Ecosystems 3 Flashcards
BIODIVERSITY
- the number and variety
or organisms that are
found within a specific
region. - New species, such as the
shark and the orchid
pictured to the right, are
constantly being
discovered by scientists.
Community
- Population
– all the members of the
same species living in the
same environment
(habitat)
– e.g. ducks in a pond
– all the populations of all
species living and
interacting in an ecosystem
or habitat
– e.g. ducks, geese, fish,
plants in a pond
- Biosphere/Biome
– a large area with the same
climate and a characteristic
group of plants and animals
– e.g. deciduous forest - e.g. fish, corals, sponges are all part of
community of a coral reef
Community
- because species interact, it is important to
preserve biodiversity of communities in order
to protect the individual species in that
community - 2 types of species that have a greater impact
on a community or ecosystem:
DOMINANT SPECIES
- so abundant that they have the biggest
biomass of any community member - removal can result in decrease in biodiversity
- e.g. primary producers in terrestrial
ecosystems
– e.g. American chestnut
DOMINANT SPECIES in Canada
➢Spruce trees have an enormous value for
wildlife.
➢With their bushy character, spruces provide
birds with great protection from the cold winter
winds and snow, and a place to hide from
predators and to make nests.
➢Birds such as white-winged crossbills, pine
siskins, red-breasted nuthatches, black-capped
chickadees and pine grosbeaks eat spruce
seeds.
➢Red squirrels and grouse may eat new buds.
➢ Black bears and porcupines sometimes nibble
the bark.
➢Deer and rabbits browse young shoots.
KEYSTONE SPECIES
- greatly affect population numbers and the
health of the ecosystem - generally not abundant
- plants or animals
- e.g. sea otter
Sense Of Value
The keystone is the brick at
the top of an arch. The
word keystone is used
figuratively to refer to the
central element of a system.
The term keystone species
is used in this sense, as an
organism that provides
stability to an ecosystem.
Negative Impact On the Ecosystem:Sea Otters
During the 20th century, sea otter populations were greatly reduced as otters
were trapped for their fur. As their numbers declined, the number of sea
urchins increased. More sea urchins began eating kelp, so the kelp biomass
decreased. When this happened, the fish that depended on kelp forests as a
habitat also declined in number. When sea otters were re-introduced, the kelp
forests recovered. Sea otters are a keystone species because they keep the
number of sea urchins in check, allowing the kelp to survive.
kelp → urchin → sea otter
Negative Impact on the ecosystem: prairie dog
As European settlement spread across the western grasslands
of North America, prairie dogs were once thought of as pests,
especially because they consumed crops and interfered with
ranching. Through poison, trapping, and guns, prairie dog
populations were drastically reduce in Canada and the United
States.
The wild prairie ecosystems suffered when populations of
this keystone species were reduced. In places where the
prairie dog has persisted, ecologists have discovered that
dog towns are important for increasing plant diversity,
turning over tonnes of soil, increasing the nitrogen content
of the soil, and allowing deeper water penetration of the
soil.
CAPTIVE BREEDING
- breeding of rare
or endangered
wildlife in
controlled
settings to
increase the
population size - e.g. black-
footed ferret at
Toronto Zoo
ECOSYSTEM ENGINEER
-species that causes such dramatic changes to the landscapes that it creates a new ecosystem
-beavers create clearings and ponds that support other organisms
ECOSYSTEM ENGINEER
Beaver’s are natures ecosystem engineers,felling trees and building dams, and changing waterways for their own benefit.But the also Benefit other species in the process,including humans as well as many species that are now in jeopardy at least in part due to the historic loss of beavers.
ECOSYSTEM ENGINEER
their dams help to control the quantity and the quality of water downstream, which both humans and animals use.Their ponds and flooded area create habitat for many plants and animals,such as fish,birds,insects and amphibians. In f act some species only live near beaver ponds
SUCCESSION
- series of changes in an ecosystem that occurs
over time, following a disturbance - e.g. beaver pond changes from:
forest → flooded forest → sunny pond → beaver meadow
SUCCESSION
- Beavers dramatically change their
environment, and those changes can last for
hundreds of years, even after the beaver have
moved on.
