BIO 5 Lecture Notes - Lecture 4: Archenteron, Body Cavity, Coelom
Document Summary
Radial cleavage- cleavage plain parallel or perpendicular to the animal-vegetal axis. Spiral cleavage cleavage plain at an oblique angle to the animal-vegetal axis. Angles start getting offset from each other. Indirect development goes through a larval stage and then metaphormosis into an adult stage. Direct development organism that hatches out of the egg. How to determine whether it"s an indirect or direct development: amount of yolk present in the egg. The general pattern is that an egg with a large amount of yolk will lead to direct development: smaller amount of yolk doesn"t give enough energy so it"s indirect. Gastrulation an important stage in an organism"s lifestyle as it sets up the structure. The blastula is a solid ball or hollow ball in certain organisms. Coelom body cavity completely lined by tissues derived from the mesoderm. Pseudocoel body cavity not lined on all sides by mesoderm. Look at the structure of body cavities.
