Animal Development II: The Domestic Chicken

BIO SCI 152 LABORATORY 11 (SPRING) Name Institution Date BIO SCI 152 LABORATORY 11 (SPRING) ANIMAL DEVELOPMENT II: THE DOMESTIC CHICKEN Answer the questions below in regards to chicken embryos at different stages of development. 1 What type of egg is the chicken egg? The Chicken egg is a type of egg laid on land unlike amphibians, are not dependent on water to keep them moist. The embryo develops within a fluid-filled sac known as the amnion, and the membranes and shell of the egg make it further resistant to desiccation. Lastly, the chicken egg has internal fertilization since the sperms cannot penetrate them. 2 What type of cleavage occurs in the chicken egg? Immature eggs develop within follicles in the single ovary of the adult female bird (two ovaries begin to develop in birds, but the second ovary degenerates). The entire yolk of a chicken "egg" is a single cell, the oocyte. 3 What are the major differences between the 48-hour and 96-hour chicken embryos? In the 48-hour embryo, there is a circulatory system. The heart is already beating at this stage, pumping blood through the vitelline blood vessels. Meanwhile, a 96-hour chicken has a strong cervical flexure, bending the body into a C confutation. Moreover, several organs are noticeably larger than in the 48- hour embryo 4 What are the four extra embryonic membranes in the chicken and what are their respective functions? How are they adaptations to a land environment? The chicken egg has got a shell, hard porous layer. The shell is porous to allow an exchange of air to the embryo. It also prevents desiccation of water from the embryo. Shell membranes and air chamber also serve similar functions. Summary question related to animal development 5 What is a yolk? How does it function in development? Yolk is the nutrient-bearing of the egg whose primary function is to supply food for the development of the embryo. Some chicken eggs have no yolk because they are laid in a situation where food supply is limited. The yolk is responsible for the initial circulation and is in charge of delivering nutrients, via a primitive aorta, to the developing embryo through a process called vitelline circulation 6 How does the amount of yolk affect cleavage and gastrulation? Give examples from the organisms you studied in this lab The amount and distribution of the yolk have the potential to determine the type of segmentation. After the sperm and egg nuclei fuse, the zygote divides by mitosis followed by cytoplasmic cleavage. This process is called meroblastic or partial cleavage which does not require...