campbl24 - This planetary nebula, NGC 6751, was formed...

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Unformatted text preview: This planetary nebula, NGC 6751, was formed several thousand years ago when the star in its center ejected some of its material. Planetary nebulae look like planets in small telescopes (plus are found hanging around stars). They are clouds of gas thrown off by stars that are nearing the ends of their lives. There is no need for concern however: our own Sun will only eject a planetary nebula like this around 6 billion years from now. The blue areas in this picture are the hottest glowing gas. The orange and red areas are cooler. NGC 6751 is 0.8 light-years in diameter, 600 times the diameter of our own solar system. Species Concepts Biological Species Concept Reproductive Isolation Not necessarily easy to apply Morphological Species Concept Phenotypic differences (fossil species) Recognition Species Concept Mating recognition Cohesion Species Concept Persistence of discrete phenotypes Ecological Species Concept Filling of ecological niches Competition for resources Evolution Species Concept Evolutionary lineages Pluralistic Species Concept Combinations of above as appropriate Patterns of Speciation Patterns of Speciation Patterns of Speciation Reproductive Isolation Geographical Isolation Habitat Isolation Behavioral Isolation Temporal Isolation Mechanical Isolation Gametic Isolation Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown Reproductive Isolation Postzygotic Isolation Geographical Isolation Habitat Isolation Behavioral Isolation Temporal Isolation Mechanical Isolation Gametic Isolation Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown Prezygotic Isolation Geographical Isolation Habitat Isolation...
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campbl24 - This planetary nebula, NGC 6751, was formed...

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