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Adaptive Radiation quiz #3

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  • How did the Cambrian explosion exemplify adaptive radiation, and what factors contributed to this event?
    The Cambrian explosion was a major adaptive radiation event about 530 million years ago, during which most major animal phyla appeared. Factors contributing to this event included increased oxygen levels from algae, the emergence of predators, the creation of new ecological niches, and the evolution of developmental genes like Hox genes that enabled complex body plans.
  • What is adaptive radiation and how does it affect the tree of life?
    Adaptive radiation is an evolutionary process where a single lineage rapidly diversifies into many species, making the tree of life bushier by filling multiple ecological niches.
  • What are two main reasons adaptive radiations occur?
    Adaptive radiations occur due to ecological opportunities, such as open niches after mass extinctions, and evolutionary innovations, like the development of new traits that increase fitness.
  • How did the Hawaiian Drosophila exemplify adaptive radiation?
    The Hawaiian Drosophila diversified into about 1,000 species, each filling different ecological niches on the Hawaiian Islands, such as laying eggs on various substrates like rotting bark or spider egg sacs.
  • What evolutionary innovation allowed angiosperms to outcompete other plant groups?
    Angiosperms developed seeds enclosed in fruit and flowers, which improved seed dispersal and reproduction, allowing them to outcompete ferns and conifers.
  • What major event is considered a classic example of adaptive radiation in animals?
    The Cambrian explosion is a classic example, during which most major animal phyla appeared in a relatively short period about 530 million years ago.
  • What environmental and biological factors contributed to the Cambrian explosion?
    Increased oxygen from algae, the emergence of predators, creation of new ecological niches, and the evolution of developmental genes like Hox genes all contributed to the Cambrian explosion.
  • How do changes in gene regulation contribute to rapid evolutionary changes during adaptive radiation?
    Changes in gene regulation, especially in regulatory genes, can cause significant differences in development and body plans, leading to rapid diversification.
  • What are homeotic genes and what role do they play in evolution?
    Homeotic genes are regulatory genes that determine the organization of body parts, and changes in these genes can cause large evolutionary changes in a short time.
  • How did Hox genes influence animal diversification during the Cambrian explosion?
    Hox genes, which control the head-to-tail body plan in animals, enabled the development of complex body structures, facilitating the rapid diversification of animal phyla during the Cambrian explosion.