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NATURAL SELECTION THEORY

NATURAL SELECTION THEORY. HARUN HUSSAIN. What I s A S cientific Theory?. How is it developed? Understand the basics of science Make observations Gather all your observations and create a hypothesis Make predictions based on your hypothesis Do an experiment to test your predictions

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NATURAL SELECTION THEORY

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  1. NATURAL SELECTIONTHEORY HARUN HUSSAIN

  2. What Is AScientific Theory? How is it developed? • Understand the basics of science • Make observations • Gather all your observations and create a hypothesis • Make predictions based on your hypothesis • Do an experiment to test your predictions Blind and double blind trials • Evidence to support your hypothesis and get it peer reviewed • A scientific theory is a well proven hypothesis of some part of the natural world • A hypothesis is an idea that can become a theory • It is developed through the scientific method by testing repeatedly • It is then confirmed through observations and experimentations

  3. What Is Natural Selection? • This is a theory by Charles Darwin and Alfred Russel • This is the process where organisms better adapted to their environment tend to survive and produce more offspring • Natural Selection is basically an explanation for the mechanism of Evolution

  4. Who Came Up With This Theory? • This is a theory by Charles Darwin and Alfred Russell • Both scientists were making observations of the geographical distributions of species • They found that different species were found in different environments • The theory tells us that there are variations in organisms of the same species • for example: • Some are tall • Some are short • Some are fat • Some are thin etc. http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3

  5. Charles Darwin • Darwin was a British scientist • He was born on the 12th February 1809 in Shrewsbury • In 1831 he joined a 5 year scientific expedition on the survey ship HMS Beagle • On his return to England he tried to solve the riddles of these observations & the puzzles of how species evolved • From this he came up with the evolution theory by the process of Natural Selection • Darwin died on the 19th April 1882 http://www.bbc.co.uk/history/historic_figures/darwin_charles.shtml

  6. Alfred Russell Wallace • Alfred Russell Wallace was a British humanist, naturalist, social critic and geographer • He was born in Monmouthshire, Wales on the 8th January 1823 • In the second half of the 19th Century he became a public figure in England • He came up with a formulation of the theory of evolution by Natural Selection and joined Darwin to come up with this theory • He died on the 7th November 1913 http://www.britannica.com/EBchecked/topic/634738/Alfred-Russel-Wallace

  7. Main Points Of The Theory… • The following briefly states the main points on the theory of Natural Selection: • Variations amongst individuals of the same species • Resources are limited • Organisms reproduce • Organisms compete against one another, i.e. for food, shelter etc • The fittest survive, they reproduce and pass on useful traits to the next generation

  8. Development of the theory… • Darwin saw that organisms produce more offspring than is needed to replace themselves, which would mean population sizes would increase • Darwin confirmed his observations with others, that population numbers tend to stay the same level • He found that resources such as food, water, places to sleep and mate are limited • He was reading work on Thomas Malthus who stated ‘Human population was increasing at a rapid pace and would soon run out of resources’ • He put these facts together to draw a conclusion that individuals compete with each other for resources http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3 Figure: modified from One Long Argument by Ernst Mayr (1991)

  9. He then made 2 other observations on individuals • He found out that individuals are unique and that they vary in almost every aspect • Himself and Russell then investigated variability by breeding pigeons because they realized that if an animal has some trait that helps it to survive the elements or to breed, it may leave more offspring behind • After some time himself and Russell argued that natural selection might produce new types of body parts from eyes to wings http://evolution.berkeley.edu/evolibrary/article/history_14

  10. He then saw that individuals will have variations which will give them a survival boost. This will give them more time to… • He then finally concluded that over time the population will change and that is his theory of evolution through Natural Selection http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3 • Reproduce • Leave a greater number of offspring

  11. Evidence • Darwin wrote ‘an unverified hypothesis is of little or no value’ • To verify this he collected a load of facts from different fields • He assembled reports from other naturalists as well as from his observations • It was hard for him to convince the people at the time, but he demonstrated a test on breeding domestic animals and plants for Natural Selection • Joseph Dalton Hooker arranged for both Darwin's and Wallace's theories to be presented to a meeting of the Linnaean society in 1858 Since 1859 the scientist community has been testing both of the scientists theories. Now it includes evidence from DNA records, fossil records and from case study sections. http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3

  12. What Are The Limitations Of Science…

  13. Questions Science Has Answered • What came first the chicken or the egg? • The chicken actually came first and many scientists have answered and proven this fact. • ‘It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first,’ said Dr Colin Freeman, from Sheffield University, who worked with counterparts at Warwick University. http://metro.co.uk/2010/07/13/the-chicken-came-first-not-the-egg-scientists-prove-447738/ • Why does hair turn grey? • Scientists say stress turns your hair grey as well as genetic factors. • A pigment called melanin makes the hair go a certain colour, but if that melanin is lost the hair starts to go grey, but hairs that lose all there pigment turn white • "There is evidence that local expression of stress hormones mediate the signals instructing melanocytes to deliver melanin to keratinocytes," notes Jennifer Lin, a dermatologist who conducts molecular biology research at the Dana-Farber / Harvard Cancer Centre in Boston. "Conceivably, if that signal is disrupted, melanin will not deliver pigment to your hair.“ http://www.scientificamerican.com/article/fact-or-fiction-stress-causes-gray-hair/

  14. Questions Science Are Currently Addressing • Is there a cure for cancer? • At the moments there isn't a cure for cancer. Its not a single disease, but a group of many diseases, cancer has been around since the dinosaurs and being caused by haywire genes, the risk is hardwired into all of us. • Scientists say ‘trough genetics we're learning more and more about what causes it, how it spreads and we are getting better at treating and preventing it’ • http://www.theguardian.com/science/2013/sep/01/20-big-questions-in-science • Are we alone in the universe? • Nasa scientists say we are not alone in the universe • "I think in the next 20 years we will find out we are not alone in the universe," NASA astronomer Kevin Hand said in footage filmed at the discussion and posted on YouTube. http://www.huffingtonpost.com/2014/07/15/we-are-not-alone-in-universe-nasa-habitable-planets_n_5588455.html

  15. Questions That Science Can Never Answer • Is there a God? • This is a question that science can never answer, because most scientists believe that the world started with a big bang, on the other hand other scientists believe there is a God and that God created the whole universe. • Scientists do not have evidence that God does or does not exist. • The big bang theory states that the universe started of from a tiny particle which the scientist now call ‘The God Particle’ Science nor religion can ever answer this questions…some scientists ask… • Before there was something, there was nothing. And out of nothing, how did we get something? What existed before the big bang, before creation, and before God? http://www.wfs.org/blogs/thomas-frey/ten-questions-neither-science-nor-religion-can-answer • Why does time exist? • Everyone thinks of time differently for example; some think it’s a setting sun, some think it’s a theory of physics and to others a philosophy to be debated • So everyone has different conceptions on why time exists, which makes it hard to answer ‘why time exists’ • Albert Einstein stated, “the only reason for time is so that everything doesn’t happen at once.” • He also said “no further explanation will be forthcoming.” • http://www.wfs.org/blogs/thomas-frey/ten-questions-neither-science-nor-religion-can-answer

  16. Resistance In New Scientific Theories

  17. There is resistance to new scientific theories because there is not enough evidence to support these new theories • More tests and research needs to be carried out before these theories can be proved • The community of scientists rely upon each other to test each others theories, methods and even repeatedly tested experiments and their outcomes. • Sometimes new theories have to be tested, however scientists don’t have all the technology to carry out tests for a new theory, but in time when they have the technology they will be able to test these theories. http://www.enotes.com/homework-help/why-there-sometimes-resistance-new-scientific-392880

  18. Examples Of Resistance To New Theories • Darwin’s theory was materialist at a time when materialism wasn’t just unpopular in respectable circles, it was considered destabilising and politically dangerous. • Whilst he was working on his theory from 1838 to 1848, England was going through political protests and strikes. • Darwin wasn’t strong in the political region he wasn’t into politics • Darwin was writing a book called ‘On the Origin of Species by Means of Natural Selection’ this was published in 1859 • After it was published it was the best seller and on top of that many scientists accepted his theory, but not all

  19. His theory was judged by the scientific institution and by religious leaders. • The critics continuously raised two related arguments: • That natural selection excluded any role for God • Also that although Darwin had cautiously avoided the subject, human beings must also be goods of natural selection. Both ideas were wrong so that’s why Darwin's theory wasn’t accepted at an early stage, there was a lot of resistance and later on scientists realised he was right so they accepted his theory http://socialistresistance.org/303/charles-darwin-reluctant-revolutionary

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