TAILIEUCHUNG - Lecture Biology (7th edition) - Chapter 24: The origin of species

This chapter define and discuss the limitations of the four species concepts, describe and provide examples of prezygotic and postzygotic reproductive barriers, distinguish between and provide examples of allopatric and sympatric speciation, explain how polyploidy can cause reproductive isolation, define the term hybrid zone and describe three outcomes for hybrid zones over time. | Chapter 24 The Origin of Species Overview: The “Mystery of Mysteries” Darwin explored the Galápagos Islands And discovered plants and animals found nowhere else on Earth Figure The origin of new species, or speciation Is at the focal point of evolutionary theory, because the appearance of new species is the source of biological diversity Evolutionary theory Must explain how new species originate in addition to how populations evolve Macroevolution Refers to evolutionary change above the species level Two basic patterns of evolutionary change can be distinguished Anagenesis Cladogenesis Figure (b) Cladogenesis (a) Anagenesis Concept : The biological species concept emphasizes reproductive isolation Species Is a Latin word meaning “kind” or “appearance” The Biological Species Concept The biological species concept Defines a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but are unable to produce viable fertile offspring with members of other populations Similarity between different species. The eastern meadowlark (Sturnella magna, left) and the western meadowlark (Sturnella neglecta, right) have similar body shapes and colorations. Nevertheless, they are distinct biological species because their songs and other behaviors are different enough to prevent interbreeding should they meet in the wild. (a) Diversity within a species. As diverse as we may be in appearance, all humans belong to a single biological species (Homo sapiens), defined by our capacity to interbreed. (b) Figure A, B Reproductive Isolation Reproductive isolation Is the existence of biological factors that impede members of two species from producing viable, fertile hybrids Is a combination of various reproductive barriers Prezygotic barriers Impede mating between species or hinder the fertilization of ova if members of different species attempt to mate Postzygotic barriers Often

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• Campbells Biology
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• Biological sciences
• Biological organization
• Systems biology
• The origin of species
• Restoration ecology
• Conservation biology
• Ecosystem dynamics
• The chemical context of life
• Water molecules
• The molecular diversity of life
• Function of macromolecules
• Membrane structure
• Metabolism transforms matter
• Cellular respiration
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• Sexual life cycles
• The gene idea
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• The molecular basis of inheritance
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• Darwin’s theory
• The evolution of populations