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Transcript
MODULE 4: Diversity, Change And Continuity Origin of the idea of origins There are many world views. For this chapter I will simplify it into two; Secular Humanism and Deism. Whatever we do in life will depend on how we view life. In secular humanism humans are placed at the centre. In Deism God is placed in the centre. From these world views scientists interpret the world around them. To illustrate I use the following example: If two people walk into a room and they find a broken cup on the floor they may interpret the FACT in different ways. Person 1 could say: “I think SOMEONE broke the cup” Person 2 could say: “I think SOMETHING broke the cup” What is the difference? SOMEONE vs SOMETHING Both these people can then go back and design an experiment based on their HYPOTHESIS. Person 1 could knock the cup of a table and check the trajectory, or drop it from a height and check the pattern of breakage (like forensic science). Person 2 could use natural elements like wind or simulated earth quakes to prove the cup could fall of the table or drop from a distance. In both cases there can be PROOF that the Hypothesis can be true , if more experiments gets conducted by more people more evidence can be collected and both of the hypothesis could become THEORIES. But both THEORIES are still based in a BELIEF system Evolution as a scientific theory and not just a hypothesis. The difference between hypothesis and theory. 1. Explain the nature of science _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ 47 | P a g e 2. Distinguish between the following concepts in a clear definition that makes sense a. Hypothesis ___________________________________________________________________________________ ___________________________________________________________________________________ b. Theory ___________________________________________________________________________________ ___________________________________________________________________________________ c. Fact ___________________________________________________________________________________ ___________________________________________________________________________________ d. Belief ___________________________________________________________________________________ ___________________________________________________________________________________ e. Law ___________________________________________________________________________________ ___________________________________________________________________________________ Origin of an idea about origins For secular humanists ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ For Deists ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Beginning of conflict between religion and science with respect to evolution. ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ 48 | P a g e The role of Erasmus Darwin, Lamarck, Charles Darwin and Alfred Wallace in the development of the theory of evolution. Erasmus Darwin Jean B De Lamarck Charles Darwin Alfred Wallace Erasmus Darwin __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Jean Baptiste de Lamarck (1744 – 1829) 1. Describe the following two “laws” of Lamarck a. Law of use and disuse : ___________________________________________________________________________________ ___________________________________________________________________________________ b. Law of inheritance of modified characteristics : ___________________________________________________________________________________ ___________________________________________________________ 2. List two examples of the application of Lamarck’s theory a. ______________________________________________________ b. ______________________________________________________ c. 3. ______________________________________________________ Lamarck’s theory is NOT ACCEPTED by most scientists today. WHY NOT? _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ 49 | P a g e _______________________________________________________________________________________ _______________________________________________________________________________________ Charles Darwin (1809 – 1882) 1. Explain the historical development of Darwin’s theory by referring to his voyage around the world and the Publication of his book _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ 2. List three observations on which Darwin based his theory a. ___________________________________________________________________________________ ___________________________________________________________________________________ b. ___________________________________________________________________________________ ___________________________________________________________________________________ c. ___________________________________________________________________________________ ___________________________________________________________________________________ 3. Complete the following table by comparing the differences between Lamarck and Darwin’s theories Jean Baptiste de Lamarck 50 | P a g e Charles Darwin Alfred Wallace __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________ 51 | P a g e Definitions Micro-evolution __________________________________________________________________________________________ __________________________________________________________________________________________ Macro-evolution __________________________________________________________________________________________ __________________________________________________________________________________________ Evidence for evolution ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ REVISION: The theory of evolution emerges from different lines of evidence e.g. fossil record (grade 10), modification by descent, and the evidence from biogeography (grade 11), genetics (grade 12) as other forms of evidence. Palaeontology ________________________________________________________________________________________________ ________________________________________________________________________________________________ Fossil ________________________________________________________________________________________________ ________________________________________________________________________________________________ How fossils support the Theory of Evolution __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ 52 | P a g e 53 | P a g e 54 | P a g e Genetics Phylogeny __________________________________________________________________________________________ __________________________________________________________________________________________ mtDNA __________________________________________________________________________________________ __________________________________________________________________________________________ Amino acid sequencing __________________________________________________________________________________________ __________________________________________________________________________________________ 55 | P a g e Darwin’s theory of evolution by natural selection Life forms have evolved from previous life forms by natural selection (link to Genetics). Most species are unable to survive in a new environment, and become extinct, but a few species may successfully adapt to a new environment. Natural selection only operates on variation in inherited characteristics (link with Genetics). Artificial selection mimics natural selection. Artificial selection as illustrated by at least one domesticated animal species and one crop species. Demonstration of principles of natural selection through camouflage and avoidance of predation, using e.g. games, models. Evolution by natural selection Selection __________________________________________________________________________ __________________________________________________________________________ Selection pressures __________________________________________________________________________________________ __________________________________________________________________________________________ Effects of selection pressures on Allele frequency 56 | P a g e Natural selection ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Conditions needed for natural selection ________________________________________________________________________________________________ ________________________________________________________________________________________________ The theory of natural selection states: Overproduction __________________________________________________________________________________________ __________________________________________________________________________________________ Struggle for survival __________________________________________________________________________________________ __________________________________________________________________________________________ Variation __________________________________________________________________________________________ __________________________________________________________________________________________ o Continuous variation ___________________________________________________________________________________ ___________________________________________________________________________________ 57 | P a g e ___________________________________________________________________________________ ___________________________________________________________________________________ o Discontinuous variation ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ o Sources that lead to variation in a species : ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Variation depends on the available alleles! Inheritance __________________________________________________________________________________________ __________________________________________________________________________________________ Example of Natural Selection using the Peppered Moth of Britain ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ 58 | P a g e ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Artificial selection ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ 59 | P a g e Inbreeding ________________________________________________________________________________________________ ________________________________________________________________________________________________ 60 | P a g e Outbreeding ________________________________________________________________________________________________ ________________________________________________________________________________________________ Cattle breeds in South Africa ________________________________________________________________________________________________ ________________________________________________________________________________________________ Artificial selection in maize ________________________________________________________________________________________________ ________________________________________________________________________________________________ 61 | P a g e Natural Selection Artificial selection Inbreeding Outbreeding Equine breeds 62 | P a g e 63 | P a g e Speciation Biological species concept: ________________________________________________________________________________________________ ________________________________________________________________________________________________ Population : ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Speciation as a mechanism for producing new species. Speciation ________________________________________________________________________________________________ ________________________________________________________________________________________________ Allopatric speciation __________________________________________________________________________ __________________________________________________________________________ ____________________________________________ Geographic speciation due to isolation. Select ONE example e.g., Galapagos finches, 64 | P a g e Figure 4. 29 How speciation could have taken place in the Galapagos / Darwin’s finches Process of allopathic speciation : ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ 65 | P a g e 66 | P a g e Adaptive radiation ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Niche differentiation ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Evolutionary adaptation ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ 67 | P a g e Sympatric speciation __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Cichlid fishes in Lake Malawi Three basic selection pressures: __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ 68 | P a g e Genetic drift __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Founder principle __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ Bottleneck effect __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ 69 | P a g e Reproductive isolation Mechanisms of reproductive isolation: - breeding at different times of the year - Species-specific courtship behaviour (animals) - Adaptation to different pollinators (plants) - Infertile offspring (e.g. mules) 70 | P a g e Human evolution Evidence for common ancestors for living primates including humans. Out of Africa hypothesis and evidence for African origins of all modern humans. All modern humans are genetically very closely related Map out the sequence of human evolution from ape-like ancestor around 5 mya to modern Homo sapiens. Emphasize the fossils found in Africa, and the simultaneous existence of several species at various times in the pas African fossils have made a huge contribution to understanding human evolution e.g. Cradle of Humankind at Sterkfontein; Great Rift Valley. OUR PLACE IN THE ANIMAL KINGDOM Interpret a phylogenetic tree to show the place of the family Hominidae in the animal kingdom 71 | P a g e CHARACTERISTICS WE SHARE WITH OTHER PRIMATES List 10 characteristics we share with other primates 1. ___________________________ 2. ___________________________ 3. ___________________________ 4. ___________________________ 5. ___________________________ 6. ___________________________ 7. ___________________________ 8. ___________________________ 9. ___________________________ 10. ___________________________ 72 | P a g e CHARACTERISTICS, WHICH MAKES US DIFFERENT FROM OTHER PRIMATES List 7 characteristics that make us different form other primates: 1. __________________________________ 2. __________________________________ 3. __________________________________ 4. __________________________________ 5. __________________________________ 6. __________________________________ 7. __________________________________ TRENDS IN HUMAN EVOLUTION List the following as changes in structure that characterise human evolution Shift of foramen magnum to a more forward position - BIPEDALISM A more rounded skull and increased cranium size A flatter face due to : 73 | P a g e o Less sloping forehead o Less protruding jaws o A more developed chin o A more rounded jaw o Increased size of skeleton o Change in dentition With reference to the organisms listed below , trace the progressive evolution of the above listed features from the apelike beings to the humans : (Using fossil evidence as indicated) Ape-like beings First apes on the same line of development as humans First bipedal primates Autralopithecines (Mrs Ples, Taung child, Little foot, Lucy) Homo habilis (Handyman) Homo erectus Homo sapiens (modern humans, Floribad man) 74 | P a g e 75 | P a g e 76 | P a g e 77 | P a g e 78 | P a g e SEARCH FOR THE CRADLE OF HUMANKIND 1. Explain what is meant by the following terminology : a. Anthropology ___________________________________________________________________________________ ___________________________________________________________ b. Palaeontology ___________________________________________________________________________________ ___________________________________________________________ c. Archaeology ___________________________________________________________________________________ ___________________________________________________________ Statement: The search for the cradle of human kind has moved from South Africa to East Africa to Central Africa in the light of new fossil evidence 2. List reasons for population movements a. __________________________________________ b. __________________________________________ c. __________________________________________ d. __________________________________________ e. __________________________________________ Out of Africa HYPOTHESIS Fossil evidence Southern Africa __________________________________________________________________________ __________________________________________________________________________ Eastern Africa __________________________________________________________________________ __________________________________________________________________________ Genetic evidence mtDNA __________________________________________________________________________ __________________________________________________________________________ 79 | P a g e __________________________________________________________________________ __________________________________________________________________________ Y chromosomes __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ 80 | P a g e Evolution in present times Examples that evolution is still occurring, e.g. the development of resistance to insecticides in insects; resistance to antibiotics in various bacteria Use of DDT and consequent resistance to DDT in insects can be explained in terms of natural selection. Development of resistant strains of TB – MDR and, more recently, XDR strains of tuberculosis-causing bacteria. Resistance to DDT 81 | P a g e
