Exam 4 - Marine Communities

community

composed of many different populations of organisms that interact in the same area

population

a group of individuals from the same species occupying a specific area

habitat

an organism’s physical location in its community

niche

an organism’s role in the community

keystone predators

have such important niches that if you remove them from their community, it would collapse; example is when sea stars are removed from a community, the mussels overpopulate

tolerance

physical and biological environmental factors affecting communities; each species can withstand a range of factors

optimal range

abundant of organisms

zone of physiological stress

few organisms

zone of intolerance

no organisms

intertidal zone

rocky, sand, mud areas; stresses are brief air exposure, temperature, salinity fluctuations, and wave action

snails

adapt to air exposure by moving to wet area

mussels

adapt to air exposure by living in groups to retain moisture

sessile

animals that can’t move; mussels and seaweed; can tolerate great water loss

to adapt to temp and salinity fluctuations…

mobile animals seek out wet areas where fluctuations are less

biological stresses

competition, predation, zonation

zonation

distinct layering species in the intertidal zone due to a combinational of air exposition and biological competition

competitive exclusion

elimination of one species by another as a result of competition; upper limit set by physical factors, lower limit set by biological factors

coral reefs

most densely populated and diverse communities

planktonic communities

drift throughout all of worlds oceans; large range

pelagic environment

zones of the ocean; 83% of productivity found in top 200m because of sunlight that produce photosynthesis

Deep scattering layer (DSL)

community of fishes, squid, and other animals that move up and down in sync with day light; congregate at bottom during the day and migrate to surface at night to feed; advantage of slower metabolism and predator avoidance

deep sea floor

animal diversity is high, but abundance is low; less food but also less competition

sources of food for deep sea floor species:

zooplankton, fecal pellets, whale and other species carcasses, hydrothermal vents

hydrothermal vent ecosystems

seawater seeps through seabed where it is warmed then rises up and dissolve minerals; when minerals condense, it forms a chimney; as the water cools, metal sulfides percipate and settle near the vent; carbon (C) and hydrogen sulfide (H2S) bind to form glucose; chemosynthesis

symbiosis

Concurrence of two species in which the life of one is closely related to the life of another

mutualism

both species benefit; ex. clownfish and sea anemone, zooxanthellae dinoflagellates and coral reefs

host

the larger organism

symbiont

The second organism that lives on/with the host

commensalism

Symbiont benefits while host unharmed; ex. whales and barnacles

parasitism

Symbiont benefits at expense of host; ex. covid-19 virus and humans

Squid weekly essay info:

Scientists in the South Sandwich Islands have found a colossal squid in its natural habitat swimming in the ocean instead of them already dead. This never happen before.