Daphnia pulex

Common Water flea ( Daphnia pulex )

The common water flea ( Daphnia pulex ) is a species of the genus Daphnia (Daphnia ).

Description

The species is formed broad and strong. It is greenish, yellowish or reddish colored and usually only slightly transparent. The females are 3 to 4 millimeters in size, the males from 1 to 1.5 millimeters. The males are recognizable by the long first antennae and the eye-catching hook on the first pair of legs. A Naupliusauge is available. Most of the shell is drawn out to a four -edged shell sting. The head tank is pulled back into an up -shifting between the shell parts tip. The " olfactory rods " of the first antenna is not enough to rostrum. The second antennas have nine feathered swimming bristles. The eye is large and consists of 22 individual eyes. The foregut has two curved greenish liver and croissants. There are two existing combs of bristles at the end claws of postabdomen ( dewclaws ).

Daphnia pulex is found in small, shallow pools and ponds as well as the riparian zone of larger bodies of water. It is very common and often occurs en masse.

Genotype

The genome of the commons water flea is decrypted. It contains 30 907 genes in 200 million base pairs, which is about a third more than in humans ( 20,251, but at 3 billion base pairs ), the highest ever known figure in the animal kingdom. It is believed that this is a prerequisite for the good adaptability of the species to changing environmental conditions. 36 percent of the discovered heredity are known by any other type.

Documents

• Heinz Streble, Dieter Krauter: The Life in the Water. Microflora and microfauna of fresh water. A field guide. Franckh - Kosmos Verlag, Stuttgart 2008, ISBN 978-3-440-11966-2