Day
T
Th
T
Th
T
Th
T
Date
Reading Topic
10/15
no class – October Vacation
10/17
More plant development
10/22
Ch. 8
Mechanisms of morphogenesis
10/24
More morphogenesis
10/29
Ch. 10
Cell differentiation
10/31 Happy Halloween!
Stem cells
11/5
quiz on Flowering video handout
Ch. 11
Organogenesis
Th
T
Th
11/7
11/12
11/14
T
11/19
Th
More Organogenesis
Ch. 12
Development of the nervous system
EXAM 2 Chapters 2, 7, 8, 10
Drosophila, plants, cell biology, differentiation
11/21
Ch. 9
The saga of the germ cell
T
11/26
More on reproduction
term paper is due at the beginning of class on Tuesday, 11/19
Th
11/28
Your
no class – Thanksgiving Break
Also remember there are two, short writing assignments, each worth 20 points.
Pick any topic in developmental biology (except your term paper topic) and learn more about it. Then
write a two page paper and include all the sources you used (those can include any sources including web
sites, newspapers, TV, etc). These are due anytime.
Comparing animals and plants:
Invented multicellularity independently
Some differences:
No germ line cells in plants
(plants are easy to clone.
No maternal factors???)
No morphogenesis in plants
(very simple fate maps)
Plant cells contain plasmodesmata
(a type of gap junction between cells)
Comparing animals and plants:
Invented multicellularity independently
Some similarities:
Totipotency
(each cell retains the entire genome = genomic equivalence)
Stem cells (called initials in plants)
Stem cell niches (called meristems in plants)
Homeotic genes
BUT the genes are different in plants vs animals
(they are not orthologs)
Animal terms = totipotent, pluripotent
Plant term = indeterminant
7.46 leaf shape
Evolution of meristems:
Pteridophytes, like ferns, have a single meristematic cell.
Gymnosperms have a multicellular, but less defined organization
(For example, they don’t have the organized layers cells of the
tunica and corpus.)
Angiosperms have the highest degree of organization.
Several orthologs are found in the meristem cells of all plants.
7.10 stem/leaf pattern
7.21 root meristem
7.15 chimera
7.16 corn meristem fates
7.13 apical meristem
7.12 stem cell regulation
STEM CELL NICHE
7.1 Arabidopsis thaliana
7.24 inflorescence meristem
http://en.wikipedia.org/wiki/Florigen
Thigmomorphogenesis =
development affected
by touch, breeze, etc.
Examples of regulation of plant development by auxin
1.) patterning the early embryo (proteins pump auxin)
2.) patterning leaf primordia = phyllotaxy
3.) patterning lateral bud growth = apical dominance
6.18 leaf
primordia
phyllotaxy
7.19 leaf lateral inhibition (incorrect hypothesis)
7.20 auxin and leaf primordia