Daphnia Details Trivia Quiz

Answer: Brine shrimp

Daphnia are crustaceans, all related to the above list somehow, but both belong to the order Cladocera, which includes brine shrimp, which are related to shrimps but are not in the same family.

Answer: Sexually and asexually

Daphnia usually breed through parthenogenesis, where a female produces live young solely from her own genes but not genetically identical. For the winter period or times of drought males are used for normal sexual reproduction, where eggs are laid that can survive the winter period and hatch when the environment becomes less hostile. Males can only be created through sexual reproduction.

Answer: Plants and animals

Though algae is the preferred diet of most, smaller invertebrates are also eaten by some, while all will also eat bacteria. In the laboratory, yeast is the normal diet.

Answer: The way they swim

While some daphnia are shaped roughly like fleas, and distantly related to all insects, they certainly do not bite or suck blood as parasites. The reason they are called fleas is the way they appear to jump through the water in sudden jerks.

Answer: Second antennae

The cause of the jumping movement while swimming is the large second antennae which are used to propel the daphnia through water. It could be compared with the butterfly stroke which has similar effects.

Answer: Feeding

The main purpose of the legs is to direct the current into their digestive tract, feeding on most unicellular material that comes in. The front two pairs of legs also act as filters to keep larger material out. The swimming is mainly carried out by the antennae.

Answer: Matsuda

Yes, though I don't know why someone named a daphnia minnehaha. Pulex means flea, which relates both to how they swim in jumps and some of their shapes. Pulex is clearly the nearest in appearance to a flea. Matsuda is the name of the man who founded Mazda cars but could make a good daphnia name if they found a new type.

Answer: Shedding their skin periodically

Like most hard shelled creatures and many reptiles the outer skin does not grow with the body so each time it becomes too tight it is shed several times until they reach adult size.

Answer: Toxicology testing

Due to their transparency, any effects of chemicals can be seen very easily, and not even always with the need of a microscope. Give a daphnia alcohol or caffeine and you can see the heart slow down or speed up accordingly before they recover back to normal.

As so few animals are transparent and so easy to look after and breed, daphnia are the easiest animals to demonstrate simple physical effects directly.

Answer: They indicate the health of the ecosystem

Though they can also be used to eat algae from fishtanks, though not while the fish are there, the daphnia populations vary directly with the pollution and other problems of their environment, so if the normal population drops then something is wrong with the area and needs to be investigated. Any animals doing this are called indicator species. Of course they are also an important food source but this does not relate to the ecosystem as a whole.