Transcript Ecosystems and communities Ecology

Ecology
Ecosystems and Communities
Weather vs. Climate
• Weather is the condition of the Earth’s
atmosphere at a particular time and place.
Atmosphere is the Earth’s “insulating blanket”
• Climate is the average yearly condition of
temperature and precipitation in a region.
Climate is caused by:
• Latitude
• Winds and ocean currents which transport
heat through the biosphere (unequal heating)
• Shape and height
of landmasses
Greenhouse Effect
The temperature on Earth stays suitable for life
due to the trapping of heat by gases in the
atmosphere causing a natural phenomenon
called the Greenhouse Effect.
Phenomenon –
an occurrence or
fact that can be
perceived by the
senses.
Climate Zones
Three main climate zones:
1. Polar – very low angle
2. Temperate
3. Tropical – near the equator
Caused by differences in heating of the Earth’s
surface.
• Latitude
• Unequal heating of the surface results in
currents
• Wind currents occur because warm air rises
and cool air sinks.
• Where would you expect to find warm air
rising? Cold air sinking?
• The same pattern occurs in the ocean’s.
• Wind over the water’s surface also creates
currents.
• Landmasses also have affect on currents.
• Example: Rain shadow
Latitude determines the angle of the
sunlight striking the earth
What Shapes Ecosystems
• Biotic – Biological or living factors that
influence organisms in an ecosystem
Ex. Plants and animals
• Abiotic – Physical or non-living factors that
influence organisms in an ecosystem
Ex. Temperature, soil type, sunlight, etc.
Habitat
• The area where an organism lives
• Contains both biotic and abiotic factors
Niche
• Full range of physical and biological conditions
in which an organism lives and the way in
which the organism uses those conditions
An organism’s habitat is its address; its niche is
its occupation.
Example: Lion lives in the savannah but it
survives in that habitat by being a top level
consumer.
Example of Niche for Anoles Lizard
Community Interactions
• Competition
• Predation
• Symbiosis
Mutualism
Commensalism
Parasitism
Competition
• This occurs when organisms try to use the
same *resources (necessities of life).
• Often results in one organism dying out
Competitive Exclusion Principle – No two species
can occupy the same niche in the same
habitat at the same time
Predation
One organism
(predator)
captures and
feeds on the
other (prey)
Symbiosis
• Occurs when two species live closely together
• Three types:
1. Mutualism
2. Commensalism
3. Parasitism
Mutualism
Both species benefit from
the relationship
Commensalism
One species benefits while the other
is neither helped nor harmed
Parasitism
One species benefits by living in or on
the other and the other is harmed
Ecological Succession
• The series of predictable changes over time is
succession.
Ecosystems constantly change due to
natural and human influences.
Ex: Further disturbances, long term
climate changes, introduction of non-native
species
Primary Succession occurs on bare rock
surfaces where no soil exists.
Ex: Lava flow or glacier melt
*Pioneer species are the first species to
populate an area following a disturbance that
causes primary succession.
Ex: Lichens
Secondary Succession occurs when a
disturbance changes a community without
removing the soil
Climax communities are those that seem to be
stable and undergoing no more change.
Changes may occur very slowly due to climate
changes or introduction of non-native species
Biomes
• Biomes are groups of communities that cover
large areas and are characterized by certain
soil and climate conditions and particular
assemblages of plants and animals.
• Each biome is identified by its particular set of
abiotic factors and characteristic ecological
community and organisms.
Tolerance - plants and animals ability to survive
under conditions that differ from their optimal
(most desirable or favorable) conditions
Microclimate – climate conditions in a small
area that differ significantly from the climate
of the surrounding area
Aquatic Ecosystems
• Determined by depth, flow, temperature, and
chemistry of the water (salts, nutrients and
oxygen).
• Grouped by the abiotic factors that affect
them (different than land biomes which are
determined by biotic factors)
• Three main categories of Aquatic Ecosystems
1. Freshwater
2. Estuaries
3. Marine
Freshwater Ecosystems
• Flowing water: Rivers, streams, creeks, and
brooks
• Standing-water: Lakes and ponds
Plankton- tiny organisms that live in fresh or
saltwater environments
Phytoplankton - single-celled algae are producers
in aquatic food webs
Zooplankton – tiny animals that feed on
phytoplankton
• Freshwater wetlands: an ecosystem that has
water covering the soil or is present at or near
the surface for a portion of the year
• Very productive ecosystems; important
breeding grounds for organisms (birds and
insects)
• Bogs, marshes and swamps
• Water can be flowing or standing and fresh,
salty or brackish(mixture of fresh and salty)
Estuaries
• Wetlands formed where rivers meet the sea
• Contain a mixture of fresh water and salt
water
• Affected by tides
• A lot of detritus (organic material that provide
food for organisms at base of food web) from
primary producers
• Examples: Salt marsh-Chesapeake Bay and
Mangrove swamp-Florida Everglades
Marine Ecosystems
• Photic Zone - well-lit upper layer; producers
can photosynthesize here (0 to 200 meters)
• Aphotic Zone – Sunlight can not penetrate due
to depth (200 meters and deeper)
• Other zones based on depth and distance
from shore: intertidal zone(close to shore),
coastal zone, open ocean, benthic zone(ocean
floor)