Taxon cycles refer to a

biogeographical Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, i ...

theory of how species evolve through

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

expansions and contractions over time associated with

adaptive Adaptation, in biology, is the process or trait by which organisms or population better match their environment Adaptation may also refer to: Arts * Adaptation (arts), a transfer of a work of art from one medium to another ** Film adaptation, a ...

shifts in the ecology and morphology of species. The taxon cycle concept was explicitly formulated by biologist

E. O. Wilson Edward Osborne Wilson (June 10, 1929 – December 26, 2021) was an American biologist, naturalist, entomologist and writer. According to David Attenborough, Wilson was the world's leading expert in his specialty of myrmecology, the study of an ...

in 1961 after he surveyed the distributions,

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s, behavior and morphology of

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...

species in the

Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from Indonesia's New Guinea in the west to Fiji in the east, and includes the Arafura Sea. The region includes the four independent countries of Fiji, Va ...

n archipelago.

Stages of the taxon cycle

Wilson categorized species into evolutionary "stages", which today are commonly described in the outline by Ricklefs & Cox (1972). However, with the advent of molecular techniques to construct time-calibrated

phylogenetic relationship In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

s between species, the taxon cycle concept was further developed to include well-defined temporal scales and combined with concepts from

ecological succession Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less. Bacteria allows for the cycling of nutrients such as ca ...

and

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

cycle theories. Taxon cycles have mainly been described in island settings (archipelagos), where the distributions and movements of species are readily recognized, but may also occur in continental biota. * Stage I: Young, rapidly expanding, undifferentiated, widely and continuously distributed species in the initial

colonization Colonization, or colonisation, constitutes large-scale population movements wherein migrants maintain strong links with their, or their ancestors', former country – by such links, gain advantage over other inhabitants of the territory. When ...

stage inhabiting small island, coastal or disturbed (marginal) habitat. Such species are hypothesized to include very good dispersers,

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...

species and ecological "

supertramp Supertramp were an English rock band that formed in London in 1969. Marked by the individual songwriting of founders Roger Hodgson (vocals, keyboards, and guitars) and Rick Davies (vocals and keyboards), they are distinguished for blending pro ...

s". * Stage II: Species that are generally widespread across many islands, but where geographical expansion has slowed,

population differentiation Human genetic variation is the genetic differences in and among populations. There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism. No two humans are genetically identical. Even m ...

has generated

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

or incipient species, and local extinction on small islands may have created gaps in the distribution. This stage includes species that have maintained a relatively good dispersal ability such as " great speciators". Early-stage "

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

es" may consist of stage II species. * Stage III: Older, well-differentiated and well-defined

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

that have moved to habitats inland (and uphill) and where reduced dispersal ability and extinctions have fragmented the distribution to fewer and larger islands. These species may be niche specialists, but novel adaptations or accidental dispersal may restart the taxon cycle. * Stage IV: Old, relictual,

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

species in the "final" stage are restricted to island interiors (mountains) on a few, large islands. This stage includes sedentary high‐elevation specialists with limited dispersal abilities and small range sizes. These species are evolutionary distinctive, as closely related species (and subspecies) have gone extinct.
The ecology and evolution of the Melanesian ants that originally inspired Wilson's hypothesis have since been shown to be consistent with the taxon cycle predictions using modern methods. Ricklefs & Bermingham (2002) estimated that taxon cycles take place over periods of 0.1-10 million years in different bird groups of the

Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc betwe ...

islands. Pepke et al. (2019) used the difference in mean age of late- and early-stage species as a lower estimate (4.7 million years) of the tempo of taxon cycling in an

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

bird family.

References

{{reflist Biogeography