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Keystone Ecology
Ecology
Ecology is the study of how living things interact with each other and their
environment.
It is a major part of Biology, it overlaps with geography, geology, climatology
and other sciences.
Ecology focuses on ecosystems and their organisms.
Ecosystem:
A system composed of organisms and nonliving components
of an environment.
Environment: The total surroundings of an organism or a group of organisms.
BIO.B.4.1.1 Describe the levels of ecological organization (i.e., organism,
population, community, ecosystem, biome, and biosphere).
Organism- individual living things
Population- a group of organisms of the same species that live in an area
Community- the various populations of organisms that live in an area
Ecosystem—collection of all the organisms that live in a particular place, together
with the non-living environment
Biosphere- the regions of the surface and atmosphere of Earth where living
organisms exist
BIO.B.4.1.2 Describe characteristic biotic and abiotic components of aquatic
and terrestrial ecosystems.
Abiotic and biotic factors
The environment includes two types of factors:
Abiotic factors – the non-living aspects of the environment. They include factors
like sunlight, soil, temperature, and water
Biotic factors- the living aspects of the environment. They consist of other
organisms including members of the same and different species.
An ecosystem consists of all the biotic and abiotic factors in an area and their
interactions.
Habitat: An area that provides an organism with its basic needs for survival.
Aquatic vs Terrestrial Ecosystems
Aquatic ecosystems: Organisms and their
environment in a body of water; can be marine
or freshwater
Terrestrial ecosystem: A community of
organisms and their environment that occurs on
the land masses of continents and islands
Examples: ponds, lakes, marshes, swamps,
rivers, streams, estuaries, bays, oceans
Examples: Many exist but major types include
tundra, taiga, temperate deciduous forest,
tropical rain forest, grassland and desert
Abiotic: water depth, sunlight, substrate, oxygen,
temperature, nutrient availability
Biotic: algae, plankton, under water plants,
insect larvae and nymphs, fish,
Abiotic: wind, temperature, rainfall, ground
water, humidity, amount of sunlight, soil
composition, intensity of daylight
Biotic: bacteria, fungi, flowering plants, trees,
invertebrates and vertebrates
Biome - A large area or geographical region with distinct plant of animal groups
adapted to that environment.
Climate (temperature, humidity,
atmospheric pressure, wind,
rainfall, and other meteorological
measurements in a given region
over long periods of time) help
determine the nature of a Biome.
Each of the major land
biomes has a characteristic
type of soil, which is
determined by several
factors, including
temperature, precipitation,
and type of vegetation.
BIO.B.4.2.1 Describe how energy flows through an ecosystem (e.g., food
chains, food webs, energy pyramids).
To survive, ecosystems need a constant influx of energy. Organisms get the
energy they need in two different ways:
Producer - An organism that uses a primary energy source (i.e. the sun) to
conduct photosynthesis or chemosynthesis. They produce food for themselves
and other organisms. Also known as autotrophs.
Consumer - An organism that obtains energy by feeding on other organisms or
their remains. Also known as heterotrophs.
Decomposers- A type of consumer that obtains nutrients by consuming dead
and decaying organic matter which allows nutrients to be accessible to other
organisms.
Food Chain: A single pathway by which energy and matter flow through
an ecosystem.
Food Web: A complex arrangement of interrelated food chains illustrating the flow
of energy between interdependent organisms.
Biological magnification
(Biomagnification): process by which
pollutants become more concentrated in
successive trophic levels of a food chain
or food web
Not a keystone term
Energy Pyramid- represents the
energy that is passed up a food
chain or web from lower to higher
trophic levels.
Trophic levels are feeding
positions in a food chain or web.
Only about 10% of energy available
at one level is available to the next
level.
Why? Because it is used for
metabolic processes or given off to
the environment as heat.
BIO.B.4.2.2 Describe biotic interactions in an ecosystem (e.g., competition,
predation, symbiosis).
Competition and Predation
Competition: When individuals or groups of organisms
compete for similar resources such as territory, mates,
water, and food in the same environment.
Predation: Interaction in which one organisms
(predator) captures and feeds on another (prey)
BIO.B.4.2.3 Describe how matter recycles through an ecosystem (i.e., water cycle,
carbon cycle, oxygen cycle, and nitrogen cycle).
Biogeochemical Cycles- The movement of abiotic factors between the living and
nonliving components within ecosystems; also known as nutrient cycles (i.e., water
cycle, oxygen cycle, and nitrogen cycle).
Water Cycle
Carbon Cycle
Nitrogen Cycle
BIO.B.4.2.4 Describe how ecosystems change in response to natural and human
disturbances (e.g., climate changes, introduction of nonnative species, pollution,
fires).
Succession - A series of predictable and orderly changes within an ecosystem over time.
How do human activities affect the environment?
Introduction of nonnative species
Nonnative Species: A species normally living outside a distribution range that
has been introduced through either deliberate or accidental human activity; also
can be known as introduced, invasive, alien, nonindigenous, or exotic.
Endemic Species: A species that is found in its originating location and is
generally restricted to that geographic area.
Extinction: A term that typically describes a species that no longer has any
known living individuals.
Examples of Nonnative Species
Gypsy Moth - brought to the US in 1868 and is a
serious defoliator of trees and shrubs in North America
Asian Carp - are a fast-growing fish that out-compete native f
for food and habitat
Dutch Elm Disease - transmitted to trees by elm bark
beetles. Since 1930, the disease has spread from Ohio
through most of the country, killing over half of the elm
trees in the northern U.S including elm at PSU
How do human activities affect the environment?
Climate change - human activities are
increasing the amount of CO2 in the
atmosphere which is increasing global
temperatures
BIO.B.4.2.5 Describe the effects of limiting
factors on population dynamics and
potential species extinction.
Population Dynamics: The study
of short-and long-term changes in
the number of individuals for a given
population, as affected by birth,
death, immigration, and emigration.
In the presence of unlimited
resources and in the absence of
predation and disease, populations
will grow exponentially.
Many natural populations show the an
S-shaped curve. As resources become
limited, population growth slows or
stops, leveling off at the carrying
capacity.
Limiting Factor: Chemical or physical factor that limits the existence, growth,
abundance, or distribution of an individual organism or a population.
Carrying Capacity: The number of individuals in a population that can be
supported in an ecosystem given the resources available and other environmental
pressures.
Predator/prey relationships