Marine life appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians which spend portions of their lives in water and portions on land. Other fish evolved into land mammals and subsequently returned to the ocean as seals, dolphins or whales. Plant forms such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton, and particularly phytoplankton, are key primary producers forming the general foundation of the ocean food chain. Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters including breathing tubes (see
Hawaiian freshwater goby Hawaiian freshwater goby The Hawaiian freshwater goby, "Lentipes concolor" ("‘o‘opu ‘alamo‘o "or "‘o‘opu hi‘u koleis"), is a species of goby endemic to Hawaii, where it occurs in mountain streams. Males of this species can reach a standard length of , while females only reach . This species is important to the native people as a food fish. In Ancient Hawaiʻi, this species, and others such as mullet and "Kuhlia sandvicensis", were cultivated in a form of freshwater aquaponics or aquatic polyculture. In this system of farming, the taro in the upland paddies (taro being the primary staple in Ancient Hawaiʻi)