Reviews & Analysis

Humans are considered to be altricial (strongly underdeveloped at birth) with respect to other primates, but this observation is driven by the strong postnatal enlargement of human brains. We inferred that the developmental stage of human brains at birth does not differ substantially from that of other fossil hominins.

Microbiomes show dynamic compositions and behaviours. The prediction of microbiome dynamics over time has proven difficult. Now, in an open system with relatively controlled environmental constraints, it is possible to correctly predict the future composition and dynamics of a resident microbial community.

We examined the interactive effects of temperature and the presence of apex fish predators on food web structure in Icelandic geothermal streams. Fish suppressed the biomass of invertebrates and thus released algae from grazing pressure, but only at higher temperatures, which illustrates how the combination of warming and apex predators triggers this trophic cascade.

Fire activity and deforestation accelerated in Remote Oceania following human settlement. However, geoarchaeology and palaeoecology indicate that peak fire activity and grassland expansion primarily coincided with high frequencies of El Niño droughts, which suggests that there are complex relationships among human land use, fire and climate in the western Pacific.

Data from 5,525 in-water reef fish surveys conducted between 1- and 30-m depth reveal predictable depth-dependent zonation across the Pacific Ocean, particularly in the absence of a local human population. By contrast, relationships between depth and biomass were reduced or absent at populated islands, which suggests a human impact on depth-dependent ecological organization.

A defensive bacterial symbiont, spreading rapidly through populations of whitefly in nature, suppresses the proliferation, sporulation and transmission of a fungal pathogen in the whitefly. The pathogen is shown to be an important driving force for rapid shifts of the symbiont in the natural niche.

Using a mechanistic model based on neutral theory, we examined the effects of the ‘Carboniferous rainforest collapse’ on early tetrapod diversity. Our findings highlight the power of mechanistic models for decoding the fossil record and underscore the criticality of adjusting for sampling biases.

Analysis of an ocean basin-scale dataset revealed the existence of clear biogeographic provinces (deep and shallow abyssal zones) delimited by the carbonate compensation depth in Pacific Ocean seabed communities. Species diversity is maintained or increases with depth owing to phylum-level taxonomic replacements.

An analysis of millions of wildlife photographs has revealed that survival and colonization probabilities of mammals in protected areas are associated with people and what they do both inside and outside these areas.

Across taxa, increased temperature has been reported to generally reduce individual body size and change the body size structure of wild communities. Our research reveals that the effects of climate warming on the body size structure of stream fishes are also dependent on the intensity of other human pressures.

Efforts to document biodiversity have created large species datasets, but new research shows that field observations are biased towards particular regions, clades, traits and time periods, and do not accurately represent global biodiversity patterns. Although specimens are only infrequently preserved in natural history collections, they show relative congruence with expected biodiversity patterns and are vital for ecological research.

In cyanobacteria, the interaction between an orange carotenoid protein and its allosteric regulator evolved when a horizontal gene transfer event first brought the two proteins together. However, the surface compatibility between the proteins had already emerged. This finding implies that specific protein–protein interactions can evolve without the action of direct natural selection.

Ensemble quotient optimization (EQO) uses patterns of variation in species abundance and ecosystem functions across microbial communities to identify microbial guilds in a systematic, objective manner. EQO is robust in recovering functional groups in soil, ocean and animal-gut microbial communities.

Using genome assemblies and comparative analyses, we identified evolutionary signatures of selection associated with repeated gains and losses of social behaviour in sweat bees. These signatures include changes in regulatory regions and young genes, as well as complementary patterns of positive and relaxed selection on proteins involved in juvenile hormone signalling.

In the period 1880 to 2020, intraspecific body-size variation increased in many mammal and bird species in North America, along with declines in average body size. These results suggest potential buffering effects against species downsizing and species capacity to cope with environmental change, but warn of an increasing possibility of maladaptation.