Evolution of new species slows down as number of competitors increases

March 25, 2008

The rate at which new species are formed in a group of closely related animals decreases as the total number of different species in that group goes up, according to new research published in PLoS Biology.

The research team believes these findings suggest that new species appear less and less as the number of species in a region approaches the maximum number that it can support.

In order for new species to thrive, they need to evolve to occupy their own niche in the ecosystem, relying on certain foods and habitats for survival that are sufficiently different from those of other closely related species.

Competition between closely related species for food and habitat becomes more intense the more species there are, and researchers believe this could be the reason for the drop-off in the appearance of new species over time.

Dr. Albert Phillimore, from Imperial College London’s NERC Centre for Population Biology, lead author on the paper, explains: “The number of niches in any given region is finite, and our research supports the idea that the rate of speciation slows down as the number of niches begins to run out.

“In essence, it seems like increased competition between species could place limits on the number of species that evolve.”

The new study used detailed analysis of the family trees, or phylogenies, of 45 different bird families. By examining the rate at which new species have arisen in each of these trees over a period of millions of years, scientists saw that the rate of appearance of new species seemed to be much higher in the early stages of the family tree, compared to more recent lower rates.

For example, when the researchers examined the phylogeny of tit birds they found that some 10 million years ago, species formed rapidly but this rate has slowed over time to perhaps a quarter of the initial rate.

Citation: Phillimore AB, Price TD (2008) Density-dependent cladogenesis in birds. PLoS Biol 6(3): e71. doi:10.1371/journal.pbio.0060071

Source: Public Library of Science

Explore further: Rapid evolution of body size enhanced dinosaur and bird survival

Related Stories

Results of the Rosetta mission before perihelion

October 30, 2015

Astronomy & Astrophysics is publishing a special feature of 46 articles that present the results obtained by the Rosetta mission before the comet 67P/Churyumov-Gerasimenko reached its perihelion.

Bees to scientists: 'We're more complicated than you think'

October 21, 2015

Chemical signaling among social insects, such as bees, ants and wasps, is more complex than previously thought, according to researchers at Penn State and Tel Aviv University, whose results refute the idea that a single group ...

Recommended for you

Amazon deforestation leaps 16 percent in 2015

November 28, 2015

Illegal logging and clearing of Brazil's Amazon rainforest increased 16 percent in the last year, the government said, in a setback to the aim of stopping destruction of the world's greatest forest by 2030.

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.