Module 5 Quiz
Explain the main points of the article "Darwin's Sea Change, or Five Years at the Captain's Table" by Stephen Jay Gould
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Describe and give examples of the three riddles about Darwin's life as described by Stephen Jay Gould in the videotape Darwin's Revolution in Thought
1) First Riddle- Who was the official naturalist on board the HMS Beagle? -McKormick 2) Second Riddle- Why did Darwin not use the word evolution? -The word evolution is not common, had a definite meaning primarily in poetry and metaphor. It means progress, "evolution" means unfolding, literally an unfolding or preordained or prearranged sequence. Darwin's theory is non-progressivist. That is what is unique about it. That is why Darwin doesn't use the word evolution. 3) Third Riddle- Why did Darwin wait 21 years in order to publish the theory of natrual selection? -Darwin waited so long because he was afraid, not afraid of exposing his belief in evolution, but afraid of the radical philosophical implications of the principle of natural selection (which was his own theory about how evolution occurred). He was afraid to expose his belief in materialism and by that the philosophical position that ran in contrary to the deep tradition of dualism.
b. Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. (pg 93) f. Polygenic traits
A polygenic trait is one whose phenotype is influenced by more than one gene. Traits that display a continuous distribution, such as height or skin color, are polygenic. These were the traits that the naturalists, taxonomists, and breeders of domesticated plants and animals that continued to believe in Darwinism observed. They saw continuous variation due to polygenic traits, whereas those who supported Mendel were only working with discrete traits (controlled by one gene).
Explain the role Alfred Wallace played in the publication of Darwin's ideas on evolution
After the HMS Beagle returned to England in 1836, Darwin waited more than 20 years to publish his book On the Origin of Species. He used this time to use the scientific process to support his hypothesis of common ancestor and natural selection. Alfred Wallace published a similar hypothesis before Darwin, which prompted Darwin to publish his book. Wallace conceived the idea of "survival of the fittest," or natural selection, and the idea that every species has come into existence from a pre-existing closely allied species after reading Malthus's treatise on human population increase. Wallace was an English naturalist who went to Amazon and Malay Archipelago. Wallace sent his hypothesis to Darwin for comment. Wallace's ideas were so close to Darwin's ideas so Darwin proposed a joint paper with Wallace. Wallace wrote an essay called "On the Law Which Has Regulated the Introduction of New Species." In this essay, he said that "every species has come into existence coincident both in time and space with a preexisting closely allied species." Darwin presented an abstract of On the Origin of Species, and Wallace's section was "On the Tendency of Varieties to Depart Indefinitely from the Original Type."
Describe what each scientist contributed toward the development of evolutionary theory d. Hutton
Believed in uniforminarianism. By 1795, the Scottish geologist James Hutton had suggested that "in examining things present we have data form which to reason with regard to what has been." His conclusion was that since "Rest exists not anywhere," and the forces that change the face of the earth move with ponderous slowness, the mountains and canyons of the world must have come into existence over countless aeons. His ideas were used in Lyell's book.
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . b. Final Causes
Aristotle. i. The "final cause," however, is the goal, or purpose for its occurrence: the pool ball moves because I wish it to go into the corner pocket. In post-medieval thought there was a final cause—a purpose—for everything; but purpose implies intention, or foreknowledge, by an intellect. Thus the existence of the world, and all of the creatures in it, had a purpose; and that purpose was God's design. This was self-evident since it was possible to look about the world and see the palpable evidence of God's design everywhere. The heavenly bodies moved in harmonious orbits, evincing the intelligence and harmony of the divine mind; the adaptations of animals and plants to their habitats likewise reflected the divine intelligence, which had fitted all creatures perfectly for their roles in the harmonious economy of nature. 1. This hindered the acceptance of evolutionary thinking because before the rise of science, the cause of events were sought not in natural mechanisms but in the purposes they were meant to serve, and order in nature was evidence of divine intelligence. Since St. Ambrose had declared that "Moses opened his mouth and poured forth what God had said to him," the Bible was seen as the literal word of God, and according to St. Thomas Aquinas, "Nothing was made by God, after the six days of creation, absolutely new." Taking genesis literally, Archbishop Ussher was able to calculate that he earth was created in 4004 BC. The earth and the heavens were immutable, changeless. As John Ray put it in 1701 in The Wisdom of God Manifested in the Works of the Creation, all living and nonliving things were "created by God at first, and by Him conserved to this Day in the same State and Condition in which they were first made."
Describe what each scientist contributed toward the development of evolutionary theory b. Moro
As early as 1718, the Abbé Moro and the French academician Bernard de Fontenelle had concluded that the Biblical deluge could not explain the fossilized oyster beds and tropical plants that were found in France. And what of the great, unbroken chain of being if the rocks ere full of extinct species?
b. Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. (pg 93) e. Mutations
Believed that mutations caused evolution and new species, not natural selection. e. Hugo de Vries believed that new species arose in a single step by alteration, called a mutation, of the hereditary material. Thomas Hunt Morgan stated that evolution must proceed by major mutational steps, and that mutation, not natural selection, was the cause of evolution.
Describe what each scientist contributed toward the development of evolutionary theory a. Kant
By 1755, Kant was arguing that the laws of matter in motion discovered by Newton and other physicists were sufficient to explain natural order. Gravitation, for example, could aggregate chaotically dispersed matter into stars and planets. These would join with one another until the only ones left were those that cycled in orbits far enough from each other to resist gravitational collapse. Thus order might arise from natural processes rather than from the direct intervention from a supernatural mind. The "argument from design"—the claim that natural order is evidence of a designer—had been directly challenged. Argument from design is from natural theology and states that God's benevolence, omniscience, and intelligence can be seen through 1) the good design of organisms 2) the harmony of ecosytems. Natural theology is an English form of argument that goes back to Boil in the 17th century and Paley and ends with Darwin's generation.
Identify what Darwin couldn't explain about variations
Darwin realized that variations are essential to the natural selection process, whereas prior to Darwin, variations were considered imperfections that should be ignored since they were not important to the description of a species. Darwin suspected that the occurrence of variations is completely random; that they arise by accident and for no particular purpose. *******Darwin didn't know the source of variation and the mechanism for passing change from generation to generation. Darwin didn't know how plants or animals passed down traits. He didn't know about genetics. Darwin had a lack of explanation for heredity.******* (pg 93) Darwin's supposition that variation was unlimited, and so in time could give rise to strikingly different organisms, was not entirely convincing because he had no idea of where variation came from.
List and describe how the following individuals influenced the development of Darwin's ideas on evolution a. Charles Lyell
Darwin took Lyell's book, Principles of Geology, with him on the Beagle. This book gave Darwin evidence that the Earth is subject to slow but continuous cycles of erosion and uplift that have gradually shaped Earth's surface. Given enough time, slow natural processes can account for extreme geological changes. Uniformitarianism inspired Darwin that species of plants and animals could possibly change slowly given enough time, and this would mean the Earth is very old. Darwin postulated that slow uniform processes explained the biological structures observed today.
Explain the real reason Darwin was on the Beagle
Darwin was on the Beagle because Captain Fitzroy was prone to hereditary mental derangement. On top of this, Captain Fitzroy knew the psychological toll that prolonged lack of human contact could take from captains since captains couldn't talk to anyone else on the boat, especially if they were of a lower social class. Naval voyages lasted many years with long stretches in between ports and very limited contact by mail with friends and family at home. Fitzroy needed the company someone of a higher social class since he was of a higher social class. Fitzroy wasn't allowed to bring on board private passengers like captains wives. A gentleman companion brought on or no other stated purpose would never do. The other supernumeraries he took wouldn't be fit for a companion since they were not of the right social class. Fitzroy advertised among his aristocratic friends for a gentleman naturalist. Darwin was of a higher social class. Darwin just happened to be an amateur naturalist too, which was great because Fitzroy wanted to beef up the Beagle's scientific mettle.
Differentiate between the fact, course, and mechanism of evolution
Evolution as a fact- No reliable observation has ever been found to contradict the general notion of common descent. It should come as no surprise that the scientific community at large has accepted evolutionary descent as a historical reality since Darwin's time and considers it among the most reliably established and fundamentally important facts in all of science. Mechanism of evolution- The mechanism by which species arise and change is evolution. The mechanism of evolution is natural selection. Course of evolution- During evolution, throughout evolution, for the duration of evolution
Explain and give examples of the following statements: a. Evolution does not always lead to more complex organisms
Evolution only leads to increases in complexity when complexity is beneficial to survival and reproduction. ***Simplicity has its perks: The more simple you are, the faster you can reproduce, and thus the more offspring you can have. Many bacteria live happy simple lives, producing billions of offspring, and continue to thrive. Another example of simple organisms are parasites that have kept only what they need to get inside and survive in their host, and are known for their loss of unnecessary traits and even whole organ systems. Natural selection can lead to greater simplicity. Explorations into caves absent of light reveal insects and other life forms that look very similar to those evolve ground, except they have lost their eyes since they live in perpetual darkness. Therefore, they became even simpler.
Describe what each scientist contributed toward the development of evolutionary theory c. Buffon
French naturalist Buffon speculated on the possibility of cosmic and organic evolution and was forced by the clergy to recant "I abandon everything in my book respecting the formation of the earth, and generally all of which may be contrary to the narrative of Moses." Buffon was one of many that concluded that the causes of natural phenomena should be sought in natural laws. Said the planets could be born by a collision between a comet and the sun, so they did not exist for a purpose. They merely came into being through impersonal physical forces. Buffon believed in uniformitarianism- the same causes that operate now have always operated. Came close to saying that living things themselves changed since the entire nonliving world is in constant turmoil. He realized that the earth had seen the extinction of countless species. He supposed that those that perished were the weaker ones. He even mused in 1766 that species might have developed from common ancestors (saying that the ass has varied from the original form, which is a horse, so we can also say that ape is a degenerate man of the family of man) Buffon thought he was wrong because of the sterility of hybrids between species, and there should be intermediate variations between species. He said we all participated equally in the grace of direct Creation.
Describe what each scientist contributed toward the development of evolutionary theory g. Lyell
His theory of uniformitarianism helped Darwin to understand that the Earth must be very old, and very slow changes like evolution could be possible in a very old Earth. However, Lyell did not believe in evolution. He was a devout Christian who believed in the philosophy of natural theology which states that the features of animals and plants were evidence of God's design. With his concept of steady change, there was no room for evolution. Lyell was such a thorough uniformitarian that he believed in a steady-state world, a world that was always in balance between forces such as erosion and mountain building, and so was forever the same. There was no room for evolution with its concept of steady change. Nonetheless, he had an enormous impact on evoltionary thought, through his influence on Charles Darwin.
Define and give examples of evolution
How organisms change over time. Evolutionary theory includes the theories of natural selection and descent with modification, stating that all living organisms have a common ancestor but each has become adapted to its environment by the process of natural selection. Proposes that species arise, change, and become extinct due to natural, not supernatural, forces. The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth. The idea that all species are related and gradually change over time. Examples- Darwin's finches. There are more than 10 different species of Darwin's finches, which are classified based on the shape of their beaks, where they live, and what they eat. The islands allowed isolated populations of birds to evolve independently, and present-day species resulted from accumulated changes occurring within each of these isolated populations over time. The finches differed in their beaks based on the different diets of the finches in their respective environments. Another example- Antibiotic resistance in bacteria such as MRSA methicillin resistant Staphylococcus aureus and Shigella sonnei. Before being exposed to antibiotics, some bacteria had variations that made them somewhat resistant to those antibiotics, but it was only after they were exposed to antibiotics that selection actually occurred. Only the cells that were resistant to the antibiotics survived. The final population of bacteria is comprised of individuals who are almost entirely resistant to those antibiotics.
List and describe how the following individuals influenced the development of Darwin's ideas on evolution b. Thomas Malthus
In Darwin's time, a socioeconomist named Thomas Malthus stressed the reproductive potential of humans. He proposed that death and famine are inevitable because the human population tends to increase faster than the supply of food and resources they depend on. When populations become too large, famine and disease break out. In the end, this keeps populations in check by killing off the weakest members. -Darwin applied this concept to all organisms and saw that the available resources were not sufficient to allow all members of a population to survive. He calculated the reproductive potential of elephants and concluded that, after only 750 years, the descendants of a single pair of elephants would number about 19 million! Obviously, no environment has the resources to support an elephant population of this magnitude. Because each generation has the same reproductive potential as the previous generation, there is a constant struggle for existence, and only certain members of a population survive and reproduce each generation. -Darwin concluded that favorable variations would be preserved, and unfavorable ones will be destroyed. Theory of natural selection.
b. Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. (pg 93) d. Thomas Hunt Morgan
In the next few decades, geneticists working with a great variety of organisms observed many other drastic changes arise by mutation: fruit flies (Drosophila) for example, with white instead of red eyes or curled instead of straight wings. These laboratory geneticists, especially Thomas Hunt Morgan, an outstanding geneticist at Columbia University, asserted that evolution must proceed by major mutational steps, and that mutation, not natural selection, was the cause of evolution. In their eyes, Darwin's theory was dead on two counts: evolution was not gradual, and it was not caused by natural selection.
Mechanism
In the science of biology, a mechanism is a system of casually interacting parts and processes that produce one or more effects. Scientists explain phenomena by describing mechanisms that could produce the phenomena. Example- Natural selection is the mechanism of evolutionary change. Natural selection is a mechanism by which adaptations might arise. Example- The mechanism by which species arise and change is called evolution.
Describe what is meant by inheritance of acquired characteristics and what it contributed to evolutionary thought as well as hindered
Inheritance of Acquired Characteristics- Lamarck believed that various specialized adaptations of species are consequences of the fact that animals must always change in response to the needs imposed on them by a continually changing environment. When the needs of a species change, so does its behavior. The animal then uses certain organs more frequently than before, and these organs, in turn, become more highly developed by such use. The classic example of Lamarckism is the giraffe: by straining upward for foliage, it was thought, the animal had acquired a longer neck, which was then inherited by its offspring. Lamarck contributed to Darwin because it helped Darwin to realize that the environment does play a role in shaping the species that live in it. However, it hindered the theory of evolution with the theory of acquired characteristics. Darwin realized that species are already born with variation, and the variations that are better suited to the environment are passed on. Lamarck was wrong that the use of an organ becomes more highly developed and then passes on to future generations.
List and describe how the following individuals influenced the development of Darwin's ideas on evolution c. J.B. de Lamarck
Jean Baptiste de Lamarck was a French naturalist/biologist who hypothesized that evolution occurs and that adaptation to the environment is the cause of diversity. Lamarck concluded that more complex organisms are descended from less complex organisms. He was on the of the first to propose that species change over time. However, he was wrong about the inheritance of acquired characteristics (that the use or disuse of a structure can bring about inherited change). -Darwin was inspired by Lamarck's acceptance of evolution and how species may be influenced by their environment to evolve. Darwin tweaked the inheritance of acquired characteristics to natural selection. *Darwin said that instead of characteristics becoming more refined through use which was passed onto offspring, organisms are already born with the different variations that don't change by need or use. The ones that have the most suitable variations for their environment are selected for. *He kept the idea of evolution but tweaked it saying we came from a common ancestor. -Darwin said that living organisms share characteristics because they have a common ancestry. In contrast to Lamarck, Darwin's observations led him to conclude that species are suited to the environment through no will of their own but by natural selection. He saw the process of natural selection as the means by which different species come about.
Describe and give examples of the two main components of Lamarck's ideas on evolution and how they contrasted with Darwin's
Lamarck's theory involved two ideas: 1) A characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used eventually disappears 2) Any feature of an organism that is improved through use is passed to its offspring Whereas Lamarck said that traits could develop and change during an animal's lifetime, Darwin believed that individuals were simply born with different traits (variation) and that these differences were mostly random. In contrast to Lamarck, Darwin concluded that species are suited to the environment through no will of their own but through natural selection. He saw the process of natural selection as the means by which different species come about. Darwin believed in the struggle to exist where those who were best suited to the environment survived and passed on their traits, whereas Lamarck believed that whatever structures are used and improved are passed onto offspring.
Explain and give examples of the following statements: b. Evolution has to work with what is available
Natural selection is a process, not a conscious force. Natural selection may not always result in a perfect solution. Selection can only act on the available genetic variation. A cheetah, for example, cannot evolve to run faster if there is no faster gene variant available. Secondly, the body has to work with the materials it already has. It can't make something out of nothing—that's why winged horses are the stuff of myth. Evolution also has to work with the developmental patterns established in distant ancestors, and the results sometimes seem very strange. For instance, you'd thin it'd make most sense for the nerve that goes from the voice box to the brain in a giraffe to take the most direct route—a length of around 10 centimeters. But because the giraffe's body plan was established in an ancestor that had no neck, the nerve goes all the way down the neck, around the heart and back again—a distance of four meters! Natural selection acts on existing heritable variation. Natural selection needs some starting material, and that starting material is heritable variation. For natural selection to at on a feature, there must already be variation, and that variation must be able to be passed on to offspring. Natural selection depends on the environment. Natural selection doesn't favor traits that are somehow inherently superior. Instead, it favors traits that are beneficial in a specific environment. Traits that are helpful in one environment might actually be harmful in another. Basically: -Natural selection acts on existing heritable variation -Natural selection depends on the environment -The body has to work with the materials it already has -Natural selection has to work with the developmental patterns established in distant ancient ancestors
Explain and give examples of the three radical features of the theory of natural selection that Gould argues are the reasons for its difficulty in being accepted by the general public (Darwin's Revolution in Thought Video) a. Naturalistic and purposelessness of natural selection
Natural selection is purposeless because it is only about organisms struggling for personal reproductive success. The fact that organisms are well designed and ecosystems are harmonious are side consequences of organisms struggling for reproductive success. Examples- Darwin got this from Adam Smith's economics. The bets way to get a well ordered economy is to let everyone struggle for personal profit and let the best ones win. Darwin made the same argument and transferred it to nature.
Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted.
Natural selection was not accepted because of its materialistic perspective that there is no purpose in life, and that there is no need for the supernatural to explain natural phenomena. Natural selection eventually became accepted in the 1940s. It was also not accepted because of the rise of genetics, where people like Hugo de Vries believed that new species arose in a single step by mutations, and where Thomas Hunt Morgan believed that evolution occurs by major mutation steps and that mutations, not natural election, was the cause of evolution. In their eyes, Darwin's theory was dead on two counts: Evolution was not gradual, and it was not caused by natural selection. Meanwhile, naturalists, taxonomists, and breeders of domesticated plants and animals continued to believe in Darwinism, because they saw that populations and species differed quantitatively and gradually rather than in bigs jumps, that most variation was continuous (like height in humans), rather than discrete, and domesticated species could be altered by artificial selection from continuous variation.
Define and give examples of uniformitarianism
People who were uniformitarianists -Based on the work of James Hutton -Made popular by Charles Lyell in the book Principles of Geology where he states that Earth is in a continuous cycle of erosion and uplift. Weathering --> erosion --> debris goes into rivers and ocean --> strata result --> strata (which contain fossils) are uplifted over periods of time from below sea level to form land. According to Lyell, these slow changes occur at a uniform rate. Although uniformitarianism has been rejected, modern geology certainly substantiates a hypothesis of slow and continual geological change. -Buffon agreed with it too States that the forces and processes observable at earth's surface are the same that have shaped earth's landscape throughout natural history. Slow, uniform processes change Earth's surface. Minor disasters. People began to think that perhaps, the Earth is very old. Uniformitarianism inspired Charles Darwin that species of plants and animals could possibly change very slowly given enough time, which means that the Earth must be very, very old. Examples of uniformitarianism- Rivers erode valleys and build deltas gradually, granite is formed by the cooling of lava, sea levels rise and fall, volcanoes may exist atop other rocks, mountains rising up and eroding away, valleys form by the erosional power of water. Anything that includes erosion or mountain building. More examples- Rain erodes mountains, molten rock pushes up to create new mountains, eroded sediments form into layers of rock which can later be lifted above sea level and eroded away again More examples- Wind erosion, water erosion, deposition of silt and mud by rivers and oceans can cause changes on Earth's surface
Explain, in general terms, what is meant by the phrase "Modern Synthesis" or "Neo Darwinism" *****
The Modern Synthesis describes the fusion of Mendelian genetics with Darwinian evolution that resulted in a unified theory of evolution. Sometimes referred to as the Neo-Darwinian theory. The Modern Synthesis was developed by a number of now-legendary evolutionary biologists in the 1930s and 1940s. Modern Synthesis- The merging of the fields of genetics, population genetics, and a lesser extent the field of paleontology, with Darwin's original ideas to form a complete picture of how evolution works. It is what present day biologists refer to when they discuss evolution.
Describe what each scientist contributed toward the development of evolutionary theory e. Lamarck
The first scientist to take the big step in believing in evolution. We are not sure what led Lamarck to his uncompromising belief in evolution; perhaps it was his studies of fossil molluscs, which he came to believe were the ancestors of similar species living today. Whatever the explanation, from 1800 onward, he developed the notion that fossils were not evidence of extinct species but of ones that had gradually been transformed into living species. To be sure, he wrote "an enormous time and wide variation in successive conditions must doubtless have been required to enable nature to bring the organization of animals to that degree of complexity and development in which we see it at its perfection; but time has no limits and can be drawn upon to any extent." -a. Lamarck studied the succession of life-forms in strata, and concluded that more complex organisms are descended from less complex organisms (pg 99) a. Lamarck believed that various lineages of animals and plants arose by a continual process of spontaneous generation from inanimate matter, and were transformed from very simple to more complex forms by an innate natural tendency toward complexity caused by "powers conferred by the supreme author of all thing." Various specialized adaptations of species are consequences of the fact that animals must always change in response to the needs imposed on them by a continually changing environment. When the needs of a species change, so does its behavior. The animal then uses certain organs more frequently than before, and these organs, in turn, become more highly developed by such use, or else "by virtue of the operations of their own inner senses." The classic example of Lamarckism is the giraffe: by straining upward for foliage, it was thought, the animal had acquired a longer neck, which was then inherited by its offspring. In the nineteenth century, it was widely believed that "acquired" characteristics—alterations brought about by use or disuse, or by the direct influence of the environment—could be inherited. Then it was perfectly reasonable for Lamarck to base his theory of evolutionary change partly on this idea. Indeed, Darwin also allowed for this possibility, and the inheritance of acquired characteristics was not finally proved impossible until the 1890s. Lamarcks ideas had a wide influence, but in the end did not convince many scientists of the reality of evolution. Cuvier rejected Lamarck's notion of spontaneous generation of life, found it inconceivable that changes in behavior could produce the exquisite adaptations that almost every species shows, and emphasized that in both the fossil record and among living animals there were numerous "gaps" rather than intermediate forms between species. · Example of Lamarck's idea of inheritance of acquired characteristics: To explain the process of adaptation to the environment, Lamarck proposed the idea of inheritance of acquired characteristics, in which the use or disuse of a structure can bring about inherited change. (For example, the long neck of giraffes developed over time because giraffes stretched their necks to reach food high in trees and then passed on a long neck to their offspring.) Lamarck thought that fossils are not evidence of extinct species, but of ones that had been gradually transformed into living species.
Define and give examples of catastrophism
The theory that changes in the earth's crust during geological history have resulted chiefly from sudden, violent, and unusual events. The doctrine that explains the differences in fossil forms encountered in successive stratigraphic levels as being the product of repeated cataclysmic occurrences and repeated new creations. A noted zoologist of the early nineteenth century, Georges Cuvier founded the science of paleontology, the study of fossils. Cuvier believed that the fixity of species (the idea that species do not change over time), yet Earth's strata clearly showed a succession of different life-forms over time. To explain these observations, he hypothesized that a local catastrophe had caused a mass extinction whenever a new stratum of that region showed a new mix of fossils. After each catastrophe, the region was repopulated by species from surrounding areas, which accounted for the appearance of new fossils in the new stratum. The result of all these catastrophes was change appearing over time. Some of Cuvier's followers, who came to be called catastrophists, even suggested that worldwide catastrophes had occurred and that, after each of these events, new sets of species had been created. Examples- meteorite impacts, super volcanoes, mega earthquakes, sudden mysterious violent mountain uplifting caused perhaps by contractions of earth as it cools, ice ages, mega floods that cover vast areas of lands.
Compare and contrast uniformitarianism and catastrophism
Uniformitarianism- Slow, steady, gradual changes is how the Earth's surface is shaped. Proposed that the earth was very old. Overturned catastrophism. Helped Darwin to realize that without an ancient Earth, there wasn't much time for evolution to occur. Processes and scientific laws operating today also operated in the past. Coincides well with evolution. Catastrophism- Fast, violent sudden events, catastrophic changes, is how the Earth's surface is shaped. Assumes that the earth is not very old (6,000-10,000 years) and fit comfortably with the prevailing religious beliefs. Coincides well with the fixity of species.
Explain and give examples of the three radical features of the theory of natural selection that Gould argues are the reasons for its difficulty in being accepted by the general public (Darwin's Revolution in Thought Video) b. Non-progressive nature of natural selection
We are not making progress. Natural selection only selects for those traits that are most suitable to the environment. What may be suitable in one environment may not be suitable in another. We are an accidental little twig on a huge branch of life. The hairy Russia in elephant isn't necessarily a better elephant, it is just adapting to a changing local environment.
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . c. Purpose
a. - Comes from the "final causes," which is Aristotle's idea. In post-medieval thought there was a final cause, or a purpose, for everything; but purpose implies intention, or foreknowledge, by an intellect. So the existence of the world and all the creatures in it had a purpose, and that purpose was God's design. The reasoning behind something. i. Basically, final causes hinders the acceptance of evolutionary thinking because evolution and natural selection are purposeless. The only thing that is happening is that organisms are striving for personal reproductive success. They are out for themselves. Not consciously. Natural selection is about the organisms that are most successful in reproductive that pass their genes to future generations. The excellence of design and the harmony of ecosystems are side consequences of natural selection. ii. (Pg 92) No longer was there any reason to look for final causes or goals. T the questions "What purpose does this species serve? Why did God make tapeworms?" the answer is "To no purpose." Tapeworms were not put here to serve a purpose, nor were planets, nor plants, nor people. They came into existence not by design by by the action of impersonal natural laws.
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . a. Scala naturae
a. Alexander Pope?? A concept derived from Plato, Aristotle (in his Historia Animalium), Plotinus and Proclus. Further developed during the Middle Ages, it reached full expression in early modern Neoplatonism. i. One of the most pervasive concepts in medieval and post-medieval thought was the "great chain of being" or scala naturae. Minerals, plants, and animals, according to this concept, formed a gradation, from the lowliest and more material to the most complex and spiritual, ending in man, who links the animal series to the world of intelligence and spirit. This "scale of nature" was the manifestation of God's infinite benevolence. In his goodness, he had conferred existence on all beings of which he could conceive, and so created a complete chain of being, in which there were no gaps. All his creatures must have been created at once, and none could ever cease to exist, for then the perfection of his divine plan would have been violated. Alexander Pope expressed the concept. These ideas were generally consistent with the Old Testament account of creation, which holds that God individually designed species and therefore they are perfect. 1. This hindered the acceptance of evolutionary thinking because evolution states that all life forms spring from a common stock. There is no "lower" or "higher" organism according to Darwin. Evolution is a tree that branches out. There is no progressionism in evolution.
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . e. fixity of species
a. Cuvier believed in the fixity of species (the idea that species do not change over time). Carous Linneaus believed in the fixity of species. The first idea came from Aristotle who believed in a static universe which held that living organisms were created initially and then remained essentially unchanged. Linneas began his career committed to the fixity of species, but began accepting evidence against such fixity apprx a century before Darwin's ideas were published. The idea that species is fixed in its physical form which it does not change (at least not enough to constitute a new species) and placed in its current habitat from which it does not move (at least not beyond significant geographic barriers such as mountain ranges or oceans). Nowadays, the idea of the fixity of species isn't even a blip on the radar. Now, we know that species are not fixed. There is fossil evidence, biogeographical evidence, anatomical evidence that species change through evolution. Today, there is even molecular evidence to back everything up.
Explain and give examples of the three radical features of the theory of natural selection that Gould argues are the reasons for its difficulty in being accepted by the general public (Darwin's Revolution in Thought Video) c. Materialistic nature of natural selection
a. Darwin was afraid of the radical philosophical implications of the principle of natural selection. Of his own take on evolution, his own theory about how evolution occurred, not on evolution itself. He was afraid to expose his belief in materialism, which contrasted the deep tradition of dualism. Dualism is where there is material stuff and then spirit stuff, where God who is the higher of the two forms. However, materialism claims that there is only matter and that all of those things we consider spirit and view with divineness and that are really just manifestations of properties of matter arranged in complex ways. i. For example, the mind is a material substrate of the neurology of the brain and that's a radical notion in the 19th century terms for which one could get in considerable trouble. Darwin said, is it really true that the love of God is really just a result of the way the neural substrate of the brain is organized?
b. Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. (pg 93) c. Hugo de Vries
a. Hugo de Vries- Mendel's work was ignored for thirty-five years, until, in 1900, three biologists discovered his paper and realized that it held the key to the mystery of heredity. One of the three, Hugo de Vries, set about to explore the problem as Mendel had, and in the course of his studies of evening primroses observed strikingly different variations arise, de novo. The new forms were so different that de Vries believed they represented new species, which had arisen in a single step by alteration, or as he called it, mutation, of the hereditary material.
Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. a. genetics and variation
a. Variation is produced through mutations and sexual reproduction. In Neo-Darwinian theory, variations can be slight or fairly pronounced, or very substantial, but are all inherited in the same manner (they are inherited as particles). Variations affect survival and reproduction: natural selection is a reality. i. Neo-Darwinism states that populations contain very extensive genetic variation that continually arise by mutation of pre-existing genes. ii. Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . d. need, use
a. need, use- Lamarck believed that various specialized adaptations of species are consequences of the fact that animals must always change in response to the needs imposed on them by a continually changing environment. When the needs of a species change, so does its behavior. The animal then uses certain organs more frequently than before, and these organs, in turn, become more highly developed by such use, or else "by virtue of the operations of their own inner senses." The classic example of Lamarckism is the giraffe: by straining upward for foliage, it was thought, the animal had acquired a longer neck, which was then inherited by its offspring. In the nineteenth century, it was widely believed that "acquired" characteristics—alterations brought about by the use or disuse, or by the direct influence of the environment—could be inherited. Thus it was perfectly reasonable for Lamarck to base his theory of evolutionary change partly on this idea. Indeed, Darwin also allowed for this possibility, and the inheritance of acquired characteristics was no finally proved impossible until the 1890s. i. Darwin stated that species are suited to the environment through no will of their own but by natural selection. He saw the process of natural selection as the means by which different species come about.
Describe the three major parts to natural selection as Darwin proposed
a. overreproduction of species- When living things produce more offspring than can survive, which leads to a struggle for survival. When an organism overproduces only the most adapted are able to survive. Darwin argued that all species overproduce, since they have more offspring than can realistically reach reproductive age, based on the resources available. b. competition for limited resources- Results in differential survival. Individuals with more favorable phenotypes are more likely to survive and produce offspring, thus passing traits to subsequent generations. c. survival of the few- Individuals possessing traits well suited for the struggle for local resources will contribute more offspring to the next generation. Survival of the form that will leave the most copies of itself in successive generaitons.
Describe what each scientist contributed toward the development of evolutionary theory h. Malthus
b. In Darwin's time, a socioeconomist named Thomas Malthus stressed the reproductive potential of humans. He proposed that death and famine are inevitable, because the human population tends to increase faster than the supply of food. Darwin applied this concept to all organisms and saw that the available resources were not sufficient to allow all members of the population to survive. He calculated the reproductive potential of elephants and concluded that, after only 750 years, the descendants of a single pair of elephants would number about 19 million! Obviously, no environment has the resources to support an elephant population of this magnitude. Because each generation has the same reproductive potential as the previous generation, there is a constant struggle for existence, and only certain members of a population survive and reproduce each generation.
Describe what each scientist contributed toward the development of evolutionary theory f. Darwin
i. (pg 91) Darwin said that it is extremely difficult to tell if natural populations are distinct species or merely well-marked varieties i. (pg 91) Even though some forms remain for long periods unaltered, successive evolutionary modifications will ultimately alter the different species so greatly that they will be classified as different genera, families, or orders i. Competition between species will impel them to become more different, for "the more diversified the descendants from any one species become in structure, constitution, and habits, by so much will they be better enabled to seize on many and widely diversified places in the polity of nature, and so be enabled to increase in numbers." "The ultimate result is that each creature tends to be more and more improved in relation to its conditions. This improvement inevitably leads to the greater advancement of the organization of the greater number of living beings throughout the world."
Describe the following concepts, who most notably used them, and explain how they hindered the acceptance of evolutionary thinking . f. perfection
i. Based on the idea of Aristotle's scala naturae that was consistent with the literal interpretation of the Bible where God had a perfect divine plan where he created a complete chain of being, in which there were no gaps. All his creatures must have been created at once, and none could ever cease to exist, for then the perfection of his divine plan would have been violated. ii. Darwin stated that probably no organism has reached a peak of perfection, and many lowly forms of life continue to exist, for "in some cases variations or individual differences of a favorable nature may never have arisen for natural selection to act on or accumulate. In no case, probably, has time sufficed for the utmost possible amount of development. In some few cases there has been what we must call retrogression of organization. But the main cause lies in the fact that under very simple conditions of life a high organization would be of no service..."
Describe why natural selection was not accepted even though common descent and evolution was accepted by naturalists. Also describe how natural selection eventually became accepted. b. blended (continuous) vs. unblended (discrete or particulate) inheritance question
i. Blended (continuous) inheritance 1. Naturalists, taxonomists, and breeders of domesticated plants and animals continued to believe in Darwinism because they saw that populations and species differed quantitatively and gradually rather than in big jumps, that most variation was continuous (like height in humans) rather than discrete, and that domesticated species could be altered by artificial selection from continuous variation. Continuous variation is the combined effect of many genes (polygenic inheritance) and are influenced by the environment. ii. Particulate Inheritance (unblended, discrete)- 1. Discrete variations were studied by the Mendelians. Discrete variations are controlled by a single gene (one copy inherited from each parent) tend to have phenotypes that fall into separate categories. They show discrete variation.
