Skip to ContentGo to accessibility page
OpenStax Logo
Biology 2e

Critical Thinking Questions

Biology 2eCritical Thinking Questions

Critical Thinking Questions

23.

What are the characteristic features of the chordates?

24.

What is the structural advantage of the notochord in the human embryo? Be sure to compare the notochord with the corresponding structure in adults.

25.

What can be inferred about the evolution of the cranium and vertebral column from examining hagfishes and lampreys?

26.

Why did gnathostomes replace most agnathans?

27.

Explain why frogs are restricted to a moist environment.

28.

Describe the differences between the larval and adult stages of frogs.

29.

Describe how metamorphosis changes the structures involved in gas exchange over the life cycle of animals in the clade Anura, and what evolutionary advantage this change provides.

30.

Describe the functions of the three extra-embryonic membranes present in amniotic eggs.

31.

What characteristics differentiate lizards and snakes?

32.

Based on how reptiles thermoregulate, which climates would you predict to have the highest reptile population density, and why?

33.

Explain why birds are thought to have evolved from theropod dinosaurs.

34.

Describe three skeletal adaptations that allow for flight in birds.

35.

How would the chest structure differ between ostriches, penguins, and terns?

36.

Describe three unique features of the mammalian skeletal system.

37.

Describe three characteristics of the mammalian brain that differ from other vertebrates.

38.

How did the evolution of jaw musculature allow mammals to spread?

39.

How did archaic Homo sapiens differ from anatomically modern humans?

40.

Why is it so difficult to determine the sequence of hominin ancestors that have led to modern Homo sapiens?

PreviousNext
Order a print copy
Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution-NonCommercial-ShareAlike License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute OpenStax, and must distribute any derivative works under the same license.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/biology-2e/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/biology-2e/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Jul 22, 2026 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.