Transcript Ecology and Population dynamics

Ecology
Reinaldo Gutiérrez
Ana Ramirez
How do abiotic factors and biotic factors affect
population size in an ecosystem?
Biotic factors such as competition, emigration, and immigration play a vital role in the
carrying capacity and population size in an ecosystem, since when populations reach a
certain size individual species in a ecosystem compete for limited resources, such as
food, and water which limits the population size in a community and therefore plays a
vital role in its carrying capacity of a community, and during emigration some organisms
live a ecosystem decreasing its population, ,and during immigration a new organism is
introduced increasing the size of the population.
Abiotic factors such , the amount of water, and sunlight available in a community also
drastically affect a community since when resources become depleted due to abiotic
factor such as a drought , many species compete for the few remaining resources left in
their environment, which as a result drastically decreases the population size in a
ecosystem when resources are limited, however when resources are plentiful,
population sizes, begin a period of exponential growth, until they reach their carrying
capacity, at that point where the competive exclusion principle takes a toll in the
population size due to competition, and many other abiotic factors, and many other
abiotic factors.
What are the different types of organisms within an
aquatic ecosystem?
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The aquatic ecosystems contain a biodiversity of life on planet earth, since it covers
seventy-five percent of our planet. The aquatic systems are divided into two parts
the photic zone (200 meters at its deepest), where photosynthesis can occur, and the
aphotic zone where photosynthesis cannot occur, but instead chemosynthesis takes
a part in providing its great diverse deep underwater ecosystems. Photosynthetic
algae called phytoplankton, and zooplankton live in the photic zone. There are
however organisms called benthos who live near the bottom of aquatic ecosystems
in a place called the benthic zone, where the water is shallow enough to allow
benthos to be in the photic zone, algae, and rooted plants can grow, When the
benthic zone is below the photic zone however, chemosynthetic autotrophs are the
only primary producers.
Freshwater Ecosystems.
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Freshwater ecosystems include rivers and streams, lakes and ponds, and freshwater
wetlands. Even though rivers and streams contain a great amount of dissolved
oxygen, they do not contain a great diversity of plants, and animals in these
ecosystems depend on terrestrial plants, and animals that live along their banks for
food, as downstream sediments build up plants establish themselves. Lakes and
ponds contain ecosystems with food webs mainly depend on plankton ( zoo, and
phytoplankton), attached algae, and plants. Water circulates in and out of lakes and
ponds and circulates between the surface and the benthos during some seasons,
providing heat oxygen, and nutrients. Wetlands are very often energy rich and highly
productive providing a breeding ground for many organisms. Wetlands have an
important role in the environment purifying water by filtering pollutants and help in
prevent flooding by absorbing large amounts of water, and slowly releasing it. The
three main types include freshwater bogs, freshwater marshes, and freshwater
swamps.
Estuaries.
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Estuaries are a special kind of wetland formed where a river meets the sea,
containing a mixture of freshwater and saltwater. Many estuaries are shallow
allowing enough sunlight to reach the benthos so photosynthesis can occur.
Although support an outstanding amount of biomass, they contain fewer species
than freshwater, or marine ecosystems, making them commercially valuable.
Estuaries serve as nursery grounds for many ecologicallly and commercial
important fish, such as bluefish, stripped bass, shrimp, and crabs.
Marine ecosystems.
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Ocean ecosystems are divided vertically into zones based on light penetration and
depth, and horizontally into zones based on distance from the shore. The shallowest
and closest to land include the intertidal zone, the coastal, and the open ocean.
Organisms in the intertidal zone are exposed to regular and extreme temperature
changes, as well as they are battered by waves, and currents, yet many marine
ecosystems are found in the intertridal zone. Coastal communities include coastal
reefs and are highly productive , and water is brightly lit, and is supplied with
nutrients by freshwater runoff from land. Open ocean includes 90 percent of the
worlds ocean area, ranging from 500 to 10,00 meters, divided into the open ocean
photic zone, and aphotic zone. In the open ocean photic zone low nutrient levels are
found, and the smallest species of phytoplankton live, but it still contains the most
photosynthesis in earth in its first 100 meters. The open ocean aphotic zone is the
deepest part of the ocean based mostly on chemosynthetic organisms, but
organisms are exposed to frigid temperatures, high pressure, and total darkness, yet
are highly productive. The amount of salinity in different areas of the ocean also
affects the different organism that live there, since the more salinity in the water the
colder it is and the different organisms that live in it for example organism in the
intertidal zone such as whales that live in the photic zone and receive more sunlight
than organisms than organisms that live in the open ocean where the water
temperatures are much colder since the sun’s rays do no penetrate that far down in
the ocean, and there is a higher level of salinity since the water temperature is much
colder, so therefore depending on how deep in the ocean organisms live the more
salinity there is and the colder the temperature it is as well, and the different
organisms that live there as well.
Potential changes to an ecosystem resulting from
seasonal changes, climate changes, and or
succession.
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Seasonal changes, climate changes ,and succession can potentially alter an ecosystem in
a variety of ways. Seasonal changes can drastically affect an ecosystem because since
every seasonal change there are different resources that are being added and being
removed from an ecosystem, and energy consumption and resources are depleted
depending on the season drastically affecting the way animals live and how they search for
the resources they need for survival, in other words the niche of the organism is altered, as
well as its tolerance under certain seasonal changes stress.
Climate just like seasonal changes can drastically affect an ecosystem. If they year after
year pattern of temperature and precipitation begin to slowly change overtime these minor
changes can drastically alter the lives and niches of organisms in an ecosystem since they
have to adapt to the new environmental conditions year after year after they have been
adapted to the other climate conditions in which they thrived in, and if serious climate
alterations begin taking place overtime their environment, overtime many species will
begin to become endangered and extinct if they do not adapt to the environmental exposed
stress and conditions.
Succession can alter an ecosystem just like seasonal and climate changes, since
succession can alter an ecosystems original environmental condition by the immigration a
pioneer species after the environment has been partially disturbed as in secondary
succession , or it can be restored to its original conditions , and in some cases it may
never recover. However another kind of succession primary succession unlike secondary
may bring about the conditions for a new ecosystem to begin and grow over long periods
of time, after new landscape has been exposed, and since there's no trace of an existing
community in the place where primary succession began. In other words succession can
change an ecosystem in a variety of ways it can introduce new species by immigration or
emigration through secondary succession after the introduction of a pioneer species to
that partially disturbed habitat, it can be restored to its original conditions over time, or it
may not recover and remain barren and desolated, or it might introduce new communities,
and eventually new ecosystems through primary succession.
Examples of what causes a reduction in biodiversity.
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Catastrophic events such as tsunamis, volcanic eruptions, and earthquake
contribute to reduction in biodiversity since these catastrophic events contribute to
death toll of many species worldwide, thus reducing the biodiversity of species that
the earth provides.
Climate changes such as global warming are another major problem that needs to be
addressed since it constantly causes the increase of global temperature throughout
the world at a steady rate of approximately 1 degree per year having a drastic effect
on the melting of the polar ice caps which in turn has killed many species living in
certain ecosystems in the poles due to the changing climate worldwide in which
animals have to change their behavior and adapt to this pattern of change which can
in turn cause major consequences in ecosystems worldwide as animals try to adapt
to these major climate changes, such as the yellow bellied marmot which is coming
out of hibernation one month earlier, in response to the rising temperatures.
Invasive and nonnative species which may be introduced by humans or may travel
to a certain ecosystem just by chance can have a drastic effect on the biodiversity in
that ecosystem. For example goats introduced by humans when they traveled to the
Galapagos islands on their voyages into the island caused a drastic effect on the
biodiversity on certain types of tortoises, that they either become extinct or are in
danger of becoming extinct since the goats introduced by humans ate all the plants
that the tortoises ate on the island, and when the plants began decreasing in
population, so did the different varieties of Galapagos tortoises since they depend
on these plants for food, and when the food became scarce due to the goats eating
them the tortoises became scarce as well, since they depended on these plants for
food.
Pros and Cons resulting from a reduction in
biodiversity.
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The pros are that a reduction in biodiversity provides for human comfort and desires
such as more land and better homes to live in, agriculture, communication, and the
advancement in the benefits of human life, as time progresses, and new innovations,
and technology in general, as we clear more land through deforestation to provide
for human needs and comfort the world experiences the ever-growing human
population transition to a better suited comfort for our own benefit, from the lives we
lived in the past.
The Cons about reduction in biodiversity is that as we enjoy the comfort that we
receive from a reduction in biodiversity we do not realize that as we benefit we are
also damaging our environment and ourselves. For example, as we keep clearing out
forests for land and agriculture, we do not realize that we are disturbing the balance
of nature and we are constantly losing the precious biodiversity that earth provides,
which we can use to benefit ourselves further since each species is unique, and it
provides certain traits that others do not which can only assist us in the
advancement in the medical field, in our search for cures to various diseases, and if
we lose that biodiversity, we may never discover that treatment or cure, that will only
help alleviate our pain and discomfort. Anyways besides the medical field if we keep
clearing out forests for land we may lose many trees that are only assisting us in
removing harmful toxics and pollutants that we put in the atmosphere through the
use of automobiles that burn fossil fuels releasing harmful pollutants into the
atmosphere, besides trees and plants in general are essential through our survival
since they absorb carbon dioxide in the atmosphere and transform into oxygen
which they release into the atmosphere which we use in order to breathe, and to
remain alive.
In other words a reduction in biodiversity can be more harmful, than it can be
beneficial to human beings.
Human impacts in the loss of biodiversity.
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Humans are the main reason that we are experiencing a major loss in biodiversity.
Humans have a major effect on the nitrogen cycle, carbon cycle, and phosphorus
cycle. Humans impact the carbon cycle by releasing carbon in the form of carbon
dioxide by burning fuels faster than carbon absorbing plants can absorb all that
carbon which eventually accumulates in the atmosphere creating a greenhouse
which traps large amounts of solar energy, which eventually accumulates overtime
increasing the global temperatures by 1 degree yearly, which in turn melts the polar
ice caps, reducing the biodiversity in the poles and around the world as many
species attempt to adapt to this changing climate (global warming). Humans impact
the phosphorus cycle by moving phosphorus around and it becomes runoff, and
once it is in runoff in can end up in large bodies of water resulting in eutrophication
to occur killing many animals in the water. Other sources of phosphate in aquatic
systems include outflow from sewage treatment facilities and runoff of animal waste
from livestock feedlots, resulting in heavy growth in algae and cyanobacteria, which
consume a great deal of oxygen as they decompose the extra, depleting the water of
dissolved oxygen, leading to reduced species diversity. Humans impact the nitrogen
cycle by using nitrogen-containing fertilizers in agriculture, under certain conditions
in which agricultural plants have access to as much water as they require , their
productivity is usually constrained by the rate at which they can obtain nitrogen
available forms, such as nitrate. Under these conditions farmers attempt to increase
the availability of nitrogen by applying fertilizers. By dumping sewage and other
types of organic matter into water bodies, which damages the environment by
lowering dissolved oxygen levels related with microbial oxidation of the organic
matter, and the presence of pathogens and parasites. Accidental fertilization of water
bodies with large quantities of nitrogen contribute to eutrophication.
Other humans impacts leading to loss of biodiversity.
A ph scale used to measure the concentration of hydrogen ions in a substance such as
Dichlorodiphenyl-Tricholoroacetic Acid (DDT) released by humans into the environment
can be vital to the survival of many species that take up this compound into their body
systems, and the higher trophic level this component reaches in a food pyramid the
more harmful it can be to consumers atop the food pyramid since they have a much
higher concentration of DDT than producers in bottom of the food pyramid since every
time these components are passed on from one consumer to the next the next this
acidic component is stored in their systems in a much higher concentration, that can
lead to birth defects of their offspring. For example eagles at the top of a food pyramid
that have high concentration of DDt may lay leg thin eggs that may result in the death of
its offspring before it is even born, this overtime may lead to a decrease in biodiversity,
since it is very harmful to many species at a higher concentration, which eventually
affects the balance of nature because the organism that these predators eat become
abundant since there is less predators to capture them, and as a result they eat more of
the primary producers, leading to a huge loss of biodiversity.