invertebratessuch

Invertebrates, spelled with standard form, are animals lacking a vertebral column. The phrase "invertebratessuch" does not reflect a recognized taxonomic group. This article uses the conventional term invertebrates and outlines their major features, diversity, and ecological roles.

They represent the vast majority of animal species and inhabit almost every environment—oceans, freshwater, forests, soil, and even some extreme habitats. They range from microscopic mites to giant squid and include a wide variety of body plans, lifestyles, and reproductive strategies. Most lack a rigid internal skeleton; instead, many rely on hydrostatic skeletons, external shells, or rigid exoskeletons.

Key groups include Arthropoda (insects, spiders, crustaceans), Mollusca (snails, clams, octopus), Annelida (segmented worms), Cnidaria (jellyfish, corals), Echinodermata (starfish, sea urchins), Nematoda (roundworms), Platyhelminthes (flatworms), and Porifera (sponges). Within each group, there is substantial diversity in form, habitat, and feeding strategies.

Ecological roles are diverse: many invertebrates pollinate crops and wild plants; others decompose organic matter and help recycle nutrients; many serve as important food sources for other animals. In soils, earthworms and mites influence structure and fertility. Humans rely on invertebrates for resources and research; model organisms such as Drosophila melanogaster (fruit fly) and Caenorhabditis elegans (nematode) have advanced biology.

Conservation and study: Invertebrates face threats from habitat loss, pollution, climate change, and overexploitation. A large fraction of species remains undescribed, especially invertebrate taxa. Protecting habitats, reducing pollution, and promoting sustainable practices help sustain their ecological roles.