The scientific study of speciation — how species evolve to become new species — began around the time of Charles Darwin in the middle of the 19th century. Many naturalists at the time recognized the relationship between biogeography (the way species are distributed) and the evolution of species. The 20th century saw the growth of the field of speciation, with major contributors such as Ernst Mayr researching and documenting species' geographic patterns and relationships. The field grew in prominence with the modern evolutionary synthesis in the early part of that century. Since then, research on speciation has expanded immensely.
The language of speciation has grown more complex. Debate over classification schemes on the mechanisms of speciation and reproductive isolation continue. The 21st century has seen a resurgence in the study of speciation, with new techniques such as molecular phylogenetics and systematics. Speciation has largely been divided into discrete modes that correspond to rates of gene flow between two incipient populations. Current research has driven the development of alternative schemes and the discovery of new processes of speciation.
Charles Darwin introduced the idea that species could evolve and split into separate lineages, referring to it as specification in his 1859 book On the Origin of Species. It was not until 1906 that the modern term speciation was coined by the biologist Orator F. Cook. Darwin, in his 1859 publication, focused primarily on the changes that can occur within a species, and less on how species may divide into two. It is almost universally accepted that Darwin's book did not directly address its title. Darwin instead saw speciation as occurring by species entering new ecological niches.
Controversy exists as to whether Charles Darwin recognized a true geographical-based model of speciation in his publication On the Origin of Species.
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Allochronic speciation (also known as allochronic isolation, or temporal isolation) is a form of speciation (specifically ecological speciation) arising from reproductive isolation that occurs due to a change in breeding time that reduces or eliminates gene flow between two populations of a species. The term allochrony is used to describe the general ecological phenomenon of the differences in phenology that arise between two or more species—speciation caused by allochrony is effectively allochronic speciation.
L'Effet Wallace, évoqué pour la première fois en 1889 par Alfred Russel Wallace, est l'hypothèse que si deux organismes sont avantagés dans la compétition pour la survie, ils ont tendance à se reproduire préférentiellement ensemble (ce que l'on nomme un isolement reproductif), ce qui finalement aboutit à la création d'une nouvelle espèce, les hybrides entre les descendants de ces deux organismes et les autres représentants de l’espèce étant non viables.
Évaluation de la qualité d'une rivière en utilisant des méthodes d'observation ainsi que des méthodes physico-chimiques et biologiques. Collecte d'échantillons sur le terrain et analyses de laboratoir
This course provides students with an overview over the basics of environmental chemistry. This includes the chemistry of natural systems, as well as the fate of anthropogenic chemicals in natural sys
This course builds on environmental chemistry and microbiology taken in previous courses. The emphasis is on quantification using the public domain package, PHREEQC, which is an excellent computation
The hypothesis that the evolution of humans involves hybridization between diverged species has been actively debated in recent years. We present the following novel evidence in support of this hypothesis: the analysis of nuclear pseudogenes of mtDNA ("NUM ...
Background: Reproductive isolation can result from adaptive processes (e.g., ecological speciation and mutation-order speciation) or stochastic processes such as "system drift" model. Ecological speciation predicts barriers to gene flow between populations ...
Plonge dans la biogéochimie de l'arsenic dans le delta de l'Asie du Sud-Est, couvrant la spéciation, l'exposition humaine, les transformations microbiennes et la contamination des eaux souterraines.
Discute de la sélection naturelle, de l'origine de l'espèce, de la compatibilité de la reproduction, des barrières à l'écoulement des gènes, de la classification des espèces, des modes de spéciation et de la polyploïdie.
Understanding macroevolutionary patterns is central to evolutionary biology. This involves the process of divergence within a species, which starts at the microevolutionary level, for instance, when two sub populations evolve towards different phenotypic o ...