Q: The text covers all areas and ideas of the subject appropriately and provides an effective index and/or glossary
The textbook covers all the relevant content that other major introductory/general biology textbooks cover, although not quite with the same depth as the most detailed texts. The index and glossary are effective and well-organized, and overall the coverage is likely appropriate as a base for most introductory biology courses. The chapters covering the diversity of organisms make for excellent reference material, providing enough information for a novice to appreciate the main characteristics of the various organisms without being overwhelming with details.
I also found that, like virtually all textbooks on the market, this text is lacks a few (in my opinion, essential) topics/ideas, that is:
• A chapter dedicated on how genetic variation can lead to phenotypic variation, including a solid explanation of what a phenotypes are (i.e., not just macroscopic traits visible to the naked eye, but also molecular, biochemical, cellular, or physiological characteristics), then some real examples where students can clearly see how a change in DNA sequence can lead to a change in RNA sequence or amount, how this may be reflected at the level of the protein and of its function, then at the cellular, physiological, and maybe morphological levels.
• A section or, better, examples interspersed throughout the relevant chapters, dealing with the idea that all phenotypes are a matter of degree, and that there is variation among individuals with the same genotype (even in the same environmental conditions). For instance, if we were to look at all of Mendel’s yellow peas, we would see that some are “yellower” than others. Similarly, tall his “tall” plants were not equally tall. Within a natural population (e.g. humans), if we look at all individuals with a certain genotype for one or a few loci, we will also see variation. Another example, hemophilia A (which is mentioned in the text) has different levels of severity, and is not truly recessive in that there is a broad range of FVIII levels observed among heterozygotes (as is the case across all genotypes), and some heterozygotes even have complete hemophilia A diagnoses.
• A section (and application of this to as many examples as possible) on the role, and crucial importance of “environment” in phenotypes, including an explanation of what “environment” is (i.e., not just the abiotic conditions outside of an organism’s body, but also the physiological and cellular microenvironments to which genes are exposed).
The reason why these topics and ideas are extremely important, especially at the introductory level, is that the “traditional” way in which genetics is taught, very deterministic, categorical, without consideration for the role of environment, has been shown to lead to, or reinforce genetic essentialism, which in turn can fuel prejudice against all kinds of groups (Donovan & Nehm provide a nice review of the relevant literature on this here: https://doi.org/10.1007/s11191-020-00180-0)
Comprehensiveness Rating: 4 out of 5
Q: Content is accurate, error-free and unbiased
I found the text to be relatively unbiased in terms of coverage when compared to other general biology texts; in particular, I appreciate it not being overly anthropocentric.
I noticed a number of inaccuracies in terminology, and sometimes in explanations, as well as a few factual errors, throughout the text. Some of these inaccuracies are likely due to the need for simplification when writing for a novice audience, but others are problematic because they reflect or reinforce common student misconceptions or misunderstanding. Here are a few examples of the latter, related to content that we cover in my class:
• Diagrams representing crossovers/chiasmata (e.g. Fig 11.3, 12.18, Fig. 17.11 in the hard copy version) inaccurately depict two non-sister chromatids “flopping over” each other instead of remaining tightly paired with their respective sisters. Sister chromatids are held together tightly by cohesins, crossovers occur before prophase, when homologs pair up (finding each other by sequence homology through base pairing).
• Figure 6.2. Energy flow diagram: shows decomposers producing heat/releasing some energy as heat, but not plants or animals. This can reinforce the frequent misconception that plants (in particular) do not release heat and instead are 100% energy efficient.
• In the Mendelian genetics chapter there are multiple inaccuracies in the section on characteristics and traits. Moreover, the ways in which genes and alleles are talked about throughout the textbook are often imprecise, and repeats and reinforces the inaccurate idea that there is a linear, direct correspondence between the presence of a given allele and the development of a given phenotype (there are a couple of excellent articles by Smith that provide examples on how to provide simple, yet accurate instruction and information in this area - https://doi.org/10.1525/abt.2014.76.4.2
and https://doi.org/10.1525/abt.2014.76.5.3 )
• The section on evidence of evolution (in Ch. 18) at times uses circular logic, presenting inferences and hypotheses as if they were evidence providing an explanation.
• The way in which photosynthesis is talked about in some instances (e.g. Fig. 6.3.), while not necessarily incorrect, reinforces students’ misconception that plants build mass from sunlight energy, as opposed to using sunlight energy to excite electrons that will drive the regeneration of ATP and reducing power utilized to turn atmospheric carbon into useful organic molecules. Because this is such a tough misconception/misunderstanding to dispel (so many students believe that plants turn energy into mass), it would be helpful if every opportunity to do so was taken advantage of.
• A minor point regarding Fig. 27.8: in developmental biology (and in reference to relevant invertebrates) the terms "anterior" and posterior" are used, and we talk about the antero-posterior axis of a developing animal. In developmental biology, we also use this for vertebrates. It would be helpful to include this in the diagram.
Content Accuracy Rating: 3 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
Generally speaking, I found the content up-to-date and free of information that could soon become obsolete. There are however a few places that could be updated:
• some of the inaccuracies that I noticed reflect outdated understanding of biological processes (e.g. descriptions of homologous chromosome pairing and crossing over at meiosis).
• Nowadays, most phylogenies and phylogenetic studies are based on genome sequence information, but this is not illustrated or presented at all in the text. The section o Limitations of Phylogenetic Trees in Ch 20 is quite outdated, as most of those limitations are overcome by the use of genomic data to construct phylogenies (the section could be updated by focusing on how using morphological characteristics has limitations, which are overcome in large part using genomics).
• The section describing what species are and how we define them is a bit outdated and incomplete, focusing only on the biological species concept, which by its definition can only apply to organisms that reproduce with each other. The concept of genetic/phylogenetic species is very commonly used nowadays, and the concepts of morphological species and ecological species could be mentioned too, since in some cases they also come into play.
• The chapter on Biotechnology and Genomics could be updated with more current techniques (e.g. hardly anyone uses Southern blots anymore; while the principle behind the technique is interesting, the diagram in Figure 17.6. does not do a good job at explaining the procedure, and the description misses the crucial digestion step, so why not illustrate northern blots, which came back into fashion with the explosion of the miRNA field?). Proteomics and transcriptomics could also be added to the other “omics” already included, as they are very commonly used nowadays.
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 text is reasonably clear and technical jargon is usually explained and/or put into context. Some of the diagrams are small and hard to read on the paper copy of the textbook (this is not an issue with the electronic version). In some cases, diagrams/figures would be clearer with some annotations (e.g. Fig. 23.9. could include some annotation pointing out which groups among those presented are considered protists, since the section is about protists).
In some cases, topics and ideas are treated in a rather abstract manner and may benefit from more context related to everyday experience. For example, the chapter on macromolecules does a great job explaining how the various macromolecules are formed, but does not tell the reader where they are formed, who forms them, or how the food we eat is broken down into its components that are then used for various purposes (over the years I have heard several students wonder why we need to eat proteins if we can make our own through the process of translation or, conversely, why do we need to do translation to produce proteins, since we get them from food).
The chapters covering various aspects of metabolism (cellular respiration, photosynthesis) provide an excellent biochemical basis to understand those processes, but do not connect to the biology of the cells and organisms that use them (e.g. where does each part of the pathway take place? Where do the waste products go? Where do the initial substrates come from, and how do they get to the location where they get processed? Where does the ATP go, and what is it used for? What about the NADH/NADPH?).
Clarity Rating: 4 out of 5
Q: The text is internally consistent in terms of terminology and framework
Overall I found the text excellent in terms of internal consistency. The only (minor) inconsistencies are in the use of scientific names of organisms, which sometimes are included and included following the common English name, and sometimes not, and in the types of end-of-chapter questions listed as “critical thinking questions”. I found these questions to vary widely in terms of how much critical thinking they really involve, with some of them requiring application of principles, use of analytical skills, or deduction, while others are very descriptive and merely require recall/paraphrasing.
Consistency Rating: 5 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.
I found the modularity excellent; the text lends itself perfectly to assigning small sections at a time, which makes it easily adaptable to almost any course.. The flip side of that is that, in my opinion, most of the topics and concepts are presented somewhat “in their own silos” – see comments related to the flow and organization. Finding a way to combine the excellent modularity with some way of making connections across topics and chapters would be amazing.
I realize that having both modularity and inter-chapter connections is not simple, and I don’t have a magic solution for it, but it would make the textbook much stronger.
Modularity Rating: 5 out of 5
Q: The topics in the text are presented in a logical, clear fashion
Unfortunately, one of the side-effects of the text’s excellent modularity is that is does not draw connections across ideas, topics, concepts or examples (something that novice students have a lot of difficulty doing for themselves, and with which they truly need all the help they can get). One could almost read the chapters in any order!
Making reference, within one section/paragraph/module to other relevant sections/paragraphs/modules in other chapters, and explicitly describing the connections, would be incredibly helpful for students, who find this notoriously challenging. Going through the textbook from my perspective as a first year instructor, and thinking about what I would assign as pre-readings for my students, I found myself jumping around allover the book and coming up with lists of paragraphs from multiple chapters, and making mental notes about additional material that I should include to help students make connections.
A few examples where connections are important and students have a lot of difficulty making them (even after being shown): relationship between DNA replication and a linear unreplicated chromosome that goes from being composed of just one DNA molecule (“one chromatid”) to a replicated chromosome composed of two sister chromatids; relationship between energy flow and metabolism within an organism and energy flow within an ecosystem; flow of mass within and organism and within an ecosystem (i.e., when an animal hibernates and loses all that fat, where does the fat goes? What does it become?); and between Mendelian and population genetics.
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 have not found any issues with the interface, but I cannot speak for a student’s perspective.
Interface Rating: 5 out of 5
Q: The text contains no grammatical errors
I must admit that I have not read every word carefully as one would do for proofreading. I have not noticed spelling errors or grammatical issues that hinder the clarity or potential for understanding the text.
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
I did not find offensive language per se, however, I found the content and examples to be white, Western, male biased. Also, as described in some of my comments under “comprehensiveness” and “accuracy”, the way in which the book talks about genetics is problematic not only in terms of accuracy, but also in terms of diversity and inclusion. Finally, I found that the way in which some of the concepts and ideas are presented are reinforcing stereotypes and/or a “dichotomous”, or “binary” view of the world. One example is in the section about sexual selection (Ch. 19), where the book states that males are often larger and more decorated. First, I am not sure this is true (are males often larger? It may be true with mammals, but what about amphibians? Arthropods? Within a species, would all males be bigger than all females?). From a diversity and inclusion perspective, the goal should always be to take advantage of the amazing variation that nature offers to show students that all kinds of situations and scenarios exist (e.g. there are cases where females are on average larger/smaller/same size as males, where males are on average more/less/equally decorated as females, etc). This is especially important when talking about a topic such as sexual dimorphism (or lack thereof), which people often implicitly try to relate to sexual dimorphism and roles in humans.
The term sex-role reversed is very laden and, if it is deemed an important technical term, it should be explained very carefully and put into context (as should the term “sex role”). There are also statements about humans and many other animals having their sex determined by their chromosomes, and although that is true in the majority of cases, there are also a non-negligible number of exceptions. From a diversity and inclusion perspective it is extremely important to take the opportunity and emphasize these exceptions not only to help making all students feel included, but also to correct the overly dichotomous/binary view held by the majority.
Similarly, although maybe to a lesser extent, I find it problematic to refer to a family member who has relatives affected by a genetic disorder as “healthy” to indicate that they themselves do not have the disorder – one can have a genetic disorder (or any disorder) and still be healthy; it is important that students move away from equating having a genetic or chronic condition to being sick or unhealthy.
I am not saying that this textbook is worse than others (I find that most textbook have at least some of these issues). However, I find these issues problematic, and if I were to use this text, I feel like I would be left with a lot of explanation to do in and out of class to counter some of these problems, just as I would with virtually all textbooks to some degree. My score for this aspect is low, but it would be low for other textbooks too. Also, this score refers to the text in terms of content only. The fact that the textbook is freely accessible is extremely positive in terms of diversity and inclusion (it removes the financial barrier that typical textbooks bring with them, which is fantastic).
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?
I do recommend this book as a potential alternative to most other first year/general biology textbooks. It is comparable to the average text and comes free of charge (the online version) or at very low cost (print), which is a very important consideration in terms of accessibility and affordability.