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York University
BIOL 3200
Jan Sapp

BIOL3200: GENESIS NOTES CHAPTER 1 Evolutionary Theory: the natural world is steadily changing; organisms have diverged from common ancestors and have been transformed over geological time Two World Views  Archbishop James Usher (17 c): calculated the origin of creation to year 4004 BC  Georges Louis Leclerc, Comte de Buffon: French naturalist who estimated that the earth was about 75,000 years old, and that plants/animals around ~37,000 years ago  Scientists Today o Universe is 10-20 billion years old, Earth is ~4.5 billion years old o Life on Earth arose ~3.5 billion years ago; hominids resembling our species arose ~4 millions years ago; Homo sapiens arose ~130,000 years ago  Traditional natural theology held the world to be static  god had formed all species just as they appear today, with no genealogical relationships between them  Ancient Greek philosophers: there were great cataclysms (e.g. Biblical flood), but Noah had saved all the species that live today  Aristotelian and Platonic view: life-forms were ordered in single-file, from the most simple inanimate objects, to plants, to animals  fixed plan of creation o Known as Scala Naturae – “Great Chain of Being”  Its increasing perfection was understood in terms of different kinds of ‘soul’  more reason, and a greater advance toward god  In contrast to scala naturae, evolutionary theory holds that all life is related and genealogical relations don’t resemble a chain/ladder, but a tree  Teleology: view that organisms and their natural relations can only be explained by purpose and intelligent design o Judeo-Christian theology puts humans above nature  created in image of god  Darwinian Evolutionary Theory: there’s no design/preconceived plan in the natural world, and organisms evolve in a makeshift way contingent on ecological conditions o Nothing is necessary or purposeful  different conditions, different world o Put humans in nature as members of the animal kingdom  Jean-Baptiste Lamarck: most prominent pre-Darwin evolutionist o Coined the term ‘biology’ for the study of the manifestation of life, and the conditions in which it occurs Revolution to Evolution  Before the Revolution, French society was a static hierarchy from birth  Structure disturbed by uprising of peasants, artisans and the middle class until Napoleon Bonaparte seized control and became emperor of France  end of rev. o After the revolution, people started believing in equality, freedom to emigrate  Word ‘evolution’ first used by Robert Grant  During Reign of Terror, the Jardin du Roi (where Lamarck was a botanist), was reorganized into a museum, where he was given a job as a zoologist o He worked in classification of invertebrates, and coined the term ‘invertebrate’  Led him to explore questions about causes of life processes/evolution  3 convergent interests that led Lamarck to evolution: o Thinking on what constituted the essence of life in simplest organisms (caloric heat and electricity) o His view of the ‘natural’ way to arrange taxa o His geological thinking (i.e. gradual change over long periods of time)  Believed the earth is incalculably old  unique view for the time period Lamarckian Myths  Myths about Lamarck o ‘Romantic genius’ ignored by his contemporaries but later rediscovered o Someone who failed to tackle adaptation/origin of species before Darwin o Lamarck based his evolution theory on inheritance of acquired characteristics o Darwin opposed the inheritance acquired characteristics  he believed in it!  He is remembered by biologists as having originated a mechanism of evolution that differed from Darwin’s  based on inheritance of acquired characteristics o Found to not occur, but it’s wrong to attribute this view to Lamarck because:  He didn’t think of it  can be traced back to Hippocratic writers  Before him, Erasmus Darwin used it as the basis for his theory  He is ridiculed for the idea, but Darwin also held the idea of inheritance of acquired characteristics (many evolutionists of the time did)  Inheritance of acquired characteristics is only one part of his theory  He thought the environment brought about heritable changes in many different ways  Ridicule of him was often said to be due to the unclear ways he expressed his ideas o Often seemed that he believed evolution was based on the desire of the animal, but what he actually meant was that the animal’s habits impacted evolution Simple to Complex  Lamarck arranged life-forms by ordering the great classes of life in a linear, graded series moving toward “perfection”  i.e. simple to complex (like scala naturae) o Lamarck’s scientific style was speculation, focusing on big systems  He said that branching/deviation from the linear order were due to the influence of certain environmental circumstances o Inheritance of acquired characteristics would account for the characters of organisms that distinguished genera and species, as well as their instincts/habits o General trend of evolution towards increasing complexity was due to an unknown inner force in nature which he called the “power of life”  Naturalists who believed in the fixity of a species believed that the structure of an animal is perfectly fit for their functions, structure of a part determines its function o Lamarck believed that new functions/habits brought about by needs led to changed structures and irregularities in the line from simple to complex  George Louis Buffon: studied living organisms and their characteristics in life; also adopted a theory of evolution according to which a few original types of animals developed, and evolved into the animals we see today via hybridization and environmental influences (Linneaus had similar view  did binary classification)  Lamarck’s theory was not well-supported by the fossil record  often whole species seemed to appear suddenly, which goes against Lamarck’s gradual evolution theory o The progressive, unified order of things he proposed was debunked by this Disconnecting the Unity of Life  Georges Cuvier: a professor of natural history at College de France, who also worked in comparative anatomy at the museum with Lamarck  main antagonist o Famous for being able to identify many characteristics about an animal just by looking at its tooth  Cuvier built a rival system based on a new approach to comparative anatomy  Cuvier was a fixist  view that species alive today are identical to ancient ones o Lamarck denied species extinction; Cuvier believed in several mass extinctions  On top of Lamarck’s reputation, Cuvier had a reputation of solid methodology and observation, and was very similar to and well-regarded by Napoleon  Cuvier claimed there are 4 distinct, unrelated divisions of animals: vertebrates, mollusks, articulates (annelids/arthropods), and radiates (starfish, coral, jellyfish) o Divisions determined by the animals’ internal anatomy, which Cuvier believed had been designed by the Creator to suit the animals’ certain functional needs  Cuvier believed that the history of life on early was marked by major catastrophes and mass extinctions  last one was the biblical flood o Implied breaks in geological time and in life on earth  he saw no connection between early animals and animals today o When catastrophe wiped out animals in a certain area, animals from other species would migrate in and invade that area  next disaster fossilizes them there  animals don’t evolve, preexisting species from other areas move in  Accounts for changes in fossil record in different regions and strata  Flaw: if there was many catastrophes, species number would have declined, not increased  some of Cuvier followers developed a solution: o There was not just one divine creation  there’s one after each catastrophe  Lamarck eventually realized his linear model didn’t reflect nature  Some scholars have claimed that Cuvier’s ideas were progressive, and that Lamarck’s ideas were looking to the past, basically copying the Great Chain of Being The Cuvier-Geoffroy Debate  Etienne Geoffroy: professor of zoology who was a famous antagonist of Cuvier o Was a follower of Lamarck  Evolution was position in opposition to the privileges of nobility and the church, and against the conservative and new professional social control of science in France  Their debate centered on two opposing approaches to comparative anatomy o Cuvier: functionalist, thought that every part of an animal was designed by a creator to contribute to the animal’s functional integrity  Function dictates structure o Geoffroy: believed that structure dictates function  Developed transcendental/philosophical anatomy, which centered on the concept that all animals had a structural plan to suit their functions  Structural plan precedes any modifications/adaptations (e.g. all vertebrates have the same basic structural plan, and are all modifications of the same being, called “the vertebrate animal”)  Geoffroy’s structuralism became the basis for determining homologous structures  Homology: traits evolving from common ancestry  Analogy: same trait but not evolved from common ancestry  People viewed Geoffroy as a philosopher/thinker, and Cuvier as a political elitist CHAPTER 2 The Origin  Darwin created his theory by proposing that that evolutionary change occurred by a struggle for existence/survival, giving rise to a natural selection of the most fit  He investigated many aspects of nature  contrast to science today (study 1 thing)  Development of his new concepts relied on studying the geographical distribution of species, and studying the ecological processes involved in the formation of species  Alfred Wallace: developed theory of natural selection independent from Darwin  Vestiges of the Natural History of Creation: most important pre-Darwinian evolution book  written by Robert Chambers, but published anonymously o Claimed evolution is a matter in which new species and the ascent of life were planned linear developments, controlled by natural law, and dictated by god o Was popular among lay readers but caused outrage among elite o Important because it helped accustom readers to think about evolution Darwin’s Bible  Darwin went aboard the HMS Beagle which is where he began his travels and work  Gained his geological knowledge – relationship between extant and extinct species – from Charles Lyell’s book Principles of Geology  Darwin was influenced by Lyell’s radical view that geological changes occurred gradually over a vast amount of time  no cataclysms, just changes brought about by factors similar in nature/intensity to those operating today (uniformitarianism) o Postulated that the early was billions of years old o Influenced Darwin because if the same processes the shaped the earth are still occurring, then they can be studied o Lyell’s theory does not necessarily imply evolution  pertains more to fossils  Became clear that fossil record progressed from simple to complex organisms o Some saw this as proof of creationism (i.e. first plants  eventually man) o Simplecomplex pattern of fossil record can be/was interpreted in many ways o Geothermal Theory: earth originated as an incandescent blob and subsequent history was a gradual cooling process accompanied by other physical changes (e.g. climate, atmospheric conditions, land/sea distribution)  Flora/fauna of each geological period designed by god to fit in well  Lyell opposed species transmutation and criticized Lamarck  proposed that new species were created to replace extinct ones, but didn’t provide a mechanism o Only accepted evolution after Darwin convinced him (on condition that it doesn’t apply to man) The Beagle Voyage  3 major observations that led Darwin to shift from believing fixity to evolution: o Relationships between living animals, and fossils of recently extinct animals in the same general location  Darwin thought that fossils were related to living organisms in the same area, not to fossils from the same time as them but in a different area o Species manifested subtle differences as they migrated from 1 place to another  Believed animals of different climatic zones in same area were related to each other  not animals from same climate but different area o Animals/plants on Galapagos islands resembled those of the nearest coast of S. America  Galapagos birds only existed there, but had a lot of similarities to S. America birds implying a common ancestor (i.e. differences leading to a separation of species developed from becoming geographically isolated) Natural Selection and Natural Theology  Waited to publish his arguments about evolution for more than 2 decades  He and Lyell both wrote about ‘struggle for existence’, but Lyell believed that although there are deviations from species (variation) that are passed down generations, these deviations are not endless  species are fixed  Edward Blyth: wrote about ‘struggle for existence’, but believed that all species were perfectly adapted by god to suit their environment and the struggle would weed out the sickle/ill-adapted ones o Conservative principle for maintaining, not changing, species  Thomas Malthus: argued that there would always be poverty, hunger and war in the world because there was a permanent imbalance between nature’s supply of food, an the human need for food and sex o Claimed that if unconstrained, human populations would grow exponentially, while food supply would grow only arithmetically o Malthus’ work highlighted the intensity of the struggle  constant selection  Patrick Matthews: fruit farmer who also wrote a theory of natural selection Wallace’s Manuscript  As Darwin as preparing to publish his theories, he received a manuscript from Wallace with basically his same theory  Wallace asked him to send it to Lyell if he thought it was a good theory  It’s not right to consider Wallace the unsung hero of evolutionary biology, because Darwin had developed the idea of natural selection years before Wallace, used way more data, etc  everything in Wallace’s sketch was way more detailed in Darwin’s Concepts in The Origin Common Descent  Argued that all species descended within their own groups, classes, families, etc, from common parents, and have all been modified in the course of descent o All true classification is genealogical  Inferred that all organic beings which have ever lived on the earth descended from one primordial form Divergence  Argued that emergence of a new variety in a species enables it to better exploit the resources of its environment  leads to specialization  An area can support more life if occupied by diverse organisms partitioning resources, than if occupied by similar organisms all requiring the same resources  Divergence into specialized niches is adaptive because it reduces competition  Divergence into niches creates taxa within taxa, etc  generates a branching genealogy, not a linear chain Gradualism  Argued that evolution was a process of continuous, gradual growth o Believed the clear-cut distinctions naturalists saw were just illusions resulting from the extinction of intermediate forms  Natural selection occurs by the accumulation of small, inherited modifications o Same forces that gradually shaped the earth  no need for supernatural forces o Natura non facit saltum  gradual change, no sudden jolts Natural Selection  Darwin’s focus on species as dynamic populations rather than types, was the most radical concept he introduced to biological thinking o Typological thinking: view that species are fixed things created by god  you can have variation within a species, but not enough to transcend the species  Rejected the idea that there were fundamental/important traits that never change within a species/certain traits that define a species  rejected essentialism o Adopted population thinking  radically new way of understanding species  Eidos: idea, type, or essence  concept in philosophy since Plato (idealism) o When applied to nature, it means species are real  natural ‘types’ exist, around which individual variation occurs  Darwin was a nominalist  rejected notion of ‘species’ and believed individual differences are real  Evolution for Darwin is a 2-step process resulting from chance and necessity: preservation of favourable variations, and rejection of injurious variations  In contrast to Lamarck (use/disuse  variation), Darwin believed almost all variation occurred randomly but that Lamarck’s theory might be true too in some cases o Darwin looked to the artificial selection used by breeders as a model of this  Heritable mutations appear occasionally, and random, and are selected purposely The Struggle for Existence  Darwin linked evolution and diversity to excessive reproduction, combined with ecological ‘checks’ on population growth (i.e. constraints) o Variation provides the fuel for evolution o Over-reproduction creates a struggle/competition  motor for selection  Linnaeus had calculated that if there were only one plant that produced 2 seeds a year, in 20 years, there would be ore than a million plants o Darwin made the same calculation for slow-breeding elephants  procreates at 30, lives to 100, has 6 offspring  15 million in 500 years o Need checks on population growth in form of competition for resources, as well as form of predation  Some species favoured at the expense of others, new varieties win if their reproduction is favoured  Competition is most severe between closely related individuals, as they share the same needs for resources  selection favours divergence Human Races Have No Biological Reality  There is no race type, and there are no genetically distinct populations of humans that define a race  WHY? o Race is a social reality but has no meaning biologically o 99.9% of human genes are common in all humans o 85% of genetic diversity exists within a racial group, only 8% of diversity exists within subgroups of any racial groups, and only 7% of genetic diversity distinguishes any one race from another  Result of cross-breeding ever since humans migrated out of Africa CHAPTER 3 Man’s Place in Nature  Evolution appealed a lot to non-scientists but Darwin also managed to convince the academic elite at Oxford and Cambridge  hard to do  Darwinists positioned their arguments against supernaturalism and against Judeo- Christian theology  T.H. Huxley: one of the 3 people Darwin sent his manuscript before publication o Had only two years of formal education  mostly self-taught  Became assistant surgeon on HMS Rattlesnake to chart seas  Studied marine invertebrates there  became prof of natural history o Huxley lineage was very famous/successful (e.g. Leonard – scholar/biographer; Julian – Evolutionary synthesis; Andrew – nobel prize) o Supported Darwin’s proposition/mechanism for production of species o Huxley was a polemicist (skilled in debate, very confrontational)  Darwin didn’t like confrontation o Ensured Origin did well in the media  wrote good reviews of it o Was critical of the idea that natural selection acting gradually on slight variations was the sole mechanism of evolution (gradualism)  Thought evolution might move faster at times – e.g. rapid jumps o Wrote Man’s Place in Nature  overview of what was known about primate and human paleontology and ethnology  First attempt to apply evolution explicitly to humans  Darwin originally didn’t really apply his theories to humans  later wrote a book about it but by then Huxley already had a lot of evidence for human evolution, links to apelike ancestors, etc Natural Theology and Agnosticism  Huxley is remembered today as “Darwin’s bulldog”  Wrote about theology/philosophy from an agnostic point of view (coined the term) o “Agnostic”  “suggestively antithetic to the Gnostic” of the Church o Way to approach knowledge  follow reason no matter where it leads, not to pretend to know things with certainty that have not been demonstrated or are not demonstrable  Natural selection introduced contingency in nature  displaced god from the explanation of adaptation, but did not necessarily displace a first cause  Darwin often said there might be an intelligent first cause, but he thought this to be beyond the intellectual reach of man  Huxley and Bishop Samuel Wilberforce o Wilberforce was known as ‘soapy Sam’ because he was a great arguer o Him and Huxley had a huge debate and Wilberforce made a rhetorical error  Asked Huxley whether it was from his mother’s side or his father’s side that he had descended from an ape Archetype and Idealism  Richard Owen: had argued with Huxley about his statement that human and ape brains are very similar o Became famous as “British Cuvier” because of his knowledge of anatomy (i.e. could identify animals from bone fragments  Coined the word dinosaur – terrible lizard; discovered/named gorillas o Later in his career, his views/theories were very different from Cuvier’s:  Heavily influenced by idealist through and was driven to find the unity of nature and rationality of nature’s plane – Transcendental Anatomist  Wrote about a principle of transcendental unity existing at a deeper level of reality than the physical  Led him to formulate concepts of homology and analogy o Homology: same organ in 2 animals  same purpose o Analogy: different organs in 2 animals  same purpose  Argued there must be some kind of archetype of vertebrates o Was often portrayed as an antievolutionist  really wanted to find a middle- ground between theology and evolution  Thought while each species had its origin in natural causes, the course st of evolution was directed by predetermined law (i.e. creator/1 cause) o Owen claimed that humans were vastly different from apes (no common ancestor) because only humans had a posterior lobe, posterior horn, and hippocampus minor, which he claimed was absent in apes  Was proven wrong  apes also have hippocampus minor Ontogeny and Phylogeny  Ernst Haeckel: one of the most prominent theoreticians of 19 c. biology o Coined terms ‘ecology’, ‘phylum’, ‘ontology’ and ‘phylogeny’ o Darwin didn’t say much about microbes and the origin of life  seemed to think human origins and human history and psychology to be much more important  Haekel thought Darwin didn’t take the origin of life seriously  Monera would bridge the gap between life and non-life  would lack hereditary material chromosomes of other cells o Argued with philosophers’ ideas that purpose in animals was given by god  Used vestigial features (e.g. human ear movement muscles) to argue o Also studied comparative embryology as evidence for evolution  Demonstrated that during the development of the embryo, key steps in evolution are repeated  “ontogeny recapitulates phylogeny”  This idea can be traced back Aristotle and ancient Greeks  Idea became known as the Meckel-Serres Law o Parallelism  Naturphilosophen believed that development of a higher animal
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