Tag Archives: rate

The Chilly Cradle of Life

Species richness is much higher in waters near the equator, but do we see that in a phylogenic tree?

Species richness is much higher in waters near the equator, but do we see that in a phylogenetic tree? (Image Credit: Rich Brooks, CC BY 2.0)

An inverse latitudinal gradient in speciation rate for marine fishes (2018) Rabosky et al., Nature  doi:10.1038/s41586-018-0273-1

The Crux

The tropical regions of the Earth are the most species-rich and diverse ecosystems on the planet, with this diversity and species-richness declining as you move further and further from the equator. One hypothesis explaining this is that speciation rates are simply higher in the tropics, meaning that more species are evolving in a given time in the tropics than anywhere else. To test for this, the authors used the largest phylogenetic tree available and analyzed speciation rates (how many new species evolve from older species) per million years.

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