Evolutionary+Biologists

Claire Watson
 * Georges-Louis Leclerc, Comte de Buffon (1707-1788)**

> **Main theory**: Common ancestry between similar organisms > **Charles Darwin** was best known for his theory of natural selection, which states that organisms with favorable variations are more likely to survive and pass these variations onto offspring. For example, a rabbit that runs faster than others may be more likely to escape from predators, and algae that are more efficient at extracting energy from sunlight will grow faster. It is on this theory Darwin based his novel “The Origin of Species” which described many of the similarities he noticed between different species during his 5-year voyage on the HMS Beagle. Darwin’s theory was very controversial at the time it was published (1858) because for natural selection to take place the earth would have to be significantly older than the 6,000 years proposed by the Catholic Church. To this day Darwin’s theory is still disputed. However, the evidence for natural selection is overwhelming and when examining specific characteristics of populations (animals always replicate, there is always variation and varied traits are passed on) it would be absurd not to draw the same conclusion Darwin did. > > James Hutton
 * French naturalist, mathematician, biologist, cosmologist and author
 * Born into wealth and prestige; was educated in law and medicine, but real interest was nature.
 * Even though he lived 100 years before Darwin, he had the beginnings of some of his ideas.
 * //Histoire Naturelle (//1749-1788) consists of 36 volumes, 8 additional volumes which he wrote through out his life from 1749 unitl his death. (It has been translated into many different languages, which makes him the most widely read scientific author of the day.)
 * Considered the similarities between humans and apes, and the possibility of a common ancestry, which was very strange at that time.
 * Believed that the environment acted directly on organisms through what he called "organic particles".
 * Also had thoughts about the origins of the solar system, speculating that the planets had been created by comet s colliding with the sun.
 * Investigated and experimented with iron, concluding that the Earth is much older than what we have have learnt. The church suggested it is 6,000, where he calculated it to be much closer to 75,000.
 * Even though his thoughts contradicted his religion, he was not an atheist. The church condemned him. He was sent away and all his books were burned.
 * Spoke against the biblical story of Noah’s flood. His reason was from observation of different parts of animals that are not useful, which suggested to him that they have evolved, rather than having been spontaneously generated.
 * Introduced many concepts that were looked into further by people that came after him.
 * Scottish geologist
 * Believed the land was composed of many products from the seas/oceans
 * Believed that while the land was forming at the bottom of the ocean, it was inhabited with animals like the land today
 * One of the first to notice the land formation cycle and its two main steps; deposition and erosion
 * Believed that land was eroded by air and water and deposited as layers in the sea, heat from the Earth’s core then consolidated the sediment into many layers of new land
 * Believed in natural selection and that not all traits can be inherited
 * Believed various characteristics in all organisms are based on non heritable variations such as climate and soil

Alfred Russel Wallace (1823-1913) · Read Tomas Malthus’ Essay on the Principle of Population where he warns that a nation could easily double its population in a few decades, leading to famine and misery for all. · When Wallace read this, it occurred to him that animals and plants should also be experiencing the same population pressure. It should take very little time for the world to be knee-deep in beetles or earthworms. But the world is not overrun with them, or any other species, because they cannot reproduce to their full potential. Many die before they become adults, there are numerous environmental assaults, and their food supply, like that of a nation, is not infinite so they must compete for survival. In this struggle for existence, survival and reproduction it does not come down to pure chance. · Wallace realized that if an animal has some trait that helps it to withstand the elements or to breed more successfully, it may leave more offspring behind than others. On average, the trait will become more common in the following generation, and the generation after that. · Wallace spent 8 years in Malay Archipelago where he independently came to the conclusion on evolution by natural selection, although he proposed the idea together with Charles Darwin in 1858. · Natural selection can be best described as all species exhibiting inheritable variations that are selected through the struggle by individuals for survival in competition within their population. Individuals with more favourable traits produce more offspring that survive than others and pass along those favourable traits. Over many generations, this process results in a change in the inheritable traits of the population.

**Erasmus Darwin ** , the grandfather of Charles Darwin, believed that all life came from a single unifying source. He published his evolutionary thoughts through poetry in one of his books titled " //Zoonomia" // . It is considered his most important scientific work in which he anticipates the views of Jean-Baptiste Lamarck. In it he concludes that one and the same kind of living filament is and has been the cause of all organic life. He was also familiar with James Burnett’s evolutionary ideas and cited him in his 1803 work, “ //Temple of Nature // ”. James Burnett selectively bred horses and noticed that degenerative qualities can be inherited by successive generations, so by selective choice of mates, the next generation of creatures can improve. He offers the first glimpse of his theory of evolution in the footnote of his poem “The Loves of Plants”; “The Temple of Nature” is his final poem which centers around his own conception of evolution and it is considered his best poetic work . --NAN

Sir Charles Lyell by Hasha Hi, I am Charles Darwin; I was born in Scotland and am British. My father exposed me to nature when I was very young and since then I have had a keen interest in nature. I had two different houses located in two totally different geological and ecological areas, which lead me to further investigate the causes of differences in nature and geological areas. My theory is called //uniformitarianism// and it is based on the idea that the earth was shaped entirely by slow-moving forces still in operation today, acting over a very long period of time. This theory helped me to explain the former changes of the Earth's surface by reference to causes now in operation. For example, earthquakes are not catastrophic at all. Earthquakes are actually a buildup of many years worth of surface irregularities, as I have studied via the field of [|stratigraphy]. Another example is volcanoes, which are also understood by the destruction that they wrought but, they are actually caused by gradual “backed-up-building.” Basically, my theory is proven my statigraphy research.

Jean-Baptist Lamarck Famous for his "use and disuse" theory, Lamarck was appointed professor of the natural history of insects and worms by the National Museum in France in 1793. Lamarck knew nothing about the subject, so he was forced to teach himself in order to keep his position. Through his studies, he coined the word "invertebrates" and used to it rename his divison "invertebrate zoology". Along with learning about this new subject, Lamarck was also in charge of organizing the collection of invertebrates in the museum. Through this time, Lamarck made his discoveries on his evolution theories. In 1809, //Philosophie Zoologique,// was published. In this book, he revealed his own theories of evolution. Lamarck stated that an organism would evolve to become more complex and as these complex organisms formed a new generation of new, simple organisms are made in their place coming from non-living matter. This idea was called spontaneous generation. He also mentioned his idea of the inertance of aquired traits. This outlined that that organisms pass on certain physiological changes due to certain environmental conditions. One famous example would be the development of a giraffe's long neck. Since it was constantly reach upward to the leaves of the trees, the next generation of griaffes would have longer necks so that they can reach the leaves on the tree. Lamarck was also famous for his theory of use and disuse, which stated that as an organism used a certain organ more, that organ would evolve,while the discontinued use of an organ would cause the organ to eventually disappear. Lamarck was the first theorist to connect environmental changes to the evolution of organisms.

Stephen Jay Gould (1941 - 2002) Stephen Jay Gould was an evolutionary theorist who created an alternative theory to gradualism with Niles Elteridge. Gradualism contended that when a new species first evolved it appeared very similar to its originator species and only gradually becomes more distinct as natural selection acts upon the species. The problem with this theory was that many distinct species appeared without any intermediate fossils to prove their gradual transition. To explain the rate of evolution, Gould proposed the theory of **punctuated equilibrium** which stated that evolution was characterized by long periods of standstill and then disrupted by episodes of very fast development of new forms. In addition, he stated that the creation of a new species, speciation, does not occur in the mainstream population of an organism where changes wouldn’t occur because of the interbreeding among similar creatures. Rather, he stated that speciation occurs on the edge of a population where a small group can easily become separated geographically thus making intermediate fossils very rare. -Tiana

George Cuvier’s Theory of Evolution: Nura Mazloom  Cuvier, a French scientist (1769 – 1832) was the creator of the concept of extinction and catastrophism and founded the field of vertebrae Paleontology. He developed his paleontological studies through the study of specimens found at various levels of strata of rock. From his observations of the changes in the species he found Cuvier theorized that species that no longer exist were wiped out by major natural disasters. He called this theory catastrophism. Despite his religious views, he did believe that all species were not created and placed on earth at once, rather that new species came to be when others became extinct. He also determined a relationship between the position of a fossil’s position in the soil and its relationship to the creatures that exist at the time. He noticed that the lower the layer of rock that the fossil was found, the less complex the organism. He also noticed that the higher the fossil, the more similar it is to the creatures that exist on earth.Cuvier did not believe in the gradual development of species like many other evolutionists. His most popular dissertation about his evolutionary beliefs is entitled “Discourse on the Revolutions of the Surface of the Earth”. From his studies of mummified cats and ibises and observing their stark similarity to their living counterparts, along with other such studies, he concluded that species don’t chane over time and that any change would cause them to die. He also thought that any similarities between creatures were due to common functions and not common ancestry.

Niles Eldredge · paleontologist and evolutionary biologist with the American Museum of Natural History · proposed the theory of punctuated equilibrium with Stephen Jay Gould · studied the evolution of mid-Paleozoic · the theory of punctuated equilibrium specifically states that… o species evolve very rapidly in evolutionary time o after the initial burst of evolution, species do not change significantly over long periods of time o speciation usually occurs in small isolated populations and therefore, intermediate fossils are very rare · this theory provides a better fit between evolutionary theory and fossil records than the gradualism evolutionary theory

//Tania-Marie Robyn//
 * Henry F Osborn (August 8, 1857–November 6, 1935)**
 * eungenisist
 * paleontologist
 * geologist
 * named the Orintholestes, Tyrannosaurus rex, Pentaceratop, Velociraptor
 * studied under Cope
 * belived in eugenics and orthogenesis
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif;">eugenics: selective breeding, breeding out of a trait
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif;">othogenesis: life has an innate tendency to move in a unilinear fashion due to some internal or external "driving force"

Thomas Malthus Born Feb 13, 1766, and died Dec 23, 1834. He was best known for his work with population dynamics. He wrote "An Essay on the Principles of Population", a series of essays which contained his ideas about the way populations worked. He created the exponential population growth model, the malthusian growth model, which states that (P(t) = Pnaughte^rt). It is one of the models to describe the way populations grow without hindrance. He also thought that population increases in a geometric ratio (2, 4, 8, 16...), while agriculture increases in a arithmetic ratio (1, 2, 3, 4, 5...). He thought that the population, if unchecked, would continue to grow and grow because passion between the sexes is an inevitable phenomenon. Because it continues to grow exponentially, the food supply would go, leading to more deaths. Disease, food shortages, and death from starvation are nature's ways to control populations. His essay on the principle of population eventually let Darwin and Wallace to independently come up with the theory of evolution. =<span style="display: block; font-family: Arial,Helvetica,sans-serif;">Richard Dawkins = Dawkins is best known for his popularisation of the gene-centred, renewed relic, view of evolution. In his role as an evolutionary biologist, interested in animal behaviour and its relation to natural selection, he advocates the idea that the gene is the principal unit of selection in evolution. Dawkins coined the word //meme// (the cultural equivalent of a gene) to describe how Darwinian principles might be extended to explain the spread of ideas and cultural phenomena. Dawkins' memes refer to any cultural entity that an observer might consider a replicator. He hypothesised that people could view many cultural entities as capable of such replication, generally through exposure to humans, who have evolved as efficient (although not perfect) copiers of information and behaviour. Memes are not always copied perfectly, and might indeed become refined, combined or otherwise modified with other ideas, resulting in new memes, which may themselves prove more, or less, efficient replicators than their predecessors, thus providing a framework for a hypothesis of cultural evolution. He also believes in a concestor, a universal common ansestor that everything has originated from that originally carried the DNA that we see it all plants and animas today.

**AUGUST WEISMANN**

German evolutionary biologist, Friedrich Leopold August Weismann, strongly supported Darwin and Wallace’s theory of evolution by natural selection. But, there was one thing he certainly did not agree on with Darwin’s theory, and that was his acceptance of the Lamarckian view of the inheritance of acquired characteristics, or “use and disuse”. To prove Darwin wrong, Weismann created his own experiment where he worked with mice. In 1883, Weismann cut off the tails of mice from twenty-one generations. He observed that twenty-second generation still had tails, and so concluded that the evidence contradicted Darwin’s theory of “disuse” and that despite obvious reasons for change in the mice, “continuity” was observed, not new variations. This experiment with mice helped him prove that hereditary information moves only from genes to body cells and never in reverse. Along with playing with mice, Weismann also discovered the germ plasm theory. He thought that multicellular organisms consist of germ cells that contain and transmit heritable information, and somatic cells which carry out ordinary bodily functions. Inheritance in a multicellular organism only takes place in the germ cells: the gametes, such as egg and sperm. Other cells of the body do not function as agents of heredity. Germ cells produce somatic cells, and more germ cells; the germ cells are not affected by anything the somatic cells learn or any ability the body acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation.