development of digestive system Flashcards
1
Q
how did the digestive system start
A
animals started with cells that digested food via food vacuoles
- phagocytosis
-choanocytes (porifera)
2
Q
how is digestion organized
A
digestion becomes compartmentalized
3
Q
how are CELLS organized
A
cells organize into fundamental tissues
4
Q
incomplete digestive tract
A
-simple sac with 1 opening
-gastrovascular cavity formed
5
Q
organisms became more complex->more complex gastrovascular cavity
A
-acoelomate
-increased surface area
6
Q
alimentary canal formed
A
-2 openings (mouth + anus)
-allows for more structures
-longer breakdown/absorption time
7
Q
alimentary canal becomes more complex
A
-associated structure develops (digestive gland)
-several digestive glands associated with stomachs
