Anthropology Mini Essays

Lecture 2: The Development of Evolutionary Theory — Before Darwin Today’s Questions • What is the theory of evolution? • What is a theory? • What ideas laid the intellectual and scientific foundation for the development of evolutionary theory? The Theory of Evolution • Evolutionary theory is a broad, explanatory framework that makes sense of observable facts about the biological world. It explains: – The diversity of life, – The geographical distribution of species, and – How species change over time in response to changing environmental conditions. What is a theory? • A theory is an explanatory framework used to unify many strains of evidence into one cohesive model for explaining an observable , natural phenomenon. A theory is a statement of scientific relationships verified through hypothesis testing. What is a theory? • Theories are not absolute truths since they can be disproved in light of new evidence. – Ex : The shift from a geocentric to a heliocentric solar system. • Theories are not facts, they are tested explanations of facts . Theories make sense of facts . Atomic Theory • Dalton’s Five Postulates 1. All elements consist of minuscule particles called atoms. 2. All atoms of a given element have are identical to each other. 3. All atoms of a given element are different than those of other elements. 4. Atoms of one element combine with other elements to create compounds. They always combine in equal amounts. 5. Atoms cannot be created, divided, nor destroyed. http://www.wisegeek.org/what -is-atomic -theory.htm#slideshow Einstein’s Theory of General Relativity • All movement is relative to other objects. • It is impossible to tell the difference between gravity and inertial force. • Large objects cause outer space to bend in the same way a marble laid onto a large thin sheet of rubber would cause the rubber to bend. http://static.bbc.co.uk/universe/img/ic/640/questions_and_ideas/general_relativity/general_ relativity_large.jpg Theories can change. • Both of these theories are largely accurate explanations of natural phenomena , although they have undergone revisions as we have learned more. – Nuclear physics has demonstrated that Dalton’s 2nd postulate is inaccurate • Isotopes of the same element can have different numbers of neutrons – And the second part of #4 has been revised , as has #5 since nuclear reactions can divide atoms . • New discoveries in quantum physics bring up some challenges to Einstein’s theory that have yet to be resolved. • Darwin’s Theory of Evolution by Natural Selection has as much, if not more, direct evidence supporting it than either of these theories and is one of the most tested and best supported scientific theories. Old Non - Western Ideas about Evolution • Chuang -Tzu ( Zhuangzi ) – 4th Century BCE China – Daoist Philosopher – Ideas about nature included possibility of change and transformation of species. – Species natural aptitudes or abilities arise in response to different environments . http://www.davidhinton.net/Images/Chuang%20Tzu044.jpg Old Non - Western Ideas About Evolution • Al -Jahiz – 9th Century C.E. – Abbasid Caliphate – Book on Animals : • "Animals engage in a struggle for existence; for resources , to avoid being eaten and to breed . Environmental factors influence organisms to develop new characteristics to ensure survival, thus transforming into new species . Animals that survive to breed can pass on their successful characteristics to offspring .“ http://sio.midco.net/dansmapstamps/alidrisi.jpg Old Western Ideas about Evolution • Aristotle — 4 th century BCE Greek Philosopher – “the theory that living things were divinely created and exist in an infinite and continuous series of forms, each one grading into the next, from simple to complex. This view goes back to the ancient Greeks and was popular from the Middle Ages through the 18th century in Europe .” (BAT Glossary) http://palaeos.com/systematics/greatchainofbeing/images/Ladder_of_Life.jpg Scala Naturae or “Great Chain of Being” Old Western Ideas about Evolution • Aristotle argued for fixity of species – Everything that exists has always existed and in the same form and does not change over time https://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Aristotle_Altemps_Inv8575.jpg/220px -Aristotle_Altemps_Inv8575.jpg Medieval Period Book of Kells , c. 800CE http://kwenivarga.files.wordpress.com/2009/11/book -of-kells2.jpg • ~5 th century – 15 th century CE – During this time period, the dominant perspective on life was derived from combining ancient Greek thought (mostly Aristotle) with Biblical interpretations (creation by the Christian God) Along Comes the Renaissance • Age of Exploration – Europe (re)discovers biodiversity around the world – Copernicus and the Heliocentric Solar System – Leonardo Da Vinci • Human Anatomy The Development of the Scientific Worldview • By the 17th century – Fixity of Species still dominant BUT… – New ideas and discoveries based on observation of the natural world that built on the Enlightenment were beginning to emerge – These ideas laid the foundation for Darwin’s Theory of Evolution by Natural Selection Enlightenment http://antwrp.gsfc.nasa.gov/apod/image/0110/gal ileo_sustermans.jpg http://www.biografiasyvidas.com/biografi a/k/fotos/kepler.jpg http://www.newton.cam.ac.uk/newton.jpg http://upload.wikimedia.org/wikipedia/co mmons/archive/6/65/20051021211809!F rancis_Bacon.jpg Galileo Kepler Newton Bacon Some ideas from the Enlightenment • Sir Francis Bacon (1561 -1626) — Empiricism, credited with the scientific method in the West • Galileo (1564 -1642) — Telescope • Johannes Kepler (1571 -1630) — Laws of Planetary Motion • Sir Isaac Newton (1643 -1727) — Laws of Motion, Calculus Systematics /Taxonomy • John Ray – 17th century minister – Biological Species Concept • reproductive isolation • species are groups of organisms that can only reproduce with each other http://www.ucmp.berkeley.edu/history/images/ra y.gif Ray’s Definition of Species • ... no surer criterion for determining species has occurred to me than the distinguishing features that perpetuate themselves in propagation from seed. Thus, no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species... Animals likewise that differ specifically preserve their distinct species permanently; one species never springs from the seed of another nor vice versa. – History of Plants (1686) Systematics /Taxonomy • Carolus Linneaus – 18th Century Swedish Naturalist – Binomial nomenclature • Genus + species • Genus — groups of similar organisms – Taxonomy — the branch of science concerned with classifying organisms http://www.linnean.org/fileadmin/images/Merchandise/Linnaeus -500.gif Linnaean Classification of Humans (updated since Linneaus to reflect modern biology) • KINGDOM Animalia • PHYLUM Chordata • CLASS Mammalia • ORDER Primates • SUBORDER Haplorhini • INFRAORDER Anthropoidea • PARVORDER Catarrhini • SUPERFAMILY Hominoidea • FAMILY Hominidae • SUBFAMILY Homininae • TRIBE Hominini • GENUS Homo • SPECIES sapiens Influence of Environment • Georges Louis Leclerc , Comte de Buffon – 18th Century French naturalist – animals that change habitat (migrate) often change in response to new environments http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/G eorges -Louis_Leclerc,_Comte_de_Buffon.jpg/466px -Georges - Louis_Leclerc,_Comte_de_Buffon.jpg Influence of Environment • Jean -Baptiste Lamarck – 18th Century French naturalist – developed a theoretical mechanism for change – Theory of Inheritance of Acquired Characteristics – TOTALLY WRONG but first person to propose a mechanism for how species change http://bio.research.ucsc.edu/people/bernardi/Marina/p ublic_html/Bio175/Bio175Website/lamarck.jpg Lamarckism Lamarck believed that giraffes stretched their necks to reach food. Their offspring and later generations inherited the resulting long necks . http://necsi.edu/projects/evolution/lamarck/lamarck/lamarck_lamarck.html Lamarckism • If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring.

He said that change is made by what the organisms want or need. For example, Lamarck believed that elephants all used to have short trunks. When there was no food or water that they could reach with their short trunks, they stretched their trunks to reach the water and branches, and their offspring inherited long trunks. Lamarck also said that body parts that are not being used, such as the human appendix and little toes are gradually disappearing.

Eventually, people will be born without these parts.

Lamarck also believed that evolution happens according to a predetermined plan and that the results have already been decided. http://necsi.edu/projects/evolution/lamarck/lamarck/lamarck_lamarck.html Geological Processes http://skepticism -images.s3 -website -us-east -1.amazonaws.com/images/jreviews/Georges - Cuvier -1800.jpg Georges Cuvier https://upload.wikimedia.org/wikipedia/commons/thumb/5/50/Charles_Lyell00.jpg/220px -Charles_Lyell00.jpg Charles Lyell Geological Processes • Georges Cuvier – 19 th century French naturalist – Catastrophism — the view that the Earth's geological landscape is the result of violent cataclysmic events. – Advocates of this theory usually believe that there have been a number of wide -spread violent and sudden natural catastrophes that have destroyed most living things. https://upload.wikimedia.org/wikipedia/commons/c/cb/Impact_event.jpg Geological Processes • Charles Lyell — 19 th century – Founder of modern geology – Uniformitarianism — the theory that changes in the earth's crust during geological history have resulted from the action of continuous and uniform processes . • Developed by James Hutton in the 18 th century, elaborated on by Lyell http://evolution.berkeley.edu/evolibrary/images/history/rockcycle2.gif Fossil Evidence http://upload.wikimedia.org/wikipedia/commons/e/e7/Mary_Anning_painting.jpg Ichthyosaur fossils Anning described http://www.ucmp.berkeley.edu/history/Anning/MystIchthys.gif Mary Anning — 19 th century British fossil expert • Made many important discoveries of Jurassic fossils in England Economic Theory • Thomas Malthus – 19th Century British Economist – Organisms can produce more offspring than resources in the environment can support, which leads to competition over access to resources http://syg2010 -01.fa04.fsu.edu/Pop_files/Malthus.jpg All of these ideas were part of the world Darwin lived in and formed an essential part of the development of his thoughts about evolution…