Transcript Wolves of Yellowstone Role of the Predator

Community
Interactions:
Symbiosis
Predation
Role a Predator Plays in the Community
Keystone Species
Chapter 37, Sections 1-7
Do Now: Identify the type of community interactions
using the following notations.
•++
•+•+o
• Mutualism
• Parasitism
• Commensalism
These are all considered a type of symbiosis. The organisms of each
species have an exclusive living relationship for an extended time. Can
you describe an example for each?
Can you name another type of interaction
which occurs in the community that would
have a + - relationship?
Predation: Interaction between
predator and prey
• Predators kill and eat other
organisms
• Broadly defined, predators
include herbivorous as well
as carnivorous organisms,
including cows, wolves,
bats, and bears
• Predators tend to be larger
than their prey. Name the
predator and the prey in
the picture.
US National Park Service
• 1912, Congress created the US
National Park Service.
• 1916, Congress passed the National
park System Organic Act – declared
that the parks were to be maintained
in a manner that leaves them
unimpaired for future generations and
established the National Park Service
(DOI).
• Stephen Mather was the first Director
of NPS. He began establishing grand
hotels and other tourist facilities in
parks with spectacular scenery to
encourage tourism by allowing private
concessionaires to operate facilities
within the parks.
Role of a Predator in the Community
• Wolves
• Yellowstone National Park –
founded in 1872
• 3,472 square miles of land
• Mid 1900’s saw the wolves
almost eliminated from
park and the lower 48
states
• Hunted by park vistors
Wolves of Yellowstone Video
Watch the video. Listen for the changes which
happened and write them in your notebook.
What Are Keystone Species?
• A keystone species holds a community together, when it
disappears, so does the biological community. Elimination of
a keystone species dramatically alters the structure and
function of a community
Food Chain of the three organisms that are involved in a trophic
cascade in Yellowstone National Park
Wolves of Yellowstone Video Vocabulary
•
Apex predator: a top-level predator with no natural predator of their own; resides at the top of a food chain.
•
Browser: an organism that eats the shoots, leaves, and twigs of trees or shrubs; elk are browsers (and grazers).
•
Browsing: the act of eating shoots, leaves, and twigs of trees or shrub.
•
Cottonwood recruitment: the growth of seedlings or sprouts above the level of browsers. In other words, the trees are able to
grow taller than the level at which elk and other browsers can eat them.
•
Grazer: an organism that feeds on grass; elk are grazers (and browsers).
•
Habitat: the home or environment of a plant, animal, or other organism.
•
Keystone species: a species that has a disproportionately large effect on its environment compared to its relative abundance.
When a keystone species is removed from a system, the ecosystem may change drastically, even if the species removed was a
small part of the entire ecosystem.
•
Trophic cascade: a trophic cascade occurs when the impact of a predator on its prey affects one or more feeding or trophic
level. Predators control the populations of their prey and thus indirectly benefit and increase the abundance of their prey’s
prey. When the apex predator is removed, the lack of population control at the next trophic level down can affect the
populations at the trophic level below. Trophic cascades must occur across a minimum of three trophic levels (e.g. secondary
consumer, primary consumer, and producer). Trophic cascades can also happen from the bottom up; for example
Why Should We Protect keystone
Species?
• They play critical roles in the cross pollination of
angiosperms (bees, hummingbirds, bats).
• Top predator keystone species help regulate the
population numbers of other species.
• The loss of keystone species can lead to population
crashes and extinctions of other species that depend
on it for ecological services.
E.O. Wilson
• “The loss of a keystone species is like a drill accidentally
striking a power line. It causes lights to go out all over”
Aldo Leopold
• “We abuse land because we regard it as a commodity
belonging to us. When we see land as a community to which
we belong, we may begin to use it with love and respect”