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136-447: Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ ; and the hindlimbs of the snake and whale . Vestigial features may take various forms; for example, they may be patterns of behavior, anatomical structures, or biochemical processes. Like most other physical features, however functional, vestigial features in

272-570: A gymnasium and a colonnade ( peripatos ), from which the school acquired the name Peripatetic . Aristotle conducted courses and research at the school for the next twelve years. He often lectured small groups of distinguished students and, along with some of them, such as Theophrastus , Eudemus , and Aristoxenus , Aristotle built a large library which included manuscripts, maps, and museum objects. While in Athens, his wife Pythias died and Aristotle became involved with Herpyllis of Stagira. They had

408-541: A "survival of the fittest" origin of living things and their organs, and ridiculed the idea that accidents could lead to orderly results. To put his views into modern terms, he nowhere says that different species can have a common ancestor , or that one kind can change into another , or that kinds can become extinct . Aristotle did not do experiments in the modern sense. He used the ancient Greek term pepeiramenoi to mean observations, or at most investigative procedures like dissection. In Generation of Animals , he finds

544-519: A complex synthesis of the various philosophies existing prior to him. His teachings and methods of inquiry have had a significant impact across the world, and remain a subject of contemporary philosophical discussion. Aristotle's views profoundly shaped medieval scholarship . The influence of his physical science extended from late antiquity and the Early Middle Ages into the Renaissance , and

680-684: A continental land mass. Oceanic islands arise due to volcanic activity or reef growth, and usually subside over time due to erosion and changing sea levels. When islands emerge, they undergo the process of ecological succession as species colonize the island (see theory of island biogeography ). New species cannot immigrate via land, and instead must arrive via air, water, or wind. As a result, organisms with high dispersal capabilities, such as plants and birds, are much more common on islands than are poorly dispersing taxa like mammals. However, some mammals are present on islands, presumably from swimming or riding on natural “rafts” that are washed away from

816-552: A daughter whom they also named Pythias. In 343/42 BC, Aristotle was invited to Pella by Philip II of Macedon in order to become the tutor to his thirteen-year-old son Alexander ; a choice perhaps influenced by the relationship of Aristotle's family with the Macedonian dynasty. Aristotle taught Alexander at the private school of Mieza , in the gardens of the Nymphs , the royal estate near Pella. Alexander's education probably included

952-438: A fertilized hen's egg of a suitable stage and opens it to see the embryo's heart beating inside. Instead, he practiced a different style of science: systematically gathering data, discovering patterns common to whole groups of animals, and inferring possible causal explanations from these. This style is common in modern biology when large amounts of data become available in a new field, such as genomics . It does not result in

1088-497: A fluid such as air. In this system, heavy bodies in steady fall indeed travel faster than light ones (whether friction is ignored, or not ), and they do fall more slowly in a denser medium. Newton's "forced" motion corresponds to Aristotle's "violent" motion with its external agent, but Aristotle's assumption that the agent's effect stops immediately it stops acting (e.g., the ball leaves the thrower's hand) has awkward consequences: he has to suppose that surrounding fluid helps to push

1224-448: A form that serves no purpose (if at the same time it is not an obstruction either) is not economically astute. These vestigial structures differ from the concept of skeuomorphism in that a skeuomorph is a design feature that has been specifically implemented as a reference to the past, enabling users to acclimatise quicker. A vestigial feature does not exist intentionally, or even usefully. For example, men's business suits often contain

1360-409: A given species may successively appear, develop, and persist or disappear at various stages within the life cycle of the organism, ranging from early embryonic development to late adulthood. Vestigiality, biologically speaking, refers to organisms retaining organs that have seemingly lost their original function. Vestigial organs are common evolutionary knowledge. In addition, the term vestigiality

1496-455: A house is the bricks, stones, timbers, etc., or whatever constitutes the potential house, while the form of the substance is the actual house, namely 'covering for bodies and chattels' or any other differentia that let us define something as a house. The formula that gives the components is the account of the matter, and the formula that gives the differentia is the account of the form. Like his teacher Plato, Aristotle's philosophy aims at

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1632-423: A huge role. More advantageous structures were selected, while others were not. With this expansion, some traits were left to the wayside. As the function of the trait is no longer beneficial for survival, the likelihood that future offspring will inherit the "normal" form of it decreases. In some cases, the structure becomes detrimental to the organism (for example the eyes of a mole can become infected). In many cases

1768-597: A linear scale, and noted various exceptions, such as that sharks had a placenta like the tetrapods. To a modern biologist, the explanation, not available to Aristotle, is convergent evolution . Philosophers of science have generally concluded that Aristotle was not interested in taxonomy, but zoologists who studied this question in the early 21st century think otherwise. He believed that purposive final causes guided all natural processes; this teleological view justified his observed data as an expression of formal design. Aristotle's psychology , given in his treatise On

1904-457: A list of 86 human organs that Wiedersheim described as, "Organs having become wholly or in part functionless, some appearing in the Embryo alone, others present during Life constantly or inconstantly. For the greater part Organs which may be rightly termed Vestigial." Since his time, the function of some of these structures have been discovered, while other anatomical vestiges have been unearthed, making

2040-402: A man a veritable walking museum of antiquities." Vestigial structures are often homologous to structures that are functioning normally in other species. Therefore, vestigial structures can be considered evidence for evolution , the process by which beneficial heritable traits arise in populations over an extended period of time. The existence of vestigial traits can be attributed to changes in

2176-480: A number of subjects, such as ethics and politics , as well as standard literary texts, like Euripides and Homer . It is likely that during Aristotle's time in the Macedonian court, other prominent nobles, like Ptolemy and Cassander , would have occasionally attended his lectures. Aristotle encouraged Alexander toward eastern conquest, and his own attitude towards Persia was strongly ethnocentric . In one famous example, he counsels Alexander to be "a leader to

2312-435: A part of particular things. For example, it is possible that there is no particular good in existence, but "good" is still a proper universal form. Aristotle disagreed with Plato on this point, arguing that all universals are instantiated at some period of time, and that there are no universals that are unattached to existing things. In addition, Aristotle disagreed with Plato about the location of universals. Where Plato spoke of

2448-498: A priori principles. Aristotle's "natural philosophy" spans a wide range of natural phenomena including those now covered by physics, biology and other natural sciences. In Aristotle's terminology, "natural philosophy" is a branch of philosophy examining the phenomena of the natural world, and includes fields that would be regarded today as physics, biology and other natural sciences. Aristotle's work encompassed virtually all facets of intellectual inquiry. Aristotle makes philosophy in

2584-418: A property or a relation to other things. When one looks at an apple, for example, one sees an apple, and one can also analyse a form of an apple. In this distinction, there is a particular apple and a universal form of an apple. Moreover, one can place an apple next to a book, so that one can speak of both the book and apple as being next to each other. Plato argued that there are some universal forms that are not

2720-418: A row of buttons at the bottom of the sleeve. These used to serve a purpose, allowing the sleeve to be split and rolled up. The feature has been lost entirely, though most suits still give the impression that it is possible, complete with fake button holes. There is also an example of exaptation to be found in the business suit: it was previously possible to button a jacket up all the way to the top. As it became

2856-568: A rudimentary condition." The wings of ostriches , emus and other flightless birds are vestigial; they are remnants of their flying ancestors' wings. These birds go through the effort of developing wings, even though most birds are too large to use the wings successfully. Seeing vestigial wings in birds is also common when they no longer need to fly to escape predators, such as birds on the Galapagos Islands . The eyes of certain cavefish and salamanders are vestigial, as they no longer allow

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2992-602: A set of six books called the Organon around 40 BC by Andronicus of Rhodes or others among his followers. The books are: The order of the books (or the teachings from which they are composed) is not certain, but this list was derived from analysis of Aristotle's writings. It goes from the basics, the analysis of simple terms in the Categories, the analysis of propositions and their elementary relations in On Interpretation , to

3128-420: A significant enough advantage in terms of fitness to avoid the effects of genetic drift or competing selective pressures . Vestigiality in its various forms presents many examples of evidence for biological evolution . Vestigial structures have been noticed since ancient times, and the reason for their existence was long speculated upon before Darwinian evolution provided a widely accepted explanation. In

3264-549: A son whom Aristotle named after his father, Nicomachus . This period in Athens, between 335 and 323 BC, is when Aristotle is believed to have composed many of his philosophical works. He wrote many dialogues, of which only fragments have survived. Those works that have survived are in treatise form and were not, for the most part, intended for widespread publication; they are generally thought to be lecture aids for his students. His most important treatises include Physics , Metaphysics , Nicomachean Ethics , Politics , On

3400-519: A species is released from its ancestral community interactions and then colonizes new niches. In response to these changing ecological pressures, island species can become much more docile than their mainland counterparts, and may grow larger (see island gigantism ) or smaller (see island dwarfism ). Some of these unique adaptations are reflected in charismatic island species such as the Malagasy hippopotamus , Komodo dragon , or pygmy mammoths . Although,

3536-538: A state of change. As resource depletion is a major issue on islands, the needs of human populations must also be taken into account. On many islands, scientists and managers are studying traditional practices of indigenous populations as potential conservation solutions. In some cases, limited-take systems that serve the community may provide a better alternative to fully closed protected areas, if there are not enough resources for proper enforcement. Public education plays an important role. A significant advancement in

3672-549: A thrown stone, in the Physics (254b10), and "natural motion", such as of a falling object, in On the Heavens (300a20). In violent motion, as soon as the agent stops causing it, the motion stops also: in other words, the natural state of an object is to be at rest, since Aristotle does not address friction . With this understanding, it can be observed that, as Aristotle stated, heavy objects (on

3808-418: A vestige of the tail of some primate ancestors, is functional as an anchor for certain pelvic muscles including: the levator ani muscle and the largest gluteal muscle, the gluteus maximus. Other structures that are vestigial include the plica semilunaris on the inside corner of the eye (a remnant of the nictitating membrane ); and (as seen at right) muscles in the ear . Other organic structures (such as

3944-440: A whole is closely linked to restoration . Active restoration on islands can be done for both animal species (translocations, induced breeding) and plant species (reforestation). Creating goals for restoration can be challenging because it is often impossible to restore the ecosystem to its “historic” or “normal” state, if that state can even be clearly defined. Restoration is never complete, as ecological communities are always in

4080-544: A woman with origins from Chalcis , Euboea . Nicomachus was said to have belonged to the medical guild of Asclepiadae and was likely responsible for Aristotle's early interest in biology and medicine. Ancient tradition held that Aristotle's family descended from the legendary physician Asclepius and his son Machaon . Both of Aristotle's parents died when he was still at a young age and Proxenus of Atarneus became his guardian. Although little information about Aristotle's childhood has survived, he probably spent some time in

4216-425: Is a change where the substrate of the thing that has undergone the change has itself changed. In that particular change he introduces the concept of potentiality ( dynamis ) and actuality ( entelecheia ) in association with the matter and the form. Referring to potentiality, this is what a thing is capable of doing or being acted upon if the conditions are right and it is not prevented by something else. For example,

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4352-454: Is a historical accident: his works on botany have been lost, but two books on plants by his pupil Theophrastus have survived. Aristotle reports on the sea-life visible from observation on Lesbos and the catches of fishermen. He describes the catfish , electric ray , and frogfish in detail, as well as cephalopods such as the octopus and paper nautilus . His description of the hectocotyl arm of cephalopods, used in sexual reproduction,

4488-419: Is also a final cause or end. Then Aristotle proceeds and concludes that the actuality is prior to potentiality in formula, in time and in substantiality. With this definition of the particular substance (i.e., matter and form), Aristotle tries to solve the problem of the unity of the beings, for example, "what is it that makes a man one"? Since, according to Plato there are two Ideas: animal and biped, how then

4624-404: Is because an adaptation is often defined as a trait that has been favored by natural selection. Adaptations, therefore, need not be adaptive , as long as they were at some point. Vestigial characters are present throughout the animal kingdom, and an almost endless list could be given. Darwin said that "it would be impossible to name one of the higher animals in which some part or other is not in

4760-487: Is completely superfluous, if that organ plays an important role in the other species of the same family. His colleague, Jean-Baptiste Lamarck , named a number of vestigial structures in his 1809 book Philosophie Zoologique . Lamarck noted " Olivier 's Spalax , which lives underground like the mole, and is apparently exposed to daylight even less than the mole, has altogether lost the use of sight: so that it shows nothing more than vestiges of this organ." Charles Darwin

4896-687: Is especially threatened by logging, hunting, fishing and plant gathering. However, islands’ vulnerability to introduced species is also due to agricultural, economic, and health differences as compared to continental land (Russel et al.). The smaller land area and population sizes of islands compared to continents create greater vulnerability to the impacts of introduced species (Russel et al.). Introduced species negatively impact ecosystems through altered predator-prey interactions that can cause harm or even local extinction to native species populations (Towns et al.). There are many examples of animal species such as birds, reptiles, and aquatic insects being harmed by

5032-435: Is functionless, it does not follow that it has descended from an ancestral sequence of functional DNA. Logically such DNA would not be vestigial in the sense of being the vestige of a functional structure. In contrast pseudogenes have lost their protein-coding ability or are otherwise no longer expressed in the cell. Whether they have any extant function or not, they have lost their former function and in that sense, they do fit

5168-440: Is important to avoid confusion of the concept of vestigiality with that of exaptation . Both may occur together in the same example, depending on the relevant point of view. In exaptation, a structure originally used for one purpose is modified for a new one. For example, the wings of penguins would be exaptational in the sense of serving a substantial new purpose (underwater locomotion), but might still be regarded as vestigial in

5304-468: Is known about Aristotle's life. He was born in the city of Stagira in northern Greece during the Classical period . His father, Nicomachus , died when Aristotle was a child, and he was brought up by a guardian. At around eighteen years old, he joined Plato 's Academy in Athens and remained there until the age of thirty seven ( c.  347 BC ). Shortly after Plato died, Aristotle left Athens and, at

5440-468: Is known for its ability to survive under harsh conditions, and it is highly adaptable, as it will eat a wide variety of organisms (Platenberg). Native frog and anole lizard populations have declined, likely due to Cuban tree frog interference (Platenberg). In contrast to the accidental introduction of the Cuban treefrog, the cane toad was deliberately introduced to control agricultural pests (Platenberg). Similar to

5576-541: Is man a unity? However, according to Aristotle, the potential being (matter) and the actual one (form) are one and the same. Aristotle's immanent realism means his epistemology is based on the study of things that exist or happen in the world, and rises to knowledge of the universal, whereas for Plato epistemology begins with knowledge of universal Forms (or ideas) and descends to knowledge of particular imitations of these. Aristotle uses induction from examples alongside deduction , whereas Plato relies on deduction from

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5712-742: Is particularly troubling as yields of coral reef fish species are an important food source for island populations. Humans have contributed to globalization and decreased effective isolation of island communities, allowing for invasion of exotic species. This can have a profound effect on the native species. In Guam , the introduced brown tree snake ate nearly all of the native vertebrate species to extinction. Feral cats and dogs have also greatly diminished native vertebrate populations on islands, through both predation and disease. Introduced ungulates are another major threat, as they graze on native vegetation and can destroy entire forests. Exotic grasses can out-compete native understory species and increase

5848-633: Is termed Island syndrome . After immigration, birds, and some reptiles or mammals, tend to become larger and predatory, showing relaxed intraspecific competition . For mammals, small species will increase in size and large species will decrease in size. This is referred to as the “island rule,” and is suggested to minimize energy expenditure. Other adaptations to life on islands include increased poikilothermy , relaxed anti-predator behavior, and reduced sexual selection in animals, and loss of herbivore defenses and reduced dispersal in plants. The formation of new islands and their isolation from

5984-413: Is the fulfilment of the end of the potentiality. Because the end ( telos ) is the principle of every change, and potentiality exists for the sake of the end, actuality, accordingly, is the end. Referring then to the previous example, it can be said that an actuality is when a plant does one of the activities that plants do. For that for the sake of which ( to hou heneka ) a thing is, is its principle, and

6120-465: Is the study of island organisms and their interactions with each other and the environment. Islands account for nearly 1/6 of earth’s total land area, yet the ecology of island ecosystems is vastly different from that of mainland communities. Their isolation and high availability of empty niches lead to increased speciation . As a result, island ecosystems comprise 30% of the world’s biodiversity hotspots , 50% of marine tropical diversity, and some of

6256-399: Is useful in referring to many genetically determined features, either morphological, behavioral, or physiological; in any such context, however, it need not follow that a vestigial feature must be completely useless. A classic example at the level of gross anatomy is the human vermiform appendix , vestigial in the sense of retaining no significant digestive function. Similar concepts apply at

6392-507: Is usually harmful or counter-adaptive. One of the earliest documented examples was that of vestigial wings in Drosophila . Many examples in many other contexts have emerged since. Human vestigiality is related to human evolution , and includes a variety of characters occurring in the human species. Many examples of these are vestigial in other primates and related animals, whereas other examples are still highly developed. The human caecum

6528-454: Is vestigial, as often is the case in omnivores , being reduced to a single chamber receiving the content of the ileum into the colon . The ancestral caecum would have been a large, blind diverticulum in which resistant plant material such as cellulose would have been fermented in preparation for absorption in the colon. Analogous organs in other animals similar to humans continue to perform similar functions. The coccyx , or tailbone, though

6664-567: Is when a single species colonizes an area and rapidly diversifies to fill all of the available niches. A common example is the assemblage of finch species documented by Charles Darwin in the Galapagos Islands . Darwin’s finches exhibited adaptive radiation by evolving different beak sizes to exploit the diversity of seeds present on the different islands. Because the distributions of these populations are limited by their island habitats, they tend to have fewer individuals than their mainland counterparts and lower genetic variation. This, along with

6800-570: The California Channel Islands , where DDT poisoning reduced bald eagle populations. This, along with an abundance of introduced feral pigs for prey, allowed golden eagles to colonize the island and replace bald eagles. However, the golden eagles also ate native island foxes . Fox population levels decreased to near extinction, while skunk populations increased due to relaxed competition with foxes. Since island ecosystems are self-contained, it should be possible to mitigate many of

6936-634: The Early Modern period. John Philoponus (in Late antiquity ) and Galileo (in Early modern period ) are said to have shown by experiment that Aristotle's claim that a heavier object falls faster than a lighter object is incorrect. A contrary opinion is given by Carlo Rovelli , who argues that Aristotle's physics of motion is correct within its domain of validity, that of objects in the Earth 's gravitational field immersed in

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7072-515: The Great Comet of 371 BC . Aristotle was one of the first people to record any geological observations. He stated that geological change was too slow to be observed in one person's lifetime. The geologist Charles Lyell noted that Aristotle described such change, including "lakes that had dried up" and "deserts that had become watered by rivers", giving as examples the growth of the Nile delta since

7208-471: The History of Animals in a graded scale of perfection, a nonreligious version of the scala naturae , with man at the top. His system had eleven grades of animal, from highest potential to lowest, expressed in their form at birth: the highest gave live birth to hot and wet creatures, the lowest laid cold, dry mineral-like eggs. Animals came above plants , and these in turn were above minerals. He grouped what

7344-538: The Macedonian capital, making his first connections with the Macedonian monarchy . At the age of seventeen or eighteen, Aristotle moved to Athens to continue his education at Plato's Academy . He became distinguished as a researcher and lecturer, earning for himself the nickname "mind of the school" by his tutor Plato . In Athens, he probably experienced the Eleusinian Mysteries as he wrote when describing

7480-451: The Milky Way was made up of "those stars which are shaded by the earth from the sun's rays," pointing out partly correctly that if "the size of the sun is greater than that of the earth and the distance of the stars from the earth many times greater than that of the sun, then... the sun shines on all the stars and the earth screens none of them." He also wrote descriptions of comets, including

7616-508: The Physics (215a25), Aristotle effectively states a quantitative law, that the speed, v, of a falling body is proportional (say, with constant c) to its weight, W, and inversely proportional to the density, ρ, of the fluid in which it is falling:; Aristotle implies that in a vacuum the speed of fall would become infinite, and concludes from this apparent absurdity that a vacuum is not possible. Opinions have varied on whether Aristotle intended to state quantitative laws. Henri Carteron held

7752-463: The occipitofrontalis muscle ) have lost their original functions (to keep the head from falling) but are still useful for other purposes (facial expression). Humans also bear some vestigial behaviors and reflexes. The formation of goose bumps in humans under stress is a vestigial reflex ; its function in human ancestors was to raise the body's hair, making the ancestor appear larger and scaring off predators. The arrector pili (muscle that connects

7888-412: The universal . Aristotle's ontology places the universal ( katholou ) in particulars ( kath' hekaston ), things in the world, whereas for Plato the universal is a separately existing form which actual things imitate. For Aristotle, "form" is still what phenomena are based on, but is "instantiated" in a particular substance. Plato argued that all things have a universal form , which could be either

8024-513: The "extreme view" that Aristotle's concept of force was basically qualitative, but other authors reject this. Archimedes corrected Aristotle's theory that bodies move towards their natural resting places; metal boats can float if they displace enough water ; floating depends in Archimedes' scheme on the mass and volume of the object, not, as Aristotle thought, its elementary composition. Aristotle's writings on motion remained influential until

8160-577: The 4th century BC, Aristotle was one of the earliest writers to comment, in his History of Animals , on the vestigial eyes of moles, calling them "stunted in development" due to the fact that moles can scarcely see. However, only in recent centuries have anatomical vestiges become a subject of serious study. In 1798, Étienne Geoffroy Saint-Hilaire noted on vestigial structures: Whereas useless in this circumstance, these rudiments... have not been eliminated, because Nature never works by rapid jumps , and She always leaves vestiges of an organ, even though it

8296-518: The Colonies , were composed by the philosopher for the young prince. After Philip II's assassination in 336 BC, Aristotle returned to Athens for the second and final time a year later. As a metic , Aristotle could not own property in Athens and thus rented a building known as the Lyceum (named after the sacred grove of Apollo Lykeios ), in which he established his own school. The building included

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8432-424: The Cuban treefrog, the cane toad is also omnivorous. Cane toad tadpoles compete for limited freshwater resources with the white-lipped frog, a native species, thus limiting their resources (Platenberg). In general, when the introduction of a nonnative species results in extinction, the ecosystem experiences losses in some trophic levels (Platenberg). For example, vertebrate herbivores that are prone to extinction change

8568-602: The Greeks and a despot to the barbarians". Alexander's education under the guardianship of Aristotle likely lasted for only a few years, as at around the age of sixteen he returned to Pella and was appointed regent of Macedon by his father Philip. During this time, Aristotle is said to have gifted Alexander an annotated copy of the Iliad , which reportedly became one of Alexander's most prized possessions. Scholars speculate that two of Aristotle's now lost works, On kingship and On behalf of

8704-750: The Persians, and philosophical questions, like the definition of braveness. A widespread speculation in antiquity suggested that Aristotle played a role in Alexander's death, but the only evidence of this is an unlikely claim made some six years after the death. Following Alexander's death, anti-Macedonian sentiment in Athens was rekindled. In 322 BC, Demophilus and Eurymedon the Hierophant reportedly denounced Aristotle for impiety, prompting him to flee to his mother's family estate in Chalcis, Euboea , at which occasion he

8840-487: The Soul and Poetics . Aristotle studied and made significant contributions to "logic, metaphysics, mathematics, physics, biology, botany, ethics, politics, agriculture, medicine, dance, and theatre." While Alexander deeply admired Aristotle, near the end of his life, the two men became estranged having diverging opinions over issues, like the optimal administration of city-states, the treatment of conquered populations, such as

8976-491: The Southern Ocean Islands, indirect effects such as invasive species and global warming can play a greater role in influencing populations than overexploitation , pollution and habitat loss . Human activities and the introduction of non-native species often cause trophic cascades , where direct effects on one species result in indirect effects on other species in the food web. An example is on Santa Cruz Island of

9112-489: The ball along to make it continue to rise even though the hand is no longer acting on it, resulting in the Medieval theory of impetus . Aristotle suggested that the reason for anything coming about can be attributed to four different types of simultaneously active factors. His term aitia is traditionally translated as "cause", but it does not always refer to temporal sequence; it might be better translated as "explanation", but

9248-399: The becoming is for the sake of the end; and the actuality is the end, and it is for the sake of this that the potentiality is acquired. For animals do not see in order that they may have sight, but they have sight that they may see. In summary, the matter used to make a house has potentiality to be a house and both the activity of building and the form of the final house are actualities, which

9384-432: The behavioral and ecological factors mentioned above, makes island species more vulnerable to extinction. The continued survival of species on islands depends on factors such as natural selection , genetic variation, natural disturbances (hurricanes, volcanic eruptions) and human-caused disturbances (introduced species, habitat loss ). Human-caused disturbances tend to be the greatest cause of mortality, and understanding

9520-574: The broad sense coextensive with reasoning, which he also would describe as "science". However, his use of the term science carries a different meaning than that covered by the term "scientific method". For Aristotle, "all science ( dianoia ) is either practical, poetical or theoretical" ( Metaphysics 1025b25). His practical science includes ethics and politics; his poetical science means the study of fine arts including poetry; his theoretical science covers physics, mathematics and metaphysics. In his On Generation and Corruption , Aristotle related each of

9656-433: The cause of earthquakes was a gas or vapor ( anathymiaseis ) that was trapped inside the earth and trying to escape, following other Greek authors Anaxagoras , Empedocles and Democritus . Aristotle also made many observations about the hydrologic cycle. For example, he made some of the earliest observations about desalination: he observed early – and correctly – that when seawater is heated, freshwater evaporates and that

9792-425: The causes of extinction facilitates conservation efforts. The movement of humans to islands has led to rapid extinction of native island species either from hunting, habitat destruction , or introduced species . Many large animals on islands have been hunted to extinction by humans. A well-known example is the dodo , once found on the island of Mauritius . It evolved to become large, flightless and docile, and

9928-537: The community (Towns). Even if the number of species introduced to an island is roughly the same as the number of extinct ones, the ecological traits are not comparable enough to make up for losses (Towns). Global warming is emerging as a strong cause of species loss on islands. This can be due to sea level rise , the intrusion of salt water into freshwater habitats, or species inability to adapt to increasing temperatures and extreme weather events. Plant species are particularly susceptible. In more isolated areas, such as

10064-410: The composite natural ones, the study of nature would be the primary kind of knowledge; but if there is some motionless independent thing, the knowledge of this precedes it and is first philosophy, and it is universal in just this way , because it is first. And it belongs to this sort of philosophy to study being as being, both what it is and what belongs to it just by virtue of being. Aristotle examines

10200-406: The concepts of substance ( ousia ) and essence ( to ti ên einai , "the what it was to be") in his Metaphysics (Book VII), and he concludes that a particular substance is a combination of both matter and form, a philosophical theory called hylomorphism . In Book VIII, he distinguishes the matter of the substance as the substratum , or the stuff of which it is composed. For example, the matter of

10336-399: The data to come to the theory of evolution . Aristotle's writings can seem to modern readers close to implying evolution, but while Aristotle was aware that new mutations or hybridizations could occur, he saw these as rare accidents. For Aristotle, accidents, like heat waves in winter, must be considered distinct from natural causes. He was thus critical of Empedocles's materialist theory of

10472-551: The definition of vestigiality. Vestigial structures are often called vestigial organs , although many of them are not actually organs . Such vestigial structures typically are degenerate, atrophied, or rudimentary, and tend to be much more variable than homologous non-vestigial parts. Although structures commonly regarded "vestigial" may have lost some or all of the functional roles that they had played in ancestral organisms, such structures may retain lesser functions or may have become adapted to new roles in extant populations. It

10608-450: The details of Aristotle's life are not well-established. The biographies written in ancient times are often speculative and historians only agree on a few salient points. Aristotle was born in 384 BC in Stagira , Chalcidice , about 55 km (34 miles) east of modern-day Thessaloniki . He was the son of Nicomachus , the personal physician of King Amyntas of Macedon , and Phaestis,

10744-486: The earliest study of formal logic, and his conception of it was the dominant form of Western logic until 19th-century advances in mathematical logic . Kant stated in the Critique of Pure Reason that with Aristotle, logic reached its completion. Most of Aristotle's work is probably not in its original form, because it was most likely edited by students and later lecturers. The logical works of Aristotle were compiled into

10880-623: The ecosystem depend on such as seabirds, can also have significant effects (Towns). Seabirds are essential to the structure of the ecosystem because they transport large amounts of nutrients into ecosystems and burrow into soils, helping vegetation (Towns). However, since human settlement, seabird communities have been severely impacted on islands across the globe (Towns). While some exotic species may perform ecological roles similar to those of extinct species, there are many roles that cannot be fulfilled by other species. Therefore, similar exotic species do not offer complete replacement for extinct species in

11016-542: The ecosystem function in plant communities. This phenomenon is seen in New Zealand, where the loss of bird species may have changed dynamics in avian-induced vegetation communities and impacted abundances of forest plants (Platenberg). Also in New Zealand, small mammalian predators such as rodents have little direct effect on vegetation but have greater effect on island faunas through extinction and displacement (Wood et al.). Pacific rats, for example, were thought to be causing

11152-407: The environment and behavior patterns of the organism in question. Through an examination of these various traits, it is clear that evolution had a hard role in the development of organisms. Every anatomical structure or behavior response has origins in which they were, at one time, useful. As time progressed, the ancient common ancestor organisms did as well. Evolving with time, natural selection played

11288-441: The fashion to fold the lapel over, the top half of buttons and their accompanying buttonholes disappeared, save for a single hole at the top; it has since found a new use as a place to fasten pins, badges, or boutonnières . As a final example, soldiers in ceremonial or parade uniform can sometimes be seen wearing a gorget : a small decorative piece of metal suspended around the neck with a chain. The gorget serves no protection to

11424-587: The field is the shift from 2-D to 3-D science in ecology. This approach offers a comprehensive understanding of ecological dynamics and human impacts on both terrestrial and marine environments. The adoption of 3-D models supports better natural resource management and informs conservation and management plans. This transition also affects how policymakers evaluate regulations, providing a more dynamic perspective on ecological and environmental challenges. Aristotle Aristotle ( Attic Greek : Ἀριστοτέλης , romanized:  Aristotélēs ; 384–322 BC)

11560-433: The final chapter of the 6th edition concluded that species have been modified "chiefly through the natural selection of numerous successive, slight, favorable variations; aided in an important manner by the inherited effects of the use and disuse of parts". In 1893, Robert Wiedersheim published The Structure of Man , a book on human anatomy and its relevance to man's evolutionary history. The Structure of Man contained

11696-442: The first century AD editor who assembled various small selections of Aristotle's works to create the treatise we know by the name Metaphysics . Aristotle called it "first philosophy", and distinguished it from mathematics and natural science (physics) as the contemplative ( theoretikē ) philosophy which is "theological" and studies the divine. He wrote in his Metaphysics (1026a16): If there were no other independent things besides

11832-533: The following. Brood size decreases with (adult) body mass, so that an elephant has fewer young (usually just one) per brood than a mouse. Lifespan increases with gestation period , and also with body mass, so that elephants live longer than mice, have a longer period of gestation, and are heavier. As a final example, fecundity decreases with lifespan, so long-lived kinds like elephants have fewer young in total than short-lived kinds like mice. Aristotle distinguished about 500 species of animals , arranging these in

11968-531: The forms as existing separately from the things that participate in them, Aristotle maintained that universals exist within each thing on which each universal is predicated. So, according to Aristotle, the form of apple exists within each apple, rather than in the world of the forms. Concerning the nature of change ( kinesis ) and its causes, as he outlines in his Physics and On Generation and Corruption ( 319b–320a), he distinguishes coming-to-be ( genesis , also translated as 'generation') from: Coming-to-be

12104-509: The four elements proposed earlier by Empedocles , earth , water , air , and fire , to two of the four sensible qualities, hot, cold, wet, and dry. In the Empedoclean scheme, all matter was made of the four elements, in differing proportions. Aristotle's scheme added the heavenly aether , the divine substance of the heavenly spheres , stars and planets. Aristotle describes two kinds of motion: "violent" or "unnatural motion", such as that of

12240-582: The gene in an ancestor of the modern infraorder of monkeys, and apes , and it now remains in their genomes , including the human genome , as a vestigial sequence called a pseudogene . The shift in human diet towards soft and processed food over time caused a reduction in the number of powerful grinding teeth, especially the third molars (also known as wisdom teeth), which were highly prone to impaction . Plants also have vestigial parts, including functionless stipules and carpels , leaf reduction of Equisetum , paraphyses of Fungi . Well known examples are

12376-699: The giant tortoises of the Galápagos Islands and the Seychelles (the Galápagos tortoise and Aldabrachelys respectively) are sometimes given as examples of insular gigantism, they are now thought to represent the last remaining populations of historically widespread giant tortoises i.e. gigantism is an ancestral trait that occurred in the absence of insular selection pressures. The collection of differences in morphology , ecology , physiology and behaviour of insular species compared to their continental counterparts

12512-428: The ground, say) require more force to make them move; and objects pushed with greater force move faster. This would imply the equation incorrect in modern physics. Natural motion depends on the element concerned: the aether naturally moves in a circle around the heavens, while the 4 Empedoclean elements move vertically up (like fire, as is observed) or down (like earth) towards their natural resting places. In

12648-523: The growth of shearwater chicks, such as loss of tissue in their feet (Towns et al.). Other examples of high-impact species to island ecosystems are the Cuban treefrog and cane toad, which were introduced to the US Virgin Islands under various circumstances (Platenberg). The Cuban treefrog has been present in the USVI since arriving unintentionally on a cargo ship in the 1970s (Platenberg). The Cuban tree frog

12784-410: The hair follicle to connective tissue) contracts and creates goosebumps on skin. There are also vestigial molecular structures in humans, which are no longer in use but may indicate common ancestry with other species. One example of this is a gene that is functional in most other mammals and which produces L-gulonolactone oxidase , an enzyme that can make vitamin C . A documented mutation deactivated

12920-618: The head of the Lyceum, who in turn passed them down to Neleus of Scepsis in Asia Minor. There, the papers remained hidden for protection until they were purchased by the collector Apellicon . In the meantime, many copies of Aristotle's major works had already begun to circulate and be used in the Lyceum of Athens, Alexandria , and later in Rome . With the Prior Analytics , Aristotle is credited with

13056-440: The image. According to Aristotle, spontaneity and chance are causes of some things, distinguishable from other types of cause such as simple necessity. Chance as an incidental cause lies in the realm of accidental things , "from what is spontaneous". There is also more a specific kind of chance, which Aristotle names "luck", that only applies to people's moral choices. In astronomy , Aristotle refuted Democritus 's claim that

13192-474: The introduction of predators such as rats, cats, and ants. For example, seabirds on islands in Hawaii are impacted by non-native predators like barn owls and ants. At a colony in Hawaii, at least 20% of wedge-tailed shearwater eggs were taken by mynas, dark-plumaged birds of the starling family (Towns et al.). Also in Hawaii, more than forty four introduced ant species, especially tropical fire ants, caused detriments to

13328-431: The left lung is greatly reduced or absent. Amphisbaenians , which independently evolved limblessness, also retain vestiges of the pelvis as well as the pectoral girdle, and have lost their right lung. A case of vestigial organs was described in polyopisthocotylean Monogeneans ( parasitic flatworms ). These parasites usually have a posterior attachment organ with several clamps , which are sclerotised organs attaching

13464-472: The list primarily of interest as a record of the knowledge of human anatomy at the time. Later versions of Wiedersheim's list were expanded to as many as 180 human "vestigial organs". This is why the zoologist Horatio Newman said in a written statement read into evidence in the Scopes Trial that "There are, according to Wiedersheim, no less than 180 vestigial structures in the human body, sufficient to make of

13600-429: The local extinction of large, nocturnal ground-dwelling lizards, and they were assumed to have minimal effect on diurnal species, those that sleep at night, such as shore skinks (Wood et al.). In places where Pacific rats were removed, however, shore skink populations rapidly changed, indicating that the rats’ impact has been underestimated (Wood et al.). The loss of a keystone species, a species that all other species in

13736-442: The loss of clamps. Coincidentally, other attachment structures (lateral flaps, transverse striations) have evolved in protomicrocotylids. Therefore, clamps in protomicrocotylids were considered vestigial organs. In the foregoing examples the vestigiality is generally the (sometimes incidental) result of adaptive evolution . However, there are many examples of vestigiality as the product of drastic mutation , and such vestigiality

13872-422: The mainland provides many unoccupied niches for species to adapt to. Since immigration of predators and competitors is limited, many organisms are able to persist in these new niches. This results in a high occurrence of endemism , where species are unique to a localized area. For example, 50% of endemic bird areas are found on islands. Endemism is often the result of adaptive radiation . Adaptive radiation

14008-408: The mainland. Of the species that arrive, only some will be able to survive and establish populations. As a result, islands have fewer species than mainland habitats. Island populations are small and exhibit low genetic variability (see founder effect ), but are isolated from the predators and competitors that they initially evolved with. This can lead to a process called ecological release , where

14144-937: The many necessary interactions between people and agencies. Once a reserve is in place, managers can then practice adaptive management and do continued community education. On land, island conservation focuses on the protection of species and their habitat. In some cases, conservation can be integrated with agricultural production. For example, the Acacia koa plantations and wooded pastures in Hawaii are anthropogenically altered ecosystems, yet allow connectivity between forest fragments and thus maintain higher diversity than would open pasture. Other directions include habitat restoration, and eradication of introduced predators, ungulates, and exotic plants (via hunting, removal or biological control ). In marine ecosystems, there has been an increasing establishment of “no-take” reserves. This allows for

14280-468: The modern zoologist would call vertebrates as the hotter "animals with blood", and below them the colder invertebrates as "animals without blood". Those with blood were divided into the live-bearing ( mammals ), and the egg-laying ( birds , reptiles , fish ). Those without blood were insects, crustacea (non-shelled – cephalopods, and shelled ) and the hard-shelled molluscs ( bivalves and gastropods ). He recognised that animals did not exactly fit into

14416-411: The molecular level—some nucleic acid sequences in eukaryotic genomes have no known biological function; some of them may be " junk DNA ", but it is a difficult matter to demonstrate that a particular sequence in a particular region of a given genome is truly nonfunctional. The simple fact that it is noncoding DNA does not establish that it is functionless. Furthermore, even if an extant DNA sequence

14552-589: The more important purpose, and remain perfectly efficient for the other.... [A]n organ may become rudimentary for its proper purpose, and be used for a distinct object." In the first edition of On the Origin of Species , Darwin briefly mentioned inheritance of acquired characters under the heading " Effects of Use and Disuse ", expressing little doubt that use "strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited". In later editions he expanded his thoughts on this, and in

14688-746: The most unusual and rare species. Many species still remain unknown. The diversity of species on islands is highly impacted by human activities such as deforestation and introduction of the exotic species . In response, ecologists and managers are directing attention towards conservation and restoration of island species. Because they are simple systems, islands provide an opportunity to study processes of extinction that can be extrapolated to larger ecosystems. Islands are attractive sites for ecological research because they provide clear examples of evolution in action. They show interesting patterns of colonization, adaptation, and speciation. Islands are surrounded by water, and may or may not exist as part of

14824-404: The oceans are then replenished by the cycle of rainfall and river runoff ("I have proved by experiment that salt water evaporated forms fresh and the vapor does not when it condenses condense into sea water again.") Aristotle was the first person to study biology systematically, and biology forms a large part of his writings. He spent two years observing and describing the zoology of Lesbos and

14960-572: The organism to see, and are remnants of their ancestors' functional eyes. Animals that reproduce without sex (via asexual reproduction ) generally lose their sexual traits, such as the ability to locate/recognize the opposite sex and copulation behavior. Boas and pythons have vestigial pelvis remnants, which are externally visible as two small pelvic spurs on each side of the cloaca. These spurs are sometimes used in copulation, but are not essential, as no colubrid snake (the vast majority of species) possesses these remnants. Furthermore, in most snakes,

15096-510: The original version of the structure in other species in order to determine the homology of a vestigial structure. Homologous structures indicate common ancestry with those organisms that have a functional version of the structure. Douglas Futuyma has stated that vestigial structures make no sense without evolution, just as spelling and usage of many modern English words can only be explained by their Latin or Old Norse antecedents. Vestigial traits can still be considered adaptations . This

15232-407: The poet Dante called him "the master of those who know". His works contain the earliest known formal study of logic, and were studied by medieval scholars such as Peter Abelard and Jean Buridan . Aristotle's influence on logic continued well into the 19th century. In addition, his ethics , although always influential, gained renewed interest with the modern advent of virtue ethics . In general,

15368-537: The reductions in floral display, leading to smaller and/or paler flowers, in plants that reproduce without outcrossing , for example via selfing or obligate clonal reproduction. Many objects in daily use contain vestigial structures. While not the result of natural selection through random mutation , much of the process is the same. Product design, like evolution, is iterative; it builds on features and processes that already exist, with limited resources available to make tweaks. To spend resources on completely weeding out

15504-713: The reestablishment of native species, and also the augmentation of commercially harvested species. However, in both terrestrial and marine systems, these actions are expensive and do not always result in the desired outcomes. For example, some non-natives become keystone species and their removal can cause more harm than good to the ecosystem. To be more effective, managers of island ecosystems should share information and learn from each other’s mistakes. Island conservation tends to focus on preservation of individual species and their habitats. However, many ecologists caution that ecological and evolutionary processes should be conserved as well. The conservation of island communities as

15640-453: The request of Philip II of Macedon , tutored his son Alexander the Great beginning in 343 BC. He established a library in the Lyceum, which helped him to produce many of his hundreds of books on papyrus scrolls . Though Aristotle wrote many treatises and dialogues for publication, only around a third of his original output has survived , none of it intended for publication. Aristotle provided

15776-417: The risk of fire. Lastly, social insects such as ants also cause major problems. Nonnative species introduced onto islands can have profound effects on an island's ecosystem, more so than nonnative species introduced to continental land (Platenberg). The higher impact of introduced and nonnative species on islands is largely a result of lower biodiversity levels (Platenburg et al.). Biodiversity on islands

15912-433: The same certainty as experimental science, but it sets out testable hypotheses and constructs a narrative explanation of what is observed. In this sense, Aristotle's biology is scientific. From the data he collected and documented, Aristotle inferred quite a number of rules relating the life-history features of the live-bearing tetrapods (terrestrial placental mammals) that he studied. Among these correct predictions are

16048-439: The seed of a plant in the soil is potentially ( dynamei ) a plant, and if it is not prevented by something, it will become a plant. Potentially, beings can either 'act' ( poiein ) or 'be acted upon' ( paschein ), which can be either innate or learned. For example, the eyes possess the potentiality of sight (innate – being acted upon), while the capability of playing the flute can be possessed by learning (exercise – acting). Actuality

16184-689: The sense of having lost the function of flight. In contrast Darwin argued that the wings of emus would be definitely vestigial, as they appear to have no major extant function; however, function is a matter of degree, so judgments on what is a "major" function are arbitrary; the emu does seem to use its wings as organs of balance in running. Similarly, the ostrich uses its wings in displays and temperature control, though they are undoubtedly vestigial as structures for flight. Vestigial characters range from detrimental through neutral to favorable in terms of selection. Some may be of some limited utility to an organism but still degenerate over time if they do not confer

16320-690: The sights one viewed at the Mysteries, "to experience is to learn" ( παθεĩν μαθεĩν ). Aristotle remained in Athens for nearly twenty years before leaving in 348/47 BC after Plato's death. The traditional story about his departure records that he was disappointed with the Academy's direction after control passed to Plato's nephew Speusippus , although it is possible that the anti-Macedonian sentiments in Athens could have also influenced his decision. Aristotle left with Xenocrates to Assos in Asia Minor , where he

16456-418: The structure could not occur without major alterations of the organism's developmental pattern, and such alterations would likely produce numerous negative side-effects. The toes of many animals such as horses , which stand on a single toe , are still evident in a vestigial form and may become evident, although rarely, from time to time in individuals. The vestigial versions of the structure can be compared to

16592-504: The structure is of no direct harm, yet all structures require extra energy in terms of development, maintenance, and weight, and are also a risk in terms of disease (e.g., infection , cancer ), providing some selective pressure for the removal of parts that do not contribute to an organism's fitness. A structure that is not harmful will take longer to be 'phased out' than one that is. However, some vestigial structures may persist due to limitations in development, such that complete loss of

16728-747: The study of more complex forms, namely, syllogisms (in the Analytics ) and dialectics (in the Topics and Sophistical Refutations ). The first three treatises form the core of the logical theory stricto sensu : the grammar of the language of logic and the correct rules of reasoning. The Rhetoric is not conventionally included, but it states that it relies on the Topics . What is today called Aristotelian logic with its types of syllogism (methods of logical argument), Aristotle himself would have labelled "analytics". The term "logic" he reserved to mean dialectics . The word "metaphysics" appears to have been coined by

16864-549: The surrounding seas, including in particular the Pyrrha lagoon in the centre of Lesbos. His data in History of Animals , Generation of Animals , Movement of Animals , and Parts of Animals are assembled from his own observations, statements given by people with specialized knowledge, such as beekeepers and fishermen, and less accurate accounts provided by travellers from overseas. His apparent emphasis on animals rather than plants

17000-507: The threats to species. Ecologists and managers are working together to prioritize areas for conservation and to quickly design and implement action plans. Not everything can be put into a reserve, so it is important to first compile pertinent information and prioritize areas of concern. Once an area has been chosen, managers must then acquire ownership and gain support. Local experts and indigenous populations should also be involved in this process. Having clearly defined goals will facilitate

17136-470: The time of Homer , and "the upheaving of one of the Aeolian islands , previous to a volcanic eruption ."' Meteorologica lends its name to the modern study of meteorology, but its modern usage diverges from the content of Aristotle's ancient treatise on meteors . The ancient Greeks did use the term for a range of atmospheric phenomena, but also for earthquakes and volcanic eruptions. Aristotle proposed that

17272-473: The traditional rendering will be employed here. Aristotle describes experiments in optics using a camera obscura in Problems , book 15. The apparatus consisted of a dark chamber with a small aperture that let light in. With it, he saw that whatever shape he made the hole, the sun's image always remained circular. He also noted that increasing the distance between the aperture and the image surface magnified

17408-434: The wearer, yet there exists an unbroken lineage from the gorget to the full suits of armour of the middle ages. With the introduction of gunpowder weapons, armour increasingly lost its usefulness on the battlefield. At the same time, military men were keen to retain the status it provided them. The result: a breastplate that "shrank" away over time, but never disappeared completely. Island ecology Island ecology

17544-411: The worm to the gill of the host fish. These clamps are extremely important for the survival of the parasite. In the family Protomicrocotylidae , species have either normal clamps, simplified clamps, or no clamps at all (in the genus Lethacotyle ). After a comparative study of the relative surface of clamps in more than 100 Monogeneans , this has been interpreted as an evolutionary sequence leading to

17680-533: Was an Ancient Greek philosopher and polymath . His writings cover a broad range of subjects spanning the natural sciences , philosophy , linguistics , economics , politics , psychology , and the arts . As the founder of the Peripatetic school of philosophy in the Lyceum in Athens , he began the wider Aristotelian tradition that followed, which set the groundwork for the development of modern science . Little

17816-657: Was familiar with the concept of vestigial structures, though the term for them did not yet exist. He listed a number of them in The Descent of Man , including the muscles of the ear , wisdom teeth , the appendix , the tail bone , body hair , and the semilunar fold in the corner of the eye . Darwin also noted, in On the Origin of Species , that a vestigial structure could be useless for its primary function, but still retain secondary anatomical roles: "An organ serving for two purposes, may become rudimentary or utterly aborted for one, even

17952-413: Was invited by his former fellow student Hermias of Atarneus ; he stayed there for a few years and left around the time of Hermias' death. While at Assos, Aristotle and his colleague Theophrastus did extensive research in botany and marine biology , which they later continued at the near-by island of Lesbos . During this time, Aristotle married Pythias , Hermias's adoptive daughter and niece, and had

18088-766: Was not replaced systematically until the Enlightenment and theories such as classical mechanics were developed. He influenced Judeo-Islamic philosophies during the Middle Ages, as well as Christian theology , especially the Neoplatonism of the Early Church and the scholastic tradition of the Catholic Church . Aristotle was revered among medieval Muslim scholars as "The First Teacher", and among medieval Christians like Thomas Aquinas as simply "The Philosopher", while

18224-513: Was said to have stated "I will not allow the Athenians to sin twice against philosophy" – a reference to Athens's trial and execution of Socrates . He died in Chalcis, Euboea of natural causes later that same year, having named his student Antipater as his chief executor and leaving a will in which he asked to be buried next to his wife. Aristotle left his works to Theophrastus, his successor as

18360-611: Was subsequently driven to extinction by humans and introduced predators. The depletion of natural resources can have dramatic effects on island ecology. On Easter Island , the depletion of the forest by humans not only resulted in widespread loss of species, but also the collapse of the island civilization. Today there are over 500 million people on islands, all dependent on local resources either directly (traditional use) or indirectly (ecotourism revenue). Population growth and development result in heavy deforestation , pollution , and over-exploitation . Overharvesting of ocean fauna

18496-588: Was widely disbelieved until the 19th century. He gives accurate descriptions of the four-chambered fore-stomachs of ruminants , and of the ovoviviparous embryological development of the hound shark . He notes that an animal's structure is well matched to function so birds like the heron (which live in marshes with soft mud and live by catching fish) have a long neck, long legs, and a sharp spear-like beak, whereas ducks that swim have short legs and webbed feet. Darwin , too, noted these sorts of differences between similar kinds of animal, but unlike Aristotle used

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