| A | B |
|---|
| Homeobox | Master genes that control expression of genes responsible for development of specific anatomical structures. |
| Gray Crescent | Part of the cytoplasm of the frog embryo that is necessary for normal development into adulthood. |
| Yolk Sac | Encloses the yolk, provides food for the growing embryo. |
| Amnion | Encloses the embryo in protective amniotic fluid. |
| Chorion | Lies under the shell and allows for diffusion of respiratory gases between the outside and the growing embryo. |
| Allantois | Analogous to the placenta in mammals; carries respiratory gases between environment and embryo and stores uric acid. |
| Animal Pole | Where most cleavage occurs; top half of frog embryo. |
| Vegetal Pole | Yolky portion where very little cleavage occurs; bottom half of frog embryo. |
| Ectoderm | The embryonic germ layer that becomes skin and the nervous system. |
| Endoderm | The embryonic germ layer that becomes the digestive tract. |
| Mesoderm | The embryonic germ layer that becomes the blood, bone and muscle. |
| Cleavage | Rapid mitotic division of the zygote that begins immediately after fertilization. |
| Gastrulation | Process that involves the rearrangement of the blastula and results in the formation of 3 embryonic germ layers. |
| Oorganogenesis | Process by which cells continue to differentiate, producing organs from the 3 embryonic germ layers. |
| Asexual Reproduction | Produces clones; offspring genetically identical to the parent cell. |
| Sexual Reproduction | Offspring are the products of two parents and might be better able to survive in a changing environment. |
| Spermatogenesis | Process of sperm production; begins at puberty and continues throughout life. |
| Oogenesis | Process characterized by the unequal cytoplasmic division and the formation of only 1 active ovum. |
| Menstruation | Monthly shedding of the lining of the uterus when implantation of an embryo does not occur. |
| Fission | A type of asexual reproduction that involves the division of an organism into 2 cells; |
| Budding | A type of asexual reproduction that involves the splitting off of new individuals from existing ones. |
| Fragmentation | When a single parent breaks into parts that regenerate into new individuals. |
| Parthenogenesis | The development of an egg without fertilization, the resulting adult is haploid. |
