Anth 1101 - Chapter 1

Chapter 1 History of our planet - History of our planet is divided into eras, which are divided into periods which are then divided into epochs - Majority of Earths history is in Proterozoic Era - The Proterozoic began with the formation of the earth, approximately 4.5 billion years ago, and ended with the first major diversification of life-forms, approximately 600 million years ago - Found the first hints of life on this planet during this era: tiny fossilized impressions suggesting clusters or chains of linked cells resembling today’s blue-green algae and bacteria (prokaryotic cells, or cells that do not contain a nucleus). - Starting around 1.2–1.5 billion years ago, life-forms became slightly more diverse. We begin to find evidence of eukaryotic cells (cells that have a nucleus, like those of all animals and plants). Paleozoic era (570-250 million years ago) - The first skeletonized species on earth - Event #1 Meteor hit the earth and caused mass extinction of 90% of earth’s life Mesozoic Era 250-65 million years ago - 10% of life survived, some of the survivors was skeletonized life - Dinosaurs - Event #2 Meteor hit the earth and killed most dinosaurs - Lots of insects survived, ancestors of birds survived, crocodiles survived and some of the first skeletal living beings. Cenozoic Era 65 million years ago-present date - Age of mammals Event #3 Currently humanity is in an event of 277x normal extinction rate (Climate change) Anthrolpology: study of humans (us) and our closest biological relatives (other members of the order Primates–Monkeys, apes and prosimians) - Primates: mammalian order to which humans belong - Anthropology divided into 4 subfields (they are committed to ensure that the knowledge they acquire is made available to nonanthropologists and is applied to issues facing humanity. - Archeology: study of material past of humans (what people of past made, how they lived and modfieied to environment) - Biological anthropology: biological facets of the human species, past & present. - Cultural anthropology: human culture (patterns of behaviour we exhibit in our families, relationships, religions, laws, everyday interactions) - - Main tools are ethnography (study of specific culture or aspects of it) - Ethnology: study of many cultures) Linguistic anthropology: study of language (origin, uses and construction) Biological Anthropology Subfields: - Paleoanthrolpogy: study of fossils (material evidence from past life) - Interconnections between human biological variations (differences in weight, height, genetics) - Biological basis of behaviour and how aspects of culture can be influenced by biology and ecology - Ecology: interrelationships between living organisms and their environment - Nonhuman primate species: what is common to all primates and what may be unique to humans Scientific Discipline Biological antrholpogy gathers information by scentific method - Scientific method: way of asking questions about ourselves and the world around us - Foundation provided by scientific method has allowed for the enormous leaps in knowledge - Observe a fact (a verifiable, observable truth) → contrust hypothesis (testable - explanation for observed facts) → test hypothesis - Hypothesis wrong (refutes it) then try another hypothesis and retest - If test supports hypothesis → try to present or publish results so others can test - Hypothesis supported again and again by multiple researchers = theory Critical Thinking: taking control of information presented to you and examining it - Where did the information come from? Facts? Observable truths? Logical? Nonfactual elements presented as facts? Science is always influenced by personal and cultural factors - Science if a methodology not a belief system - Researchers with differing backgrounds and irentations look at data in different ways and ask different questions resulting in various types of answers - Variations of answers are beneficial to practices of science because the more questions asked and observations made the more tests conducted = more knowledge gained Paradigm: predominant ways of thinking about ideas - Main paradigm of biological anthropology is evolution by natural selection - When bioligcal anthrolpogists examin a given fossile, questions asked are related to how the patterns and processes of evolution have impacted the form and function of the fossil Greek and Roman Legacy - Scalae Natura (Great Chain of Being) = all forms of life on planet can be ranked in order from most important to least - In this era: gods at top; angels below god; humans next; all beasts of land, sea and air Infleunced how people saw the world for centuries; humans are superior to other life forms Essentialism: notion of ideal types (each organism has a true, ideal form and all living representatives of that organism are slight deviations from the ideal type) - This provides an explanation for the slight variations we see in different forms, even among members of same species Niche: niche is a description of the way an organism makes a living in the world, and that world that it lives in, and their relationship. Evolutionary thought emerged (P.26) -four scientists stood out for their contributions to the evolutionary story -John Ray (1628–1705), an English naturalist, classified plants and animals on the basis of similarities and differences - Edward Tyson (1650–1708) for his work in comparative anatomy of a young chimpanzee. - Robert Hooke (1635–1703) believed that fossils represented extinct organisms and proposed that extinctions occurred because of changes in the earth -Nicolas Steno (1638–1686) founded the science of stratigraphy- the study of the rock and soil layers of the earth. He proposed that the strata of the earth represented a chronological history of a constantly changing planet. More evolutionary scientists (P 27-28) - Carolus Linnaeus (1707–1778), was the “father” of taxonomy —the system of naming and classifying organisms that we still use today with modifications. - He used binomial nomenclature —a two-name system—to identify and group different forms. He grouped clusters of organisms that were most similar to one another into categories called species and then grouped species into higher categories called genera. Genera could then be grouped into even higher categories, such as family, order, and phylum -Buffon thought there was a dynamic relationship between organisms and their environment. -he believed that life-forms were the outcome of active processes and that biblical creation “started the ball rolling” and led to a proliferation of form. Erasmus Darwin and Lamarck (P.29) - He believed that life had arisen from God and that the process of speciation—gradual change of one species into another— had produced the diversity of forms we see on the planet. -While Erasmus Darwin may have been the first to put forward formal ideas about evolution, it is Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744–1829), who first clearly laid out a theory of evolution. -Lamarck believed in dramatic and significant change both in species and individual organisms. -Lamarck proposed a process of evolution with three major components: the will to change, the inheritance of acquired characteristics, and the law of use and disuse. All of these components are based on the notion that the environment challenges organisms Starta and Lyell - These scientists suggested that geological processes (erosion, mountain formation, and so on) observed in the present are the same as those that were functioning in the past - They proposed the concept of deep time, meaning that the earth must be older than 6000 years for the uniform processes of geological change to have had sufficient time to result in such geological features as the Alps. Charles darwin -Charles Darwin (1809–1882) who, along with Alfred Russel Wallace (1823–1913), formulated the currently accepted theory of evolution - By 1844 he had a working version of his theory of evolution, which he eventually called “descent with modification via natural selection.” -He saw that within a species no two individuals were exactly alike. Members of a species are all highly similar in form, but they vary in specific traits, such as beak form, leg length, or feather colors -Darwin realized that all organisms that are born do not survive because the environment challenges them. Acquiring food and reproducing are difficult, and not all organisms in a species do so equally well. There is a competition for survival, or more specifically for reproductive success. -Organisms whose traits best adapt them for their environment are said to have the best fit with that environment. -Darwin realized that variation does not arise from a will to change but is actually found in the existing traits of individuals in a population and is passed to offspring. Darwin called this mechanism of change natural selection. Darwin's experiment -Over time, the descendants of the original colonizing finches with beak shapes that helped them do a little better in the new environment left more offspring. Because beak shape is heritable, over time, the better fit variants came to make up the majority of the population. -In Darwin’s and Wallace’s view, organisms fit into their environment not because they were created that way but because generations of interaction between the traits of those organisms and the challenges of the environment resulted in descent with modification -His view was essentially nonreligious or nonspiritual and thus unwelcome in Darwin’s time.