Similarities between Bird alimentary canal and cockroach
Answers
Answer:
DIGESTIVE SYSTEM
The digestive system includes the alimentary tract and all glands and organs associated with digestion and assimilation of food in animals.
Digestion is the breakdown of large molecules of food into simple and absorbable form for use by animals. Ingestion is the taking in of food from outside through the mouth. Egestion is the discharge of undigested and unabsorbed food from the alimentary canal. Absorption is the passage of food through the wall of the alimentary canal. Assimilation is the manufacture of the body’s own materials from the absorbed substances and their use in metabolism.
TYPES OF DIGESTIVE TRACTS
There are two types of digestive tracts:
A. Incomplete digestive tract: has only one opening- the mouth which serve for ingestion and egestion e.g Hydra, Planaria
B. Complete digestive tract: has two openings to the outside world- mouth (for ingestion) and anus (for egestion) e.g. earthworm, goat
Complete digestive system has an advantage that incoming food does not mix with outgoing undigested food materials and each part is specialized to perform different functions.
Alimentary Canal of invertebrates
Animals have different alimentary tracts which vary in size, complexity, mode of feeding or the type of diet.
Alimentary canal of Planaria
Planaria is a free-living flatworm that feeds on small aquatic animals- zooplankton. It has a simple digestive tract with one opening- the mouth. The digestive tract consist of a ventrally placed mouth, muscular pharynx and intestine. The pharynx can be protruded when attacking a prey. Digestion is intracellular and undigested food is egested through the mouth. Digested food is distributed through the body by diffusion.