Navigation Links
More species in the tropics because species have been there longer

Why are there more species in the tropics than in the temperate regions of the globe? Many of the world's species live in the tropics (perhaps more than half), but the reason has been debated for more than 100 years.

Many researchers have hypothesized that climatic factors somehow cause species to originate more quickly in tropical regions. In a paper appearing in the November issue of The American Naturalist, John Wiens and a group of researchers from Stony Brook University have shown that, contrary to expectations, species seem to evolve at similar rates in tropical and temperate regions. What causes the difference in species numbers between tropical and temperate regions is not something special about the tropics that leads to more rapid speciation, but rather that the temperate areas were colonized more recently, leaving less time for species to originate and accumulate in these regions.

The researchers studied the causes of high tropical species richness in treefrogs in the Americas. Combining analyses of evolutionary trees based on DNA sequences with GIS-based methods for analyzing the effects of climate on species distributions, the researchers found no relationship between how quickly species originate within a group and whether that group is tropical or temperate.

However, they did find a strong relationship between when each region was colonized and the number of species there today. Thus, the high species richness of tropical regions seems to be explained by the ancient origin of many groups in the tropics, more recent colonization of temperate regions, and by the inability of most tropical species to tolerate the variable temperatures of temperate areas.

According to John Wiens, the study has important conservation implications: "If the pattern we see in treefrogs holds true for most other groups, then the tropics may have more ancient lineages and more genetic diversity per species than temperate regions. So ther e may be far more loss of diversity going on as we lose tropical rainforests than would be suggested by the number of species alone."
'"/>

Source:University of Chicago Press Journals


Related biology news :

1. New species from old data
2. Same mutation aided evolution in many fish species, Stanford study finds
3. Fibril Shape Is The Basis Of Prion Strains And Cross-species Prion Infection
4. Reservoirs may accelerate the spread of invasive aquatic species, researchers say
5. Small species back-up giant marsupial climate change extinction claim
6. Aggressive aquatic species invading Great Lakes
7. Bush, Cheney and Rumsfeld are now species of slime-mold beetles -- but strictly in homage
8. Internet viruses help ecologists control invasive species
9. An (ecological) origin of species for tropical reef fish
10. Ancient DNA helps clarify the origins of two extinct New World horse species
11. Invasive parasite destroying fish species

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:8/23/2017)... , Aug. 23, 2017  The general public,s help is being enlisted ... bacteria that live in and on the human body –and are believed ... The Microbiome Immunity ... human microbiome, starting with the gut. The project's goal is to help ... credit: IBM ...
(Date:6/14/2017)...  IBM (NYSE: IBM ) is introducing several innovative ... to developing collaboration between startups and global businesses, taking place ... the event, nine startups will showcase the solutions they have ... France is one ... a 30 percent increase in the number of startups created ...
(Date:4/24/2017)... , April 24, 2017 ... and partner with  Identity Strategy Partners, LLP (IdSP) ... "With or without President Trump,s March 6, 2017 ... Terrorist Entry , refugee vetting can be instilled with ... resettlement. (Right now, all refugee applications are suspended ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... Netherlands and LAGUNA HILLS, Calif. ... Institute of Cancer Research, London (ICR) ... MMprofiler™ with SKY92, SkylineDx,s prognostic tool to risk-stratify patients with ... known as MUK nine . The University of ... which is partly funded by Myeloma UK, and ICR will ...
(Date:10/11/2017)... Bay, Florida (PRWEB) , ... October 11, 2017 ... ... and Drug Administration (FDA) has granted orphan drug designation to SBT-100, its novel ... (sdAb) for the treatment of osteosarcoma. SBT-100 is able to cross the cell ...
(Date:10/10/2017)... , ... October 10, 2017 , ... ... Center’s FirstHand program has won a US2020 STEM Mentoring Award. Representatives of the ... for Excellence in Volunteer Experience from US2020. , US2020’s mission is to change ...
(Date:10/10/2017)... Oct. 10, 2017 SomaGenics announced the receipt ... to develop RealSeq®-SC (Single Cell), expected to be the ... RNAs (including microRNAs) from single cells using NGS methods. ... need to accelerate development of approaches to analyze the ... "New techniques for measuring levels of mRNAs in ...
Breaking Biology Technology: