Quiz 4

Question 1

Tripoblastic

Answer 1

*3 major body focuses— acoelomate, pseudocoelomate, eucoelomate

Question 2

Acoel-

Answer 2

~ gastrodermis in center cell
~ ex: flatworms, tape worms
~ parynchyma (cells/cellular packing)(think of packing peanuts)(derived from mesoderm-mesodermal)
~ solid bodied

Question 3

Pseudo-

Answer 3

~ epidermis in outer layer
~ ex: round worms
~ gastrodermis in center
~ fluid filled (stiff but not as stiff as acoel-)(think of animal ballons)
~ fluid creates tugur (standing) pressure; holds body togehter

Question 4

Eu-

Answer 4

~ epidermis outer layer
~ gastrodermis center
~ ex: most animals beyond worms
~ peritoneum (have to cross)
~ mesentery (almost an encasing-like sheet)(not stiff but not loose; wobbly)(things such as veins and arteries cut through the mesentery)
~ main area of the encasing is the body cavity

Question 5

Eucoelomates (Protostomes)

Answer 5

~ stoma=mouth; mouth afterwards
~ starts as a zygote (embryo is not growing but is just dividing)
~ mouth (will build an anus later)
~ spiral cleavage
~ Gastrula
- Mesoderm (schizocoely=split body cavity)

Question 6

Eucoelomates (Deuterostomes)

Answer 6

~ ball of cells
~ called a morula=solid
~ anus (will build a mouth later) (humans fall in this category)
~ radial cleavage
~ Gastrula
- Mesoderm (pockets)(mesodermal tissue)(enterocoely)
~ at this point we are tripoblastic

Question 7

cell fate

Answer 7

~ the fate of a cell that you break off an embryo
- P= set early (once in this stage cells already know what to do)(no twinning) (cells will die off if broken apart)
- D= set late (identified twins)

Question 8

Segmentation

Answer 8

~ serial repetition of parts
- structures are repeated; will be the same; can be both internal & external