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
Short food supply chains Short food supply chains Short food supply chain (SFSCs) is a broad range of food production-distribution-consumption configurations, such as farmers' markets, farm shops, collective farmers' shops, community-supported agriculture, solidarity purchase groups. More in general, a food supply chain can be defined as "short" when it is characterized by short distance or few intermediaries between producers and consumers. SFSCs were originally identified as examples of "resistance" of farmers to modernization of the food system, characterized by the development of supply chains based on long-distance trade. Resistance consists in the fact that, by selling directly to consumers, farmers bypass intermediaries and thus