If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

The species problem in protozoa revisited

$30.41 plus tax (Refund Policy)

Buy Article:

Abstract:

The biological species concept as coined by Ernst Mayr is not applicable to many protists which reproduce by inbreeding or asexually. An extended concept supplementing the biological species concept was suggested by T. M. Sonneborn after intensive studies on differently reproducing species of the Paramecium aurelia complex. In his concept based on the hypothesis that inbreeding or asexually reproducing taxa also evolve as discrete units, he suggested that a species should be recognized as an evolving entity that has undergone a threshold of minimum evolutionary divergence. However, Sonneborns idea was poorly received. We examine different morphological and molecular characters discovered and applied in taxonomy since Sonneborn developed his hypothesis. We conclude that there is now an abundance of objective characters to arrive at sound judgement about the complexity of the genetic differences necessary to delimit species in Sonneborns sense when the biological species concept is not applicable. In addition, combined morphological and molecular studies reveal that, although many free-living protists may be globally distributed, geographical patterns and local distribution also occur.

Document Type: Research Article

DOI: http://dx.doi.org/10.1078/0932-4739-00003

Affiliations: 1: Institut für Zoology, Universität Leipzig, Talstraße 33, 04103 Leipzig, Germany;, Email: schlegel@rz.uni-leipzig.de 2: Institut für Biologie II, RWTH Aachen, Kopernikusstraße 16, 52056 Aachen, Germany

Publication date: December 1, 2003

Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more