Oviparity vs Viviparity Flashcards
What is the basic composition of terrestrial oviparious animals’ eggs?
outer layer - calcium carbonate, 2 soft membranes
inside egg - air cell, yolk
What is a hard shell covered with which allows for diffusion?
thousands of pores
As the incubation of an egg progresses, oxygen level ____ as carbon dioxide levels ____.
decrease; increase
via lost water vapor
Why are eggs laid in thick vegetation much thinner than those laid in open areas?
it helps to keep the fetus protected and prevents much water loss
Ex. Mound builders of Australia
Which kind of organisms retain the fetus within the mother until birth and gives birth to live young?
viviparous
What are some examples of viviparous organisms?
mammals
What kind of organisms retain the egg within the body, but the mother gives live birth?
ovoviviparous
What are some examples of ovoviviparous organisms?
sharks (20%)
What is an advantage to ovoviviparity?
the young are better developed after birth
What is a disadvantage to ovoviviparity?
the mother has a lot of strain carrying fully shelled eggs
What kind of organisms are mammals but also lay eggs?
monotremes
Which kind of organisms have a uterus that holds the embryo, and are born in very early stages where the fetus crawls into a pouch where it completes it’s development?
marsupials
their pouch is called a marsupium
What are some examples of marsupials?
kangaroos and opossums
What kind of organisms have placental embryos where the placenta links the blood supply between the embryo and the mother?
eutherian mammals
