Exam 43: Animal Development

An X ray shows that a patient has a region in her upper spine where several vertebrae are fused on one side, causing curvature of the spine.The doctor tells her that the defect occurred during embryogenesis when

The extraembryonic membranes in an amniote allow the embryo to develop within a shell on land.What do these membranes allow the embryo to do that an amphibian embryo is unable to do?

Refer to the figure showing some of the manipulations carried out by Spemann on developing amphibians. Experiment 2 resulted in

As in chick development, in humans the amnion forms from the

A cell is said to be _______ after the point at which its developmental fate will not change, even if the cell's surroundings are altered.

What will happen if a researcher, working with developing amphibians, transplants a piece of ectoderm destined to become the epidermis (outer layer of skin) from one early gastrula to a location destined to be neural tissue in another early gastrula? What will happen if the transplant is made between late gastrulas?

Following fertilization and two rounds of cell cleavage, each of the four cells of a frog embryo has a centriole that is preparing for the next cleavage.The centriole in each of these cells can trace its origins back to the original centriole provided by the _______ prior to the first cleavage.

A researcher interested in studying development and function of the allantois in a vertebrate wants to select a species with a relatively large allantois.A good recommendation would be to

Somites are derived from

Formation of the endoderm and mesoderm during gastrulation in frogs results from

Which statement about placental mammals is true?

You are examining microscope slides of an early lizard embryo.You see that the neural plate is beginning to fold upward, and lying below it is a rodlike structure that you identify as the _______.

The _______ eventually develop into vertebrae, ribs, trunk muscles, and dermis.

Refer to the figure showing a stage of gastrulation in the frog. If a piece of ectoderm destined to be epidermis (outer layer of skin) is removed from a gastrula of the stage seen in the figure and put into a location destined to be neural tissue in a similarly aged gastrula, which result is the most likely?

Which result did Hans Spemann get when he bisected a salamander zygote, isolating the gray crescent in one of the two resulting cells?

Gastrulation is the stage of development

The mesoderm

Transformation of the zygote into a mass of cells occurs via

The order in which mammalian Hox genes are expressed during development

If you were developing an embryology lab and wanted to include animals that display diverse cleavage patterns (complete and incomplete, with different orientations of mitotic spindles), which types of animals might you include? If possible, select animals that are model organisms, and list the cleavage patterns they represent.