Imagine a scientist finds the fossils of an extinct Ichthyosaur and finds this morphological similarity of Ichthyosaurs and modern dolphins: bones indicating flippers and a tail for swimming. The scientist guesses that Ichthyosaurs may form a monophyletic group with the dolphins, based on this morphological similarity. What is one method or line of reasoning that scientists could NOT use when testing the hypothesis that dolphins and Ichthyosaurs form a monophyletic group? Imagine a scientist finds the fossils of an extinct Ichthyosaur and finds this morphological similarity of Ichthyosaurs and modern dolphins: bones indicating flippers and a tail for swimming. The scientist guesses that Ichthyosaurs may form a monophyletic group with the dolphins, based on this morphological similarity. What is one method or line of reasoning that scientists could NOT use when testing the hypothesis that dolphins and Ichthyosaurs form a monophyletic group?Take blood samples and use DNA evidence to determine a more complete phylogenetic tree, because biologists have not successfully obtained DNA from IchthyosaursCollect more data about the presence and absence of many more characters of both dolphins and ichthyosaur bonesMake sure that the flippers and tail in both Ichthyosaurs and dolphins are due to homology, rather than analogySee if the living sister group to dolphins is more closely related to dolphins than is the IchthyosaurUse the principle of parsimony to decide which of several trees is most parsimonious Solution d). See if the living sister group to dolphins is more closely related to dolphins than is the Ichthyosaur Observing the physical features of the animals to determine the phylogenic relationship is not a scientific approach. However, tracking the phylogenic relationship using the DNA samples, homology, collecting the fossil data will be helpful..

1. Imagine a scientist finds the fossils of an extinct Ichthyosaur and finds this morphological
similarity of Ichthyosaurs and modern dolphins: bones indicating flippers and a tail for
swimming. The scientist guesses that Ichthyosaurs may form a monophyletic group with the
dolphins, based on this morphological similarity. What is one method or line of reasoning that
scientists could NOT use when testing the hypothesis that dolphins and Ichthyosaurs form a
monophyletic group?
Imagine a scientist finds the fossils of an extinct Ichthyosaur and finds this morphological
similarity of Ichthyosaurs and modern dolphins: bones indicating flippers and a tail for
swimming. The scientist guesses that Ichthyosaurs may form a monophyletic group with the
dolphins, based on this morphological similarity. What is one method or line of reasoning that
scientists could NOT use when testing the hypothesis that dolphins and Ichthyosaurs form a
monophyletic group?Take blood samples and use DNA evidence to determine a more complete
phylogenetic tree, because biologists have not successfully obtained DNA from
IchthyosaursCollect more data about the presence and absence of many more characters of both
dolphins and ichthyosaur bonesMake sure that the flippers and tail in both Ichthyosaurs and
dolphins are due to homology, rather than analogySee if the living sister group to dolphins is
more closely related to dolphins than is the IchthyosaurUse the principle of parsimony to decide
which of several trees is most parsimonious
Solution
d). See if the living sister group to dolphins is more closely related to dolphins than is the
Ichthyosaur
Observing the physical features of the animals to determine the phylogenic relationship is not a
scientific approach. However, tracking the phylogenic relationship using the DNA samples,
homology, collecting the fossil data will be helpful.