BIO 475 Lecture Notes - Lecture 15: Allelopathy, Invasive Species, Zooplankton
10/3/17
What affects the distribution and abundance of a species?
● Physical features of the environment
● Dispersal and recruitment
● Predation and herbivory
● Disease
● Competition
● Disturbance
Mechanisms of competition among corals
● Direct
○ Mesenterial filaments
■ Thick ribbon like extension that run along border of mesentery
■ Used to capture food, ex. Zooplankton
■ Aid in capture and digestion of food materials may also assist in inhibiting
substrate competitors.
■ Typically bright white
■ Full of nematocysts/ sting prey or competitor
● Can digestive competitor(eating comp. Coral species)
■ Some species more prone to producing these than others
○ Sweeper tentacles
○ Overgrowth
○ Allelopathy
■ Production of toxins that will inhibit other organisms from coming too
close
● Indirect
○ Overtopping
■ Corals growing out and over, shading corals below it (limit sun access)
○ Allelopathy
■ Depends on contact
● de Santo et al.
○ Comparing competitive ability against native coral
○ Took colonies and put the M. hispida directly next to Tubastrea, and looked for
competition
■ Looking for production of mesenterial filaments
○ Graphs look at over time after being put next to each other
○ Put in contact; produce mesenterial filaments quickly
■ 6,12,and 18hrs
■ Low filaments production after 18 hrs
○ Production of mesenterial filaments primarily by M. hispida with Tubastrea, but
not with a congeneric filaments ( two species of the same genus)
○ In the field; over time, Tubastrea won. And M. hispida started to die
■ Invasive species competitively dominant to original species
● Marhaver
find more resources at oneclass.com
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○ When coral species bleached, began to produce large amount of mesenterial
filaments
○ Would extend these onto turf algal mats
■ Without zoox, other energy source needed
○ Using mesenterial filaments when metabolically stressed
● Sweeper Tentacles: really long tentacles, filled with nematocysts
○ Appear to be used in defense of coral’s living space and may successfully deter
mesenterial filament attacks from more aggressive corals.
● Overgrowth(direct) and Overtopping (indirect)
○ Millepora good at overgrowing
● Allelopathy: “direct inhibition of one species by another using noxious or toxic chemicals”
○ Tied extract to corals
○ Galaxaura had more negative impacts than others
■ Produces more alleo-toxic chemicals
○ Thacker et all.
■ Saw that with treatment, sponge tissues started to die
● Indicated something toxic in other sponge tissue
Results of competitive Interaction
1. Competitors share the limited resource
a. Both organism are hampered, growth and population numbers limited
b. Coexisting; usually with same species
2. One competitor out competes the other
a. Competitive exclusion principle: two organisms in direct comp for same
resource, one will win and exclude the other completely
b. No two species with the exact same requirements can coexist in the same place
at the same time. Can’t occupy same niche
3. Coexistence of competing species
a. Resource partitioning; utilizing same resource, overtime, they begin to diverge
slightly in resource use (physiological/ecological adaptation)
b. Ex. surgeonfish; both feed on turf algae on same reef, evolved different types of
gill rakers to eat different types of algae (turf vs. detritivore). Differences in guts
to make up for different food source they are consuming
4. Fusion: corals cut into fragments and grown in nursery, by 90 days they get close, 139
they start to fuse. Critical size needed and aids in competitive ability. Fusing with another
individual of same species highly advantageous
a. Infers enhanced fitness
i. Looking at aggregated sediment in Red Sea, look at what happen when
spat came in contact. Fused or reject one another
ii. Single genotype wins
iii. Multipartner worst
iv. Highest surviving was multipartner
Aggregation vs. Defense
● A Lot of nematocysts must be using a lot of energy to defend themselves
○ Favia fragum fused less often, fought frequently
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Thick ribbon like extension that run along border of mesentery. Aid in capture and digestion of food materials may also assist in inhibiting substrate competitors. Full of nematocysts/ sting prey or competitor. Some species more prone to producing these than others. Production of toxins that will inhibit other organisms from coming too. Corals growing out and over, shading corals below it (limit sun access) Took colonies and put the m. hispida directly next to tubastrea, and looked for competition. Graphs look at over time after being put next to each other. Put in contact; produce mesenterial filaments quickly. Production of mesenterial filaments primarily by m. hispida with tubastrea, but not with a congeneric filaments ( two species of the same genus) When coral species bleached, began to produce large amount of mesenterial filaments. Would extend these onto turf algal mats. Sweeper tentacles: really long tentacles, filled with nematocysts.
