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8.3 – Evolution as an Ongoing Process

8.3 – Evolution as an Ongoing Process. Co-evolution traits developed through natural selection in one species affects the evolution of others as they adapt to those changes a mutualistic relationship exists between flowering plants and pollinators

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8.3 – Evolution as an Ongoing Process

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  1. 8.3 – Evolution as an Ongoing Process Co-evolution • traits developed through natural selection in one species affects the evolution of others as they adapt to those changes • a mutualisticrelationship exists between flowering plants and pollinators • adaptations for bright flowers and strong scent attract more pollinators, which have adapted to be able to access the nectar in a particular flower, sometimes to extremes (i.e. hawkmoth and orchid with 40 cm spur) • as plants adapted to herbivorous insects by producing toxins, insects were selected that were immune (i.e. Monarch larvae which are tolerant to milkweed toxin and are able to store it to become toxic to predators)

  2. Mimicry • sometimes, evolution is not mutualistic, as some species evolve to resemble another in order to gain a survival advantage

  3. The Evolution of Complex Features • natural selection is not random and, in fact, is the opposite of chance and can easily account for complex structures and relationships • the gradual production of an eye through cumulative selectionwould require that each stage in the evolution of a complex eye must have benefited the organism • if a worm ancestor experienced a mutation that resulted in light-sensitive cells may have caused it to stop moving toward light thus avoiding predators or desiccation • such an advantage would be selected until the entire population would exhibit light-sensitive cells • if another mutation produced a pit, a mechanism to detect the direction of light would be produced which would allow the worm to move away from the light which would also be strongly selected for • a deeper pit would increase directionality but decrease sensitivity, which could be improved with a lens

  4. Adaptation of Existing Structures to New Functions • features that evolved for particular functions can be adapted for different functions (i.e. chitin provides protection in a marine environment, while it provides support and prevention of desiccation on land) • wings were selected against in penguins which inhabit islands and other remote locations, but were modified into flippers for hunting prey in the ocean where they are more abundant than on the land or ice

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