Ecological Principles
Interactions among animals and
the environment
Ecological Principles
1
What is Ecology?
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A combination of biotic and abiotic factors
Biotic
Abiotic
Predator-prey interactions
Salinity
Symbiotic relationships
Temperature
Competition
Pressure
Species interactions
Non-biological factors
In the real world these factors are not easily separated
Ecological Principles
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Key Ecology Terms
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Species: natural group of interbreeding individuals,
which are reproductively isolated from other
groups
Population: all the species in a given area
Community: several populations, which occur in an
area
Ecosystem: a series of communities and the
surrounding environment
Ecological Principles
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How Populations Grow
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Ecological Principles
Resources
Carrying capacity
Limiting resource
Self-regulating
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Competition
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Barnacle and mussels compete for space
Ecological Principles
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Competition: refers
to the interaction
between organisms
for a necessary and
limiting resource
Intraspecific
Interspecific
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The Results of Competition
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Natural selection: production of offspring by
the best-adapted individuals in a population
Evolution: a change in the genetic makeup of
a population
To be successful a species must find the right
balance between specialization and
generalization
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Niche: the role a species plays in the community
Ecological Principles
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Predation
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Predation is the act
of one animal eating
another
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Coevolution - the
predator evolving in
response to
adaptations of the
prey, or vice versa
Ecological Principles
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Living Together
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Symbiosis
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Commensalism
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Mutualism
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Parasitism
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Ecological Principles
Ectoparasites
Endoparasites
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Flow of Energy
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Autotrophic: organisms which capture energy
to make organic matter
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Producers
Heterotrophic: organisms that capture
energy by eating
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Herbivores - eat strictly producers
Carnivores or piscivores - eat meat or fish
Omnivores - generalists
Apex predators - top predators
Ecological Principles
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Trophic Structure
Ecological Principles
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Sandy Shoreline Community
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Soft bottom communities
are found in areas where
sediment has accumulated
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Dominate the east coast of
the U.S and the gulf coast
Due to the environmental
conditions most animals
bury themselves in the
substrate.
Ghost crab
Ecological Principles
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Environmental Conditions
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Wave action is the most important physical factor
and correlates directly with beach slope and grain
size
Ecological Principles
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Living in the Sediment
Aerobic
Respiration
 Anaerobic
Respiration
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Hydrogen
sulfide
(H2S)
Anoxic
Ecological Principles
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Sandy Beach Zonation
Fauna Composition
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Coquina clams
Ecological Principles
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Noticeably absent are
the plants, due to lack
of stable substrate
Crustaceans, bivalves,
and polychetes
dominate sandy
beaches
Predators?
Feeding strategies?
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Sandy Beach Food Web
Ecological Principles
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Mole Crabs
Ecological Principles
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Locomotion
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Ecological Principles
Bivalves use a muscular
foot for locomotion
Mole crabs and other
arthropods use
appendages for
burrowing
Sea cucumbers and
worms both feed and
burrow at the same time
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Meiofauna
Ecological Principles
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