Question

Who observed that embryos never pass through the adult stages of their ancestors?
A. Von Baer
B. Charles Darwin
C. Ernst Haeckel
D. Richard Owen

Answer 1

Hint: The term “Embryo” refers to the early developmental stage of an animal while it is in the egg or within the uterus of the mother.

Complete answer:
Embryonic development, also known as embryogenesis, is the development of an embryo. Embryonic development starts with the fertilization of an egg cell by a sperm cell. Once fertilized, the ovum becomes a single diploid cell known as a zygote. Let us analyze the given options to find out the correct answer.

Option A: Karl Ernst von Baer was a german scientist. He gave laws of embryology (or laws of development) to explain the observed pattern of embryonicity. According to Von Baer's third law, animals from different species start out similar and become more dissimilar from one another as ontogeny proceeds. The embryo of one species never resembles the adult of another species. Instead of recapitulating other animals' adult forms, von Baer's third law theorized that animal embryos diverge from one or a few shared embryonic forms. Therefore, this is the correct option.

Option B: Charles Darwin was an English naturalist, geologist, and biologist. He is best known for his contributions to the science of evolution. His proposition that all species of life have descended over time from common ancestors is now widely accepted and considered a foundational concept in science. Therefore, this is an incorrect option.

Option C: Ernst Haeckel discovered and described hundreds of species, coined key terms, such as ecology and ontogeny/phylogeny, and was well known for his popularized version of the “recapitulation theory” during the embryonic development of animals. Therefore, this is an incorrect option.

Option D: Richard Owen was an English biologist, comparative anatomist, and paleontologist. He is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Therefore, this is an incorrect option.

Thus, the correct option is A, Von Baer.

Note: It is to be noted that Ernst Haeckel proposed a theory of recapitulation called the biogenetic law, which states that ontogeny recapitulates phylogeny.