An open circulatory system is a type of blood circulation system where the blood, rather than being confined to vessels, bathes the organs directly in a cavity called the hemocoel. This system is found in many invertebrates, including arthropods and mollusks, and is characterized by lower pressure and slower blood flow compared to closed circulatory systems.

Open Circulatory System

Blood circulation system

A hemocoel is a primary body cavity found in arthropods and some mollusks where blood freely circulates around organs, functioning as part of an open circulatory system. This cavity allows for efficient nutrient and waste exchange despite the absence of a closed network of blood vessels.

Hemocoel

Invertebrates are animals that lack a vertebral column, making up approximately 97% of all animal species, and include diverse groups such as insects, arachnids, mollusks, and crustaceans. They play crucial roles in ecosystems as pollinators, decomposers, and as part of the food web, highlighting their ecological importance despite their lack of a backbone.

Invertebrates

Arthropods are a diverse group of invertebrates characterized by their exoskeleton, segmented bodies, and jointed appendages, making them the largest phylum in the animal kingdom. They play crucial roles in ecosystems as pollinators, decomposers, and as a food source for other animals, while also including species that are significant pests and disease vectors.

Arthropods

Mollusks are a diverse group of invertebrates that include species such as snails, clams, and octopuses, characterized by a soft body often protected by a hard shell. They play vital roles in ecosystems as grazers, predators, and prey, and have significant economic importance in fisheries and aquaculture.

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