paraphrase answers that correspond with their questions.

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paraphrase answers that correspond with their questions.

1. List three different species concepts and explain the main requirements of each.

  • Morphological Species Concept: In this concept species are differentiated by their physical features and appearances which is called diagnostic traits.
  • Evolutionary Species Concept: In this concept, species depend on morphological traits identifying species from one another, and it indicates speciation in the fossil records as well as the fact that species members have distinct evolutionary paths that are shared. Abrupt changes in traits are necessary to reveal evolution of new species.
  • Phylogenetic Species Concept: In this concept, the evolutionary family tree is utilized to distinguish species based on on common ancestors that are shared between different groups. This concept defines a species as “the smallest set of interbreeding organisms” with a common ancestor that is shared, and monophyly is the main requirement for defining species in this particular concept.
  • 2. Explain how frogs that have different courtship calls but look similar can be different species.
    • This is because they are cryptic species, which can look identical but have differences in other ways. The morphological species concept indicates that the diagnostic traits indicate the distinct physical characteristics that distinguish them from one another. The cryptic species of frogs, like the leopard frogs of the Rio Grande, southern, and northern, could be reproductively isolated and result in different mating calls.
  • 3. Describe the various pre- and post-zygotic mechanisms that pose reproductive barriers using Fig. 17.4 on p. 311.
    • The three pre-mating prezygotic isolating mechanisms are habitat, temporal, and behavioral isolation. Habitat means that different habitats are occupied by species at the same locations, temporal means that distinct seasons/times indicate distinct reproduction, and behavior indicates that differences of behavior alter mating. Mechanical and gamete isolation are mating isolating mechanisms, and mechanical means that the two species have different sexual organs that separate them from breeding, while gamete isolation indicates that sperm is unable to fertilize the egg efficiently. The postzygotic isolating mechanisms include zygote mortality (zygote does not survive after fertilization), hybrid sterility (offspring is sterile), and F2 Fitness (the hybrid is fertile but the next generation has reduced fitness)
    • 4.During the last Ice Age, deer mice in Michigan became separated by a large glacial lake and are now two different species. Identify the mode of speciation.
    • Habitat isolation separates them, and the mode of speciation is allopatric speciation.
  • 5. List the evidence you would need to show that the five species of big cats, Panthera leo (lion), tigris (tiger), P. pardus (leopard), P. onca (jaguar), and P. uncial (snow leopard) are an example of and adaptive radiation.
    • The evidence needed would be evidence of organisms exploiting ne environments, and the changing world would offer evidence for new development of species suited to mate with one another and select different forms of food. There would need to be evidence for allopatric speciation, reduced competition, expanded resources, and the specific adaptation to new environments.
  • 6. Predict the outcome of convergent evolution on the variety of cichlid fish in a newly discovered African Rift Valley lake compared to other lakes within similar microhabitats.
    • The cichlid fish would convergently evolve to have similar biological traits with unrelated species of the same environment, specifically those that are in lakes with similar microhabitats.
  • 7. Explain how the punctuated equilibrium model provides an alternative explanation to the theory of catastrophism proposed by Cuvier (see Chapter 15)
    • The punctuated equilibrium model would allow for new species to evolve when there are sudden changes that occur when there is a period of time that had few or no changes in the species, causing a “few transitional forms” of different species. This would be an alternative explanation to catastrophism proposed by Cuvier.
  • 8. Discuss how the study of developmental genes supports the possibility of rapid speciation in the fossil record.
    • Studying developmental genes could reveal rapid speciation in fossil records because there are some genes that “can bring about radical changes in body shapes and organs” (310). Altering the gene expression could alter or speed up developmental processes, therefore allowing for rapid changes in fossil records.
  • 9. Identify the developmental genes that influence macroevolution.
    • The Pax6 gene helps form the eye, the homeotic genes will indicate location of repeated structures that are present in vertebrates, the Tbx5 gene is responsible for developing limb buds, and the Pitx1 gene reduces the development of pelvic fin buds while in the embryo.