Annelida
- Invertebrate
- Protosome- during embryonic development the first opening, blastopore, forms the mouth
- Coelomates- has true coelom- a fluid filled cavity in the body that contains the digestive tract and other organs.
- Segmented body, first animals to be segmented, giving them better locomotion
- Sexual reproduction hermaphrodites- each organism has both male and female parts, but these animals cannot self fertilize
- Clitellum- structured used to hold eggs
- Bilateral symmetry, but possess little sensory organs
- Its digestive tract is a tube within a tube, consisting of a crop, a gizzard and intestine
- The crop is used to grind their food
- Annelids were the first animals to develop a ganglion, or in other words, a primitive brain
- Nephridia- a primitive kidney used to excrete nitrogenous waste, urea
- Oxygen and carbon dioxide is diffused through their moist skin
- Their blood contains hemoglobin which is a protein used to transport oxygen
- Closed circulatory system- blood is not contained, blood mixes with other body fluids