Download Ecosystems - Biology R: 3(AE) 4(B,E)

Ecosystems
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• What composes an ecosystem?
• What are some organisms that can survive
in our backyard, but not in other places in
the world?
• What are some organisms that could not
survive in our backyard?
• Why?
Climate
• Many organisms require a specific set of environmental
conditions in order to grow.
• In an atmosphere, temperature, precipitation, and other
environmental factors combine to produce weather and
climate
• Weather = day to day conditions of Earth’s atmosphere
at a particular time and place
– Solar energy from sunlight and atmospheric gases effect
temperature, weather, and climate
• Climate = average conditions of temperature and
precipitation in a particular region
– Factors of climate include trapped heat, latitude, winds, currents,
elevation, and precipitation
Greenhouse Effect
• Temperature on Earth remains within a livable
range because the biosphere has an insulating
atmosphere
• Carbon dioxide, methane, water vapor, and
some other atmospheric gases trap heat energy
and maintain Earth’s temperature range
• Greenhouse effect = natural situation where a
layer of greenhouse gases retain heat energy
from sunlight inside the Earth’s atmosphere
Latitude
• Remember: Earth is a sphere tilted on its axis,
so solar energy reaches different parts at
different angles, resulting in different heating
distributions
• Earth has three main climate zones:
– Polar = cold areas at the poles of the Earth where the
sun’s rays strike Earth at a very low angle
– Temperate = between polar and tropic zones, more
affected by changing angle of the sun during the year,
so ranges from hot to cold depending on the season
– Tropical = near the equator receiving more direct
sunlight, so the climate mostly warm all year
Winds and Currents
• The unequal heating of Earth’s surface
drives winds and ocean currents, which
transport heat throughout the biosphere
• Wind forms because warm air near the
equator rises and cool air over the poles
sinks towards the ground
• Ocean currents form because cold water
near the poles sinks and flow along the
ocean’s bottom and rises in warmer water
What shapes an ecosystem?
• Remember: Ecosystems are influenced by a
combination of biological and physical factors
• Biological influences on organisms within an ecosystem
= biotic factors
– The ecological community ex. Birds, trees, mushrooms, bacteria,
frogs, etc.
• Physical, or nonliving, factors that shape ecosystems =
abiotic factors
– Climate, temperature, precipitation, humidity, wind, nutrient
availability, soil type, sunlight, water
• Together, biotic and abiotic factors determine the survival
and growth of an organism and the productivity of the
ecosystem in which the organism lives
What shapes an ecosystem?
• The area where an organism lives including biotic and
abiotic factors = habitat (“address”)
• The full range of physical and biological conditions in
which an organism lives and the way the organism uses
those conditions = niche (“occupation”)
– Ex. Place in food web, range of temperatures for survival, type of
food it eats, how it obtains food, physical environmental
condition requirements
• The combination of biotic and abiotic factors determines
the number of different niches
• No two species can share the same niche in the same
habitat, however, different species can occupy niches
that are very similar, but are still different niches
Quick Activity
• Describe the biotic and abiotic factors in
an ecosystem you know…
• Describe the habitat and niche of an
organism you know…
Community Interactions
• When organisms live together in
ecological communities, they interact
constantly, helping shape the ecosystem
• Community interactions, such as
competition, predation, and various forms
of symbiosis, can powerfully affect an
ecosystem
Competition
• Competition occurs when organisms of the same
or different species attempt to use an ecological
resource in the same place at the same time
– Resource = any necessity of life (water, nutrients,
light, food, or space)
• Direct competition usually results in a winner
and a loser (the loser fails to survive)
• The competitive exclusion principle = no two
species can occupy the same niche in the same
habitat at the same time
Predation
• An interaction in which one organism
captures and feeds on another organism
– Predator = organism that does the killing and
eating
– Prey = organism that is the food
Symbiosis
• Any relationship in which two species live
closely together
• Symbiosis = “living together”
• The types of symbiosis include:
– Mutualism
– Commensalism
– Parasitism
Mutualism
• In this relationship
both organisms
benefit from the
association. (+,+)
Commensalism
• In this relationship
one organism is
benefited and the
other is neither
helper nor harmed.
(+, 0)
•
Parasitism
• In this relationship,
the parasite benefits
at the expense of the
host. (+, -)
Ecological Succession
• Ecosystems and communities may appear stable
temporarily, but they are always changing due to abrupt
or human disturbances or natural fluctuations in the
environment
• As an ecosystem changes, older inhabitants gradually
die out and new organisms move in, causing further
changes in the community = ecological succession
– Primary succession = occurs on bare rock
– Pioneer species = first species to populate an area (lichens)
– Secondary succession = a disturbance changes an existing
community
– Climax community = mature, stable community after specific,
predictable stages of succession
BIOME
• OUR PLANET HAS AMAZING DIVERSITY OF
ORGANISMS THAT LIVE IN MANY DIFFERENT
ECOSYSTEMS
• THE VARIETY OF ECOSYSTEMS ARE CLASSIFIED
INTO CATEGORIES CALLED BIOMES
• BIOMES = PARTICULAR PHYSICAL ENVIRONMENT
THAT CONTAINS CHARACTERISTIC PLANTS AND
ANIMALS
• THE BIOME IS ALSO THE MOST COMMON CLIMAX
ECOSYSTEM THAT WILL FORM IN LARGE CLIMATIC
AREAS.
• CLIMATE DIAGRAM = GRAPH SUMMARIZING
TEMPERATURE AND PRECIPITATION IN SPECIFIC
BIOMES
TERRESTRIAL BIOMES
• TERRESTRIAL BIOMES ARE THOSE BIOMES THAT
FORM ON LAND.
• THE MAJOR PLANT AND ANIMAL ASSOCIATIONS
(BIOTIC FACTORS) ON LAND ARE DETERMINED BY
THE MAJOR CLIMATE ZONES OF THE WORLD,
MODIFIED BY LOCAL LAND AND WATER
CONDITIONS.
• CLIMATES WILL VARY AS TO TEMPERATURE, SOLAR
RADIATION, AND PRECIPITATION.
• THE PRESENCE OR ABSENCE OF WATER IS A
MAJOR LIMITING FACTOR FOR TERRESTRIAL
BIOMES.
MAJOR LAND BIOMES
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TROPICAL RAIN FOREST
TROPICAL DRY FOREST
TROPICAL SAVANNA
DESERT
TERMPERATE GRASSLAND
TEMPERATE WOODLAND AND SHRUBLAND
TEMPERATE FOREST
NORTHWESTERN CONIFEROUS FOREST
BOREAL FOREST (TAIGA)
TUNDRA
Aquatic Ecosystems
• Habitats in water environments
• Aquatic ecosystems are determined
primarily by the depth, flow, temperature,
and chemistry of the overlying water
(abiotic factors)
Major Aquatic Biomes
• Freshwater
• Estuaries
• Marine water
Freshwater ecosystems
• Flowing-water ecosystems = rivers, streams, creeks, etc
– Organisms are well adapted to the rate of flow
– Usually turbulent water at beginning with plenty of oxygen
– As water flows downhill, it slows and sediments build up, plants
grow, and organisms can make homes
• Standing-water ecosystems = lakes and ponds with
water circulating within them
– Water circulation distributes heat, oxygen, and nutrients
– Phytoplankton = single celled algae forming base of aquatic food
webs
– Zooplankton = planktonic animals that feed on phytoplankton
– Plankton = tiny, free-floating or weakly swimming organisms that
live in both freshwater and saltwater environments
Freshwater wetlands
• Freshwater wetlands = water covers soil or it is
present near the surface of the soil for part of the
year and are usually breeding grounds for
insects, fishes, amphibians, and migratory birds
– Bogs = form in depressions left by ice that melted
thousands of years ago
– Marshes = shallow wetlands along rivers and contain
cattails
– Swamps = water flows slowly and tress and shrubs
are present
Estuaries
• Brackish wetlands formed where rivers meet the
sea (mix of fresh and salt water)
• Detritus = tiny pieces of organic material that
provide food for organisms at the bottom of
estuary’s food web (worms, clams, sponges)
• Serve as spawning and nursery grounds
– Salt marshes = temperate-zone, grasses above tide
and seagrasses under water
– Mangrove swamps = coastal, tropical zone, mangrove
trees
Marine ecosystems
• Photic zone = well-lit upper layer where photosynthesis
can occur allowing algea and other producers to grow
– Intertidal zone = organisms are submerged part of the day and
exposed to air, sunlight and temperature changes the remainder
of the day while battered by waves
– Coastal ocean = rich in photosynthetic organisms, plankton, and
other organisms including kelp forests and coral reefs
• Aphotic zone = permanently dark where chemosynthetic
autotrophs survive
– Open ocean = aka “oceanic zone” = largest marine zone with
low nutrients, small producers, low productivity, fish of all shapes
and sizes (swordfish to octopus to dolphins to whales)
– Ocean trench = high pressure, frigid temperatures, and total
darkness with chemosynthetic producers
– Benthic zone = ocean floor contains benthos (sea stars,
anemones, marine worms) feeding on detritus that drifts down
from the produces near the surface