According to recapitulation theory, the growth of this biological structure resembles the successive adult stages of an animal’s remote ancestors. For 10 points each:
[10e] Name this multicellular structure formed from a dividing zygote after a sperm fertilizes the egg. In humans, this structure implants itself in the endometrial lining and becomes a fetus nine weeks after conception.
ANSWER: embryos [prompt on blastocysts or blastulas or morulas or blastomeres]
[10m] Anatomical structures with similar embryonic origins may have this property if they share a common ancestor, despite serving different purposes. Primate arms and bat wings have this property, contrasted with analogy.
ANSWER: homology [accept homologous structures]
[10h] This subfield of biology with a rhyming name studies deep homology to explain how dissimilar organs are controlled by highly-conserved genes like PAX6 (“packs-six”), which is part of this subfield’s “gene toolkit.”
ANSWER: evo-devo [or evolutionary developmental biology; accept evo-devo gene toolkit; prompt on evolutionary biology or developmental biology]
<Editors, Biology>