NEETZoologyEvolution
During embryonic development, all vertebrates including humans develop a row of vestigial gill slits just behind the head. This structure is functional only in fishes and is not found in other adult vertebrates. Which scientist used this specific observation to propose embryological support for evolution, and what was the fundamental flaw in their conclusion as identified later?
Options
- AKarl Ernst von Baer; the flaw was his conclusion that human embryos pass through an adult fish stage.
- BErnst Haeckel; the flaw was his assumption that vestigial organs have no function in any vertebrate.
- CErnst Haeckel; the flaw was his assumption that embryos pass through the adult stages of other animals.
- DKarl Ernst von Baer; the flaw was his assumption that gill slits are functional in human embryos.
Correct answer
C. Ernst Haeckel; the flaw was his assumption that embryos pass through the adult stages of other animals.
Step-by-step solution
Ernst Haeckel proposed embryological support for evolution based on the observation that all vertebrate embryos develop certain common features, such as a row of vestigial gill slits, which are absent in adults. However, Karl Ernst von Baer disapproved this proposal after careful study. Von Baer pointed out the fundamental flaw in Haeckel's reasoning: embryos never pass through the adult stages of other animals. Therefore, the similarities in embryonic stages do not mean that higher vertebrate embryos represent the