There are several types of invertebrates??? What are the species of invertebrates

The classification of invertebrates is not yet completely consistent because the opinions of zoologists have not yet been unified. In recent years, based on the results of various studies, together with the newly established phylum Platozoa and Loricifera in 1971 and 1983, there has been a tendency to divide invertebrates into 33 phyla. It mainly includes the phylum Protozoa, the phylum Pores (Sponges), the coelenterates, the Platyzoa, the Linear Animals, the Molluscs, the Annelids, the Arthropodas, the Echinoderms, and the Hemichordates.

There are many species of invertebrates, accounting for about 97 species in the animal kingdom, of which the phylum Arthropod is the first phylum and the mollusc phylum is the second phylum.

Divided into arthropods. Coelenterate. Mollusca. Annelid.

Basis for classification of invertebrates].

The nervous system of invertebrates is cord-like and is located on the ventral surface of the digestive tract; Whereas, vertebrates are tubular and located on the back of the digestive tube.

The heart of an invertebrate is located on the back of the digestive canal; The vertebrates are located on the ventral surface of the digestive tract.

Invertebrates have no skeleton or only exoskeleton, no true endoskeleton and vertebrae; Vertebrates have endoskeletons and vertebrae.

In 1822, J B de Lamarck divided the animal kingdom into two categories: vertebrates and invertebrates. In 1877, the German scholar e Haeckel called stigma, sea squirt, Wenchang fish and other animals and vertebrates as chordates, and ranked them alongside the phylum invertebrates, and reduced vertebrates to a subphylum in the phylum Chordates in the classification system, and placed them alongside the subphylum Hemichordate (stigma), the subphylum Chordate (sea squirt) and the cephalic chordate subphylum (Wenchang fish). Since the 70s, hemichordates have been formed into separate phyla, and since the latter three groups belong to the category of invertebrates, invertebrates actually include all animal phyla except for the subphylum vertebrates, which is a general name in zoology, rather than a formal taxonomic order.

Species] The species of invertebrates are very diverse, with about 100 million species (about 50,000 vertebrate species) extant, and even more extinct species. The number of phylum it includes is constantly increasing due to the development of zoology. As various aspects of animals are studied in greater detail and their kinship is better understood, the taxonomic status of each phyla often changes.

Invertebrates include protozoa, echinoderms, molluscs, flattened animals, annelids, and other species. Protozoa: paramecium, amoebea, etc. Echinoderms: starfish, sea urchins.

sea cucumbers, etc. Molluscs: mussels, snails, squid, etc. Flattened animals: pork tapeworms, bloodsucking insects, etc. Annelids: Earthworms.

Grasshoppers, sand scorpions, etc. <

Invertebrates include protozoa, echinoderms, molluscs, flattened animals, annelids, and other species.

1. Protozoa: paramecium, amoebae, etc.

2. Echinoderms: starfish, sea urchins, sea cucumbers, etc.

3. Molluscs: mussels, snails, squid, etc.

4. Flattened animals: pork tapeworms, bloodsucking insects, etc.

5. Annelids: earthworms, grasshoppers, sand scorpions, etc.

Invertebrate classification:1. Protozoa, such as paramecium, amoeba and other single-celled animals.

2. Sponge animals are a kind of multicellular animals without tissue differentiation, and household sponges are actually imitations of sponge animals, even the name is it.

3. Coelenterates, such as hydra, anemones, jellyfish, etc.

4. Flattened animals, such as planarians, tapeworms, schistosomiasis, etc.

5. Nematodes, such as roundworms, nematodes, etc.

6. Annelids, such as earthworms, sand silkworms, etc.

7. Molluscs, such as snails, mussels, squid, octopus, etc.

8. Arthropods, such as insects, shrimp and crabs, spiders, centipedes, etc.

9. Echinoderms, such as sea urchins, starfish, sea cucumbers, etc. The above order is from lowest to highest.

Invertebrate characteristics:

Invertebrates are a relatively lower group of animals that do not have vertebrae. Corresponds to vertebrates. Both the variety and the number are huge.

From the perspective of living environment, there are traces of them in the ocean, rivers, lakes, ponds, and land; In terms of lifestyle, there are types of free life, parasitic life, and symbiotic life.

From the point of view of the way of reproducing offspring, some species can reproduce asexually, some species can reproduce sexually, some species can reproduce both asexual and sexual, and some species can also reproduce larvae and parthenogenesis.

Including protozoa, echinoderms, molluscs, flattened animals, annelids, etcCoelenterate. , arthropods, nematozoa, etc.

A sub-discipline of zoology. In animal classification, animals are divided into two categories: vertebrates and invertebrates according to whether they have vertebrae in their bodies. The science that studies the classification, morphology, physiological characteristics, geographical distribution, reproduction, evolution, etc. of invertebrates is called invertebrate zoology.

Invertebrate zoology includes: protozoology, helminthology, entomology, molluscs, crustaceans, etc.

Morphological characteristics. Most invertebrates are small, but molluscs are cephalopod king squid.

Animals of the genus can reach a body length of up to 18 meters, a wrist length of 11 meters, and a weight of about 2 tons. Most of the invertebrates are aquatic, and most of the seafood, such as foraminifera, radiolaria, bowl jellyfish, polyps, squid and echinoderms, etc., are all seafood, and some species live in freshwater, such as hydroids, some snails, mussels, freshwater shrimp and crabs.

Snails, rat women.

and so on, living on humid land. Spiders, myriapods, and insects are mostly terrestrial animals. Invertebrates mostly live freely.

Among the aquatic species, the small battalion floats for a life; Those with shells crawl underwater (e.g., shrimps, crabs), or are buried in sediment (e.g., silkworms), or are fixed to aquatic objects (e.g., barnacles).

oysters, etc.). Invertebrates also have many parasitic species, parasitic on the surface or body of other animals and plants (such as parasitic protozoa, flukes, tapeworms).

Echinocephalus, etc.). Some species such as roundworms.

and ascaris suis can be harmful to humans.