EEB214H1 Lecture 2: Darwin's Idea
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Department
Ecology & Evolutionary Biology
Course
EEB214H1
Professor
Jennifer Carpenter
Semester
Winter

Description
EEB214 –Lecture 2: Darwin’s Idea Charles Darwin (1809-1882) in England • John Edmonston, a free slave from the West Indies, tutored Darwin on how to prepare bird skins o he got into naturalism in Scotland while wandering around and observing plants and animals o learned to preserve birds through John • his family told him to become a priest • went to Cambridge to start studying • while at seminary Darwin began collecting beetles o there was much diversity in this area, unified species o they all look so different from each other o Why was there so much variation in nature? • Darwin was influenced by many people at Cambridge o joined a naturalist club • William Paley o philosopher in his program o used the same reasoning that everything was designed • Adam Sedgwick – geologist • William Whewell – geologist • John Henslow – botanist • They helped talked to Darwin about life • Why these changes occur overtime • Darwin red his grandfathers during, another physician o found trans mutation o species can change from the past to a new one o this wasn’t his idea though • Darwin went on his famous trip on the HMS Beagle from 1831-1836 o he was talking to Henslow to go on the trip o Darwin was not hired as a naturalist on the boat, but there to have dinner etc. o after the naturalist resign, Darwin took over • Fitzroy gave Darwin a copy of Lyell’s book o the force that shape geology today, [things that make mountains] are the same forces that are acted in the past o how these natural forces came to be, and how long they’ve been around • Darwin started thinking more about his grandfather’s idea of Transmutation—that new species can be generated from existing species o how those natural forces could be the driving force behind transmutation • 1838, Darwin read Robert Malthus’s essay, On the Principle of Populations o Malthus described life in human population as ‘a struggle for existence’ o human population grow faster than they can produce food o when this happens, food runs short, famines happen and people die o Darwin knew that traits could vary, and that variation was heritable o he also talked to animal breeders and asking them how to pick which animals to breed o knows that traits are inheritable o this variation in nature can be passed on through generations • Darwin combined two ideas o Heritable differences lead to different rates of survival and reproduction o these two going together might have the trait that makes them survive o overtime, population change and you might have those traits that make you survive • Evolution by natural selection is when individuals differ from one another, and some of differences affect an individual’s ability to survive and reproduce, and so they will leave more descendants, and ultimately increase in frequency in the population, causing the population to change overtime o no survival of the fittest o survival and reproduction of which individual can pass on their next generation • For evolution to happen three things need to be true: o variation o reproduction: heritable ▪ make sure the offspring looks like the parent ▪ heritability o differences in survival and reproduction ▪ some individuals have to survive longer than others ▪ has to be variations in the traits, and fitness [how many offspring] • a population of things will change overtime if you have these three things • Example: pigeons variation o brown pigeons vs. gray pigeons o if gray pigeons get killed, then next generation, the brown pigeons will expand • evolution is about the population as a whole changing, not individual change • If this continues, these gray pigeons will die out and next generation will only have brown pigeons • evolution is exploiting the problem with how evolution is acting Evidence #1—Artificial Selection • humans activity selecting which organism gets to breed and passing onto the next generation • humans are INTENDING to create some specific trait • By selecting for different traits humans have created different vegetables • Big leaves, red leaves, many small flowers o cauliflower are both flowers but all the same plants o he used a lot of evidence from crops • Darwin spent a lot of time talking to pigeon fanciers o these people as a hobby grow pigeons, look for weird ones with interesting traits and make more to look weird o by breeding normal pigeons, it can become weird o breeding can only be physical traits • In Darwin’s time an individual with a new phenotype was called a “sport” o called a mutation today o bright blue lobsters o forms appear suddenly [out of the blue] o If those traits are acted on in the environment, it can happen in nature too • When humans intentionally select for a certain traits we call it Artificial Selection o humans breed dogs from wild wolves o in the last 10,000 years • Starring in
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