Sea-urchins
Which organism is a classic model for studying regulative development?
Ascidians belong to which phylum?
Chordata
What event establishes the dorsal-ventral axis in Xenopus embryos?
Corical rotation
What structure marks the future posterior end and the start of gastrulation in chick embryos?
Koller's sickle
Name the three germ layers.
endoderm, Mesoderm, Ectoderm
What process creates micromeres in sea urchins?
Asymmetric fourth cleavage
What maternal determinant specifies muscle cell formation in ascidians?
Macho-1 mRNA
Which structure acts as a signaling center essential for dorsal axis formation in amphibians?
Spemann-Mangold organizer
It's an organizing center marking the anterior end of the primitive streak, equivalent to the Spemann-Mangold organizer.
What is Hensen’s node
During neurulation, what structure does ectoderm form?
Neural tube
What pattern of cleavage is observed in sea urchin embryos?
Radial cleavage
What is unique about adult C. elegans reproductive biology?
They are mainly hermaphrodites capable of self-fertilization.
What signals induce mesoderm formation in Xenopus embryos?
Nodal signals from vegetal cells
What type of cleavage do mammalian embryos undergo?
Rotational cleavage
What cells migrate away from the neural tube and form peripheral nerves and facial structures?
Neural crest cells
Which experimenter demonstrated regulative development using sea urchins?
Hans Driesch
How is the anterior-posterior axis first established in C. elegans embryos?
By the site of sperm entry into the egg
What process forms a tightly bound cell cluster called the morula in mammals?
compaction
Blocks of mesoderm that form skeletal muscles, vertebrae, and ribs.
What are somites
What proteins mark posterior cell lineage and germ cell precursors in C. elegans embryos?
P-granules
What model describes the process by which somite boundaries are specified through oscillating gene expression and signaling gradients?
The clock and wavefront model