Download Mid-Term Exam, ECOL 340, March 8th 2007

Mid-Term Exam, ECOL 340, March 8th 2007
This exam is 25% of your class grade or 250 points.
Name________________________________________________
(1) Matching (14.4% of point total) 36 points
____Calyx
____Seed Plants
____Clade
____Cooksonia
____Origination rate
A. Sugar Maple
B. Oaks
C. All organisms that share a common ancestor
D. Autopolyploidy
E. Early ‘experimental’ reproductive structures of
gymnosperms. No longer present.
____Ring Porous
F. Archegonium has been reduced and is absent
____Diffuse Porous
G. Change in gene frequencies in a population
____Sympatric speciation H. First recognizable Embryophyte from fossil record
____Allopatric speciation I. Restriction of gene flow between populations due
to a physical barrier
____Archegonia
J. ‘Jacket’ of cells surrounding developing zygote
____Pollen grain
K. Immature microgametophyte
____Angiosperms
L. Chromosome duplication
____Salpinx
M. Together with extinction important for influencing
standing stocks of diversity.
____Heterospory
N. All sepals
____Strobili
O. Ovary
____An integumented
megasporangium
P. Reproductive structures that contain a high
concentration of sporangia
____Polyploidy
Q. Retain megaspores within their megasporangia
____Evolution
R. Evolved independently in the microphyll and
megaphyll lines of evolution
N,Q,C,H,M,B,A,D,I,J,K,F,E,R,P,O,L,G
(2) Names (7.2% of point total) 18 points
____Plank
____G.G. Simpson
____G.L. Stebbins
____R. Fisher
____S. Wright
____Dixon
____V. Grant
____C. Darwin
____ Malthus
A. Concept of the ‘fitness landscape’
B. Evolution of Angiosperms is an “abominable
mystery”
C. Cohesion Tension Theory
D. Fundamental Theorum of Natural Selection
E. Only Botanist in the Evolutionary Synthesis
F. Hybrid speciation
G. Essay on “the principle of the population”
H. Important in the Evolutionary Synthesis
I. Light can be particle like (quanta). Energy in
quanta is proportional to the wavelength
I,H, E, D, A, C, F, B, G,
1
Short Answer (16% of point total) 40 points
4 POINTS
(3) The earliest vascular plants diverged into two major lines of
tracheophyte evolution. What were the names of these two **initial**
lines of tracheophyte evolution?
B and C a) Rhyniophyta b) Zosterophylophyta
c) Trimerophytophyta
d) Lycophyta
e) Progymnospermata
3 POINT EACH – For #4-6
(4) The following five statements refer to the Rosids and the Asterids, as
presented in class. Which statement is not true.
B
(a) species with a tubular corolla can be found in either clade.
(b) the Rosid clade is the more primitive of the two.
(c) triaperturate pollen can be found in either clade.
(d) they possess double fertilization.
(e) alkaloid secondary compounds can be found in either clade
(5) Seed plants and Progymnosperms share a common ancestor within this
ancient group of land plants.
A
(a) Rhyniophyta ; (b) Zosterophylophytes; (c) Archiofructus; (d) Lycophyta
(6) Enations are an example of –
C
(a) a megaphyll, (b) a trait associated with the seed plants, (c) differing
ways of evolving leaf-like structures, (d) plays an important role in the
reproduction of the sporophyte, (e) none of the above
5 POINTS
(7) List the following groups in order of the number of extant species
(e.g. 1 = most diverse, 5 = least diverse)
_2_Bryophytes, _3_Pteridophytes, _1_Angiosperms, _4_Gymnosperms,
_5_Zosterophylophytes
2
4 POINTS
(8) Describe in at least three sentences what the (i) Antenna and the (ii)
Reaction Center is and what it does. Also, use a simple drawing to also
help you answer the question.
The antenna complex consists of
Many chlorophyll molecules that
‘harvest’ light energy and then
channels the excitation energy to the
Reaction center. The RC is a
special pair of chloropyll molecules
that transfer excited electron to
acceptor molecule. The arrangement
of the antenna and reaction center is spatial with several light harvesting antenna
arranged around a reaction center.
6 POINTS
(9) List three plant taxa that dominated Carboniferous forests (hint Fossil
Fuel!)
Here are five acceptable taxa – Lycophytes (club mosses), Spenophytes
(Horsetails), Pteridophytes (ferns), Progymnosperms, Eary seed plants
3 POINTS EACH (#10-13)
(10) What is the currently accepted date for the first appearance of
photosynthesis?
~3.6 billion years (plus or minus 0.5 billion)
(11) What is the currently accepted date for the first appearance of land plants?
~430 millioin years ago (plus or minus 50 million)
(12) What is the currently accepted date for the first appearance of Angiosperms?
~140 million years ago (plus or minus 30 million)
(13) The gametophyte generation retains its eggs and juvenile diploid embryos
within the ____ Archegonium ____
Longer Answer (24% of point total) 60 points
(14) Outline the essential 6 steps for Evolution by Natural Selection to occur
12 POINTS
1-many offspring or potential for exponential growth
2-competition for space and resources
3-offspring differ in their ability to compete and obtain resources
4-differential survival/reproduction
5-variation in heritable
6-mean phenotype (genotype) of next generation has changed
3
(15) List three main functions of photosystems I and II?
6 POINTS HERE
-stealing electrons
-capturing light energy
-producing high energy compounds
-producing proton gradient to produce ATP
(16) List three major trends associated with the basic land plant life-cycle (Hint,
think changes that have occurred from the life-cycle of a typical Green Algae).
6 POINTS
i) Reduction in size of the gametophytic portion of the life cycle
ii) Elaboration in size of the sporophytic portion of the life-cycle
iii) Less reliance on water for dispersal of spores and male gametes
(17) During class many examples of convergent evolution were given. List
3 likely (and differing) examples of convergent evolution within land
plants.
6 POINTS
There are many potentially correct answers . . Here are a few
- Succulent growth form (Aloe a Monocot and cactaceae a Carophylaceae)
- Petal-like structureCaryophylaceae
- Fused tubular flower
(18) List the three ‘functions’ of xylem. For each ‘function’ please:
10 POINTS (5 points for Water transport function)
(i)
List the cell types and the associated specialized cell name(s) for
that function;
(ii)
Indicate if a given cell type is restricted to a certain major land
plant clade(s).
(1) Water and fluid transport
Vertical transport - Sclerenchyma (tracheids, vessels).
Vessels (with the exceptions of the
Gnetophytes(gymnosperm), are restricted to the angiosperms.
Tracheids are found in all Tracheophytes.
Horizontal transport - Parenchyma (Ray parenchyma).
Schlerenchyma (Ray Tracheids – are
found only in Gymnosperms.
(2) Support
4
Sclerenchyma (Fibers) Fibers are only found within
Angiosperm xylem.
(3) Storage
Parenchyma (Ray Parenchyma)
(19) Please provide mathematical definitions for the following physical attributes
of plants. Include in your answer: (a) What does this equation express? (2)(b) A
short but complete description for each parameter within each mathematical
definition (2); and (c) Provide at least three sentences why each mathematical
equation is important for understanding land plant evolution (3).
14 Points
(1)
 ri4 P
Ji 
8 li

This is the Poiseuille equation. Ji is the flux of fluid within a tube. ri is the radius
of a tube,  is the fluid viscosity, li is the length of the tube.  P/ li is the pressure
gradients or the change in pressure over the change in length of pipe.
Poiseuille equation is important for plant evolution as it describes how the
flow rate of fluid through a pipe (such as a vessel or tracheid) is influenced by its
dimensions (radius and length). Selection can act on flow rates of fluid through
the xylem primarily through changes in radius and/or length. For example if the
radius of a tube (vessel, tracheid) increases then flow rate will increase
dramatically because of the 4th power dependence of flow rate on tube radius.
This equation like explains why tracheid and vessel radius tends to have
increased over evolutionary time as transport distance has increased.
(2)
This is Fick’s law. dS/dt is the rate of diffusion of a solute, S, . Di is the diffusion
coefficient for a given solute (usually treated as a constant), A is the surface
through which diffusion occurs.  Ci/ x is the concentration gradient. Fick’s law
is important as most resources within plants are transported by diffusion at some
C 
dS
 Di A i 
 x 
dt
point. In order to maximize or minimize rates of diffusion selection can act on the
area, A, over which solutes are diffused as well as the concentration gradient 
Ci/ x.

Definitions (12% of point total) 30 Points
5
(20) For each term/character please provide a definition. (i) Make sure to
write two sentences for each. (ii) Stress the functional and/or ecological,
and/or evolutionary importance of each. 6 Points Each
Cellulose
A polymer of glucose consisting of Beta 1-4 bonds that are ‘unbreakable’ (cannot
be digested) by animals. The most abundant biocompound on earth - crucial for
increased biochemical stability and increased plant height over evolutionary time.
Bordered pit
A passage through the 20 cell wall of xylem elements (tracheids – common in
conifers) which allows for the lateral conduction of water and helps minimize
embolisms. The opening is surrounded by thickened 2 o cell wall to provide
biochemical support from element collapse due to more negative water potential.
Angiosperm seagrasses
These are plants that have ‘come full circle’ and have reinvaded aquatic
environments. They are of note evolutionarily as the main trend in Embryophyte
evolution has been to constantly invade more xeric environments.
Embolism – Results if the tension on the water column (driven by transpiration)
within the xylem becomes so severe that the water column breaks. This is when
the cohesive and adhesive forces on the water column are overcome. An
embolism is a partial vacuum or an ‘air bubble’ in the xylem stream. The xylem
(tracheid or vessel) becomes useless. Selection to minimize embolisms has
been important in shaping xylem morphology.
Hypanthium – A cup-like floral structure within Angiosperms that marks the fusion
of petals, sepals and anthers. A trait that characterizes the Rosid clade. A
hypanthium is an example of convergent evolution of a ‘tubular fused flower’ and
likely reflects selection for specific types of animal pollination.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
6
Long-answer (30% of point total) 72 points
(21) On a separate sheet of paper please:
(1) Draw the phylogeny of the land plants. (40)

Only include the major extant land plant clades discussed in class.
Include the following: Mosses, Flowering Plants (and all the major
clades and grades within), Gymnosperms, Charophytes, Lycopods,
Pteridophytes, hornworts, Sphenophyta (horsetails), Liverworts,
Chlorophytes, Prokaryotic Photosynthetic bacteria
(2) Label on your phylogeny – (14)
(3)

the BOTANICAL NAME for the clades that are the Seed Plants,
Vascular Plants, Land Plants, and the Flowering Plants.

Also, be sure to include the green algae and the likely extant
green algae clade that shares a common ancestor with the
land plants.

Be sure to include the major clades and grades of the
Flowering plants
(3) At each node of your phylogeny please: (20)

List the characters (or character) [also think adaptations here]
associated with each group.

Up to the angiosperm node, speculate on the likely selective
pressures which led to the evolution of the characters
associated with each node. Provide at least one to two
sentences for each trait.
Tree with some of the possible answers for character(s) for each node.
There are others. Selective pressures depend on the characters listed, but
generally revolve around the theme of adapting to more xeric
environments.
7
Caryophyllales
PSN Bacteria
Chlorophytes
Gymnosperms
Angiosperms
(flowering plants)
Charophytes
Carpel
Spermatophytes
Seed
Egg retention
Chlorophyll a,b
Colochaete like ancestor
8