Chapter 1

Question 1

what are the seven stages of embryogenesis?

Answer 1

1. gametogenesis
2. fertilization
3. cleavage
4. gastrulation
5. organogenesis
6. larval stage
7. maturity

Question 2

what occurs during gametogenesis?

Answer 2

sperm and oocyte come together

Question 3

what occurs during fertilization?

Answer 3

zygote forms

Question 4

what occurs during cleavage?

Answer 4

rapid mitotic cell division

-the cytoplasm is divided into smaller cells called blastomeres that form a morula (big ball of cells)

-the cells start to turn into a blastula with a hollow center

Question 5

what occurs during gastrulation?

Answer 5

formation of the primordial germ cell layers

-the fluid-fill cavity (blastocoel) allows for morphogenesis

-a pore (blastopore) starts to form on the opposite side of sperm entry allowing for the cells to migrate and form layers creating a dorsal lip

Question 6

what type of movement occurs during gastrulation to form the blastopore?

Answer 6

invagination

Question 7

what are the three germ layers and what to they become?

Answer 7

endoderm: gut
mesoderm: NS, skin
ectoderm: muscle, cartilage, bone

Question 8

what occurs during organogenesis?

Answer 8

cells form tissues and organs (NS FIRST)

Question 9

what is a neurual?

Answer 9

ectoderm forms a tube (neural tube)

Question 10

what are somites?

Answer 10

paired blocks of mesoderm, repeats
(ribs, spinal cord)

Question 11

what is the notocord?

Answer 11

sends signals to cells for what to become and where
-organizing factor

Question 12

what occurs during the larval stage?

Answer 12

hatching, birth
-longest stage

Question 13

what occurs during the maturity stage?

Answer 13

the organism becomes sexually mature

Question 14

what are the eight famous developmental biology researchers in order?

Answer 14

1. Aristotle (350 BC)
2. Harvey (1651 AD)
3. Malpaghi (1672 AD)
4. Wolff (1767)
5. Pander (1817)
6. von Baer (1828)
7. Darwin (1842)
8. Weismann (1875)

Question 15

what is Aristotle known for?

Answer 15

believed that menstrual fluid and sperm made a baby (sperm carved the fluid)

-oviparous, viviparous, ovoviviparous
-placenta, umbilical cord

Question 16

what is the difference between oviparous, viviparous, and ovoviviparous?

Answer 16

oviparous: egg
viviparous: alive birth
ovoviviparous: egg hatches inside

Question 17

what does holoblastic and meroblastic mean?

Answer 17

holoblastic: everything divides
meroblastic: only embryo divides, not yolk

Question 18

what is William Harvey known for?

Answer 18

ex ovo omnia
- everything comes from egg, even viviparous

-studied chick blastoderm (appeared as red dot)

-amniotic fluid & jelly coat

Question 19

what Marcello Malpaghi known for?

Answer 19

believed in preformation (homounculus, unrolled)
-everything already in sperm, just very tiny, then it unrolls in the egg

-used a microscope to look at early stages of embryos
-able to see primordial groove, somites, circulatory system

Question 20

what is Kaspar Friedrich Wolff known for?

Answer 20

discovered epigenesis (de novo)
-saw flat tissue bend to form sheets, materials divide to form something different
-something forms from nothing!

-vis essentialis (essential force)
-there is a force in the universe that pushes things in the world to become more complex

Question 21

what is Christian Pander known for?

Answer 21

discovered the triploblastic “three-layers”

took advantage of the growing universities

INDUCTION = each layer tells the other layers what to do

Question 22

what is Karl Erst von Baer known for?

Answer 22

discovered THE EGG

-made four principles

Question 23

what are the von Baer principles?

Answer 23

1. the general features of large group animals appear before specialized features of small group animals (head -> feathers, scales, skin)
2. less general features come from more general features (limbs -> wings, fin)
3. embryo of a species departs instead of passing through lower animals (gill arch example)
4. early embryos of higher animals only resemble lower animal embryos, never the adult form

Question 24

what is Charles Darwin known for?

Answer 24

embryonic resemblances = species connectedness
-things that looked alike as embryos shows community of decent

embryonic resemblances are inappropriate to adult forms (python has legs as embryo)

late- & post- embryonic adaptations are caused by adult form , not embryonic lifestyle

Question 25

what is Weismann known for?

Answer 25

studied viceroy & monarch butterflies -identical adult, different embryo

Question 26

what is homology?

Answer 26

similar structures arise from a common ancestor -wing vs arm -gill arch

Question 27

what is analogy?

Answer 27

similar structures arise from similar function, not ancestor -bird wing vs butterfly wing

Question 28

what is fate mapping?

Answer 28

trace cell lineage & follow a single cell to watch and see what it becomes -very difficult

Question 29

what is grafting?

Answer 29

took chick (host) and quail (donor) cells because they have same antibodies -able to follow the darker quail nucleus in the chick to see what it becomes

Question 30

what is audioradiography?

Answer 30

made donor cell radioactive and were able to track the cell through development in the host -same species!

Question 31

what is vital & fluorescent tracing?

Answer 31

dyed a clump of cells and followed them

Question 32

what is morphogenesis?

Answer 32

how we generate shapes -cellular connects, cell divisions, cell shape, cell movement, cell growth, cell death, cell secretions (sticky, push away, signals)

Question 33

what is the difference between mesenchymal cells and epithelial cells?

Answer 33

mesenchymal: loosely packed, not attached to each other epithelial: intercalated (sheets), start as layers

Question 34

what are the 6 ways mesenchymal cells do morphogenesis?

Answer 34

Condensation (becomes epithelial) Cell Division Cell Death Migration (move at certain times) Matrix Secretion & Degradation (removal of layers) Growth (hypertrophy)

Question 35

what are the 7 ways epithelial cells do morphogenesis?

Answer 35

Dispersal (becomes mesenchymal) Ingression (cells move from outward to inward) Change Shape or Growth (remain attached but change) Migration (form fewer rows) Cell Division (w/in column or row) Matrix Secretion & Degradation (removal of layers) Migration (formation of free edges)

Question 36

what is invagination?

Answer 36

infolding of sheet

Question 37

what is involution?

Answer 37

inward movement to inner side of exterior cells

Question 38

what is ingression?

Answer 38

surface cells move inward

Question 39

what is delamination?

Answer 39

splitting of sheets to form more layers

Question 40

what is epiboly?

Answer 40

movement of sheets as a unit to enclose deep layers

Question 41

what is a defect? what are the two main types?

Answer 41

something that lacks as a result of incompleteness, inadequacy, or imperfection -malformation, disruption

Question 42

what is a malformation?

Answer 42

GENETIC -instructions wrong in genes -mutation, aneuplodies, translocation (break point)

Question 43

what is Piebaldism?

Answer 43

neural crest cells lacking KIT protein -leads to white marks on forehead & stomach -has other symptoms associated

Question 44

what is a disruption?

Answer 44

ENVIRONMENTAL -caused by teratogens

Question 45

how is thalidomide an example of a disruption?

Answer 45

drug given to pregnant women in the 50s, led to prevented limb growth in the child

Question 46

what is a syndrome?

Answer 46

collection of symptoms that occur together due to one break in the DNA

Question 47

what does congenital mean?

Answer 47

disease or abnormality present at birth

Question 48

what is allometry?

Answer 48

growth of different body parts at different rates (baby head)

Question 49

what did Alan Turing do?

Answer 49

cracked the german "enigma" code and helped win WW2 created the Reaction-Diffusion Model

Question 50

what is the reaction-diffusion model?

Answer 50

Substance P: producer, slow, local travel Substance S: stopper, fast, distant travel -creates a gradient where cells in the middle get more P and cells on the outside get more S