Week 6.3 Development of Evolutionary Thought PDF

Development of Evolutionary Thought EULA FAITH MIRACLE V. ANDAM | General Biology 2  Introduction The discovery of evolutionary principles first took place in Western Europe and was made possible by advances in scientific thinking that dated back to the sixteenth century....

Development of Evolutionary Thought EULA FAITH MIRACLE V. ANDAM | General Biology 2  Introduction The discovery of evolutionary principles first took place in Western Europe and was made possible by advances in scientific thinking that dated back to the sixteenth century. Charles Darwin was the first person to explain the basic mechanics of the evolutionary process. But while he was developing his theory of natural selection, a Scottish naturalist named Alfred Russel Wallace independently reached the same conclusion.  Introduction Throughout the Middle Ages, one predominant feature of the European worldview was that all aspects of nature, including all forms of life and their relationships to one another, never changed. Consequently, it was generally accepted that all life on earth had been created by God exactly as it existed in the present, and the belief that lifeforms couldn’t change came to be known as fixity of species. Genesis 2:19 - And out of the ground the Lord God formed every beast of the field, and every fowl of the air; and brought them unto Adam to see what he would call them: and whatsoever Adam called every living creature, that was the name thereof.  Introduction The plan of the entire universe was viewed as God’s design. In what is called the “argument from design” or “teleological argument” anatomical structures were engineered to meet the purpose for which they were required. In fact, an Irish archbishop named James Ussher (1581–1656) analyzed the chapter of Genesis and concluded that the earth was created in 4004 B.C. Archbishop Ussher wasn’t the first person to suggest a recent origin of the earth, but he was the first to propose a precise date for it.  The Scientific Revolution For Europeans, the discovery of the New World and circumnavigation of the globe in the fifteenth century overturned some very basic ideas about the planet. For one thing, the earth could no longer be thought of as flat. Also, as Europeans began to explore the New World, their awareness of biological diversity was greatly expanded as they became aware of plants and animals they hadn’t seen before.  The Scientific Revolution In 1514, a Polish mathematician named Copernicus challenged the notion, proposed more than 1,800 years earlier by the Greek philosopher Aristotle, that the earth, circled by the sun, moon, and stars, was the center of the universe. Copernicus’ theory didn’t attract much attention at the time; however, in the early 1600s, it was restated by an Italian mathematician named Galileo Galilei.  The Scientific Revolution Throughout the 16th and 17th centuries, European scholars developed methods and theories that revolutionized scientific thought. Their technological advances, such as the invention of the telescope, permitted investigations of natural phenomena and opened up entire new worlds for discoveries such as never before had been imagined. But even with these advances, the idea that living forms could change over time simply didn’t occur to people. Precursors to the Theory of Evolution Jean-Baptiste Lamarck John Ray Georges Cuvier James Hutton Carolus Linnaeus Charles Darwin  John Ray - He was the first person to recognize that groups of plants and animals could be distinguished from other groups by their ability to mate with one another and produce offspring. - He placed such groups of reproductively isolated organisms into a single category, which he called the species.  John Ray - Ray also recognized that species frequently shared similarities with other species, and he grouped these together in a second level of classification he called the genus. Carolus Linnaeus - He developed a method of classifying plants and animals. - In his famous work, Systema Naturae (“The System of Nature”), first published in 1735, he standardized Ray’s use of genus and species terminology and established the system of binomial nomenclature.  Carolus Linnaeus - Although the system, now known as binomial nomenclature, was partially developed by the Bauhin brothers, Gaspard and Johann, Linnaeus was first to use it consistently throughout his book. - He also added two more categories: order and class.  Carolus Linnaeus - Another of Linnaeus’ innovations was to include humans in his classification of animals, placing them in the genus Homo and species sapiens. - Linnaeus also believed in fixity of species, although in later years, faced with mounting evidence to the contrary, he came to question it. Georges-Louis Leclerc, comte de Buffon - In his Natural History, first published in 1749, he repeatedly stressed the importance of change in the universe and in the changing nature of species. - Buffon’s recognition of the external environment as an agent of change in species was an important innovation; however, he rejected the idea that one species could give rise to another.  Erasmus Darwin - He publicly expressed his views that life had originated in the seas and that all species had descended from a common ancestor. Jean-Baptiste Lamarck - Lamarck, like Buffon, suggested a dynamic relationship between species and the environment such that if the external environment changed, an animal’s activity patterns would also change to accommodate the new circumstances. Jean-Baptiste Lamarck - According to Lamarck, these physical changes would occur in response to bodily “needs,” so that if a particular part of the body felt a certain need, fluids and forces would be directed to that point and the structure would be modified. Jean-Baptiste Lamarck Lamarck incorporated ideas into his theory of evolution: - Use and Disuse – Individuals lose characteristics they do not require or use and develop characteristics that are useful and can be passed on to next generations. - Inheritance of Acquired Characteristics – Individuals inherit the acquired traits of their ancestors.  Jean-Baptiste Lamarck - Moreover, he coined the term biology to refer to studies of living organisms.  Georges Cuvier - He was a French vertebrate paleontologist who introduced the concept of extinction to explain the disappearance of animals represented by fossils. - He insisted on the fixity of species. - So, rather than assume that similarities between certain fossil forms and living species indicated evolutionary relationships, he suggested a variation of a theory known as catastrophism.  Georges Cuvier - Catastrophism was the belief that the earth’s geological features are the results of sudden, worldwide cataclysmic events like the Noah’s flood.  Thomas Malthus - In 1798, he wrote An Essay on the Principle of Population, which inspired both Charles Darwin and Alfred Wallace in their separate discoveries of natural selection. - In his essay, Malthus argued for limits to human population growth and pointed out that human populations could double in size every 25 years if they weren’t kept in check by limited food supplies.  Thomas Malthus - Darwin and Wallace accepted Malthus’ proposition that population size increases exponentially while food supplies remain relatively constant, and they extended it to all organisms.  Thomas Malthus - But what impressed them the most was something Malthus hadn’t written about. They both recognized the important fact that when population size is limited by the availability of resources, there must be constant competition for food and water. And competition between individuals is the ultimate key to understanding natural selection.  James Hutton - He was a Scottish naturalist who believed that Earth's landscapes like mountains and oceans formed over long period of time through gradual processes. - In geology, gradualism is a theory developed by James Hutton according to which profound changes to the Earth, such as the Grand Canyon, are due to slow continuous processes and not to catastrophes as proposed by the theory of catastrophism. - Founder of Modern Geology  James Hutton - This theory inspired an evolution theory in paleontology, called gradualism, according to which the species appeared by the gradual transformation of ancestral species.  Charles Lyell - He was a Scottish geologist, supported the view of Hutton, and he was also Charles Darwin’s friend and mentor. - In his Principles of Geology, first published during the years 1830 –1833, he stated that the force and processes observable at earth’s surface are the same that have shaped earth’s landscape throughout natural history. - Uniformitarianism is the idea that the changes on the Earth occur in uniform ways leading to patterns that could possibly predict future changes.  Charles Darwin - The thought that species change had been suggested and debated well even before Charles Darwin, an English naturalist, began to explore the idea on evolution. He stated that evolution happens by natural selection (published on On the Origin of Species by Means of Natural Selection) which explains how genetic traits of a species may change over time.  Charles Darwin - Darwin coined the term fitness to refer to an organism’s relative ability to survive and produce fertile offspring. Nature selects the variations that are most useful. Therefore, he called this type of selection natural selection. Charles Darwin 37 Direction: Identify the people below and their contributions in the development of evolutionary thought. Choose your answer from the box. Charles Darwin Principles of geology Charles Lyell Principle of use and disuse Jean Baptiste de Lamarck Theory of Gradualism James Hutton The Origin of Species’ Thomas Malthus Essay on the Principle of Population