Darwin and his theory of evolution

Man, the apes and monkies have all evolved from a common ancestor

Events of his life that led to the theory of evoluion

He was sent out a survey ship called the Beagle to map the cost of south America

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the five years that he spent on hte ship tansformed Darwin. He had been a sympathetic, subtle observer of birds, flowers, life in his own countryside, now South America exploded all that for him into a passion. He came home convinced that species are taker in different directions when they are isolated from one another; species are not immutable.

Reading an essay on Population by the Reverned Thomas Malthus and he was stuck by his thought

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He was stuch by Malthus's thought when he said htat population multiplies faster than food. If that is true for animals, then they must compete to survive: so that nature acts as a selective force, killing off the weak, and forming new species form the survivors who are fitted to their environment. AND HE FINALLY GOT A THEORY BY WHICH TO WORK.

Important terms

The principle of Divergence is the most important factor in the evolution of new species

Natural selection

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Is the process by which new species were brought into existence. It was the process of interaction between:Changes in the environmentCompetition between and within speciesthe variation naturally occurring within species and it was driven bythe excess of procreation over the numbers the environment can support

Some important propostions for Darwin

Proposition 1

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Aritficial selection has had a marked effect on the form of domesticated plants and animalb, although it has only been applied for a small number of generations

Proposition 2

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there were a similar force acting in nature over millions of years

Proposition 3

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There is a force between species and within species in the circumstances of a tendency for population growth to out run the means of sustenance. Only a few of those annually born can live to propagate their kind. There is a force between species and within species

Proposition 4

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If a change occurs in the physical environment, individuals will be exposed to new circumstances, and competition from a different set of inhabitants. These changes will favour the transmission of features that are advantageous in the new conditions.

Propostion 5

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All species are characterised by variation between individuals. In any new environment there will be different conditions from place to place.

Darwin misunderstood

DARWIN MISUNDERSTOOD 1Evolution is a “ladder of progress”, a steady march of progress with organisms constantly getting better.

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Natural selection does weed out individuals unfit for a particular environment but conditions are constantly changing and what is “better’ under one set of conditions may not be under other conditions.

DARWIN MISUNDERSTOOD 2 Evolutionary theory is a theory about the origin of life.

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the origin of life is not the main focus of evolutionary theory but rather the way life changes after its origin. Evolution shows us that species are not immutable but that they change over time trhough natural selection.

DARWIN MISUNDERSTOOD 3. The fact that the fossil record is not complete shows evolutionary theory to be false.

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Fossilization is a very rare event. There must be specific conditions for a creature to be fossilized and many organisms, particularly those without a hard skeleton, rarely fossilize at all.

DARWIN MISUNDERSTOOD 4 Because evolution is not observable or testable it is not science.

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Evolution is both observable and testable!1. The fossil record.2. Study of living species e.g. Darwin’s Finches.3. Artificial selection in the laboratory.4. Genetic mutation e.g. in fruit flies.

DARWIN MISUNDERSTOOD 5 Evolution and religion are incompatiblec

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Religion and evolution are very different things. In science, only natural causes are used to explain natural phenomena, while religion deals with beliefs that are beyond the natural world.