What is Developmental Biology and How do we Research it?

Question 1

What is developmental biology?

Answer 1

Union of genetics and embryology

Question 2

Preformation

Answer 2

All structures preformed and just grow in size

Question 3

Epigenesis

Answer 3

New structures develop progressively during development

Question 4

William Harvey

Answer 4

1st to use house mouse for study, seminal work in chick refuting spontaneous generation, and ovum is necessary.

Question 5

Marcello Malpighi

Answer 5

Father of microscopic anatomy, supported preformation

Question 6

August Weismann

Answer 6

Germ plasm theory: specific cells are different

Nuclear determinant theory: every cell has the same DNA

Question 7

Ernst Haeckel

Answer 7

Proponent of preformation, proposed the recapitulation theory, and introduced concept of heterochrony (change in rate and timing of development which is an evolutionary shift)

Question 8

Wilhelm Roux

Answer 8

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

Question 9

Mosaic development:

Answer 9

Differential arrangement of localized nuclear determinants

Question 10

Hans Driesch

Answer 10

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

Question 11

How did Hans Driesch found totipotency and pluripotency?

Answer 11

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.

Question 12

Hans Spemann

Answer 12

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.

Question 13

Gudrun Ruud

Answer 13

Pioneering work in regeneration and grafting, and work in salamander development

Question 14

Kristine Bonnevie

Answer 14

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.

Question 15

Karl Ernst von Baer

Answer 15

Prolific in areas of evolution and embryology, discovered blastula stage and notochord, cofounder of germ layer theory, and von Baer Laws.

Question 16

Heinz Christian Pander

Answer 16

Cofounder of germ layer theory, chick development, and discovered conodonts

Question 17

Joseph Needham

Answer 17

Chemical embryologist, investigated the concept of induction

Question 18

Gavin de Beer

Answer 18

An early evo-devo researcher, seminal work in heterochrony (Paedomorphosis) and homology, credited with integrating developmental biology into the modern synthesis

Question 19

Viktor Hamburger

Answer 19

Synonymous with chick development, “Hamburger-Hamilton Stages”, nerve growth.

Question 20

J.B.S. Haldane

Answer 20

Coined the term “cloning”, introduced primordial soup, work in genetics and genetic linkage, Haldane’s principle on size

Question 21

Ernest Everett Just

Answer 21

Pioneering work in invertebrates, fertilization, fast block to polyspermy, and parthenogenesis

Question 22

Edward B. Lewis

Answer 22

Pioneering work in Drosophila, Hox genes (Bithorax), and complementation test

Question 23

Rita Levi-Montalcini

Answer 23

Pioneer in chick development, focusing on nerve growth.

Discovered and isolated nerve growth factor

Question 24

Stanley Cohen

Answer 24

Pioneer in growth factors, isolated nerve growth factor, and discovered epidermal growth factor.

Question 25

Christiane Nusslein-Volhard

Answer 25

Nobel winner, Groundbreaking work in Drosophila, Chick, Zebrafish.
Hox, Hedgehog, Toll, and more she has had a hand in it.

Question 26

Haploinsufficiency and Semi-dominance

Answer 26

Often not revealed until stressed during development. Wild type normal, heterozygous mutant deformed, and homozygous mutant lethal.

Question 27

Recessive mutant

Answer 27

Often fatal. Wild type and heterozygous mutant are normal phenotypes with homozygous mutant leaving vestigial wings or fatal.

Question 28

3 embryonic germ layers

Answer 28

Ectoderm (outer layer), mesoderm (middle layer), and endoderm (internal layer). Cell movement places layers in correct position within cell. Active cell differentiation rapidly increases.
Zygote to blastula to gastrula to germ layers or germ cells.

Question 29

Ectoderm

Answer 29

Outer surface, epidermal cells of skin, central nervous system, neuron of brain, neural crest, pigment cell (melanocyte).

Question 30

Mesoderm

Answer 30

Dorsal, notochord, paraxial, bone tissue, intermediate, tubule cell of the kidney, lateral, red blood cells, head, facial tissue.

Question 31

Endoderm

Answer 31

Digestive tube, stomach cell, pharynx, thyroid cell, respiratory tube, lung cell.

Question 32

Germ cell

Answer 32

Male sperm, female egg

Question 33

How can we be sure what cells contribute to larval, juvenile, and adult structures?

Answer 33

Lineage tracing. Dye staining on embryos and genetically modifying model organisms (transgenic DNA)

Question 34

In vivo

Answer 34

In a living organism

Question 35

In vitro

Answer 35

In the lab

Question 36

In situ

Answer 36

In the original place

Question 37

What did transplantation experiments allow?

Answer 37

Lineage tracing via chimeras. ex. Chick-Quail

Question 38

What can you add to sophisticate lineage tracing?

Answer 38

Fluorescent dyes

Question 39

Which theory and author was von Baer’s laws directly refuting?

Answer 39

Ernst Haeckel Recapitulation Theory (developmental stages recapitulate adult evolutionary stages)

Question 40

What do transitional forms do, both fossil and living?

Answer 40

Give insight into the changes in developmental processes over time and space.

Question 41

What do changes in form allow us to make predictions on?

Answer 41

How major phenotypics changes came to be, and test these hypotheses using model species.

Question 42

Homology

Answer 42

Denotes sameness.
Denotes inheritance (structures, organs, genes, etc.) through shared common ancestry. 
Ex. vertebrate forelimb, which is composed of the same bones in all vertebrates, regardless of function.
Structures that are similar due to function (convergent), but not shared inheritance, are analogous (homoplasious)