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Biology: OpenStax

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Biology Cover is copyrighted by Rice University. It is not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.

Description: Published by OpenStax College, Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

Author: Yael Avissar, Rhode Island College, Jung Choi, Georgia Institute of Technology, Jean DeSaix, University of North Carolina, Vladimir Jurukovski, Suffolk County Community College, Robert Wise, University of Wisconsin, Connie Rye, East Mississippi Community College

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Biology: OpenStax by Yael Avissar, Rhode Island College, Jung Choi, Georgia Institute of Technology, Jean DeSaix, University of North Carolina, Vladimir Jurukovski, Suffolk County Community College, Robert Wise, University of Wisconsin, Connie Rye, East Mississippi Community College is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.


Review this book

Reviews for 'Biology'

Number of reviews: 3
Average Rating: 3.57 out of 5

1. Reviewed by: Dr. Kate Pettem
  • Institution: Camosun College
  • Title/Position: Instructor, Biology
  • Overall Rating: 3.7 out of 5
  • Date:
  • License: Creative Commons License

Q: The text covers all areas and ideas of the subject appropriately and provides an effective index and/or glossary

• The text appears to be very comprehensive. The index at the start of the text is very useful for navigation.
• The glossary appears comprehensive, however, many duplicates (ie. hydrophobic and Hydrophobic) were noted in the index. Furthermore, these duplicates appear to reference different pages.
• The listing of key words with definitions at the end of each chapter is a useful feature, since students can reference key words for that specific chapter easily and quickly.
• Yes it is but a lack of internal referencing is evident.

Comprehensiveness Rating: 4 out of 5

Q: Content is accurate, error-free and unbiased

• Diagrams and written content both appeared to be accurate.
• One exception: it appears that there is an error on page 150 in the image labeling frontal and transverse planes in the goat (at least the image doesn’t seem to match the description in the text).
• The reviewers did not notice any bias in the text. Any ethical issues (for example, reproductive technologies) were handled carefully but with technical accuracy.
• Error page 371. Paternal leakage means that not every mitochondrial DNA is from the female.
• Error p. 322 color is spelled with the American spelling.
• Error p.375 I was unaware that Rosalyn Franklin was considered for the Nobel prize…should have been.
• Typo in bicarbonate image in Ch.2
• p.214 error (again) in the equations/arrows.

Content Accuracy Rating: 4 out of 5

Q: Content is up-to-date, but not in a way that will quickly make the text obsolete within a short period of time. The text is written and/or arranged in such a way that necessary updates will be relatively easy and straightforward to implement

• Content seemed very up-to-date.
• The reviewers noticed that care was taken to include recent findings (for example, neurogenesis and BrdU labeling; epigenetics; personalized medicine).
• The basics / foundations were covered in an appropriate manner so that the text will not become out of date very quickly.
• The sections on anatomy and physiology of the human body had a nice mix of explaining structures and functions, and linking these with disorders to make the content more relevant and interesting.
• I have no impression that it will be quickly out of date.

Relevance Rating: 5 out of 5

Q: The text is written in lucid, accessible prose, and provides adequate context for any jargon/technical terminology used

• Text was written clearly and was fairly engaging to read. Overall text was a good mix between technical / scientific jargon and everyday language.
• Many examples and connections were included to help students stay interested (for example, links in the macromolecules section to “low carb” diets and Celiac disease).
• Learning objectives presented at the start of each section are also very useful for students to focus their reading. Learning objectives were phrased in a clear way using verbs to help students understand exactly what is expected of them.
• End of chapter questions are also a nice addition for students to practice (especially since answers are provided at end of text).
• The depth at which material is covered seems appropriate for a first year majors biology course.
• I found real problems with chapters 12-15 and 17. I found them very densely written. Concepts did not flow one into another. Lack references to previous text sections to review basic concepts, like meiosis.
• P.375 PCR is introduced before it is explained.
• P. 451 How can student “get” cDNA in one sentence?
• P.451 Probes must be explained much more completely.
• P.459 I think linkage maps belong elsewhere.
• P.464 I think a microarray image is very important here.
• I think the entire first paragraph of chapter 7 needs a do over.

Clarity Rating: 3 out of 5

Q: The text is internally consistent in terms of terminology and framework

• Overall most of the text reads as if a single author were involved; no major differences in writing style were noted between chapters.
• The layout and flow of the text (intro paragraph, learning objectives, text, etc) was consistent throughout.
• I felt there were distinctly different voices and styles between the Genetic portions and the other parts.
• I don’t think chapter 7 will be useful in a non-majors course build on basic concepts. Where could I direct a student without any biology background to begin?
• Chapter 7 glycolysis gives all the steps, but where is the simple overview?

Consistency Rating: 3 out of 5

Q: The text is easily and readily divisible into smaller reading sections that can be assigned at different points within the course (i.e., enormous blocks of text without subheadings should be avoided). The text should not be overly self-referential, and should be easily reorganized and realigned with various subunits of a course without presenting much disruption to the reader.

• Use of bolded key words helps readers pick out important terms.
• The number and placement of headings and sub-headings seemed appropriate – not too many that the flow of text was disrupted, but not too few that readers would have to stretch on and on with simple text.
• Headings and subheadings are clearly labeled so sections can be found easily.
• Text didn’t self-reference too much, which is very useful for classes that only cover part of the text.
• I thought this was very poor. I could not image how to part of a chapter to cover the basics of a topic. Very evident in Cellular respiration chapter
• p.401 A very odd experiment to throw in.
• Jumping to the electron transport system is an odd way to start in 7.1.

Modularity Rating: 3 out of 5

Q: The topics in the text are presented in a logical, clear fashion

• Overall, topics seem to flow nicely within individual chapters and also are appropriately ordered within the larger Units.
• Complex topics are built up slowly and in a logical way.
• Rather good in Chapters 1,2,16,18 and 19.
• Rather poor in 7, 12-15 and 17.

Organization Rating: 3 out of 5

Q: The text is free of significant interface issues, including navigation problems, distortion of images/charts, and any other display features that may distract or confuse the reader

• Interface is overall clearly laid out, but is not particularly engaging visually
• The margins are very large, resulting in a proportionately small text size. Images in the text also do not make a very good use of space. A two-column format may be more appropriate.
• Poor use of page space / too much white space also makes this text a poor fit for reading online, particularly on devices such as iPad, tablet, eReaders where screen size is smaller and the text /content is intended to fill the entire screen space.
• Overall figures / images were good and clearly demonstrated the concepts, although occasionally they look somewhat unprofessional when compared to other similar texts. Occasionally figures also look grainy / blurry or as if they are low-resolution images (ex. Page 149).
• The “Art Connection” headings seem unnecessary. These images are similar or complimentary to others displayed in the main text, and labeling them as “Art” seems strange.
• Would it be possible to move the image credits to an Appendix at the end of the text? They create unnecessary clutter on the page / in the figure caption.
• Use of tables was appropriate and any information in tables was presented in a clear and organized manner, without extraneous details.
• I thought many images had a random quality. For example 14.3, a dead mouse image was unhelpful in understanding this classic experiment.
• Especially in the first image for the chapter. 12.1, 15.1,16.1,17.1 all were poor choices. 18.1 too dark. 12.7 needed to show red, white and pink phenotypes.
• p.356 Where is the phenotype associated with the G/C phenotype?
• p.358 Please show the McClintock strategy as well.
• p.359 Why show a karyotype where the colours don’t match up for the homologues? Ie #21’s and #10’s
• Show more water molecules in shell of hydration image fig. 2.15
• Include blood in pH figure 2.19

Interface Rating: 2 out of 5

Q: The text contains no grammatical errors

• No grammatical errors were noted.
• Exception: Noted unnecessary use of ( ) on pg. 122 – an entire sentence was inside the parentheses.

Grammar Rating: 5 out of 5

Q: The text is not culturally insensitive or offensive in any way. It should make use of examples that are inclusive of a variety of races, ethnicities, and backgrounds

• Content did not seem culturally insensitive or offensive.
• I noticed nothing culturally insentitive.

Cultural Relevance Rating: 5 out of 5

Q: Are there any other comments you would like to make about this book, for example, its appropriateness in a Canadian context or specific updates you think need to be made?

• Career Connections are great throughout, but some appear to be written from an American perspective. Special interest topics also fail to mention Canadian content (for example, laws governing reproductive technologies and “designer babies”).
• Links to online content varied in quality and ability to engage students in a dynamic way. Some videos were very good and modern, while some animations seemed overly simplistic.
• Nothing caught my attention regarding Canadian content. (other than the colour/color thing)
• I think you need to hire someone to give the text a consistent voice and internal refences.


2. Reviewed by: Kuo-Hsing Kuo
  • Institution: University of Northern British Columbia
  • Title/Position: Associate Professor
  • Overall Rating: 3.4 out of 5
  • Date:
  • License: Creative Commons License

Q: The text covers all areas and ideas of the subject appropriately and provides an effective index and/or glossary

The text is well-written and easy to read and understand.

Comprehensiveness Rating: 4 out of 5

Q: Content is accurate, error-free and unbiased

The textbook is aimed to provide fundamental knowledge at a general reading level. The content is up to date with no glaring and serious mistakes. However, there are several mistakes that do need to be corrected. For instance, in Figure 40.15/Page 1178, the branch after the Thoracic aorta is named the Abdominal aorta; its branches include the Celiac trunk, Superior Mesenteric artery (mistakenly labeled as Gastric artery)…, and it becomes the Common Iliac artery (mistakenly labeled as Iliac artery) …

Content Accuracy Rating: 2 out of 5

Q: Content is up-to-date, but not in a way that will quickly make the text obsolete within a short period of time. The text is written and/or arranged in such a way that necessary updates will be relatively easy and straightforward to implement

The textbook has taken good advantage of the use of figures in describing concepts and structures. I would agree that the relevance is one of the strengths of the textbook.

Relevance Rating: 4 out of 5

Q: The text is written in lucid, accessible prose, and provides adequate context for any jargon/technical terminology used

The textbook may need some improvements with clarity. For instance, in Figure 41.5/page 1194, the major and minor calyces are introduced unclearly in the description and there are no labels provided to follow.

Clarity Rating: 3 out of 5

Q: The text is internally consistent in terms of terminology and framework

The terminology and framework are consistent throughout the whole text.

Consistency Rating: 4 out of 5

Q: The text is easily and readily divisible into smaller reading sections that can be assigned at different points within the course (i.e., enormous blocks of text without subheadings should be avoided). The text should not be overly self-referential, and should be easily reorganized and realigned with various subunits of a course without presenting much disruption to the reader.

The textbook is divisible into smaller reading sections and it is self-referential.

Modularity Rating: 4 out of 5

Q: The topics in the text are presented in a logical, clear fashion

It is acceptable for a general reading level.

Organization Rating: 4 out of 5

Q: The text is free of significant interface issues, including navigation problems, distortion of images/charts, and any other display features that may distract or confuse the reader

The interface is acceptable. It would definitely improve the interface if there were a softer color scheme. The contrast of the colors is too strong which detracts the reader from the content.

Interface Rating: 3 out of 5

Q: The text contains no grammatical errors

I found there are no issues.

Grammar Rating: 4 out of 5

Q: The text is not culturally insensitive or offensive in any way. It should make use of examples that are inclusive of a variety of races, ethnicities, and backgrounds

The majority of the photos in this textbook are images adopted from American-based resources. It may be more suitable for Canadian students if there were more images from Canada-based resources.

Cultural Relevance Rating: 2 out of 5

Q: Are there any other comments you would like to make about this book, for example, its appropriateness in a Canadian context or specific updates you think need to be made?

The content and organization of the textbook have great potential to be a popular textbook if the clarity and interface were improved. I still would not recommend my students this current version as it may not be easy to follow and is at times confusing.

3. Reviewed by: Joan Sharp
  • Institution: Simon Fraser University
  • Title/Position: Senior Lecturer
  • Overall Rating: 3.6 out of 5
  • Date:
  • License: Creative Commons License

Q: The text covers all areas and ideas of the subject appropriately and provides an effective index and/or glossary

The text covers most necessary areas, but not always with clarity or accuracy. The index and glossary are fine.

In Chapter 18, the text only includes the biological species concept, with no discussion of its weaknesses or limitations. Other species concepts should be included and the pros and cons of each should be discussed.

Comprehensiveness Rating: 4 out of 5

Q: Content is accurate, error-free and unbiased

I noted many errors in the text and I’m sure there are many more.
• On page 65, the text states, “Hydrogen bonds are also involved in various recognition processes, such as DNA complementary base pairing and the binding of an enzyme to its substrate, as illustrated in Figure 2.28.” The figure illustrates the former, but not the latter. Plus the right hand side of the drawing is labeled as Cytosine bonded to adenine. Why are two base pairs (T-A and incorrectly labeled C-G) shown? Students will be confused and uncertain how the two strands are represented. Although the text states that H-bonds create the double-helix structure, this is not shown in the Figure.
• On page 90, the text states, “Being the outermost structure in animal cells, the plasma membrane is responsible for the transport of materials and cellular recognition and it is involved in cell-to-cell communication.” Why only animal cells?
• On page 96, the text states, “The structural difference between a normal hemoglobin molecule and a sickle cell molecule—which dramatically decreases life expectancy—is a single amino acid of the 600.” No, the sickle cell hemoglobin only decreases life expectancy in homozygous individuals.
• There are two errors on page 125: “Have you ever noticed that when you bite into a raw vegetable, like celery, it crunches? That’s because you are tearing the rigid cell walls of the celery cells with your teeth.” No, it’s not the cell walls. It’s the lignified schlerenchyma cells. “Fungal and protistan cells also have cell walls.” No, not all protists have cell walls.
• On page 159, crenation does not mean shrinkage but refers to the effect of shrinkage on the cell membrane.
• On page 186, the text states, “ATP is a highly unstable molecule.” No, not at the range of pH in most cells. If this statement were true, the energy of ATP could not be used to supply energy to reactions within cells.
• In Chapter 8, the text states, “The energy extracted today by the burning of coal and petroleum products represents sunlight energy captured and stored by photosynthesis almost 200 million years ago.” No, fossil fuels formed in the Paleozoic, which ended 252 mya.
• On page 243, the text states, “Every single atom of matter and energy is conserved, recycling over and over infinitely.” No, this is not so. Energy is conserved, but does not recycle, as energy is lost as heat in each chemical reaction.
• In Chapter 11, the text states, “Spores are haploid cells that can produce a haploid organism or can fuse with another spore to form a diploid cell.” Spores never fuse with other spores to form diploid cells. It also states, “Some plants produce spores.” No, all plants produce spores.
• This statement on page 488 is not necessarily true: “A geographically continuous population has a gene pool that is relatively homogeneous. Gene flow, the movement of alleles across the range of the species, is relatively free because individuals can move and then mate with individuals in their new location. Thus, the frequency of an allele at one end of a distribution will be similar to the frequency of the allele at the other end.” It’s inaccurate to claim that allele frequencies do not change over the range of a species.
• On page 503, the text states, “Evolutionary theory states that humans, beetles, plants, and bacteria all share a common ancestor, but that millions of years of evolution have shaped each of these organisms into the forms seen today.” No, billions of years.
• In Figure 45.10, there is no such thing as “the carrying capacity of seals”. Carrying capacity is a feature of a population’s environment, not of the population.
• The text uses the terms primitive and advanced for extant taxa. This terminology is out-of-date and reinforces student misconceptions of evolutionary change as goal-directed and progressive.

There are a number of concepts or topics that are very poorly explained. In some cases, it appears that the authors do not fully understand them. Here are some examples; I’m sure there are many more.
• On page 52, the text states, “Like hydrogen bonds, van der Waals interactions are weak attractions or interactions between molecules. Van der Waals attractions can occur between any two or more molecules and are dependent on slight fluctuations of the electron densities, which are not always symmetrical around an atom. For these attractions to happen, the molecules need to be very close to one another. These bonds, along with hydrogen bonds, help form the three-dimensional structure of the proteins in our cells that is necessary for their proper function.” In fact, interactions between R-groups on amino acids are more important than Van der Waals attractions in stabilizing 3D structure in proteins.
• In Figure 5.12 and throughout the text and chapter questions, the terms hypertonic, isotonic, and hypotonic are used to describe single solutions. You cannot refer to solutions as hypertonic, isotonic, and hypotonic except in comparison to other solutions. The text and figure reinforce a common and significant student error that prevents clear understanding of this key concept.
• On page 749, the text says, “In the following Cenozoic Era, mammals radiated into terrestrial and aquatic niches once occupied by dinosaurs.” No, the aquatic reptiles of the Mesozoic were not dinosaurs. Many seven-year-olds could correct the authors on this one.
• On page 1304, the text states, “Animals faced with temperature fluctuations may respond with adaptations, such as migration, in order to survive.” This reinforces a common and deeply rooted student misconception that organisms adapt in order to survive. Frankly, I was surprised and appalled to see this sentence in a university level textbook.
• On page 1360, the explanation of keystone species is very weak and insufficient to answer the critical thinking question at the end of the chapter.
• The very brief discussion of sociobiology on page 1372 is biased, sketchy, and inaccurate: “Sociobiology also links genes with behaviors and has been associated with biological determinism, the belief that all behaviors are hardwired into our genes.”
• The text generally takes a traditional approach to behavior, with insufficient discussion of behavioral ecology.

Content Accuracy Rating: 2 out of 5

Q: Content is up-to-date, but not in a way that will quickly make the text obsolete within a short period of time. The text is written and/or arranged in such a way that necessary updates will be relatively easy and straightforward to implement

I noted quite a few examples of out of date terminology and concepts. I’m sure there are many more.
• Archaea get very short shrift in this textbook. On page 30, the text says, “Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles.” This would be fine if the text then went on to explain that we now realize that Archaea are far more widespread than previously thought, but the discussion ends there. In fact, throughout the textbook, bacteria are mentioned in contexts where bacteria and archaea should both be included. Students are generally not familiar with archaea and it seems the authors of this textbook share this lack of understanding.
• On page 479, the text states that “Natural selection [is] also known as “survival of the fittest.” This outdated phrase is not challenged or revised.
• The terms “warm-blooded” and “cold-blooded” are used throughout the text, e.g., page 749: “The mostly cold-blooded dinosaurs ceded their dominance of the landscape to more warm-blooded mammals.” These terms are highly inaccurate. Terrestrial vertebrates differ in the source of body heat and in the variation in temperature they experience and can tolerate, not in the temperature of their blood. The biologically accurate terms are ectothermic and endothermic. Again, this seems to reflect a lack of understanding on the part of the authors, as the inaccurate terms are used consistently.
• The terms higher and lower organisms are used throughout the text. This is outdated terminology that has no place in a general biology textbook.
• There are many cases in which the authors refer to plants and animals, rather than including all relevant taxa. Again, this reinforces student misconceptions and lack of familiarity with fungi, protists, and prokaryotes. Examples are found on page 27: “A community is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the forest’s community;” in Figure 6.3: “Both plants and animals use cellular respiration to derive energy from the organic molecules originally produced by plants;” and on page 228: “Photosynthesis is essential to all life on earth; both plants and animals depend on it.”
• On page 804, the text states, “The notochord, however, is not found in the postnatal stage of vertebrates.” On page 807, it says, “In adult vertebrates, the vertebral column replaces the notochord, which is only seen in the embryonic stage.” Not so! Consider extinct vertebrate taxa (e.g., ostracoderms and Placoderms) and extant taxa (e.g., lungfishes) that have unconstricted notochords.
• On page 807, the text states, “Based on molecular analysis, vertebrates appear to be more closely related to lancelets (cephalochordates) than to tunicates (urochordates) among the invertebrate chordates. This evidence suggests that the cephalochordates diverged from Urochordata and the vertebrates subsequently diverged from the cephalochordates.” Nope, that’s out of date. More recent genomic analysis has identified cephalochordates as the most basal chordates. Tunicates and vertebrates are sister taxa that diverged more recently. Urochordate and vertebrate embryos share a novel embryonic tissue layer: migratory neural crest cells.
• On page 808, the text states, “We will consider hagfishes and lampreys together as jawless fishes, the agnathans, although emerging classification schemes separate them into chordate jawless fishes (the hagfishes) and vertebrate jawless fishes (the lampreys).” This is incorrect and out-of-date. In fact, recent genomic evidence shows that hagfishes and lampreys form a clade, the cyclostomes: Hagfishes and lampreys share four unique miDNA families. The term Agnatha was abandoned long ago, as jawless fishes include cyclostomes and ostracoderms and are not a clade.

Relevance Rating: 3 out of 5

Q: The text is written in lucid, accessible prose, and provides adequate context for any jargon/technical terminology used

There are a number of examples of complex terms or concepts that are not clearly explained. Here are some examples:
• In Chapter 3, the Evolution Connection on cytochrome C is not well explained: “When human and rhesus monkey sequences were compared, the single difference found was in one amino acid. In another comparison, human to yeast sequencing shows a difference in the 44th position.” This suggests that humans and yeast are as closely related as humans and rhesus monkeys. And why specify the position of the one change? The significance of these comparisons is not explained.
• On page 94, the term homology is used but not clearly defined or explained.
• Figure 3.32 is not helpful and does not show H-bonding or antiparallel arrangement clearly.
• Unless I missed it, the R in Figure 2.27 is undefined.
• On page 54, this sentence requires a fuller explanation: “Cells can only survive freezing if the water in them is temporarily replaced by another liquid like glycerol.”
• This explanation on page 58 is overly simplified: “So how do the cells of the stomach survive in such an acidic environment? How do they homeostatically maintain the near neutral pH inside them? The answer is that they cannot do it and are constantly dying. New stomach cells are constantly produced to replace dead ones, which are digested by the stomach acids.”
• On page 154, the text states, “For example, think about someone opening a bottle of ammonia in a room filled with people. The ammonia gas is at its highest concentration in the bottle; its lowest concentration is at the edges of the room. The ammonia vapor will diffuse, or spread away, from the bottle, and gradually, more and more people will smell the ammonia as it spreads.” No! This is an example of convection, NOT diffusion. Diffusion plays a key role in the movement of molecules across plasma membranes, which are only 8 nm thick. Many students imagine that diffusion explains the spread of molecules of dye in a beaker of water or the movement of molecules of scent in a room and this example feeds this misconception. It is also important to emphasize to students that diffusion is an effective and important process for transport of molecules over small distances but is completely irrelevant at macrocopic scales. See Vogel (1994) Dealing honestly with diffusion. American Biology Teacher 56:7, 405-407.
• On page 242, the discussion of CAM and C4 photosynthesis is far too brief.
• On page 285, the text states, “Cells in G0 phase are not actively preparing to divide. The cell is in a quiescent (inactive) stage that occurs when cells exit the cell cycle.” A G0 cell is far from quiescent metabolically and this term will mislead students.
• On page 313, the explanation of The Red Queen Hypothesis in the Evolution Connection is very weak and unclear.
• On page 481, the text fails to explain why a mutation may be neutral.
• On page 496, the explanation of punctuated equilibrium is very weak.
• On page 518, the term linkage disequilibrium is very poorly explained.
• In Chapter 19, the discussion of some evolutionary mechanisms, e.g., nonrandom and assortative mating, is very sketchy.

Chapter 20 shows a very weak understanding of a key topic: phylogeny. Students struggle with “tree-thinking”, a necessary skill for anyone who plans to continue in biology. Phylogenetic trees are poorly explained in this chapter and the discussion on how to construct them is confusing. I honestly do not think that the author has a clear understanding of this important topic.
Some examples:
• On page 524, phylogeny is very poorly defined: “Phylogeny describes the relationships of an organism, such as from which organisms it is thought to have evolved, to which species it is most closely related, and so forth.” Ouch!
• On the same page, “ Scientists consider phylogenetic trees to be a hypothesis of the evolutionary past since one cannot go back to confirm the proposed relationships.” Yes, phylogenetic trees represent hypotheses about evolutionary relationships, but not because these hypotheses cannot be tested!
• In Figure 20.7: “For example, the bones in the wings of bats and birds have homologous structures.” This is a poor example, since these wings are both homologous as vertebrate forelimbs and analogous as wings. Later, the text (page 530) says, “Some structures are both analogous and homologous: the wings of a bird and the wings of a bat are both homologous and analogous.” True, but the author does not explain why these structures are both homologous and analogous!
• The chapter appears confused about how time is represented in phylogenetic trees, saying both that trees do and do not have a time axis.
• On page 534, the text states, “The vertebrate in Figure 20.10 is a shared ancestral character.” Huh?
• The discussion of horizontal gene transfer is very lengthy but very poorly written. For example, the discussion of Lake’s work would not be accessible to general biology students. It’s not clear that the author understands it, frankly.

Clarity Rating: 2 out of 5

Q: The text is internally consistent in terms of terminology and framework

Many terms are used before they are defined. I noted several examples and I am sure that there are many more.
• On page 24, the term “germline cells” is used but is not clearly defined.
• In Figure 1.16, just before three domains are introduced, many taxa (species and higher taxa) are introduced with no context.
• On page 80, the term “daltons” is used but not defined.
• The term “emulsification of fats” is used on page 90 but not defined or explained until page 988.
• On page 151, the term “monocyte” is used but not defined.
• On page 538, the terms “proteobacteria” and “Gram-negative bacteria” are introduced without explanation.

It’s unusual to address adaptive radiation and extinction primarily in the ecology chapters instead of the evolution section. Personally, I do not support this organization.

Consistency Rating: 3 out of 5

Q: The text is easily and readily divisible into smaller reading sections that can be assigned at different points within the course (i.e., enormous blocks of text without subheadings should be avoided). The text should not be overly self-referential, and should be easily reorganized and realigned with various subunits of a course without presenting much disruption to the reader.

The text is fine in this regard.

Modularity Rating: 5 out of 5

Q: The topics in the text are presented in a logical, clear fashion

I noted several examples in which material is explained clearly in one part of the text, with inaccurate or inconsistent information in other places. I’m sure there were many others.
• On page 188, the text states, “Due to this jigsaw puzzle-like match between an enzyme and its substrates (which adapts to find the best fit between the transition state and the active site), enzymes are known for their specificity.” No, it’s not like a jigsaw puzzle. This will confuse students, many of whom have trouble grasping induced fit, which is introduced on the next page.
• On page 482, the text states, “Although natural selection may work in a single generation on an individual, it can take thousands or even millions of years for the genotype of an entire species to evolve.” The idea that evolution and speciation require millennia is included as a misconception later in the chapter!
• On page 676, the text confounds green algae and charophytes, referring to all green algae as charophytes. The distinction between charophytes and the other taxon within the green algae was made clearly in Chapter 23. The distinction is also clear on page 682.

Organization Rating: 3 out of 5

Q: The text is free of significant interface issues, including navigation problems, distortion of images/charts, and any other display features that may distract or confuse the reader

I did not note any problems with the interface.

Interface Rating: 5 out of 5

Q: The text contains no grammatical errors

The text contains few grammatical and spelling errors. Here are a few errors that I noted:
• On page 54: Unites States
• In Figure 4.6: “Relatives sizes on a log scale”
• On page 123: “… proteins synthesis is an essential function of all cells”
• On page 176, this sentence is very poorly written, with a full and confusing sentence in brackets: “Photosynthesis is the primary pathway in which photosynthetic organisms like plants (the majority of global synthesis is done by planktonic algae) harvest the sun’s energy and convert it into carbohydrates.”
• Gene and allele names/letters and variables in equations should be italicized, but are not. This is a problem throughout the text.
• On page 486, this sentence is incomplete: “Define species and describe how species are identified as different”

Grammar Rating: 4 out of 5

Q: The text is not culturally insensitive or offensive in any way. It should make use of examples that are inclusive of a variety of races, ethnicities, and backgrounds

The text is not culturally insensitive and uses a wide variety of examples.

Cultural Relevance Rating: 5 out of 5

Q: Are there any other comments you would like to make about this book, for example, its appropriateness in a Canadian context or specific updates you think need to be made?

There are many examples (e.g., government regulations such as the FDA, examples of careers) that are American and explicitly not Canadian.

American spelling is used throughout, which is fine with me.

The text has some good features.
• Learning outcomes are specified throughout and are clear and complete.
• The Career Connection sections are good, although they are definitely American and not Canadian.
• The critical thinking questions are generally pretty good. Do students have access to answers to these questions and to the others included in some figures? If so, how?
• One of the best features is the Everyday Connection sections, which are imaginative and will be interesting to students.
• The introduction to scientific approach and the culture of science is generally good.

One very serious weakness of this text is the art: the figures, the animations, and the Art Connection features. They are very basic and do little to help students visualize biological concepts and structures. Some of them (Figure 5.11, Figure 18.6) are truly awful.

Currently available textbooks have made huge strides in producing carefully rendered and accurate illustrations and animations that are produced by talented teams of artists and animators. I realize that it is impossible to provide this quality of artwork in an open source textbook, but I think it is also important to recognize how important such features are for students attempting to visualize complex structures and to master difficult concepts. It is a false savings to provide a free textbook that lacks features that are crucial and necessary to student understanding of what is, frankly, very challenging material.