ARTHROPODS
Arthropod- a class of animals in the phylum, Arthropoda. these are invertebrate animals, lacking a backbone, and an exoskeleton, outer shell. also, Arthropods are characterized by the appendages on their body. Arthropods consist of animals such as insects, arachnids, crustaceans, and more.
Spiders: spiders are labeled arachnids. Arachnids, just like other insects, are arthropods. A spider’s excretory system works together with its digestive system. Just like humans, after a spider consumes its food, it travels down the esophagus, to the stomach and intestines, then stopping at the anus. a spider's body consists of two main parts, in the front lies the esophagus and stomach. While in the back segment, the intestine, digestive tubules, and anus are located. The waste moving down the digestive tubes in a spider travels down malpighian tubules, or to a human its "kidneys." There it forms the solid waste to not release any excess water. Spiders try to preserve as much water as it can.
Crabs: crabs are a crustacean. Crustaceans consist of a large percentage of the arthropoda phylum. a crabs excretory is similar to many other crustaceans. The food is digested and then passed down to the intestine, just like most other organisms. However, in a crab and other crustaceans, there are two other organs that serve a special purpose; the antennal gland and maxillary gland. Both glands are similar in structure, a sac with an opening at the end. each are treated just like a bladder in a human. when a crustacean grows and becomes an adult, usually only one of the two glands are functioning.
Fly: a fly, also known as a basic insect. a fly's excretory system is very similar compared to a spider and many other insects and arachnids. After the digestion process of the consumed food moving down the esophagus then traveling to the intestine. The malpighian tubules play a large role in a fly's excretory system as well as its hindgut. the malpighian tubule and hindgut get rid of the nitrogenous waste in the fly's body. The anus of the fly retains up to ninety per cent of the fly's water when it is excreting its waste. After the fly has excreted the waste from its body, its anus reabsorbs the water back into the body. The purpose of this is to keep as much fluid as possible so the fly can survive in harsh climate conditions.