What are the characteristics of the arthropod phylum Crustacea

Crustaceans, the 3rd outline in the phylum Arthropods. The number of species is second only to insects and arachnids. The vast majority of aquatic species are mostly marine.

The body is segmented, and some segments of the chest heal with the head, forming a cephalothorax, which is covered with a hard cephalothorax. Each somite almost has one pair of appendages, and often remains primitive in the form of two branches, with two pairs of antennae. Breathe with gills.

<> arthropods include Crustacea, Arachnids, Arachnids, Myriapoda, Insecta, etc.

1. Crustaceans: thorax and body segments healed, with a hard cephalothorax, two pairs of antennae, mostly aquatic.

Such as shrimp, crabs, tide insects.

2. Arachnid: composed of cephalothorax and abdomen, no antennae, 6 pairs of appendages in the cephalothorax, the first pair is the anchopathy, the second pair is the horn whiskers, and the last 4 pairs are the feet, most of them live on land, such as spiders, scorpions, ticks, and mites.

3. Limb-stomachia: large, gill, aquatic, divided into cephalothorax and abdomen, cephalothorax with cephalothorax and tail spines on the abdomen, such as horseshoe crab (hou).

4. Myriapoda: The body is divided into two parts: the head and the trunk, a pair of antennae, several eyes, and a long trunk, composed of multiple body segments, such as Malu.

Centipede. 5. Insecta: Adults are divided into three parts: head, thorax and abdomen, with mouthparts, a pair of antennae, 2 pairs of feet in the thorax, no feet in the abdomen, and an exoskeleton with chitin on the body surface. There are many species, accounting for 3 4 of all animals, such as dragonflies, butterflies, beetles, mosquitoes, flies.

Crustaceans are:Fairy shrimp, Daphnia, one-eyed dragon, fish lice,Barnaclesand copepods, crayfish, lobsters, shrimp,Tide bugs, bulb tide bugs, sand fleas and ground turtle insects.

Crustaceans of the world.

There are many types, about 10,000 kinds. Crustaceans such as shrimp and crabs are nutritious, delicious and have high economic value. Some carapaces are also used as bait for economic animals such as fish. Among crustaceans, there are also some species that are harmful, such as parasites such as fish lice.

It is very harmful to fish.

Methods of reproduction of crustaceans:

Crustaceans reproduce by laying eggs. The eggs of crustaceans in saltwater hatch into tiny larvae, which are not the same as adults. Juvenile crustaceans in freshwater, except that their bodies are smaller than their adults, look very similar to adult crustaceans.

Small crustaceans.

It is very important as the main food of fish. Lobsters, crabs, and shrimp are very good food for humans, and many people also eat crayfish.

Crustaceans are also used as "cleaners", and they help keep beaches and streams clean. On the other hand, some crustaceans are dangerous pests that destroy crops or burrow into docks and seawalls.