Download MarBio ECOLOGY

CHAPTER 10:
An Introduction to ECOLOGY
What is ECOLOGY?
..the study of the interactions of organisms
with one another, other species, and their
environment..
What terminology do we utilize in ECOLOGY to
explain various aspects of interrelationships?
• habitat=an organism’s natural environment
• natural selection or evolutionary adaptation= survival of
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the fittest; best adapted individuals survive in the
population
biotic=living environment
abiotic=non-living environment
population=same species
community=different populations
ecosystem=community with physical environment
How do populations grow?
• exponential (J-shape) growth curve:
•
uncontrolled growth, population “explosion”; will
occur only if conditions will support the
population
logistic (S-shape) growth curve: population
grows exponentially until it reaches it’s “carrying
capacity”- the largest population size that can be
sustained by the available resources.
COMPETITION:
the interaction that results
when a resource is in short supply and one
organism uses the resource at the expense of the
other.
TYPES OF COMPETITION:
• intraspecific=when members of same species
compete
• interspecific=competition with members of other
species
• competitive exclusion=when one species
eliminates any by outcompeting it.
• resource partitioning=sharing of a resource by
specialization, coexisting, or dividing the
resource.
EATING EACH OTHER and
LIVING TOGETHER
REMEMBER THIS STUFF FROM BIOLOGY?
• predation=one organism eats another
• predator=the “eater”
• prey=the “eaten”
term is usually reserved for carnivores= eaters of other
animals
• inducible defenses=defense mechanisms that are used
only in response to predators
• coevolution=a species evolving in response to another
species=an “arms race” of sorts:prey gets better at
escape, while predator gets better at capture.
how about “SYMBIOSIS”:
living in, on, or near another
organism
• mutualism=both organisms benefit
• commensalism=one organism benefits
while the other is unaffected
• parasitism=one organism benefits while
the other is harmed
ENERGY FLOW:
• autotrophs=get energy from the sun; sometimes from
chemicals (chemosynthesis)
• heterotrophs=organism that obtains energy from eating
other organisms
Energy flow can be observed by observing trophic
relationships:
• producers=autotrophs that make their own food
• consumers=heterotrophs that eat other organisms
• food chain=interconnection of organisms in trophic
levels
• food web=complex interwoven food chains
TROPHIC LEVELS and
TROPHIC PYRAMIDS
primary producers-primary consumerssecondary consumers-tertiary consumers;
includes the top predators (apex predator)
PYRAMIDS:
• pyramid of energy
• pyramid of numbers
• pyramid of biomass
ZONATION:
where and how organisms live
• benthic (benthos)=live on or buried in the
ocean bottom, may be sessile
• pelagic=live in the water column, includes
plankton (phytoplankton and zooplankton)
• nekton=animals that can swim well
enough to oppose the currents
MORE ZONATION:
With regards to the benthic region:
• intertidal zone (littoral)=boundary between land and
sea, shallowest part of the continental shelf
• subtidal zone (sublittoral)=continental shelve area
beyond the intertidal, includes bathyal, abyssal, hadal
zones depending on depth (lumped together as “deepsea floor”)
With regards to the pelagic region:
• neritic zone=lies over the shelf
• oceanic zone=beyond the shelf break
Additional zones exist based on depth of water
PELAGIC ZONES:
• epipelagic=shallowest; plenty of sunlight
• mesopelagic=650 ft to 3000 ft, not
enough sunlight, no photosynthesis, not
completely dark
• bathypelagic, abyssaopelagic and
hadopelagic=no sunlight (deep sea
environment)