Looking for classes? Ksquare Career Institute, Bengaluru →
Which one of the following statements is correct?
A
there is no evidence of the existence of gills during embryogenesis of mammals
B
all plant and animal cells are totipotent
C
ontogeny repeats phylogeny
D
stem cells are specialized cells
Detailed Solution
Ontogeny is the developmental history of an individual, and phylogeny is the evolutionary history of its race.
Ernst Haeckel proposed the biogenetic law or recapitulation theory, which states that ontogeny repeats (recapitulates) phylogeny, i.e. an organism passes through its ancestral stages during its embryonic development. This is the correct statement among the four.
The embryos of all vertebrates, including mammals, develop a row of vestigial gill slits just behind the head, so there is evidence of gills during the embryogenesis of mammals.
All plant cells with a nucleus are potentially totipotent, but most animal cells are not.
Stem cells are undifferentiated, unspecialised cells that can divide and give rise to specialised cells.
So the correct statement is that ontogeny repeats phylogeny.
Ernst Haeckel proposed the biogenetic law or recapitulation theory, which states that ontogeny repeats (recapitulates) phylogeny, i.e. an organism passes through its ancestral stages during its embryonic development. This is the correct statement among the four.
The embryos of all vertebrates, including mammals, develop a row of vestigial gill slits just behind the head, so there is evidence of gills during the embryogenesis of mammals.
All plant cells with a nucleus are potentially totipotent, but most animal cells are not.
Stem cells are undifferentiated, unspecialised cells that can divide and give rise to specialised cells.
So the correct statement is that ontogeny repeats phylogeny.