Cambrian Explosion Research Articles

Short-stasis signatures in Cambrian and Ordovician shallow-marine sandstones: Implications for the ichnological record and time preserved at outcrop

Shallow-marine sandstones are an archetypal facies in the stratigraphic record of the Cambrian Explosion and the Ordovician Radiation but have been considered uninformative due to erosional signatures, time-incompleteness, and unfossiliferous outcrops. New analyses of the Carnedd-y-Filliast Grits (Furongian, Wales) and littoral sandstone successions from Laurentia and Baltica reveal that bedding planes in such outcrops commonly register sedimentary stasis. Most stasis intervals were brief, reflecting 1) a high sedimentation frequency; 2) post-depositional substrate resculpting by wave action during ‘active-layer stasis’, inhibiting infaunal colonization and rendering the surface representative of only the interval immediately preceding burial; and 3) the low preservation-potential of longer-stasis surfaces, which mainly occur within heterolithic packages that, in low-subsidence settings, are commonly eroded and replaced by amalgamation surfaces between sandstones. The short-stasis signature of littoral sandstones renders meter-scale architectural elements relatively time-complete but biases their fossil record at outcrop. Short-stasis surfaces are high-resolution snapshots but form incomplete representations of ancient ecosystems compared to surfaces that capture longer intervals. As such, the predominance of short-stasis surfaces contributed to the low ichnodiversity and sparse fossil content of littoral sandstones, implying that early Palaeozoic littoral ecosystems were more biodiverse than their known record suggests.

Himatiichnus mangano igen. et isp. nov., a scalidophoran trace fossil from the late Ediacaran of Namibia.

Himatiichnus mangano igen. et isp. nov., a new trace fossil from the late Ediacaran Huns Member of the Urusis Formation, southern Namibia, comprises intertwining tubes exhibiting dual lineation patterns and reminiscent of both modern and early Cambrian examples of priapulid worm burrows. These similarities support the interpretation of a total-group scalidophoran tracemaker for H. mangano, thus providing direct evidence for the first appearance date of Scalidophora in the late Ediacaran ca 539 Ma. This new material is thus indicative of the presence of total-group scalidophorans below the Cambrian boundary and supports inference of a lengthy Precambrian fuse for the Cambrian explosion.

Pilot Federated Analysis Projects

The Cambrian explosion of Trusted Research Environments (TREs) will inevitably lead to increased data siloing and potentially decrease achievable data science. Federated access to data is a mitigation against this risk. The presentation will cover two major infrastructure demonstrator projects to address this need and start the UK journey towards interconnected TRE’s. TELEPORT was an infrastructure to connect TREs and allow all the data assets to be seen through a single pane of glass while leaving them in situ; the analysis can be performed on each data asset, as well as combining data from multiple TREs to derive knowledge. The analysis is performed within the construct of a pop-up TRE, which is a temporary project-specific TRE. The data governance model is operated in an as-is state, with all egress controls being applied upon extraction of research output. This method has been termed Federated Data. TREFX is a set of infrastructure based around international GA4GH standards and the RO-CRATE concept to provide a platform to send complex workflows to the TRE’s to be performed upon the data assets, with the output post egress checking to be re-packed into the inbound RO-CRATE prior to being returned to the researcher. This method addresses both federated analysis and method reproducibility. This project was extended to cover ADDI workloads for dementia. Both solutions were jointly developed by Swansea University / SeRP and share common elements. Future work will see both these products being combined into a hybrid approach as well as spin-out products and services.

Why animals construct helical burrows: Construction vs. post-construction benefits.

The extended phenotype of helical burrowing behavior in animals has evolved independently many times since the Cambrian explosion (~540 million years ago [MYA]). A number of hypotheses have been proposed to explain the evolution of helical burrowing in certain taxa, but no study has searched for a general explanation encompassing all taxa. We reviewed helical burrowing in both extant and extinct animals and from the trace fossil record and compiled 10 hypotheses for why animals construct helical burrows, including our own ideas. Of these, six are post-construction hypotheses-benefits to the creator or offspring, realized after burrow construction-and four are construction hypotheses reflecting direct benefits to the creator during construction. We examine the fit of these hypotheses to a total of 21 extant taxa and ichnotaxa representing 59-184 possible species. Only two hypotheses, antipredator and biomechanical advantage, cannot be rejected for any species (possible in 100% of taxa), but six of the hypotheses cannot be rejected for most species (possible in 86%-100% of taxa): microclimate buffer, reduced falling sediment (soil), anticrowding, and vertical patch. Four of these six are construction hypotheses, raising the possibility that helical burrowing may have evolved without providing post-construction benefits. Our analysis shows that increased drainage, deposit feeding, microbial farming, and offspring escape cannot explain helical burrowing behavior in the majority of taxa (5%-48%). Overall, the evidence does not support a general explanation for the evolution of helical burrowing in animals. The function and evolution of the helix as an extended phenotype seems to provide different advantages for different taxa in different environments under different physicochemical controls (some traces/tracemakers are discussed in more detail due to their association with body fossils and well-constrained physicochemical parameters). Although direct tests of many of the hypotheses would be difficult, we nevertheless offer ways to test some of the hypotheses for selected taxa.

Resurgence of cloudinomorph fossils with possible cnidarian affinity at the peak of the Cambrian Explosion (Cambrian Series 2, Stage 3) in southern Shaanxi, China

AbstractDuring the Precambrian–Cambrian transition, tubicolous animals were prevalent among small shelly fossils. These include the oldest‐known skeletal fossil Cloudina from the terminal Ediacaran, and anabarites and hyoliths from the early Cambrian; considered to be possible annelids, cnidarians, and molluscs, respectively. Tubular fossils have important bio‐stratigraphic significance during this period, and their diversity and evolutionary radiation trend herald the Cambrian explosion. However, the relative morphological simplicity of these fossils and lack of preserved soft‐body information has resulted in poor taxonomic constraints. Here, numerous tubular fossils exhibiting multi‐stage cylindrical or conical cups were recovered from the middle–upper Guojiaba Formation of Cambrian Series 2, Stage 3, in Mianxian, South China. One new genus (Mianxiantubus) and three new species (M. cyathiformis, M. obconicus, and M. varius) were established to accommodate the morphological diversity of the fossils. However, their affinities remain contentious and undetermined and have been tentatively ascribed to Cnidaria. The possible morphology and growth patterns of Mianxiantubus suggest a close relationship with cloudinomorph fossils, although it is notably distinct from the quintessential cloudinids owing to the presence of transverse septa. Moreover, many other tubular fossils have been recovered from the same level, which may extend to the overlying Xiannvdong Formation (Stage 3), co‐occurring with archaeocyathids. This suggests that tubicolous organisms continued to diversify and occupied specific ecological niches even during the peak phase of the Cambrian explosion, dominated by bilateral epifaunal vagrants.

Geodiversification: The Evolution of Geodiversity Through Time

Geodiversity has gained significant attention in the last three decades due to various research endeavouring to bridge the gap between geo- and biodiversity. This paper points at yet another parallel between the two disciplines: just as biodiversity expansion (i.e. biodiversification) can be evaluated through time, geodiversity change can also be observed on a timescale and referred to as ‘geodiversification’. The paper firstly reviews the biodiversification definition and some of its major events including the Cambrian explosion and Great Ordovician Biodiversification Event (GOBE) and suggests that being palaeontological, these can also be regarded as geodiversification events. In relation to that, the paper defines geodiversification and provides examples of important geodiversification events in the Earth’s history and some local-scale examples. The results show that major biodiversification events can occur due to the evolution of geodiversity.

First multi-proxy chronostratigraphy of the lower Cambrian Byrd Group, Transantarctic Mountains and correlation within East Gondwana

Antarctica and Australia were sutured together at the equator during the major pulse of animal biodiversification associated with the Cambrian radiation. However, the lack of detailed systematic chemostratigraphic and biostratigraphic sampling of lower Cambrian sedimentary successions from Antarctica has significantly impeded precise age determination and correlation with Cambrian strata on other palaeocontinents. This study is the first to present integrated, simultaneously sampled biostratigraphic and chemostratigraphic (δ13C isotopes) data from the same measured stratigraphic sections through the lower Cambrian Byrd Group in the Transantarctic Mountains. Shelly fossil assemblages (brachiopods, tommotiids, molluscs, bradoriids, trilobites) from the Holyoake Range and Churchill Mountains facilitate direct correlation with the Dailyatia odyssei Zone of South Australia (Cambrian Stages 3–4), and trilobites provide strong correlation between the Starshot Formation and the Cymbric Vale Formation in western New South Wales. A new ID-TIMS radiometric date of 514.96 ± 0.16 Ma from a tuff in the lower Cymbric Vale Formation is similar to dates from tuff beds in the Third Plain Creek Member of the Mernmerna Formation in the Flinders Ranges, providing an important absolute-age tie point between these lower Cambrian successions. Chemostratigraphic data from the upper Shackleton Limestone in the Holyoake Range capture a negative δ13C excursion that can be correlated to negative values within the multi-peaked MICE (cycles V–VIII in Siberia). Integrated faunal and chemostratigraphic data indicate a Cambrian Stages 3–4 age, giving robust chronostratigraphic context for the upper Shackleton Limestone–Holyoake Formation–Starshot Formation succession for the first time, permitting reconstruction of the depositional history of the lower Cambrian of Antarctica and global correlation of Byrd Group strata.

Tracking of Ubiquitin Signaling through 3.5 Billion Years of Combinatorial Conjugation.

Ubiquitination is an evolutionary, ancient system of post-translational modification of proteins that occurs through a cascade involving ubiquitin activation, transfer, and conjugation. The maturation of this system has followed two main pathways. The first is the conservation of a universal structural fold of ubiquitin and ubiquitin-like proteins, which are present in both Archaea and Bacteria, as well as in multicellular Eukaryotes. The second is the rise of the complexity of the superfamily of ligases, which conjugate ubiquitin-like proteins to substrates, in terms of an increase in the number of enzyme variants, greater variation in structural organization, and the diversification of their catalytic domains. Here, we examine the diversity of the ubiquitination system among different organisms, assessing the variety and conservation of the key domains of the ubiquitination enzymes and ubiquitin itself. Our data show that E2 ubiquitin-conjugating enzymes of metazoan phyla are highly conservative, whereas the homology of E3 ubiquitin ligases with human orthologues gradually decreases depending on "molecular clock" timing and evolutionary distance. Surprisingly, Chordata and Echinodermata, which diverged over 0.5 billion years ago during the Cambrian explosion, share almost the same homology with humans in the amino acid sequences of E3 ligases but not in their adaptor proteins. These observations may suggest that, firstly, the E2 superfamily already existed in its current form in the last common metazoan ancestor and was generally not affected by purifying selection in metazoans. Secondly, it may indicate convergent evolution of the ubiquitination system and highlight E3 adaptor proteins as the "upper deck" of the ubiquitination system, which plays a crucial role in chordate evolution.

Organ systems of a Cambrian euarthropod larva

The Cambrian radiation of euarthropods can be attributed to an adaptable body plan. Sophisticated brains and specialized feeding appendages, which are elaborations of serially repeated organ systems and jointed appendages, underpin the dominance of Euarthropoda in a broad suite of ecological settings. The origin of the euarthropod body plan from a grade of vermiform taxa with hydrostatic lobopodous appendages (‘lobopodian worms’)1,2 is founded on data from Burgess Shale-type fossils. However, the compaction associated with such preservation obscures internal anatomy3–6. Phosphatized microfossils provide a complementary three-dimensional perspective on early crown group euarthropods7, but few lobopodians8,9. Here we describe the internal and external anatomy of a three-dimensionally preserved euarthropod larva with lobopods, midgut glands and a sophisticated head. The architecture of the nervous system informs the early configuration of the euarthropod brain and its associated appendages and sensory organs, clarifying homologies across Panarthropoda. The deep evolutionary position of Youti yuanshi gen. et sp. nov. informs the sequence of character acquisition during arthropod evolution, demonstrating a deep origin of sophisticated haemolymph circulatory systems, and illuminating the internal anatomical changes that propelled the rise and diversification of this enduringly successful group.

Active methane release from the early Cambrian seafloor? Clues from Ba isotopes

The Cambrian Explosion coincided with a global greenhouse climate, but the mechanism behind this warming event remains unclear, impeding our understanding of their essential link. To address this, an integrated study of δ138Ba, δ34S, Scanning Electron Microscopy, and Energy Dispersive Spectroscopy was carried out on the lower Cambrian shales from a range of water depths in the Nanhua Basin of South China. These shales are characterized by variably elevated Ba concentrations (>10,000 ppm), primarily hosted by barite and Ba-feldspar, with the latter found only in a deep-water setting. The Ba-isotopic compositions of the study shales (δ138Ba, −0.15‰ to +0.60‰), along with the large size and euhedral shape of barite crystals and associated soft-sediment deformation, indicate that barite and Ba-feldspar were formed in porewaters close to the sulfate-methane-transition zone during early diagenesis under sulfate-rich and sulfate-poor conditions, respectively. We propose that low sulfate in the early Cambrian ocean, coupled with the high organic matter content of the sediment, may have resulted in large methane emissions from the sediment to the atmosphere, generating an early Cambrian greenhouse climate at the time of the Cambrian Explosion.

Shallow-water redox evolution from the Ediacaran to the early Cambrian: Linkages to the early animal innovations

The oceanic oxygenation from the Ediacaran to the early Cambrian (ca. 635–520 Ma) has been commonly linked with the radiation or innovation of early metazoans. However, in this period, the spatio-temporal changes in redox states have not been well constrained for shallow seawater that is proposed to be potential habitats for most metazoans. Here, we report new iodine (I) concentration and Cerium anomaly (Ce/Ce*) data from two Ediacaran–Cambrian carbonate successions in South China. Combined with published data, the new database provides more insights into the evolution of shallow-water redox states on the continental margin. Overall low I/(Ca + Mg) (0.07–1.092 μmol/mol) and high Ce/Ce* (0.64–0.91) indicate frequent presence of low oxygen waters on the Yangtze margin in the early-middle Ediacaran (ca. 635–575 Ma). The initial increases of shallow-water oxygen levels occur from the middle Ediacaran (< ca. 575 Ma), coincident with the rise of the Ediacara biota. However, large variabilities of I/(Ca + Mg) (0.003–4.53) and Ce/Ce* (0.1–0.92) through different sections from the late Ediacaran to the early Cambrian (ca. 575–520 Ma) suggest highly dynamic redox states on both spatial and temporal scales before the Cambrian explosion in a narrow sense. The new I/(Ca + Mg) and Ce/Ce* data bolster the case that the Ediacaran–Cambrian oceans have much lower oxygenation levels than recent fully oxygenated oceans, and frequent redox fluctuations in habitats may have stimulated the early animal innovations.

Unveiling an ignored taphonomic window in the early Cambrian Chengjiang Biota

Abstract The exceptionally preserved soft-bodied fossils from the Chengjiang Biota of southwest China have proved to be critical for our understanding of the biodiversity and ecology of the Cambrian explosion of animals. Almost all previously reported soft-bodied Chengjiang fossils are from the event mudstone beds (EB) of the Yu’anshan Formation. Here, we present the first comprehensive investigation of the soft-bodied fossils from the interbedded background mudstone beds (BGB), based on collections made across the past decade, and characterize their preservation. Soft internal cellular organs/tissues, such as digestive tracts and glands, cardiovascular systems, nervous systems, and musculature, are predominantly preserved as carbonaceous compressions, in contrast to their iron oxide–rich preservation in the EB. Our work highlights two distinct preservation modes within a single Burgess Shale–type Lagerstätte, possibly due to the complex interplay of decay, kerogenization, and pyritization.

Marine redox and nutrient dynamics linked to the Cambrian radiation of animals

Abstract The early Cambrian witnessed an increase in metazoan ecosystem complexity, likely linked to enhanced oxygen and nutrient availability. However, while improved stratigraphic and geochemical records suggest that the Cambrian explosion occurred under highly dynamic redox conditions, mechanistic links to nutrient availability and early Cambrian evolutionary innovations are poorly constrained. Here, we report paleoredox and nutrient data for two drill cores documenting late Cambrian Stage 2 to Stage 3 (ca. 522–514 Ma) strata from the Yangtze block, South China. The development of water-column euxinia during Cambrian Stage 2 led to extensive recycling of P, fueling elevated primary production and hence an increase in atmospheric and shallow-marine oxygen concentrations. The resulting expansion of oxygenated shelf area promoted sedimentary P retention and, in combination with a diminished supply of P from upwelling, drove a transition to oligotrophic shallow-marine conditions during Cambrian Stage 3. Reduced primary production and limited water-column oxygen consumption allowed for the stabilization of oxygenated continental shelf habitats that supported a burgeoning biotic complexity.

The effects of clays on bacterial community composition during arthropod decay

Fossilization, or the transition of an organism from the biosphere to the geosphere, is a complex mechanism involving numerous biological and geological variables. Bacteria are one of the most significant biotic players to decompose organic matter in natural environments, early on during fossilization. However, bacterial processes are difficult to characterize as many different abiotic conditions can influence bacterial efficiency in degrading tissues. One potentially important variable is the composition and nature of the sediment on which a carcass is deposited after death. We experimentally examined this by decaying the marine shrimp Palaemon varians underwater on three different clay sediments. Samples were then analyzed using 16S ribosomal RNA sequencing to identify the bacterial communities associated with each clay system. Results show that samples decaying on the surface of kaolinite have a lower bacterial diversity than those decaying on the surface of bentonite and montmorillonite, which could explain the limited decay of carcasses deposited on this clay. However, this is not the only role played by kaolinite, as a greater proportion of gram-negative over gram-positive bacteria is observed in this system. Gram-positive bacteria are generally thought to be more efficient at recycling complex polysaccharides such as those forming the body walls of arthropods. This is the first experimental evidence of sediments shaping an entire bacterial community. Such interaction between sediments and bacteria might have contributed to arthropods’ exquisite preservation and prevalence in kaolinite-rich Lagerstätten of the Cambrian Explosion.

Seawater barium and sulfide removal improved marine habitability for the Cambrian Explosion of early animals.

An increase in atmospheric pO2 has been proposed as a trigger for the Cambrian Explosion at ∼539-514Ma but the mechanistic linkage remains unclear. To gain insights into marine habitability for the Cambrian Explosion, we analysed excess Ba contents (Baexcess) and isotope compositions (δ138Baexcess) of ∼521-Myr-old metalliferous black shales in South China. The δ138Baexcess values vary within a large range and show a negative logarithmic correlation with Baexcess, suggesting a major (>99%) drawdown of oceanic Ba inventory via barite precipitation. Spatial variations in Baexcess and δ138Baexcess indicate that Ba removal was driven by sulfate availability that was ultimately derived from the upwelling of deep seawaters. Global oceanic oxygenation across the Ediacaran-Cambrian transition may have increased the sulfate reservoir via oxidation of sulfide and concurrently decreased the Ba reservoir by barite precipitation. The removal of both H2S and Ba that are deleterious to animals could have improved marine habitability for early animals.

The Cambrian Explosion of Electromobility X

The Cambrian Explosion of Electromobility X

Sustained increases in atmospheric oxygen and marine productivity in the Neoproterozoic and Palaeozoic eras

A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system.

Depositional facies and evolution of sponge-microbial-constructed carbonate platforms in the lower Cambrian (Stage 3), Tarim basin, China: Understanding from anatomy

The early Cambrian was generally considered the earliest time interval while the archaeocyaths could act as the constructors in building reef framework although commonly coexisting with the microbial constructors (Epiphyton and Renalcis) in the course of the “Cambrian explosion”; however, this kind of metazoan-microbial buildups has not yet been reported in Tarim Basin. To delineate facies (associations), spatiotemporal variations, reef-building processes of metazoan-microbial constructed ramps/shelves and evolution, detailed anatomy was carried out upon the lower Cambrian Xiaoerbulak Formation (or Stage 3) exposed continuously along a marginal transect (∼2 km wide) in Aksu area, northwestern Tarim Basin. Three platform types with distinctive facies associations are distinguished: (1) sponge-microbial biostrome/mound-colonized homoclinal and distally-steepened ramps recorded respectively in the Lower Member and basal Middle Member, (2) Archaeocyath-Epiphyton reef- and microbial reef-rimmed platforms (or shelves) in the mid-upper Middle Member, and (3) microbial biostrome-colonized ramp in the Upper Member, thus illustrating the evolution from the ramp to reef-rimmed platform and final reversion to the ramp system. Four and a half third-order depositional sequences are further identified: one in the Lower Member, two in the Middle Member and one and half (TST) in the Upper Member, although, at least, one sequence was absent in the platform/ramp interior. All these can be well correlated with those in equivalent successions identified elsewhere around the world, implying a basic control of eustatic changes on platform development and evolution. Moreover, syndepositional faulting/sliding that occurred off the ramp margin, as demonstrated by slope failure/collapse, may have enhanced the relief difference between the inner and mid-outer ramps, promoting metazoan-microbes to colonize and build up wave-resistant architecture on the uplifting margin, forming the reef-rimmed platform (or shelf) system as typified in the Middle Member. Meanwhile, the development of wave-resistant, metazoan-microbial reef complexes also benefited from their concurrently-gained calcifying ability, which likely resulted from the instinctive biotic responses to the changes in climate and oceanic chemistry (i.e., pCO2, seawater Mg/Ca ratio) in the early Cambrian. The new datasets of this study fill previous information gap on the early Cambrian metazoan-involved buildups that had controlled the platform configuration and evolution in Tarim Basin, which thus are critically important for better understanding of climatic/environmental controls on their occurrence and evolution of the time-specific reef complexes in the course of “Cambrian Explosion”. Additionally, these datasets would provide a useful analogue for perceiving the facies-constrained porosity and heterogeneity in the deeply buried counterparts in the basin, helpful for making exploration strategy for the deeply-buried hydrocarbon resources.

Carbon-isotope stratigraphy of the Lower Cambrian (Cambrian explosion) in northwestern Yangtze Platform, China: Implications for global correlation

The Archaeocyathid Extinction Carbon Isotope Excursion (AECE) and Mingxinsi Carbon Isotope Excursion (MICE) are major events in the Early Cambrian sedimentary records but controversially heterogeneous in their magnitudes, as well as local and global correlations. This paper presents a high-resolution δ13Ccarb profile from the Shiliu section in the western Yangtze Platform (China) that spans the lower part of the Lower Cambrian. The investigated Lower Tianheban interval (∼110 m) is dominated by marine carbonates (lime mudstones) alternating occasionally with thinly-bedded black shale and mudstone interbeds. The investigated micritic carbonates were examined through a multi-technique protocol, combining petrographic and geochemical assessments, to evaluate the degree of sample preservation. The δ13Ccarb values (−2.4‰–1.8‰) show an insignificant correlation with the δ18Ocarb values (−12.6‰ to −8.7‰, R2 = 0.012), the Mn/Sr ratios (R2 = 0.001), and Al concentrations (R2 = 0.041). This supports the preservation of predominantly at least near-primary δ13Ccarb signatures, which can be utilized to reconstruct a reliable, high-resolution δ13Ccarb profile for chemostratigraphic correlations in the area and beyond. The profile displays a lower positive excursion of ∼3‰ overlain immediately by a negative excursion of ∼2.3‰. The archaeocyath zonation scheme suggests that the lower excursion is correlated with the global MICE event and the upper excursion with the AECE event. The results provide an alternative option for interpreting the carbon isotope excursions in the Lower Cambrian within the Yangtze Platform as well as other equivalent sections at a global scale.

Self-organisation of early stress response in the biology of cancer.

The early stress response by AP-1 (FOS/JUN), supported by upregulation of c-Myc and involved in cell-fate changes and adaptation to hostile environments, is increased in cancer. The review shows the biphasic character of this response with negative feed-back typically lasting a few hours as a feature of the genome regulation by self-organising criticality. It involves rapid splitting of the pericentromeric heterochromatin clusters, opening of the active chromatin, and a massive transcription acceleration wave. Phylostratigraphic analysis revealed that AP-1 genes evolved in the Cambrian explosion ~500 Mya integrating the protein interaction networks of reproduction including proto-placenta intertwined with cytokine and immunity pathways, sex determination, oocyte maturation, and embryonal stemness. The peak of this response as part of accelerated cell senescence led by AP-1 and IL-1β was found in breast cancer cell-line resistant to doxorubicin. Adaptability of aggressive cancer to treatments can be explained by emergent stress response evolutionarily protecting reproduction.