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Researcher in cell cycle control. Russell coauthored experiments showing inhibitory phosphorylation of Cdc2 by human Wee1, connecting kinase action with regulation of cell division.^[ref]

The pectoral girdle supports the anterior paired appendages and connects them with the trunk. In humans, the scapula and clavicle provide a mobile arrangement for the upper limb. Comparative anatomy asks which components and connections are shared among vertebrate lineages.

The penis is an external organ containing the terminal urethra and erectile tissue. In human anatomy it participates in urinary outflow and reproductive delivery. Its vascular erectile mechanism is distinct from the neural and muscular coordination of ejaculation.

Coauthor of Anatomy and Physiology 2e by J. Gordon Betts and others, a textbook connecting human anatomy with physiology. Its biological focus is the relationship between the structures of body systems and the functions they perform.^[ref]

Coauthor of research on brain responses to skin warming and cooling. The study connected controlled thermal stimulation with regional signals measured by positron emission tomography in awake humans.^[ref]

A phalanx is a bone of an anatomical digit. Human fingers and toes have serially arranged phalanges, with counts differing among digits. The term identifies a segment within a digit rather than a whole finger or toe.

A physician is a medically trained professional who investigates and manages human disease and disorders of function. Medical reasoning connects a person's history and examination findings to explanations of altered anatomy and physiology, while comparing alternative causes rather than treating one symptom as a diagnosis.

A polar body is a small product of the unequal divisions of oogenesis. The divisions separate chromosomes while retaining most cytoplasm in the developing ovum. Producing several chromosome-containing products therefore need not mean producing several equivalent eggs.

In the standard human account, the first polar body follows the first meiotic division; completion of the second division produces another. Their formation illustrates the difference between chromosome segregation and equal partition of cellular resources.^[ref]

A substance or other agent contributing to pollution. Its effect cannot generally be inferred from the human biological population alone.

The primary visual cortex, often abbreviated V1, is an early cortical stage of visual processing. Its neurons have receptive fields: changing a stimulus in a particular part of the visible scene can change their spike trains. Orientation selectivity adds a further distinction: at the same location, a properly aligned bar can evoke a strong response while a rotated bar evokes little. Simple cells make the dependence on local position and visual contrast especially clear. See the original experiments under orientation selectivity and simple cell.

In their 1962 study, David Hubel and Torsten Wiesel recorded from forty cats under thiopental anesthesia, maintained light anesthesia while monitoring cortical electrical activity, and used succinylcholine to stabilize the eyes. White-light patterns were projected onto a screen $1.5\mathrm{m}$ away. Extracellular single-unit recording with tungsten electrodes sampled individual units; receptive fields were mapped separately for each eye. This connected controlled stimulus geometry to individual spike trains. ^[ref]

These acute, anesthetized-cat recordings do not directly measure human perception or responses during awake behavior. The useful idea is a local description of structure: a population can distinguish where a feature lies, which way it is aligned, and which side is brighter. The signed spatial filter model of a simple cell turns that idea into a computable example. One neuron's preferred stimulus does not establish recognition of an entire object. Likewise, orientation selectivity in one neuron and an orderly map of preferences across primary visual cortex are different findings: rodents can have strong orientation selectivity without the orderly arrangement typical of some other species. ^[ref] The existing correlation-based development of visual cortical maps and orientation-map self-organization sections describe hypotheses about how organization develops.

Researcher in antibody engineering. Jones and collaborators replaced antigen-recognition regions of a human antibody with mouse counterparts, connecting retained binding specificity with the design of humanized antibodies.^[ref]

Qafzeh is a cave locality in the Levant with early Homo sapiens remains. Its importance lies in the evidence it supplies for human presence outside Africa before the later widespread expansion of living human populations. Anatomical identification, the age of the enclosing deposits and evidence about occupation are separate observations that must be combined when reconstructing dispersal.

Researcher in early human history. Ferring and collaborators investigated the Dmanisi occupation record and its dating to about 1.85–1.78 million years ago, connecting archaeological evidence with the timing of early human dispersal.^[ref]

Reproductive anatomy concerns the organs, ducts and supporting structures involved in gamete production, delivery and support of developing offspring. Human gonads produce gametes and hormones, while other structures perform transport, secretion or gestational roles. Shared proximity to urinary structures does not make the two systems identical.^[ref]

The respiratory system supplies the pathways and exchange surfaces for movement of respiratory gases. In humans, the trachea and branching airways conduct air to alveoli, while the respiratory diaphragm and other respiratory muscles change thoracic volume. Ventilation moves air; exchange with blood additionally requires an appropriate surface and circulation.

The rhesus macaque, Macaca mulatta, is an Old World monkey used in research on physiology, animal behaviour and neuroscience. Its importance as a model depends on the particular trait and comparison, not on an assumption of complete equivalence to humans.

Researcher whose work connects chemical evidence of dairying with human evolution. Evershed and collaborators studied the history of milk use and lactase persistence in Europe, separating evidence for dairy consumption from the inherited capacity to digest milk in adulthood.^[ref]

Coauthor of research on brain responses to skin warming and cooling. The study connected controlled thermal stimulation with regional signals measured by positron emission tomography in awake humans.^[ref]

Saccharomyces cerevisiae is a particular species of yeast, used in baking, brewing and laboratory research. During ordinary vegetative growth it reproduces by budding: a smaller daughter grows from the mother before separation. Laboratory strains can be maintained as either haploid or diploid biological cells. This makes it possible to investigate genes in a single eukaryote, then use controlled crosses and meiosis to connect a genotype to a phenotype. See Burgess, Powers and Mell, Budding Yeast Saccharomyces cerevisiae as a Model Genetic Organism (2017), pp. 1–2.

The practical value of Saccharomyces cerevisiae as a model organism is the combination of easy laboratory cultivation, accessible genetics, and cellular functions shared with other eukaryotes. A haploid strain has one set of chromosomes, so a changed allele is not accompanied by a second copy at that genetic locus. But a mutation need not produce an observable phenotype under every condition. The yeast is also a whole organism, not a miniature human: transferring a result requires evidence that the relevant function is shared in the target system. See Duina, Miller and Keeney, Budding Yeast for Budding Geneticists (2014): cultivation, genetic tools and conserved functions.

For a concrete example, Hartwell, Culotti and Reid's 1970 work followed temperature-sensitive Saccharomyces cerevisiae strains with successive microscope photographs. Failure to complete a particular part of the cell cycle helped identify required gene functions. Their distinction between when a function is required and where a cell finally stops is especially instructive: the visible endpoint need not be the time of the underlying defect. See Hartwell, Culotti and Reid, Genetic control of the cell-division cycle in yeast. I. Detection of mutants (1970): primary abstract. This is a useful way to turn an observable change in a biological cell into a question about genes and causal order.

In alcoholic fermentation, Saccharomyces cerevisiae converts sugars into ethanol and carbon dioxide. The carbon dioxide helps dough rise; the ethanol is useful in alcoholic drinks. The metabolism also supports production of ATP, a usable cellular energy carrier. This is one metabolic ability of one species, not the definition of every yeast. See Clark, Douglas and Choi, Biology 2e, 7.5: alcohol fermentation and the Burgess, Powers and Mell account above.

For glucose, the ideal net stoichiometry isOne molecule of glucose supplies six carbon chemical atoms: four end up in the two ethanol molecules and two in the two carbon dioxide molecules. The twelve hydrogen and six oxygen chemical atoms also balance. This is a net material balance across several enzyme-catalyzed steps, not a single chemical reaction step or the complete bookkeeping for cellular energy carriers. The standard pathway accounting yields a net two ATP per glucose: the initial breakdown produces the ATP, while the later conversion to ethanol regenerates a coenzyme needed to keep the breakdown going. See Clark, Douglas and Choi, Biology 2e, 7.2: net ATP accounting and the section 7.5 cited above.

At complete conversion, this toy gives $20\mathrm{mmol}$ of ethanol and $20\mathrm{mmol}$ of carbon dioxide. The carbon balance is $6\times 10=2\times 20+1\times 20=60\mathrm{mmol}$ of carbon chemical atoms. A real culture also builds cellular material, can use other metabolic routes, and may retain dissolved carbon dioxide; the toy is a reference balance rather than a prediction of collected gas or beverage yield.

Although alcoholic fermentation does not require molecular oxygen as a reactant, the presence of molecular oxygen does not force Saccharomyces cerevisiae to stop fermenting. De Deken's 1966 experiments reported predominantly fermentative glucose use during exponential growth in air. Consequently, bubbles do not establish either absence of molecular oxygen or an exclusively fermentative metabolism. See De Deken, The Crabtree Effect: A Regulatory System in Yeast (1966): primary abstract.

Systems and practices that safely separate human waste from contact with people and the environment. It connects infrastructure and behavior with interruption of fecal contamination pathways.^[ref]