I. Primexine development in Passiflora racemosa Brot.: overlooked aspects of development

Developmental stages during the tetrad period were examined in detail by transmission electron microscopy with an emphasis on substructure. Our purpose was to find out whether the sequence of sporoderm developmental events provides additional evidence for our recent hypothesis on the underlying cause of exine ontogeny as a sequence of self-assembling micellar mesophases initiated by genomically given physicochemical parameters. Osmiophilic globules encrusting the surface of postmeiotic microspores and tapetal cells are temporary prepattern units which come first. The second prepattern structures are highly ordered bundles of microfilaments and microtubules which determine the position of microspore surface invaginations and clusters of the glycocalyx inside them. The first glycocalyx units are microgranules which during the middle tetrad stage rearrange into radially oriented rod-like units. The latter form lens-like clusters of the glycocalyx-1, located inside the invaginations. These clusters predestine the position of the future luminae in the exine reticulum. The second glycocalyx layer is laid down as a continuous layer over the whole microspore surface and has similar substructure, that is radial rods. Glycocalyx-2 is a framework for procolumellae which appear at the late tetrad stage. Therefore, the sequence of substructural units in the primexine is: globules, microgranules, rod-like units, and layers of radially oriented rods tightly packed in the periplasmic space. This sequence corresponds to the first three mesophases of self-assembling micelles: spherical micelles, cylindrical micelles, and layers of hexagonally packed cylindrical micelles (middle mesophase). We observed the same sequence in other species during primexine development, and the findings of this study provide new evidence for our hypothesis.     

Sporoderm and tapetum development in Eupomatia laurina (Eupomatiaceae). An interpretation

For the first time, the developmental events in the course of exine structure establishment have been traced in detail with TEM in Eupomatia, with the addition of cytochemical tests. A new look at unfolding events is suggested using our recent hypothesis on self-assembling micellar mesophases. The process proved to be unusual and includes “ghost” stages. The first units observed in the periplasmic space are spherical ones (= normal spherical micelles). These accumulate, resulting in a granular layer up to middle tetrad stage. Sporopollenin precursor accumulation on these units makes the ectexine layer looking as homogenous at late tetrad stage. Simultaneously, the columns of globules are added in the periplasmic space, which reminds an attempt to form columellae; but, the process failed. Instead, a fimbrillate endexine layer of compressed globules appears. The latter augments via additional globules, appearing in the periplasmic space in the free microspore period. The endexine formation is double-stepped spatially and temporally. The second, lamellate endexine layer (laminate micelles) appears late in development, when the channeled intine-I is already established—a very unusual feature. Moreover, a “fenestrated” stage comes unexpectedly at vacuolate stage, when hitherto amorphous ectexine appears pierced by cavernae—the results of reversal of normal spherical micelles (constituents of ectexine) to reverse the ones that open their cores for the entrance of hydrophilic nutrients from tapetum and give them over to the microspore cytoplasm by exchanging their solubilizates.     

Exine and tapetum development in Symphytum officinale (Boraginaceae). Exine substructure and its interpretation

After detailing the exine ontogeny, our purpose was to find out whether the sequence of sporoderm developmental events corresponds to self-assembling micellar mesophases, initiated by genomically determined physicochemical parameters and induced by surfactant glycoproteins at increasing concentrations. Indeed, a scaffolding of the future exine, i.e., the glycocalyx, initiates with scattered clots, which then appear as clusters of spherical and worm-like micelles, derived from surface-active glycoproteins. At the middle tetrad stage, a continuous layer of the glycocalyx emerges, consisting of parallel, tightly packed cylinder-like units, which we interpret as a layer of cylindrical micelles, the so-called middle mesophase. These units bear dark-contrasted particles, arranged in strings or columns. These sites of the glycocalyx units?Cmicelles accumulate initial sporopollenin, hence the term ??sporopollenin acceptor particles?? (SAPs). This process leads to the appearance of procolumellae at the late tetrad stage. The glycocalyx units are rooted into callose and into the microspore cytoplasm. After formation of the tectum and the foot layer, the endexine initiates as a thin layer, and the latter develops into a very thick layer in the post-tetrad period. When callose disintegrates, ??bouquets?? of SAPs become evident on the tectum, which were evidently hidden inside the callose layer; these structures self-assemble into supratectal gemmae. An unusual, ??hybrid?? type of tapetum was observed. What is observed in Symphytum exine development allows us to obtain more evidence for the hypothesis of the participation of micellar self-assembly in sporoderm development and to bring together the concepts of micelles and of SAPs.     

II. Exine development in Passiflora racemosa Brot.: post-tetrad period. Overlooked aspects of development

Developmental stages during the post-tetrad period are examined in detail with TEM and SEM, with emphasis upon substructure. Our purpose was to find out whether the sequence of sporoderm developmental events gives additional evidence for our recent hypothesis on the underlying cause of exine ontogeny as a sequence of self-assembling micellar mesophases, initiated by genomically given physico-chemical parameters. Four different layers of the endexine are developed in the post-tetrad period. The first one is a layer of white line centered lamellae which appear as a demarcation line between ect- and endexine. The second layer is sponge-like and consists of “roots” of columellae and a layer between them. The third layer consists of basally disposed radially elongated granules which appear in the aperture sites only. The fourth layer emerges in interapertural sites only and is formed as stacks of uneven lamellae. Therefore, the sequence of substructural units in primexine is the next: white-lined lamellae, a layer of honeycombed substructure, globule-to-rod-like granules, stacks of wavy lamellae. These sequences correspond to the next four mesophases of self-assembling micelles: neat (=laminate) micelles, high-concentrated emulsion of sponge-like (=foam-like) substructure, spherical-to-cylindrical micelles, and laminate micelles with fenestrated laminae. Reiteration of the micellar mesophases, participating in endexine development, is observed during the post-tetrad period.     

Pollen wall ontogeny in <Emphasis Type="Italic">Polemonium caeruleum</Emphasis> (Polemoniaceae) and suggested underlying mechanisms of development

By a detailed ontogenetic study of Polemonium caeruleum pollen, tracing each stage of development at high TEM resolution, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Polemonium caeruleum, observed in the microspore periplasmic space, are spherical units, gradually transforming into columns, then to rod-like units (procolumellae), the appearance of the initial tectum, growth of columellae in height and tectum in thickness and initial sporopollenin accumulation on them, the appearance of the endexine lamellae and of dark-contrasted particles on the tectum, the appearance of a sponge-like layer and of the intine in aperture sites, the appearance of the foot layer on the base of the sponge-like layer and of spinules on the tectum, and massive sporopollenin accumulation. This sequence of developmental events fits well to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental exine simulations) strong evidence that genome and self-assembly probably share control of exine formation. It is highly probable that self-assembly is an intrinsic instrument of evolution.     

An integral insight into pollen wall development: involvement of physical processes in exine ontogeny in Calycanthus floridus L., with an experimental approach

We aimed to understand the underlying mechanisms of development in the sporopollenin-containing part of the pollen wall, the exine, one of the most complex cell walls in plants. Our hypothesis is that distinct physical processes, phase separation and micellar self-assembly, underpinexine development by taking the molecular building blocks, determined and synthesised by the genome, through several phase transitions. To test this hypothesis, we traced each stage of microspore development in Calycanthus floridus with transmission electron microscopy and then generated in vitro experimental simulations corresponding to every developmental stage. The sequence of structures observed within the periplasmic space around developing microspores starts with spherical units, which are rearranged into columns to then form rod-like units (the young columellae) and, finally, white line centred endexine lamellae. Phase separation precedes each developmental stage. The set of experimental simulations, obtained as self-assembled micellar mesophases formed at the interface between lipid and water compartments, was the same: spherical micelles; columns of spherical micelles; cylindrical micelles; and laminate micelles, separated by gaps, resembling white-lined lamellae. Thus, patterns simulating structures observed at the main stages of exine development in C. floridus were obtained from in vitro experiments, and hence purely physicochemical processes can construct exine-like patterns. This highlights the important part played by physical processes that are not under direct genomic control and share influence on the emerging ultrastructure with the genome during exine development. These findings suggest that a new approach to ontogenetic studies, including a consideration of physical factors, is required for a better understanding of developmental processes.     

A new look at sporoderm ontogeny in Persea americana and the hidden side of development

Background and Aims

The phenomenon of self-assembly, widespread in both the living and the non-living world, is a key mechanism in sporoderm pattern formation. Observations in developmental palynology appear in a new light if they are regarded as aspects of a sequence of micellar colloidal mesophases at genomically controlled initial parameters. The exine of Persea is reduced to ornamentaion (spines and gemmae with underlying skin-like ectexine); there is no endexine. Development of Persea exine was analysed based on the idea that ornamentation of pollen occurs largely by self-assembly.

Methods

Flower buds were collected from trees grown in greenhouses over 11 years in order to examine all the main developmental stages, including the very short tetrad period. After fixing, sections were examined using transmission electron microscopy.

Key Results and Conclusions

The locations of future spines are determined by lipid droplets in invaginations of the microspore plasma membrane. The addition of new sporopollenin monomers into these invaginations leads to the appearance of chimeric polymersomes, which, after splitting into two individual assemblies, give rise to both liquid-crystal conical ‘skeletons’ of spines and spherical micelles. After autopolymerization of sporopollenin, spines emerge around their skeletons, nested into clusters of globules. These clusters and single globules between spines appear on a base of spherical micelles. The intine also develops on the base of micellar mesophases. Colloidal chemistry helps to provide a more general understanding of the processes and explains recurrent features of pollen walls from remote taxa.     

On the mechanism of SDS‐induced protein denaturation

To understand the mechanism of ionic detergent‐induced protein denaturation, this study examines the action of sodium dodecyl sulfate on ferrocytochrome c conformation under neutral and strongly alkaline conditions. Equilibrium and stopped‐flow kinetic results consistently suggest that tertiary structure unfolding in the submicellar and chain expansion in the micellar range of SDS concentrations are the two major and discrete events in the perturbation of protein structure. The nature of interaction between the detergent and the protein is predominantly hydrophobic in the submicellar and exclusively hydrophobic at micellar levels of SDS concentration. The observation that SDS also interacts with a highly denatured and negatively charged form of ferrocytochrome c suggests that the interaction is independent of structure, conformation, and ionization state of the protein. The expansion of the protein chain at micellar concentration of SDS is driven by coulombic repulsion between the protein‐bound micelles, and the micelles and anionic amino acid side chains. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 186–199, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Provinciality of the Mediterranean lower Jurassic brachiopod fauna: Causes and plate-tectonic implications

The composition of 23 “NW European” and “Mediterranean” Lower Jurassic (Pliensbachian) brachiopod faunas is compared at the species level. On the basis of this quantitative approach, the two “provinces” can be delimited more sharply than by earlier qualitative studies. In the author's opinion the most reasonable cause of the provinciality is as follows: in the Middle Triassic a segment of the European shelf became rifted, detached and drifted toward the open Tethys ocean. Being isolated, the brachiopods of this province could produce evolutionary lineages different from the European ones. If the presence of this contiguous and separate Triassic—Jurassic microcontinent characterized by Mediterranean brachiopod faunas is assumed, this factor should be borne in mind in the reconstructions concerning the closure of the Tethys (= Alpine orogeny).     

Formulation and Characterization of Phytophenol-Carrying Antimicrobial Microemulsions

Phytophenols were solubilized in nonionic surfactant micelles to form antimicrobially active and thermodynamically stable microemulsions. Formulation of phytophenols in microemulsions has previously been shown to improve their antimicrobial activity in model microbiological and food systems. Carvacrol and eugenol were incorporated in micellar solutions of two nonionic surfactants (Surfynol® 485W and Surfynol® 465) by mixing at room temperature. Particle size of formed microemulsions was determined by dynamic light scattering, and structural information about the mixed micellar system was obtained by nuclear magnetic resonance spectroscopy (NMR). Uptake of carvacrol and eugenol in surfactant micelles as determined by ultrasonic velocity measurements was very rapid, e.g., below the maximum additive concentration, the phytophenols were completely solubilized in the micelles in less than 30 min. Depending on the surfactant–phytophenol combination, the self-assembled surfactant–phytophenol aggregates had mean particle diameters between 3 and 17 nm. Elucidation of the structure of aggregates by 1H NMR studies indicated that micelles had a “bracket-like” structure with phytophenols being located inside the palisade layer of the micelle in direct contact with adjacent surfactant monomers. Encapsulation of phytophenols in surfactant micelles enables the incorporation of large amounts of hydrophobic antimicrobials in aqueous phases. Formulation of antimicrobial microemulsions may thus offer a means to deliver high concentrations of phytophenols to the bacterial surfaces of foodborne pathogens to affect kill.     

Multizooidal Budding in Parasmittina trispinosa (Johnston) (Bryozoa,Cheilostomata)

Two principally different wall types occur in the bryozoan colony: Exterior walls delimiting the super-individual, the colony, against its surroundings and interior walls dividing the body cavity of the colony thus defined into units which develop into sub-individuals, the zooids. In the gymnolaemate bryozoans generally, whether uniserial or multiserial, the longitudinal zooid walls are exterior, the transverse (proximal and distal) zooid walls interior ones. The radiating zooid rows grow apically to form “tubes” each surrounded by exterior walls but subdivided by interior (transverse) walls. The stenolaemate bryozoans show a contrasting mode of growth in which the colony swells in the distal direction to form one confluent cavity surrounded by an exterior wall but internally subdivided into zooids by interior walls. In the otherwise typical gymnolaemate Parasmittina trispinosa the growing edge is composed of a series of “giant buds” each surrounded by exterior walls on its lateral, frontal, basal and distal sides and forming an undifferentiated chamber usually 2–3 times as broad and 3 or more times as long as the final zooid. Its lumen is subdivided by interior walls into zooids 2–3, occasionally 4, in breadth. This type of zooid formation is therefore similar to the “common bud” or, better-named, “multizooidal budding” characteristic of the stenoleamates but has certainly evolved independently as a special modification of the usual gymnolaemate budding.     

Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence

It has long been assumed that serial homologues are ancestrally similar—polysomerism resulting from a “duplication” or “repetition” of forms—and then often diverge—anisomerism, for example, as they become adapted to perform different tasks as is the case with the forelimb and hind limbs of humans. However, such an assumption, with crucial implications for comparative, evolutionary, and developmental biology, and for evolutionary developmental biology, has in general not really been tested by a broad analysis of the available empirical data. Perhaps not surprisingly, more recent anatomical comparisons, as well as molecular knowledge of how, for example, serial appendicular structures are patterned along with different anteroposterior regions of the body axis of bilateral animals, and how “homologous” patterning domains do not necessarily mark “homologous” morphological domains, are putting in question this paradigm. In fact, apart from showing that many so-called “serial homologues” might not be similar at all, recent works have shown that in at least some cases some “serial” structures are indeed more similar to each other in derived taxa than in phylogenetically more ancestral ones, as pointed out by authors such as Owen. In this article, we are taking a step back to question whether such assumptions are actually correct at all, in the first place. In particular, we review other cases of so-called “serial homologues” such as insect wings, arthropod walking appendages, Dipteran thoracic bristles, and the vertebrae, ribs, teeth, myomeres, feathers, and hairs of chordate animals. We show that: (a) there are almost never cases of true ancestral similarity; (b) in evolution, such structures—for example, vertebra—and/or their subparts—for example, “transverse processes”—many times display trends toward less similarity while in many others display trends toward more similarity, that is, one cannot say that there is a clear, overall trend to anisomerism.     

Delimitation of evolutionary units in Cuvier’s dwarf caiman, <Emphasis Type="Italic">Paleosuchus palpebrosus</Emphasis> (Cuvier, 1807): insights from conservation of a broadly distributed species

An important goal of evolutionary and conservation biology is the identification of units below the species level, such as Evolutionarily Significant Units (ESUs), providing objectively delimited units for species conservation and management. In this study we tested the hypothesis that Cuvier’s dwarf caiman (Paleosuchus palpebrosus)—a species broadly distributed across several biomes and watersheds of South America—is comprised of different ESUs. We analyzed mitochondrial cytochrome b sequences of 206 individuals and 532 unlinked ddRAD loci of 20 individuals chosen from amongst the mitochondrial haplogroups. Analysis of the cytochrome b sequences revealed four mitochondrial clusters, while STRUCTURE analysis of ddRAD loci detected three genomic clusters with different levels of mixture between them. Using the Adaptive Evolutionary Conservation (AEC) framework we identified three ESUs: “Amazon”, “Madeira-Bolivia” and “Pantanal”; one of them composed of two different Management Units (MUs), “Madeira” and “Bolivia”. In general, based on the comparisons with other crocodilian species, genetic diversity of each lineage was moderate however, the Madeira MU showed fivefold lower genetic diversity than other geographic groups. Considering the particularities of each Paleosuchus palpebrosus conservation unit, we recommend that the conservation status of each is evaluated separately. Tropical biodiversity is largely underestimated and in this context the broadly distributed species are the most likely candidates to harbor distinct evolutionary lineages. Thus, we suggest that conservation research should not neglect species that are generally considered of Least Concern by IUCN due to the taxon’s broad geographic distribution.     

Phylogeny of the Metazoa Based on Morphological and 18S Ribosomal DNA Evidence

Cladistic analysis of traditional (i.e. morphological, developmental, ultrastructural) and molecular (18S rDNA) data sets (276+501 informative characters) provides a hypothesis about relationships of all meta-zoan higher taxa. Monophyly of Metazoa, Epith-eliozoa (= -03non-Porifera), Triploblastica, Mesozoa, Eutriploblastica (=Rhabditophora+Catenulida+“higher triploblasts”=Neotriploblastica, including Xeno- turbellida and Gnathostomulida), Rhabditophora, Syndermata (=“Rotifera”+Acanthocephala), Neotrichozoa (=Gastrotricha+Gnathostomulida), Nematozoa (=Nematoda+Nematomorpha), Panarthropoda (=Onychophora+Tardigrada+ Arthropoda), Cephalorhyncha, Deuterostomia, Ambulacralia (=Hemichordata+Echinodermata), Chordata, Phoronozoa (=Phoronida+“Brachiopoda”), Bryozoa, Trochozoa (=Eutrochozoa+Entoprocta+ Cycliophora), Eutrochozoa, and Chaetifera (=Annelida+ Pogonophora+Echiura) is strongly supported. Cnidaria (including Myxozoa), Ecdysozoa (=Cepha- lorhyncha + Nematozoa + Chaetognatha + Panarthropoda), Eucoelomata (=Bryozoa+Phoronozoa+Deuterostomia+Trochozoa, possibly including also Xenoturbellida), and Deuterostomia+Phoronozoa probably are monophyletic. Most traditional “phyla” are monophyletic, except for Porifera, Cnidaria (excluding Myxozoa), Platyhelminthes, Brachiopoda, and Rotifera. Three “hot” regions of the tree remain quite unresolved: basal Epitheliozoa, basal Triploblastica, and basal Neotriploblastica. A new phylogenetic classification of the Metazoa including 35 formally recognized phyla (Silicispongea, Calcispongea, Placozoa, Cnidaria, Ctenophora, Acoela, Nemertodermatida, Orthonecta, Rhombozoa, Rhabditophora, Catenulida, Syndermata, Gnathostomulida, Gastrotricha, Cephalorhyncha, Chaetognatha, Nematoda, Nematomorpha, Onychophora, Tardigrada, Arthropoda, Echinodermata, Hemichordata, Chordata, Phoronozoa, Bryozoa s. str., Xenoturbellida, Entoprocta, Cycliophora, Nemertea, Mollusca, Sipuncula, Echiura, Pogonophora, and Annelida) and few i ncertae sedis g roups (e.g. Myzostomida and Lobatocerebromorpha) is proposed.     

Structural analysis of the S-Layer of Lampropedia hyalina

The two-dimensional (2D) structure of the regularly structured surface layer (S-layer) of the gram-negative eubacterium Lampropedia hyalina has been determined at the molecular level to a nominal resolution of 2.1 nm by transmission electron microscopy and digital image processing. The inner, or “perforate,” layer consists of dimeric block-shaped units located at two-fold symmetry axes. These morphological dimers associate around three-fold symmetry axes to form a continuous layer with p6 symmetry and a lattice constant of 14.6 ± 0.4 nm. Scanning transmission electron microscopy (STEM) yields a mass-per-area (MPA) value for the perforate layer of 3.5 kDa/nm². The outer, or “punctate,” layer is composed of long, roughly cylindrical units centered on six-fold symmetry axes, which are connected by six fine linking arms joining at the three-fold symmetry axes to create a hexagonal layer with a lattice constant of 25.6 ± 0.5 nm. The MPA of the “composite”-i.e., perforate plus punctate—layer is 10.2 kDa/nm².     

Cholera toxin modifies diverse GTP-modulated regulatory proteins

Using thin layer chromatography (TLC) and various colorimetric procedures, the exometabolite of $\text{Leishmania}\text{donovani}$ was shown to be a novel glycopeptidophosphosphingolipid. In aqueous medium the exometabolite aggregated to form micellar structures of high molecular weight. Purity of the various preparations and the novel nature of the micellar structures was demonstrated by TLC. These micelles are unique because they do not break up upon solvation in organic solvents. This indicates that once the supramolecular structure is established, its integrity is maintained by forces other than the apolar ones involved in its formation.     

Challenging limits: Ultrastructure and size‐related functional constraints of the compound eye of Stigmella microtheriella (Lepidoptera: Nepticulidae)

With a body length of only 2 mm, the nepticulid Stigmella microtheriella (Stainton, 1854) is one of the smallest moths known to date. We investigated the optical design of its lemon‐shaped compound eyes, which measure 83.60 μm in anterior–posterior and 119.77 μm in dorso‐ventral direction. The eyes consist of about 123 facets, each of the latter just 9.9 μm in diameter. Transmission electron microscopy reveals an optical design with features intermediate between apposition and superposition optics similar to that known from two other small species of moths (one Nepticulid and one Gracillarid). Size‐related evolutionary adaptations of the ommatidial organization include (1) the involvement of only five rhabdomeres in the formation of the distal rhabdom (2) the complete absence of a rhabdomere of the eighth (= basal) retinula cell, (3) the “hourglass” shape of the rhabdom with a characteristic narrow waist separating distal from proximal portion, and (4) the reduction to one single layer of tracheoles as an adaptation to the overall restricted space available in this minute eye. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

Neuronal organization of the accessory olfactory bulb of the lizard Podarcis hispanica: Golgi study

The neuronal organization of the accessory olfactory bulb (AOB), which receives sensory information from the vomeronasal organ, was described in a squamate reptile (Podarcis hispanica) by means of light microscopy. Using the Golgi-impregnation method, seven neuronal types could be distinguished: Periglomerular cells constitute a morphologically heterogeneous population of small neurons located between and around the glomeruli. The mitral cells are diffusely distributed in the AOB. Their cell bodies are usually located within the mitral cell layer, but some of them could be also observed in the plexiform layers. Mitral cells were classified into three subgroups on the basis of their sizes and dendritic tree morphologies. Thus, the “outer mitral cells” have the biggest cell bodies, and their distal secondary dendrites are mainly distributed rostrocaudally in the external plexiform layer. The “inner mitral cells” have large cell bodies, and their secondary dendrites are distributed dorsoventrally and are located deeper than those of the other two subgroups. The third type, the “small mitral cells,” is the smallest one among mitral cells in the AOB, and from their cell bodies, only two main dendritic trunks arise. The granule cells are composed of several categories based on their different cell body locations and dendritic tree morphologies. Thus, the “superficial granule cells” are located exclusively in the external plexiform layer and have small dendritic fields. The “middle granule cells” have fusiform cell bodies—situated in the internal plexiform layer—and present a wide dendritic projection area. Finally, the “deep granule cells” are distributed throughout the granule cell layer and include a great variety of dendritic tree morphologies. The distribution and morphological features of all neuronal types constituting the AOB of Podarcis were compared with those reported on other vertebrates. The results suggest that the lamination pattern and neuronal organization of the AOB in lizards are more similar to that of mammals than to that of the remaining vertebrates.     

Functionality Versus “Typical Product” Measures of Technological Progress

Technological progress and adoption are fundamentally interconnected with environmental challenges faced by society. At the product level, researchers often explore the interplay between technological change and the environment by tracking trends in impacts per unit functionality—for example, gasoline consumed per distance traveled by a vehicle. In this article, we explore an alternative measure: “typical product.” A typical product measure accounts for changes in consumers’ demand and use of products as product quality improves—for example, gasoline consumed for a typical driving pattern for a vehicle. We compare and contrast functionality and typical product measures through a case study of electricity use to fabricate Intel desktop microprocessors from 1995 to 2006. The functionality normalization is measured in terms of electricity use per transistor produced. Results show rapid and sustained exponential decrease. The “typical product” measures electricity use per typical desktop microprocessor of a given year (e.g., a Pentium II in 1998, a Pentium IV in 2002). Results show that, despite fluctuations, energy use per typical microprocessor is roughly constant over the 12‐year period. The explanation of this result is that although technological progress dramatically reduces the energy needed per transistor, it also induces demand for more powerful chips, which contain many more transistors. The typical product measure has applications in defining functional units in life cycle assessment, characterizing rebound effects, and measuring energy efficiency trends.