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Evolution - Coggle Diagram
Evolution
Speciation
Selective process
directional selection
is a mode of negative natural selection in which an extreme phenotype is favored over other phenotype, causing the allele frequency to shift over time in the direction of that phenotype
Diversifying Selection
Changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into 2 distinct groups
Stabilizing Selection
Stabilizing selection is a type of natural selection in which population stabilizes on a particular non extreme trait value.
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Allopatric Speciation
a species population becomes separated by a geographic barrier,whereby reproductive isolation evolves producing 2 seperate species
Sympatric speciation
the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic species
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Evidence of Evolution
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Comparative anatomy
Vestigal structure
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genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species, but have been retained during the process of evolution
Homologous structures
Common structures in different organisms that may have different functions but reflect inheritance from a common ancestor
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Comparative embryology
as organisms go from a fertilized egg to birth, their development, repeats evolutionary history
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Mechanisms of Evolution
Natural Selection
Those individuals with alleles that give them adaptations to the environment allowing them to survive and reproduce more often so that theses allels are more common in the gene pool.
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Sexual Selection
those individuals with allels that are 'sexy' get to mate more often so that 'sexy' allels are more common in the gene pool
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Artificial Selection
the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations
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Darwins theory
Intellectual influences
voyage of beagle
In 1831 when Darwin was just 22 years old he set sail on a scientific expedition on a ship called the HMS beagle. He was the naturalist on the voyage. As a naturalist it was his job to observe and collect specimens of rocks, animals, plants, and fossils whenever the expedition
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Thomas MAtthus
Demographer/economist , humans' reproductive ability is greater than the earths surface
Charles Lyell
Geology, Charles Lyle, that proved that the earth was enormously old and geological processes still in motion
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Church of ENgland
1809-1882, born into the British upper class. church very important in ideological support for the British empire
Grandfather
Erasmus who believes that species could change over time. He wrote about it in poetry and was ostricized because of it and its political implications
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The theory
- That biological types or species do not have a fixed, static existence but exist in permanent states of change and flux
- That all life, biologically considered, takes the form of a struggle to exist - more exactly, to existent produce the greatest number of offspring and creations
- That this struggle existance culls out those organisms less well adapted to any articular ecology and allow those better adapted to flourish - a proccess called Natural selection
- That the genetic variations ultimately producing increased survivability are random and not caused by God or by the organisms own striving for perfection
- That natural selection is cumulative, thus evolution requires enormously long periods of time, so long, in fact the everyday experience of human beings provides them with no ability to interpret such histories
