Question

In the development of a frog embryo, which of the following would be the spearman’s primary organizer?
(a)Dorsal ectoderm
(b)Dorsal lip of the blastopore
(c)Archenteron
(d)Neural tube
(e)Notochord

Answer 1

Hint: The process of formation and development of an embryo is known as embryogenesis. The embryogenesis starts with the fusion of the egg cell and sperm cell and gets fertilized, from which a zygote (diploid) is developed. The newly formed zygote later goes through the mitotic divisions and forms a multicellular embryo.

Complete answer:
In the development of a frog embryo, the dorsal lip of the blastopore would be the spearman’s primary organizer. The research by Hans Spemann (German embryologist) and his colleague Hilde Mangold did a transplantation experiment in frogs which led to the discovery of organizers.
-In embryology, an organizer is the morphogenetic effect caused by one organic tissue which produces a chemical molecule that affects another part of the embryo to form a part which otherwise would not have produced.
-Hans Spemann and Hilde Mangold experiments proved that the dorsal lip of blastopore makes the neural tubes, cartilaginous skeletons, mesoderm etc and therefore called as the Specman's primary organizer.
So, the correct answer is 'Dorsal lip of the blastopore'.

Note: -Frogs are amphibians which live on both land and water. The life cycle of frogs involves the formation of tadpoles, which looks similar to fishes and lives completely in water during this period and later develop legs and adapt to land.
-Sex determination in frogs is influenced by environmental factors. The temperature around the egg
determines the sex of the progeny.
-Pulmonary respiration is also called the lung respiration which frogs use while they live on the land where they are more physically active for the need for movement, swimming, hunting, and jumping and this demands more quantity of oxygen.