Marine Botany Midterm 2014
Name:_________________________
Compare and Contrast the following items (20pts):
1) spore vs gamete
Spore: unicellular, must settle & grow, product of mitosis(Mt) or meiosis (Me)
Gamete: unicellular, must fuse or die, product of mitosis(Mt) or meiosis (Me)
2) monoecious vs dioecious
Dioecious- having the male & female reproductive structure borne on separate individual plants; said of the species
-two houses
Monoecious- having the male & female reproductive structure borne on the same individual plants
-one house
3) phycoplast vs. phragmoplast
Phycoplast: microtubules parallel to dividing plane -rare in algae
Phragmoplast: double microtubules perpendicular to dividing plane-common in algae & land plants
4) haplontic vs diplontic
Haplontic: 1N thallus, the zygote is the only diploid stage
Diplontic: 2N thallus, the gametes are the only haploid stage
5) parenchymatous vs. coenocytic thallus construction
Parenchyma – undifferentiated, isodiometric cells generated by a meristem
Cells division in any plane , not filamentous
Coenocytic – thallus made up of filaments, multi- nucleate, lacking crosswalls, siphonous
1
Marine Botany Midterm 2014
Name:_________________________
Match with the correct Division: Chlorophyta, Heterokontophyta, both, or neither (12 points)
a. Plantae __Chloro__________________
b. Chlorophyll A _Both___________________
c. Flowers
d. Phycobilins
e. Amylose
f.
_______Neither_____________
_____Neither_______________
___Chloro_________
Thylakoids in stacks of 2-6 _________Chloro___
g. Bacteria ______Neither____________
h. Flagella ____Both_____________
i.
Haplontic life history _____Chloro_________
j.
2 endosymobiotic event ____Hetero__________
k. Chromalvaeolates ______Hetero_________
l.
Mannitol___________Hetero___________
Match the following Classes or Orders to the appropriate characteristic, term, or genus. Each term will be used
only once. (10 points)
Cladophorales ___C_____
A. parenchymatous thallus
Ulotricales ___J_____
B. clockwise basal body orientation
Chlorophyceae _____B____
C. marimo balls
Charophyceae
D. modern representative of ancestral green (most primitive)
____G____
Trebouxiophyceae ____F____
E. one nucleus & radial symmetry
Dasycladales
F. e.g. Prasiola
__E______
Caulerpales ___I_____
G. broad band microtubule roots, closely related to land plants
Fucales _____H___
H. monoecious or dioecious
Prasinophyceae ____D____
I. group contains coenocytic mass-spawners
Ulvales ______A____
J. Codiolum phase
2
Marine Botany Midterm 2014
Name:_________________________
Define the terms below (20pts):
1) algae:
convenience term encompassing various distinctly related gro ups of aquatic photsynthetic eukaryoes
polyphyletic group containing, cyanobacteria, diatoms, dinoflgellates, red, green and brown algae
2) physode:
special vesicles in the cytoplasm of heterokonts that store tannins
3) hypnozygote:
thick walled resting stage of the 2n zygote in Chlamdymonous sexual life history when there is not enough
light or nitrogen
4) saxicolous:
Growing on rock
5) plurilocular sporangia:
structure where spores are formed that is divided into many small chambers :one spore/gamete per chamber
6) functional anisogamy:
Gametes look the same but act differently in heterokontophyta, female gamete release phermones and males swim
towards females
7) pneumatocyst:
-a large float containing gas found in heterokontophyta
-provide buoyancy to lift the blades toward the surface,
allowing them to receive more sunlight for Ps
- can hold O2, CO2, CO
8) holocarpic reproduction:
- Entire thallus turns into gametes
9) ectocarpene: pheromone released by female gamete in ectocarpales
10) alginic acid- found in cell walls of heterokontophyta, surrounds the microfibrills,allows cell walls to be
elastic,flexible, and to osmoregulate
3
Marine Botany Midterm 2014
Name:_________________________
Create a dichotomous key to separate the following genera: Fucus, Codium, Silvetia, Chlamydomonas,
Cladophora. You may not use taxonomic names of divisions, classes, or orders, but should instead use
characteristics of the divisions, classes, orders or genera (10 pts)
Codium, Cladophora, Clamydomonas- Chl B, lutien,neoxanthin, starches (Amylose, Amylopectin), 2 membranes,
thylakoids stacks 2-6, flagella- isokont, variable #, haplontic
Codium & Cladophora- counterclockwise basal bodies,cruciate microtubule roots, cell wall, closed
spindle,furrowing,phragmoplast
Codium- ceonocytic, siphonous, biflagellate, anisogamous,multinucleate, no division of cytoplasm with cell walls,
clotting compounds, diplontic, utricles, gametangium, invasive on the east coast
Cladophora-large, multinucleate cells divided by crosswalls,isomorphic alteration of generations, ret iculate or
multiple discoid chloroplasts,can form marimo balls,branched filamentous,
Chlamydomonas- haplontic,unicells,hypnozygote, palmenoid stage,cupshaped chloroplast,orange eyespot,mapped
genome,cruciate microtubules,clockwise basal bodies,cell wall,closed spindle,phycoplast, furrowing
Fucus, Silvetia- Chl C,fucoxanthin, sugars (Laminarian,Chrysolaminarian,Mannitol), 4 membranes, thylakoids
stacks of 3, heterokont- one is hairy, diplontic, oogamous, parenchymatous, apical growth, receptical, conceptica l,
Fucus- midrib, 8 eggs per oogonium Silvetia- playdough stipe, 2 eggs per oogonium
Please label the components (A through E) of the P-I curve below (7pts):
A_Photosynthetic Rate (y axis)
E
B Compenstion point
(photosynthesis= respiration)
C initial slope = photsynthetic
efficiency, theta
A
C
D light intensity or irradiance (x
axis)
E __photoinhibition________
B
D
What aspect of the light reactions in photosynthesis might cause a higher value for P-max?
More PSU
4
Marine Botany Midterm 2014
Name:_________________________
Draw a life history diagram as indicated below. Please label ploidy (N or 2N) of all stages, when meiosis and
mitosis occur, and sketch (very generally) the algae look like. (20 pts)
1) Circle the order you are illustrating: Either Ulotrichales or Fucales
What type of life history does it exhibit?___Haplontic or Diplontic________________
Ulotricales- haplontic
1N thallus (1N gametophyte) mitosis1N gametesfuse2N zygote meiosis occurs in zygote1N
Life Cycle
of the Ulotrichales
codiolum
stage1N
spores (zoospores) 1N thallus
Haplontic
e.g. Ulothrix
syngamy
1N gametes
2N
zygote
meiosis
occurs
in zygote
1N gametophytes
1N
codiolum
stage
1N zoospores
Fucales- diplontic- oogamous
2N thallus meiosis1N gametes(one flagellated, and one not )fuse2N zygote grows 2N thallus
2) Isomorphic Alternation of Generations: gametophyte & sporophyte loof the same
What order exhibits this life history?___Ulvales
1N gametophytemitosis1N gametes (2 flagella look the same)fuse2Nzygote2N
sporophytemeiosis1N zoospores ( four flagella)grow into 1N gametophyte
5
Marine Botany Midterm 2014
Name:_________________________
Short Ans wer (25 pts):
1. What determines the upper and lower limits of algae in the intertidal?
Upper limit- abiotic factors- tide, temperature, light intensity, sand & physiological tolerance of the species
Lower limit- biotic factors- herbivory, competition
2. Explain how Luchenco & Cubit changed the way people thought about heteromorphic life histories of certain
marine algae as adaptations to variation in herbivory?
Heteromorphic life histories was thought to be due to seasonal conditions, but proved that they were driven by
herbivory. When herbivores were excluded upright morphs grew no matter the season.
3. In the paper by Sousa, Disturbance in marine boulder fields: the non equilibrium maintenance of species
diversity. Which size boulders had the highest diversity? How did he determine this?
Medium sized boulder highest diversity
Surveyed small, medium and large boulder to count number of species
Secured small & medium boulder so that they wouldn’t roll, look at how diversity changed to factor out size of
boulder from disturbance level
4. Explain the phenology of sexual reproduction by green algae on Caribbean Coral Reefs as described by Clifton
and Clifton.
Holocarpic reproduction- seasonallybefore the wet season begins-gamete release is synchronous and species and
gender specific, different genuses release at similar times, while similar species release gametes at different times
5. What happens during a secondary endosymbiotic event?
Heterotrophic eukaryote eats photosynthetic eukaryote
Nucleus from photosynthetic eukaryote is lost
Results in photosynthetic eukaryote. Chloroplast has 4 membranes.
6
Marine Botany Midterm 2014
Name:_________________________
Short essay: (20 pts)
1) Light is one of the most important factors affecting photosynthetic organisms and how light travels through
water is important in algal growth. Describe in detail the effects of light on algal growth. Include in your
answer a description of light attenuation (what is it, how do different wavelengths respond, and how do
algae deal with it).
Attenuate: to lessen in severity, intensity, or amount
At ~ 100 m even in clearest water, only 1% of surface radiance makes it through
Light attenuation is due to:
Absorption (red- long wave length, low-energy wavelengths absorbed first, by water itself.)
Scattering (violet-high energy, short wave lengths scatter due to water molecules and particulates)
Across species:
Different Divisions have different pigme nts, allow species to gather different wavelengths of light
Within species
Irradiance not spectral quality
1) produce more accessory pigme nts-change ratio of accessory pigments
2) produce more photosynthetic pigments- Change size of PSUs-antennae + reaction cente r (large r is
more efficient at low light levels)
3) morphology matters- thicker fronds, arrange ment of chloroplasts, More surface to capture light,
crustose algae should do best in dim habitats, less self shading, Thicker thalli should have a growth
disadvantage in dim habitats, also self-shading
2) The rocky intertidal is a rough place to be an alga and yet so many algae are found there. Please describe
the challenges that algae in the rocky intertidal face and adaptations these algae have to overcome such
harsh conditions.
Challenges: Abiotic: Light, Temperature, Salinity, Nutrients, Water Motion, TIDES, Sand Burial
Biotic: Herbivory, Competition,Epiphytism
Adaptations:
- Wicked holdfasts for attachment
- Morphology that minimizes drag, shear stress
- Tolerant of high temps (H2O temperature typically 10-17 degrees C along Central Coast; in tide pools, up to
30 degrees C)
- Desiccation tolerance (some algae can survive 60-90% water loss), some require low tide for survival
- Synchrony in gamete release (e.g. intertidal Fucoids, like Silvetia compressa)
- Photoprotective pigments
7
Marine Botany Midterm 2014
Name:_________________________
8