Categories: All - species

by Darby Rich 13 years ago

820

Invertebrate Phylogenetic Tree

Invertebrates are categorized into several phylogenetic groups based on their evolutionary relationships and body structures. The Lophotrochozoa, with nearly 139,000 species, include diverse organisms such as flatworms, molluscs, and segmented worms.

Invertebrate Phylogenetic Tree

Invertebrate Phylogenetic Tree

Deuterostomia

Example Organisms: Sea stars (Asterios forbesii) and Sea cucumbers (Parastichopus californicus)
Defined primarily by DNA similarities, not developmental similarities
Two main groups:Echinodermata and Chordata (three groups of chordata are invertebrates: they consist of lancelets, tunicates, and hagfishes), and includes hemichordata
About 59,085 species

Ecdysozoa

Example Organisms: Parasitic nematode (Trinchinella spiralis) and Fruit flies (Drosophila melanogaster)
They are the most species-rich animal group, proven by having more known species than all other protist, fungus, plant, and animal groups combined
Two main groups: Nematoda and Arthropoda, which includes loriciferans, priapulans, tardigrades, velvet worms, roundworms, insects, crustaceans, and arachnids
Nearly 1,030,000 species

Lophotrochozoa

They are a part of clades Eumetazoa and Bilateria
Example Organisms: Sea mat (Membranipora membranacea) and the Giant squid (Architeuthis dux)
Known and indentified by molecular data, that also has the most diverse animal clade in terms of body form
Six main groups: Platyhelminthes, Rotifera, Ectoprocta, Brachiopoda, Mollusca, and Annelida. These include flatworms, ectoprocts, rotifers, lamp shells, ribbon worms, molluscs, segmented worms, acanthocephalans, and cycliophoran
Nearly 139,00 species

Cnidaria

They are a part of clade Eumetazoa, but not Bilateria
Example Organism: Sea wasp (Chironex fleckeri)
They have radially symmtrical bodies
Includes corals, jellies, and hydras
10,000 species

Calcarea and Silicea

NOT a part of clade Eumetazoa or Bilateria because they do not have tissues
Example Organism: Azure vase sponge (Callyspongia plicifera)
They lack true tissues, but are still defined as animals
Informal name: "sponges"
1,500 species