Ch. 1 Flashcards
_______ is the study of the period between fertilization and birth
embryology
Modern developmental biology begins with _______ and ends with _______
Begins: formation of sperm and egg cells
ends: doesn’t really end
What are the 3 major approaches to developmental biology
1) anatomical
2) experimental
3) genetic
What 2 objectives does development accomplish?
1) cellular diversity
2) continuation of life
_______ - how does a single fertilized egg produce so many different cell types?
differentiation
_______ - what processes control the elaboration of cell and tissue patterns?
pattern formation
_______ - how do cells organize into functional structures?
morphogenesis
_______ - How do cells know when to stop/start dividing? How is this regulated?
growth
_______ - how are germ cells set apart? what instructions make them special?
reproduction
_______ - How do some cells (stem cells) retain the ability to form new structures?
regeneration
_______ - How is development integrated into the context of habitat?
environmental integration
_______ - how do changes in development create new body forms? what change are possible?
evolution
______ - stages of development between fertilization and birth/hatching
embryogenesis
______ - fusion of gametes stimulates egg to begin development
fertilization
______ - rapid mitotic divisions divide the zygote into many blastomeres that form a blastula
cleavage
______ - dramatic cell rearrangements leads to the formation of the 3 germ layers
gastrulation
_______ - cells organize into tissues and organs
organogenesis
_______ - change from one form to final sexually mature adult form
metamorphosis
______ - differentiation and development of a germ cell that will form gametes
gametogenesis
What are the 2 major areas of a developing egg?
1) vegetal hemisphere
2) animal hemisphere
_______ contains yolk that serves as nutrients for embryo
vegetal hemisphere
_______ upper half of the egg (divides rapidly) where embryo proper will form
animal hemisphere
Fertilization accomplishes what 3 tasks?
1) zygote formation
2) axis formation (cytoplasmic movement)
3) activation of molecules for cleavage and gastrulation
_______: a series of extremely rapid mitotic divisions (WITHOUT GROWTH) that divide the enormous volume of the egg into smaller cells
cleavage
_______: a sphere of cells produced by cleavage
blastula
_______: small cells produced by cleavage, make up the blastula
blastomeres
_______: fluid filled cavity forms in the animal himesphere that allows cell movements during gastrulation
blastocoel
_______:
gastrula
Gastrulation begins with the formation of a dimple on the opposite side of sperm entry called the _______
blastopore
Organogenesis begins with _______
notochord development , a rod of mesodermal cells just below the ectoderm
When the notochord developes in an embryo, the embryo is called a _______
neurula
cells along the periphery of the neural tube become segmented into ______ which are precursors to back muscles, dermis, and vertebrae
somites
What are the major life cycle variations: (3)
1) ovipary (hardshell eggs)
2) vivipary (live birth)
3) ovovivipary (egg inside mothers body)
What are the 2 different types of cleavage:
1) holoblastic cleavage (entire egg divided)
2) meroblastic cleavage (part of egg divided)
cleavage is characterised by a series of rapid ______ divisions (highest rate in body) that divide the egg into many smaller _______
mitotic
blastomeres
In cleavage, the patterns of initial divisions and the placement of the blastomeres is under the control of _______ and _______ already stored in the oocyte prior to fertlization
mRNA and proteins
division without growth is possible in cleavage because of the elimination of G1 and G2 in the cell cycle, what is this modified cell cycle called?
biphasic cell cycle
Cleavage is influenced by _______ and _______ which determines the division plane of blastomeres and rate of cleavage
1) orientation of mitotic spindle
2) distribution of yolk
Holoblastic cleavage is found in eggs that have _______ yolk, while meroblastic cleavage found in eggs that have _______ yolk
very little
lots of
Holoblastic cleavage where the yolk is evenly distributed is called _______
Isolecithal
Holoblastic cleavage where there is slight vegetal disposition of yolk is called _______
mesolecithal
What are the 4 different types of Isolecithal cleavage?
1) radial cleavage
2) spiral cleavage
3) bilateral cleavage
4) rotational cleavage
What 2 animals undergo radial cleavage?
1) echinoderms
2) amphioxus
What 3 animals undergo spiral cleavage?
1) annelids
2) molluscs
3) flatworms
What animal undergoes bilateral cleavage (holoblastic)?
tunicates
What 2 animals undergo rotational cleavage?
1) mammals
2) nematodes
What animal undergoes displaced radial cleavage (mesolecithal)?
amphibians
Meroblastic cleavage where there is dense yolk throughout the egg is called _______
telolecithal
Meroblastic cleavage where there is yolk concentrated at the center of the egg is called _______
centrolecithal
What are the 2 types of telolecithal cleavage?
1) bilateral cleavage
2) discoidal cleavage
What 2 animals undergo bilateral cleavage (meroblastic)?
1) cephalopods
2) molluscs
What 3 animals undergo discoidal cleavage?
1) fish
2) reptiles
3) birds
What animals undergo superficial cleavage (centrolecithal)?
most insects
Gastrulation is what makes animals animals, _______ and _______ do not gastrulate
plants and fungi
What development stage develops the 3 primary germ layers?
gastrulation
What are the 3 germ layers?
1) endoderm
2) mesoderm
3) ectoderm
What development stage develops the 3 body axis?
gastrulation
What are the 3 body axis?
1) dorsal/ventral
2) anterior/posterior
3) left/right
What are the 5 different types of cell movement during gastrulation?
1) invagination
2) involution
3) ingression
4) delamination
5) epiboly
What does the ectoderm form? (2)
1) epidermis
2) nervous system
What does the mesoderm form? (3)
1) connective tissue
2) organs
3) bones
What does the endoderm form?
lining
- the innermost layer of the embryo
- the lining of the digestive tube and respiratory system
Whats a triploblastic organism and whats a diploblastic organism
3 layer vs 2 layer
What are the two major types of embryonic cells?
1) epithelial cells (tightly connected)
2) mesenchymal cells (unconnected/loosely connected)
_______: diagrams that show what adult or larval structures are produced by cells/regions of the embryo
fate maps
- by observing dye marking
_______ = the use of dev bio to show common evolutionary ancestry through embryonic and larval similarities
evo-devo
_______ structures are those with underlying similarities in structure with different function
homologous
- used as an argument for common decent
_______ structures are those with similar functions but with a dramatically different structure
analogous
- used as an argument to support independent evolutionary paths
_______: examines how structures and morphology change during development
comparative embryology
_______: studies how changes in developmental timing/patterns may affect evolutionary changes and constrain the types of changes possible
evolutionary embryology
_______: study of birth defects
teratology
- thalidomide in pregnant women
What does teratogens mean in greek?
monster formers
