What is Developmental Biology and How do we Research it? Flashcards
What is developmental biology?
Union of genetics and embryology
Preformation
All structures preformed and just grow in size
Epigenesis
New structures develop progressively during development
William Harvey
1st to use house mouse for study, seminal work in chick refuting spontaneous generation, and ovum is necessary.
Marcello Malpighi
Father of microscopic anatomy, supported preformation
August Weismann
Germ plasm theory: specific cells are different
Nuclear determinant theory: every cell has the same DNA
Ernst Haeckel
Proponent of preformation, proposed the recapitulation theory, and introduced concept of heterochrony (change in rate and timing of development which is an evolutionary shift)
Wilhelm Roux
Pioneer in experimental embryology, proponent of preformation, then mosaic epigenetist, most known for methods, all daughter cells are different and no other cell is exactly the same
Mosaic development:
Differential arrangement of localized nuclear determinants
Hans Driesch
Work in sea urchin helped refute preformation and nuclear determination, showed early blastomeres were capable of forming complete organisms separately, mosaic theory replaced by regulations, unequal distribution in the cytoplasm, and FATHER of totipotency/pluripotency
How did Hans Driesch found totipotency and pluripotency?
Separated cells at the two cell stage. One cell normally died, but the other cell survived and developed into a normal larva. Sometimes both survived and became individuals. This refutes nuclear determination, because it produced whole animals, not half. DNA is the same, but proteins and cytoplasm are different.
Hans Spemann
Proposed concept of induction, experimentally proved the concept in grafting experiments in amphibian embryos, he took small pieces of tissue and moved to other organisms and recorded what happened.
Hilde Mangold worked under Hans.
Gudrun Ruud
Pioneering work in regeneration and grafting, and work in salamander development
Kristine Bonnevie
Pioneer in chromosomal research, heredity, and inheritance.
Studies in polydactylism, dwarfism, and other disorders in isolated populations.
How do traits associate. Did bottleneck experiments on species and looked at what changed.
Karl Ernst von Baer
Prolific in areas of evolution and embryology, discovered blastula stage and notochord, cofounder of germ layer theory, and von Baer Laws.
Heinz Christian Pander
Cofounder of germ layer theory, chick development, and discovered conodonts