Download Chapter 9 Activity 5 Competition Among Organisms

Chapter 9 Activity 5:
Competition Among Organisms
ACS
Biology
Competition
• Please write down what the word
competition means to you below.
Definitions of Competition
•
The act of competing, as for profit or a prize; rivalry.
•
A test of skill or ability; a contest. Example: a skating
competition.
•
Rivalry between two or more businesses striving for
the same customer or market.
•
A competitor: The competition has cornered the
market.
•
Ecology: The simultaneous demand by two or more
organisms for limited environmental resources, such
as nutrients, living space, or light.
Ecological Competition
• Biological competition factors: predators,
prey, parasites, etc.
• An organism's niche may be further described by
how it relates to other organisms. Squirrels require
oak trees and acorns for food. They compete with
chipmunks and deer and acorn weevils for the
acorns, and must avoid predators like hawks, and
so on.
Ecological Competition
• Predator: any organism that exists by
preying upon other organisms.
• Prey: an animal hunted or seized for food,
especially by a carnivorous animal.
• Symbiosis: describes close and often
long-term interactions between different
biological species.
Types of Symbiosis
• Parasitism: type of symbiotic relationship
between organisms of different species in which
one, the parasite, benefits from a prolonged,
close association with the other, the host, which
is harmed.
• Mutualism: describes any relationship between
individuals of different species where both
individuals benefit.
• Commensalism: describes a relationship
between two living organisms where one
benefits and the other is not significantly
harmed or helped.
Ecological Competition
• Physical competition factors necessary for
survival and reproduction: temperature,
humidity, pH, soil, sunlight, etc.
• Gardeners of course are familiar with many of
these parameters. When you buy plants or seeds
you buy them with your garden in mind; some
plants cannot live in wet soils, others require
shade, still others need acid soils. Animals
likewise have similar requirements; a tropical lizard
like the iguana cannot survive the cold winter of a
temperate forest.
Ecological Competition
• It is common for organisms to compete for
limited resources or limiting factors such
as food, water, sunlight or space.
• A limiting factor can limit the size of a population.
• If there is not enough resources for both
organisms, they will be forced to compete
for survival.
• A resource is any factor or material that is
required for survival, growth and
reproduction.
Types of Competition
• Competition can occur between organisms
of the same species.
• INTRASPECIFIC COMPETITION
• Example: Male birds of the same species will battle
fiercely for the ownership of a territory.
• Competition between the same species is
an important factor in evolutionary
change.
• “Survival of the fittest”
Types of Competition
• Competition can occur between species of
different species.
• INTERSPECIFIC COMPETITION
• Example: Both hawks and owls hunt mice.
» Hawks hunt during the day
» Owls hunt at night
• In laboratory experiments, usually only
one species survives but in nature, two
competitive species can survive together
because an ecosystem is much more
complex than a lab setting.
Types of Competition
• Animals are usually involved in
interference or contest competition.
• This occurs when one organisms directly
affects the ability of the other organism to
obtain or use a resource by physical
contact.
• Example: Guarding or defending a resource;
animals fighting over territory.
• Example: Some plants secrete chemicals which
prevent the seeds of other plants from growing in
the area (allelopathy).
Types of Competition
• Plants are usually involved in exploitation
or scramble competition.
• This occurs when two species differ in
their abilities to use or obtain a resource.
• Example: The tallest plants or plants with the
“best” developed root system will survive.
Nonnative vs. Native Species
• Sometimes a new species that has not
been in an area before is introduced into
an ecosystem.
• Nonnative species or exotic species
• This can occur in two ways:
• Accidental or intentional
• Human actions are the main means of invasive
species introduction.
• Native species are organisms that are
typically found in an area.
• Native species and nonnative species
often end up in competition.
Invasive Species
• When a nonnative species has a negative
affect on an ecosystem, then the species
is considered to be an invasive species.
• Can affect the environment negatively in
the following ways:
• Economically
• Environmentally
• Human health
• Invasive species can be plants, animals
and/or other organisms.
Examples
• How does the damage occur?
• A population of an invasive species may relocate
to an area with fewer predators or disease,
therefore, the invasive species population may
grow out of control.
• Organisms that an invasive species may prey upon
may not have developed necessary defense
mechanisms.
• Native species may not be able to compete
successfully with the invasive species and are
often pushed to extinction.
• The spread of nonnative organisms
destroys healthy, diverse ecosystems.
Artificial vs. Intentional Introduction
• Many species invade new habitats
naturally or unintentionally.
• Example: Rats may travel to new land on a ship
• Many species are brought to new areas
when humans move.
• Humans find comfort in familiar plants and
animals.
• Increased travel and trade are providing
new opportunities for the spread of
nonnative species.
Susceptibility to Nonnative Species
Invasion
• The greater the human-induced
disturbance, the greater the chance that
an area will be invaded by exotic species.
• Example: European starlings and house
sparrows (nonnative birds) do well in
disrupted areas such as cites, suburbs
and farms.
• House sparrows were introduced to Brooklyn in
the 1850’s and they expanded throughout North
America.
• They are rarely seen in extensive forests,
grasslands, etc.
Governmental Involvement
• These terms have been clearly defined by
the government and laws have been
created as a preventative measure.
• Why is the government so concerned with
invasive species?
• Scientists believe that the introduction of
invasive species is the second greatest
destroyer of biodiversity.
Chapter 9 Activity 6:
Succession in Communities
ACS
Biology
Succession
• Please write down 5 words that come to
mind when you think about a forest fire?
Succession
• Succession is the gradual change in an
area.
• It is re-growth that occurs after an
environmental change such as a forest fire
or a volcanic eruption.
• The area changes from a very unstable to
a stable, final community over a long
period of time.
Example
• How does a forest fire hold promise
for new life?
• Within a few weeks after a fire, the
ground will eventually turn green again
as annual and perennial plants return.
• These plants can tolerate full sunlight
and high soil temperatures.
• The ash provides very fertile soil.
• Within 2-3 years, shrubs and young
trees begin to grow rapidly.
• A few years later, most would never be
able to tell that the area had once been
devastated by a fire.
• Eventually the forest will reach maturity.
• This process is not limited to just
forests.
Types of Succession
• Primary Succession
• Occurs in an area where no other community
existed before.
• Example: On land behind a moving glacier, a
newly formed volcanic island, or after man-made
structures are built.
• Secondary Succession
• Occurs following destruction
of a community.
• Example: Re-growth
after a forest fire,
volcanic eruption, flood
or tornado.
Primary Succession
• Primary succession is essentially the same thing as
soil formation.
• There is no community because there is no soil.
• All that is present at the beginning of primary succession
is mineral material; sand, volcanic ash, lava, bare rock,
etc.
• Soil contains organic material (living bacteria, fungi, plant
roots, animals, etc. and the dead and decomposing parts
of these creatures).
• In primary succession, the initial organic matter is added
to the mineral substrate by the pioneer plants.
• Pioneer plants become established on the bare mineral
material from spores, or seeds that are blown, washed,
or carried into the area by animals.
Primary Succession
These photos show primary succession,
the development of a community where none
was before. The images were taken at
Acadia National Park in Maine. Here, you
can see a whole sere in one view; first to
appear on the bare rock are lichens and
algae. These secrete acids which begin to
extract nutrients from the rock and which
form tiny cracks which are widened by
freezing and thawing.
As the cracks widen they trap enough organic
material and moisture for mosses to take
hold. Larger cracks have enough soil to support
grasses and small shrubs. The largest cracks
come together to form small basins where trees
can take root, although the tree in the photo below
didn't make it too long; perhaps a drought
exhausted the water in the small basin. However,
in the background the climax coniferous forest is
visible where enough soil has accumulated to
support the trees.
Secondary Succession
• Secondary succession is the reconstruction of
an ecosystem following a disturbance that
damages or removes all or part of the existing
community, BUT leaves the soil intact.
• Because soil is already present, the rate of
secondary succession is much faster than
primary succession.
• Pioneer species become established from
spores or seeds surviving in the soil or in
surrounding undisturbed areas.
• Secondary succession occurs when the life of an
area is not completely wiped
Secondary Succession
Fire plays a complex role in succession. Usually, a fire stops the progression of
succession and sets the stage for new, secondary succession as plants take root and
grow in the soil enriched by the mineral ashes. In some cases, however, fire plays an
even more important role. It maintains the climax community by removing competitors
that would otherwise gradually change the area to a different type of community.
The shrub land habitat of southern California is maintained by fire, which eliminates
large trees. The picture below shows a large fire burning a hillside; any trees that had
been growing there would be killed and the shrubs and other plants adapted to fire
would spring back quickly and reclaim the habitat.
Stages of Succession
• Each community goes through a succession of
plant and associated animal species.
• The first community to appear is called the
pioneer community.
• The first species present are called pioneer species.
• There are several in-between stages called
seral stages.
• The final community that remains and can
maintain itself is called the climax community.
• Examples: Well established biomes, such as the desert that
have characteristic organisms and a specific climate.
Pioneer vs. Climax Communities
• Differences between pioneer and climax communities:
• Pioneer Community
• Harsh environment
• Inefficient energy flow
• Low species diversity
• Less stable
• Climax Community
• Favorable environment
• Efficient energy flow
• High species diversity
• More stable