IX - Community Processes: Species Interactions & Succession Flashcards
Niche
role that an organism plays in an ecosystem.
Niche can also be defined by
range of conditions & resources within
which an organism can live
Conditions
many physical attributes of the
environment, though not consumed, that influence
biological processes & population growth
Conditions examples
temperature, salinity, acidity
Resources
substances or parts of the environment used
by an organism & consumed or otherwise made
unavailable to other organisms
Resources examples
food, water, &
nesting sites for animals; water, nutrients, & solar
radiation for plants
Niche is not the same as
Habitat
Habitat
Actual place an organism lives
fundamental niche
the full range of conditions & resources that an organism could theoretically use in the absence of competition with other species.
realized niche
the portion of the fundamental niche that an organism actually occupies; actual range of conditions & resources that an organism uses.
Nich overlap between species leads to
Competition
Competition causes organisms to not be able to
occupy the full fundamental niche
Generalists
Broad niches
Specialists
Narrow niches
Examples of generalists
cockroaches,
coyotes, dandelions, humans
Examples of specialists
spotted owls, which require old–growth forests in the Pacific Northwest; giant pandas, which eat primarily bamboo in bamboo forests of China
Generalists may have advantage when
environmental conditions change
Specialists may have advantage when
environmental conditions remain constants
Native species
species that normally live
& thrive in a particular ecosystem
Nonnative/exotic species
originate in other
ecosystems; may enter an ecosystem
by migration or by deliberate or
accidental introduction by humans
Example of nonative species
"killer bees", wild bees from Africa were imported to Brazil to increase honey production, but instead displaced native bees, decreased honey production, spread, & posed threat because of aggressive behavior
Indicator species
species that
serve as early warnings that a
community or ecosystem is being
damaged
Examples of indicator species
Decline of migratory songbirds in North America indicates loss & fragmentation of habitat in mesoAmerica & South America Presence of trout in mountain streams is an indicator of good water quality Presence of spotted owls is indicator of healthy old– growth forest.
Keystone species
species that play a
critical role in an ecosystem
Keystone species examples
Sea otter -> prevent sea urchins from depleting kelp beds
dung beetles -? remove, bury, & recycle animal waste
Beavers -> build dams & create habitat for other species
Major types of biotic interactions includes
Interspecific competition
Predation
Symbiosis
interspecific competition
when
two or more species use the same
limited resource (food, space, etc.)
and adversely affect each other
interspecific competition example
fire ants and native species
of ants in North America; fire ants
are better competitors & sharply reduce populations of up to
90% of native species.
predation
members of one
species (predator) feed on another
species (prey)
predation example
lion feeding on gazelle
Symbiosis
a long–lasting
relationship in which species live
together in intimate association
Types of symbiosis
parasitism
mutualism
commensalism
Parasitism
one organism
(parasite) lives on part of another organism
Parasitism example
flea living on a dog
Mutualism
two species interacting in a
way that benefits both
Mutualism example
flowering plants and
insects
Commensalism
one organism benefits from
another, but neither helps nor harm that other organism
Commensalism example
epiphyte growing on a tree (epiphyte benefits & tree not effected, unless there are many epiphytes
Lichens and mycorrhizae has a
symbiotic relationship
Types of interspecific competition includes
interference competition
exploitation competition