24. History of Life on Earth

Which adaptive radiation is correctly matched to the extinction event that preceded it?

Which of the following statements about the Cambrian Explosion are true?

I) Before the Cambrian Explosion, most organisms had soft bodies.

II) The Permian extinction created new ecological niches that were exploited during the Cambrian Explosion.

III) After the Cambrian Explosion, new morphological features like limbs and jaws are observed.

The evolution of the Hox gene cluster likely allowed for what key evolutionary innovation?

In arthropods, the Hox genes Ubx and abd-A are largely expressed in the same tissues. The illustrations below show in red which tissues both Ubx and abd-A are expressed in three species of arthropods. Based on this illustration, which statement is consistent with the data?

_{Images adapted from: Jennifer K. Grenier, Theodore L. Garber, Robert Warren, Paul M. Whitington, Sean Carroll}

_{Evolution of the entire arthropod Hox gene set predated the origin and radiation of the onychophoran/arthropod clade,}

_{Current Biology, Volume 7, Issue 8, 1997, Pages 547-553,}

_{ISSN 0960-9822,}

_{https://doi.org/10.1016/S0960-9822(06)00253-3.}