Download Option C - LaPazColegio2014-2015

Option C.1 –Species and Communities
Understandings
 The distribution of species is affected by limiting
factors.
 Community structure can be strongly affected by
keystone species.
 Each species plays a unique role within a community
because of the unique combination of its spatial
habitat and interactions with other species (niche)
 Interactions between species in a community can be
classified according to their effect.
 Two species cannot survive indefinitely in the same
habitat if their niches are identical.
The distribution of species is
affected by limiting factors
 The distribution of species is affected by limiting factors
 Abiotic: light, atmosphere, water, temp, salinity, soil
conditions
 Biotic: other organisms – predator/prey, symbiosis,
parasitism, competition (inter/intra specific)
Community structure can be
strongly affected by keystone
species.
 A keystone species is not necessarily the most
abundant, but it has a large impact on the overall
function of the ecosystem
 Keystone predators
 Keystone prey
 Keystone mutualists
 Keystone host
 Keystone modifiers
Each species plays a unique role within a community
because of the unique combination of its spatial habitat
and interactions with other species (niche)
 each species occupies a
unique ecological niche that
encompasses all aspects of its
way of life
 type of habitat in which it
lives, the environmental
factors necessary for its
survival, and the methods by
which it acquires its
nutrients
 define how the species exists
within its ecosystem
Interactions between species in a
community can be classified according to
their effect.
 An ecological community consists of all the interacting
populations in an ecosystem.
 The populations in a community interact in the following
ways:
Type of
Interaction
Effect on
Species A
Effect on
Species B
Competition between A and B
Harms
Harms
Predation
by A on B
Benefits
Harms
Parasitism by A on B
Benefits
Harms
Mutualism between A and B
Benefits
Benefits
Competition
 Intraspecific
 between members of
the same species in a
population
 Interspecific
 between members of
different species within
a community
Two species cannot survive indefinitely in
the same habitat if their niches are
identical.
P. aurelia
P. caudatum
(a) Grown in separate flasks
(b) Grown in the same flask
Competitive Exclusion
What Is Symbiosis?
 an intimate, prolonged interaction between organisms
of different species
 one species always benefits, but the second species may be
unaffected, harmed, or helped
 commensalism:
 one species benefits and the other is unaffected
 parasitism:
 one species benefits and the other is harmed
 mutualism:
 both species benefit
What Is Symbiosis?
 lichen is a mutualistism between an algae and a
fungus, which appears to be a single organism.


fungal body provides support and protection
photosynthetic algae provides food
What Is Symbiosis?
 Corals involve a symbiotic relationship
between Zooxanthellae (photosynthetic
algae) and corals building cnidarians.
What Are Predator–Prey Interactions?
 Predators and prey co-evolve.
 When a predator consumes its prey, one species benefits at
the expense of another
 Parasites live on or inside their prey, or host, and feed on
its body without necessarily killing it
 Herbivores are also predators that do not necessarily kill
the prey on which they feed
Option C.3 –Impacts of Humans on Ecosystems
Understandings
 Introduced alien species can escape into local ecosystems
and become invasive.
 Competitive exclusion and the absence of predators can lead
to reduction in the numbers of endemic species when alien
species become invasive.
 Pollutants become concentrated in the tissues of organisms
at higher trophic levels by biomagnification.
 Macroplastic and microplastic debris has accumulated in
marine environments (plastic video)
Option C.4 –Conservation of Biodiversity
Understandings
 An indicator species is an organism used to assess a specific





environmental condition.
Relative numbers of indicator species can be used to
calculate the value of a biotic index.
In situ conservation may require active management of
nature reserves or national parks.
Ex situ conservation is the preservation of species outside
their natural habitats.
Biogeographic factors affect species diversity.
Richness and evenness are components of biodiversity.