Cnidaria
Cnidaria comes from the Latin word "cnidos" which means "stinging nettle."
Found mostly in aquatic and marine environments, they have a distinguishing feature called cnidocytes, microscopic intracellular stinging capsules.
Types of cnidarian:
jellyfish, squid and coral
There are over 10,000 species of cnidarians, mostly found in aquatic environments.
Digestion
In the cnidarian, digestion starts when prey is caught by the nematocyst (stinger) and brought to the mouth with contraction of the tentacles. The nematocysts contain poisonous chemicals which kill their prey. The food is then passed to and broken down in the gastrovascular cavity where the essential nutrients they need are absorbed. Since they have a one-way digestive system it means that the same opening that takes in food to be digested is the same opening that lets out undigested waste.
Found mostly in aquatic and marine environments, they have a distinguishing feature called cnidocytes, microscopic intracellular stinging capsules.
Types of cnidarian:
jellyfish, squid and coral
There are over 10,000 species of cnidarians, mostly found in aquatic environments.
Digestion
In the cnidarian, digestion starts when prey is caught by the nematocyst (stinger) and brought to the mouth with contraction of the tentacles. The nematocysts contain poisonous chemicals which kill their prey. The food is then passed to and broken down in the gastrovascular cavity where the essential nutrients they need are absorbed. Since they have a one-way digestive system it means that the same opening that takes in food to be digested is the same opening that lets out undigested waste.