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when and why poeple started explaining things by evolution Lernen beginnen
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It changed in 17th century - due to development of knowledge, possibility of traveling to foreign lands
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example of structural smiliarities between species Lernen beginnen
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five digits on each had and foot in primates; why do we walk on two legs etc
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Bones from older geological strata differ from those in more recent strata -> change in organic structure over time
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Similarities in embryological development development across different species, even dissimilar ones
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18-19th century; He noticed that species aren't static, that there are some similarities in species
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2 major causes of species change in lamarck's theory Lernen beginnen
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1. Natural tendency for each species to progress toward a higher form 2. Inheritance of acquired characteristc (black will have black child)
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Lamarck's mechanism for change: Lernen beginnen
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Believed animals must struggle to survive, leading to the secretion of fluid by nerves. This fluid was thought to enlarge the organs involved in the struggle
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He developed the theory of evolution, proposing that all living things share a common ancestor and change through natural selection Darwin figured out that giraffe's neck became longer because those with longer necks survived better. So there were no fluids, just genetics
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THE DIFFERENTIAL SURVIAL AND REPRODUCTION OF INDYVIDUALS DUE TO DIFFERENCES IN PHENOTYPE Favourable variations persist, unfavorable ones decline. Repeated over generations, this process lead to the development of new adaptations
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• 3 essential concepts: (so that natural selection could exist, there need to be): Lernen beginnen
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1. Variation 2. Inheritance 3. Differential reproductive success
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Diversity of traits within population
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The transmission of certain traits from parents to offspring
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Differential reproductive success Lernen beginnen
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a. The uneven ability of individuals with specific traits to survive and produce offspring, influencing evolutionary change
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sometimes sexes differ significantly in size and structure
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the preference by one sex for certain characteristics in individuals of the other sex
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Two primary means by which sexual selection operates: Lernen beginnen
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1. Intersexual selection 2. Intersexual competition
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one sex displays a certain trait or behaviour with the goal of attracting and mating with the opposite sex (mantis)
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occurs between members of the same sex. They compete for the opportunity to mate with the opposite sex (lions)
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random changes facilitated by processes like mutations, founder effect, genetic bottlenecks
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random hereditary changes in DNA
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A small population establishes a new colony, and the genetic makeup of the founders differs from the original population (chitas)
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Population shrinkage due to random events like earthquakes, results in survivors carrying only a subset of the original population's genes
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