Download Ecosystems and Communities

ECOSYSTEMS AND
COMMUNITIES
BIOTIC VS. ABIOTIC FACTORS
Biotic factor: living component of an
ecosystem
Abiotic factor: nonliving component
of an ecosystem
HABITAT VS. NICHE
Habitat: the area where an
organism lives, including the biotic
and abiotic factors that affect it
Niche: an organism’s habitat plus
its role in an ecosystem
COMMUNITY INTERACTIONS
Competition: when organisms of the
same or different species attempt
to use an ecological resource at the
same time
Example: in a forest, broad-leaved
trees may compete for sunlight by
growing tall, spreading out their
leaves and blocking sun to shorter
plants
Competitive exclusion principle: no two species
can occupy the same niche at the same time
COMMUNITY INTERACTIONS
Predation: an
interaction in which
one organism
captures and feeds
on another
organism
Example: Some
types of bears
capture and eat
fish
COMMUNITY INTERACTIONS
Symbiosis
Parasitism: symbiotic
relationship in which
one organism
benefits while the
other is harmed
Example: fleas, ticks
and lice feed off
the blood and skin of
mammals
COMMUNITY INTERACTIONS
Symbiosis
Mutualism: symbiotic
relationship in which
both organisms
benefit
Example: oxpeckers
eat the insects off
large mammals in
Africa
Cleaner wrasse
COMMUNITY INTERACTIONS
Symbiosis
Commensalism: symbiotic relationship in
which one organism benefits while the
other is neither harmed nor does it
benefit
Example: Remoras eat the small pieces
of food that are created when sharks
eat
Shark and a remora
A whale with barnacles
Learning Targets
• Learning Target: I can learn about the limiting
factors and how they can affect population
dynamics. I can properly construct and
interpret graphs.
POPULATION
GROWTH
Exponential Growth:
rapid period of
growth that occurs
under conditions with
unlimited resources
Logistic Growth: when
a population’s growth
slows or stops after a
period of exponential
growth.
How might this happen?
Limiting factors: factors that limit the
growth of a population
 Food
 Sunlight
 Water
 Dissolved oxygen
 Nutrients in soil
 Disease
Carrying capacity: the largest number
of organisms that an environment can
consistently support