Unit 1 – Introduction to Ecosystems (1.1)
Community Ecology
● Focuses on the interactions among species within a community, examining how
these interactions affect species distributions and population dynamics.
Competition (-/-)
● The struggle between individuals to obtain a shared, limited resource, such as food,
space, or sunlight.
● Example: Goldenrod can grow taller than surrounding wildflowers, allowing it to
capture more sunlight, outcompeting shorter plants.
● Competitive Exclusion Principle: States that two species competing for the same
limiting resource cannot coexist over the long term; eventually, one species will
outcompete the other.
● Resource Partitioning: Occurs when two species divide a resource based on
behavioral or physical differences, allowing them to coexist by reducing direct
competition.
○ Example: Different species of warblers (small songbirds) coexist in the same
tree by foraging in separate sections: one species may feed on insects in the
upper branches, while another feeds in the middle, and a third in the lower
branches.
● Temporal Partitioning: A form of resource partitioning where species use the same
resource at different times, reducing overlap and competition.
● Example: Two species of animals may feed on the same plant but at different
times of day or seasonally.
● Spatial Partitioning: Another form of resource partitioning where species utilize
different areas within a habitat to access similar resources.
○ Example: Different bird species may occupy various levels of a forest canopy,
accessing similar food sources without direct competition.
● Morphological Partitioning: A type of resource partitioning where species evolve
physical differences (morphological traits) that allow them to use resources in
distinct ways, reducing competition.
○ Example: Darwin’s finches in the Galápagos Islands have different beak
shapes and sizes suited for consuming specific types of food. Some finches
have strong, thick beaks for cracking seeds, while others have slender beaks
for catching insects.
Predation (+/-)
Community Ecology
● Focuses on the interactions among species within a community, examining how
these interactions affect species distributions and population dynamics.
Competition (-/-)
● The struggle between individuals to obtain a shared, limited resource, such as food,
space, or sunlight.
● Example: Goldenrod can grow taller than surrounding wildflowers, allowing it to
capture more sunlight, outcompeting shorter plants.
● Competitive Exclusion Principle: States that two species competing for the same
limiting resource cannot coexist over the long term; eventually, one species will
outcompete the other.
● Resource Partitioning: Occurs when two species divide a resource based on
behavioral or physical differences, allowing them to coexist by reducing direct
competition.
○ Example: Different species of warblers (small songbirds) coexist in the same
tree by foraging in separate sections: one species may feed on insects in the
upper branches, while another feeds in the middle, and a third in the lower
branches.
● Temporal Partitioning: A form of resource partitioning where species use the same
resource at different times, reducing overlap and competition.
● Example: Two species of animals may feed on the same plant but at different
times of day or seasonally.
● Spatial Partitioning: Another form of resource partitioning where species utilize
different areas within a habitat to access similar resources.
○ Example: Different bird species may occupy various levels of a forest canopy,
accessing similar food sources without direct competition.
● Morphological Partitioning: A type of resource partitioning where species evolve
physical differences (morphological traits) that allow them to use resources in
distinct ways, reducing competition.
○ Example: Darwin’s finches in the Galápagos Islands have different beak
shapes and sizes suited for consuming specific types of food. Some finches
have strong, thick beaks for cracking seeds, while others have slender beaks
for catching insects.
Predation (+/-)
