where the supply of potential energy making elements and compounds outstretched the requirements of life, therefore organisms continued to adapt to fill all available niches as opposed to competing with one another. Pathogens existed by this time, and were able to leech resources from their single cell hosts, kill them, and move on to the next host after multiplying. On top of this, resources for all organisms alive at the time were being stretched by the increasing population of species' and also the diversity of unique species. Alias, the exhaustible materials used by species were limited, and they would have to 'fight for their right' to survive. To do this, natural selection would give them a competitive advantage over other organisms and perhaps relieve stress caused by competition within the species (intraspecific). One noted event in the origins of life is the emergence of protists. Although these organisms were single celled like all other organisms, they were notably bigger, some being visible to the human eye. This adaptation must have been a selective advantage at the time, either over competitors or taking advantage of an ecological niche. In fact, the adaptive change is believed to be anatomical. Unlike other organisms, the protists contained cell organelles, which meant that a fundamental difference in the way life operated had arisen in the case of the protists. The occurrence of the protists was so unique that the diversity of them substantiates the Animalia and Plantae classifications, because differentiating characteristics were noted, i.e. the presence of organelles. Basically, protists are unique because they possess a nucleus which contains the genetic information of the cell and alias the organism. Previous species were more simple in their nature, and did not possess such a complex cellular structure. The mitochondria is present in both animal and plant cells in today's world, suggesting that the arrival of the mitochondria in the evolutionary chain was slightly before recognizable taxonomical differences between animals and plants. The mitochondria is unique in the sense that the organelle contains its own DNA, which is derived from its parents. Naturally, as the mitochondria is responsible for the breakdown of organic molecules to release energy (i.e. respiration), this DNA was responsible for the reactions involved to do this. The remarkable thing about mitochondria is their striking similarity to that of a species of amoeba, where the structure of the two are similar. In this particular species of amoeba, symbiotic bacteria enact what the mitochondria does in more advanced cell structures. The end of this symbiotic relationship no doubt increased parasitism, due to the fact that cells now possessed their own energy supply, they could be exposed and eradicated by the pathogens of the time. Although geological records for this period are sketchy to say the least, evidence suggests that organelles continued to diversify in this period, further differentiating the taxon that we use today to class them. Hair like structures called cilia and flagella were developing in some species, allowing them to move with wind and water currents. This general progression and diversification has lead to the range of functions that cell organelles perform in modern organisms. The most unusual thing about natural is its repetition of a particular characteristic across a broad band of species. Such a situation arises when looking the development of unicellular organisms at the time. The organelles developing within these species all have structural similarities in relation to function. As in the example above, the mitochondria on a single cell is very similar to that of an entire species, yet mitochondria are found in almost all forms of organisms that have existed on Earth. A push-pull relationship is notable in the evolution of these organisms. In one instance, they become more similar, either because the similarity is an advantage or because environmental pressure was forcing natural selection and thus the species to evolve in this way. On the other hand, organisms were diversifying to occupy previously sterile environments, therefore adapting to better suit their new environment. On the other hand of this, other organisms (as above) would adapt closer to them, due to less competition in the habitat and natural selection favoring a move to this environment. In other words, nature at the time, both parasites and uni-cellular organisms, were more in less in equilibrium, continuing to expand but also moving away/moving closer in relation to other organisms...life continued to change into the Cambrian Period, over half a billion years ago. The beginning of the Cambrian era saw a widespread arrival of multi-cellular organisms, particularly in the form of sponges. These species, who inhabited the Earth around half a billion years ago, could grow up to 1 metre across, making this distinctly different from the previous unicellular organisms. This was the beginning of cell specialization into tissues, where particular tissues could perform functions to the well-being of the organism at large. The interesting thing about specialization at the time is the fact that if you segregated the cells of these organisms, each cell could still live independently. This is a prolonged example in evolution where characteristics within organisms are similar to that of whole organisms, as in the mitochondria example mentioned at the foot of the previous page. In fact, some multi-cellular species possess organelles that are indistinguishable from some species. The accumulative induction of advantageous characteristics held by species was obviously being learned by the genome of other organisms, i.e. the permutations and advantages are common and widespread. One major event in time is the development of sexual reproduction. Previous species method of reproduction was simply mitosis, repeated cell division which produced new organisms, and exact copy of their ancestors. Of course, mutations and other factors over time changed their genome causing them to evolve. But with sexual reproduction, genetic information is shared between organisms, meaning that the permutations involved in the long term involving the genome of species greatly increased. This is because of all the variances involved in meiosis meant that the possible genotype of offspring increased, and natural selection could take effect on the unique organisms. Consider the following: Previous life did not use sex as a means of reproduction, they replicated making exact copies of themselves, genetic diversity was only increased by mutation and new chemical reactions occurring on Earth making simple proteins, more modern organisms share genetic information by sexual reproduction, 50% of genetic material is taken from each unique parent, the offspring is unique, containing only 50% of genetic material from each parent, plus any change caused by natural selection and mutations, overall, diversity in the species is increased, causing differences, and thus selective advantages/advantages in comparison to one another within the species, and in relation to their environment. Due to the increased possibilities that life could diversify to with the advent of sex, genetic variation greatly increased, and filled the ecosystems niches to a further extent. Competition for resources with species and against other organisms would be increasing in relation to past times, as populations increased and resources diminished. In light of natural selection and 'survival of the fittest', organisms would have to fight for their right to survive, and be able to adapt fast enough to their environment to stand the test of time. In light of this predicament to life on Earth, further diversity continued, with the creation of distinct animals and plants arriving on the Earth's surface. There are over two million species of arthropods, who initially arrived on Earth in the middle of the Cambrian period. Naturally, they were more evolved than their ancestors in a variety of ways and thus possessed their own unique characteristics. Essentially, arthropods are characterized by possessing jointed limbs and an exoskeleton. They are the most successful animal Phylum on the planet, in regards to population size and species diversity. There is thought to be over 2 million types of arthropod in today's world. The exoskeleton may illustrate what life was like at the time. It is of a defensive, protective nature to possess a shell, thus this suggests that competition was quite fierce in the Cambrian era, both from parasites and potential predators. The arthropods were also the first taxon of species to exhibit more advanced receptors in the form of eyes (photoreceptors) and the development of various chemoreceptors that could be used in both the external and internal environment. Such developments have naturally been advantageous over time, illustrated by ourselves. Since the arthropods possessed such desirable features, their survival over the long term is apparent by their genetic diversity, elaborated upon below. As life originated in the sea, the sea was still a valuable ecological niche to the numerous species of the time. Crustacean means insect of the sea, and is a Subphylum of the Arthropoda Phylum. Although abundant, the crustaceans remain relatively simple in the grand scheme of life, and thus did not diversify well in comparison to other organisms. Some of the species in this class were able to occupy the freshwater ecosystem over time, though not successful as what could have been. Competition from more adaptive organisms would have been a biotic factor here. The continued use of feet was evident in these organisms, as a continuation of the organisms mentioned on the previous page of the timeline. The fact that the species' limbs were now jointed, they could move more flexibly and thus had an advantage. Many crustaceans are herbivores, meaning they obtain food from the consumption of plants. They are of great importance to aquatic ecosystems, and are above species of phytoplankton (micro-scopic plants) in the food chain. This can be related to in the freshwater ecology tutorial investigating food chains and plankton. Also, many crustacean animals feed on mollusks, the more evolutionary primitive animals mentioned on the previous page. Including centipedes and millipedes, these species take advantage of the advent of feet and organs assisting movement across the ground. Since the Myriapods have so many legs, the co-ordinated escape from predators is slow. This has led to them adapting and evolving chemical defenses when potential biological danger comes too close. They also harness the use of chemoreceptors to assist them in their external environment, as well as physiological adaptations to assist them in burrowing into the ground, another method of defense, and also a way of diversifying into ground based environments over time. Arachnids were one of the first taxon of species to occupy dry land, the first transition from dry land from the life origins of the sea. Due to these bold creatures' actions, their ancestors have successfully realized their species goal of survival, occupying previously sterile, unchallenged environments. This would have occurred around a quarter of a billion years ago, approximately the same distance in time between the present > then and then > the origin of life. As a side note, it is quite interesting to note that humans begin to occupy space at around the same time scale involving life moving from the sea to land. The Class Insecta of the Arthropoda Phylum is by far the most successful and diverse taxon on planet Earth. In fact, there are more species of insect than any other species combined. This surely illustrates that insects have particular selective advantages that allow them to take the most advantage of the environment that they live in. The development of insects was a stamping of authority by animals species on life developing at the time. Insects possess all the selective advantages of the arthropods mentioned on the previous page plus their own unique advantages with each species of them. Here are some reasons as to why insects enjoyed their continued existence over such a long period of time (beginning over 400 million years ago). Since some insects developed wings, they could easily escape from predators and travel large distances without any danger in the form of other animals in the air. The more primitive insects, most likely the first insects are wingless, thus this suggests that flying was a natural selective advantage at the time and has continued to be for many insect species. Insects would develop respiratory complications if they grew to an abnormal size. In light of this, the wide range of insect species are small in size, meaning they can occupy small areas and require a small amount of food in order for them to survive. A general rule of thumb in biology is that smaller organisms produce offspring faster, and as organisms of the time reproduced sexually, this meant that the crossing of genetic information was more frequent. This in turn meant that variation in the genome of the species increased as a whole, and thus continued to diversify and compete. Just like the other arthropods, took the opportunity to occupy dry land, and thus evolved to cater for their new environment. Evolutionary adaptations mapped out in insect species points out the minimum water transpired by the organisms, illustrating their relatively audacious transition from a wet environment to dry land. Insects also occupy the sea, though face stiffer competition from the continuous evolution that was happening there with other species, creating environmental pressure and an occupational threshold of habitats. Insects continued to evolve the sense developed by other arthropods and their ancestors, and were capable of interpreting auditory, visual and chemical stimuli. Over the evolutionary timeline we have followed, although plants have not been mentioned much, insects were heavily dependent on plant life. Both insects and plants have co-evolved with one another, and if you had removed one of them at any point in history, scores of species would have never existed in today's world. Butterflies undergo a process called metamorphosis, which is a transition from embryonic to adult form of a species. In the case of the butterfly, adults hatch eggs within plants to camouflage them against potential damage and predators who may eat the eggs. In other cases, insects are herbivores, and thus eat plants as a means of nutrition. In reverse instances, plants like the Venus Fly Trap engulf insects within their defensive mechanisms and kill them. Insects pollinate plants, providing a way for plants to create offspring and successfully pass their genome through the generations. Some species of insects are capable of communicating with one another. This would be one of the first instances of this in the evolutionary chain, and remarkably happening hundreds of millions of years ago. Bees are an example of a social insect, who perform a waggle dance in front of fellow bees from the same hive to indicate the quality and navigational source of a food supply. Indeed, insects were an important factor in life's transition from water to land. While insects and similar types of organism strived to occupy land, the sea was teaming with life aiming to secure their long term survival. As a consequence of this, reproduction occurred and genetic variation increased. This results in the arrival of fish, who were adapting to live in the largest ecosystem on earth, water. There are over 20 000 species of fish, all of which have diversified over time to aptly occupy a particular habitat. Since aquatic environments vary greatly in regards to its characteristics, fish diversity also varies greatly. Depending on season, chronological point in time, depth of water and many other factors, temperature will affect how a fish species would occupy or even exist in an ecosystem. An example is some species being better suited to tropical warm waters while others occupy the polar regions of Earth in its present day. Fish have diversified to occupy saltwater and freshwater in the best way possible. This is further illustrated in the animal water regulation tutorial page. The main reason for this being a significant factor is the effect that salt has on osmoregulation, thus fish have underwent significant anatomical adaptations to occupy the respective environments. Other species may represent competition, danger, a source of food or provide a symbiotic relationship.
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Здесь был кролик. Но его убили.
Человеки < кроликов, йа считаю. |
Освободи буффер обмена, игра :) 
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