Chapter 27.1, Problem 5MI

Summary Introduction

To analyze:

The importance of deuterostome development.

Introduction:

Any of a significant division of the set of all animals that incorporates the reciprocally even creatures, (for example, the chordates) with uncertain cleavage and a mouth that doesn't emerge from the blastopore is known as deuterostome.

Explanation of Solution

The evolutionary tree branches at deuterostomes, marking this development as a major transition in animal phylogeny. Only echinoderms and the chordates that evolved after echinoderms have this type of development.

By not needing the adjustment of the shafts, deuterostome eggs can be loaded up with materials, similar to yolk proteins, that permit the undeveloped organism to grow further prior to incubating, so the mother can gracefully the energy expected to form into a grown-up, permitting the undeveloped organism to sidestep a larval stage.