Common water flea
| Common water flea | ||||||||||||
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Common water flea ( Daphnia pulex ) |
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| Scientific name | ||||||||||||
| Daphnia pulex | ||||||||||||
| Leydig , 1860 |
The common water flea ( Daphnia pulex ) is a species from the genus Daphnia ( Daphnia ).
description
The species is broad and strongly shaped. It is greenish, yellowish or reddish in color and usually only slightly transparent. The females grow to 3 to 4 millimeters, the males 1 to 1.5 millimeters. The males can be recognized by the long first antennae and the conspicuous hook on the first pair of legs. A nauplius eye is available. Most of the time, the shell is drawn out into a square shell spike. The head armor is pulled back into a corner that is pushed between the shell parts. The "smelling sticks" of the first antenna do not reach the rostrum . The second antennae each have nine feathered floating bristles. The eye is large and consists of 22 individual eyes. The foregut has two curved, greenish liver squirrels. There are two combs made of bristles on the end claws of the post abdomen (dewclaws).
Daphnia pulex occurs in small, shallow ponds and ponds, as well as on the banks of larger bodies of water. It is very common and often occurs in large numbers.
heritage
The genome of the common water flea has been deciphered. It contains 30,907 genes with only 200 million base pairs and thus about half more than that of humans (20,000 to 23,000 genes, but with 3 billion base pairs), the highest known number in the animal kingdom to date. It is assumed that this is a prerequisite for the species' ability to adapt well to changing environmental conditions. 36 percent of the genetic traits discovered are not known to be of any other species.
supporting documents
- Heinz Streble , Dieter Krauter : Life in a drop of water. Microflora and microfauna of freshwater. An identification book. Franckh-Kosmos Verlag, Stuttgart 2008, ISBN 978-3-440-11966-2 .
Web links
Individual evidence
- ↑ John K. Colbourne et al .: The Ecoresponsive Genome of Daphnia pulex . In: Science . Vol. 331, No. 6017 , February 4, 2011, p. 555-561 , doi : 10.1126 / science.1197761 .