Transcript Slide 1

4-1 The Role of Climate
• Weather vs. Climate
– Weather: day-to-day condition of Earth’s
atmosphere at a particular time & place
– Climate: the average, year-after-year conditions
of temperature and precipitation in a particular
region
• Influenced by: atmosphere trapping heat, latitude,
winds & ocean currents, precipitation, shape &
elevation of land masses
Greenhouse Effect
• Natural situation in
which heat is
retained in Earth’s
atmosphere by
carbon dioxide,
methane, water
vapor, and other
gases
• Necessary to keep
temperatures
suitable for life
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface
The Effect of Latitude on Climate
• Latitude
– Distance north or south of the equator
• Due to Earth’s tilt on its axis, solar radiation
strikes different parts of the Earth’s surface at
an angle that varies throughout the year.
• Produces three main climate zones
– Polar zones
– Temperate zones (seasons)
– Tropical zone
Different Latitudes
90°N North Pole
Sunlight
Arctic circle
66.5°N
Sunlight
Tropic of Cancer
Most direct sunlight
23.5°N
Equator
0°
Tropic of Capricorn
23.5°S
Sunlight
Arctic circle
66.5°S
Sunlight
90°S South Pole
Heat Transport in the Biosphere
• Unequal heating of Earth’s surface drives winds &
ocean currents
• Winds form because warm air rises and cold air
sinks
• Landmasses can interfere with movement of air
masses
– Mountains cause moist air to rise
– Air mass cools, moisture condenses, causes
precipitation
– Causes a rain shadow (dry climate) on the far side of
the mountains
Ecosystems are influenced by a combination of
biological and physical factors.
Biotic Factors
• Biological influences (living
components)
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Animals
Plants
Fungi
Protists
bacteria
Abiotic Factors
• Physical factors (nonliving
components)
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Temperature
Precipitation
Humidity
Wind
Nutrients
Soil
Sunlight
Abiotic Factors
Biotic Factors
ECOSYSTEM
Habitat vs. Niche
• Habitat (address)
– The area where an organism lives
– Includes both biotic and abiotic factors
• Niche (occupation)
– The full range of physical & biological conditions in
which an organism lives and the way in which the
organism uses those conditions
– Eating & obtaining food, physical conditions needed
for survival, when & how it reproduces, etc.
– No two species can share the same niche in the same
habitat
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Spruce tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Describing a Niche
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Place in a food web
Temperature range
Food (what it eats)
How it obtains food
What eats it
Physical conditions
When & how it reproduces
Any other important requirements,
relationships, etc.
Community Interactions
• Competition
• Predation
• Symbiosis
– Mutualism
– Commensalism
– Parasitism
Competition
• 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)
• Competitive exclusion principle
– No two species can occupy the same niche in the
same habitat at the same time
Predation
• Interaction in which one organism captures
and feeds on another organism
– Predator: organism that does the killing and
eating
– Prey: the food organism
Symbiosis
• Any relationship in which two species live closely
together
• Mutualism
– Both species benefit from the relationship
– Flowers & insects
• Commensalism
– One benefits and the other is neither helped nor harmed
– Barnacles attached to whales
• Parasitism
– One organism (parasite) lives in or on another organism
(host) and harms it
– Parasites usually weaken, but don’t kill, their hosts
– Tapeworms living in mammals, fleas on mammals
Ecological Succession
• Series of predictable changes that occurs in a
community over time
• Can result from slow changes in the physical
environment or sudden disturbances from human
activities
• Primary Succession
– Occurs on surfaces where no soil exists
– Ex: Volcanic eruptions building new islands, rock after
glaciers melt
• Pioneer species: 1st species to populate an area
• Secondary Succession
– Succession following a disturbance that destroys a
community without destroying the soil
– Ex: After wildfires or abandoned farmland
Biomes
• Complex of terrestrial communities that covers a
large area and is characterized by certain soil and
climate conditions and particular assemblages of
plants and animals
• Not all kinds of organisms can live in every biome.
– Adaptation: inherited characteristic that increases an
organism’s ability to survive and reproduce
– Tolerance: ability to survive and reproduce under
conditions that differ from their optimal conditions
– Microclimate: the climate in a small area that differs
from the climate around it
The Major Biomes
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Tropical rain forest
Tropical dry forest
Tropical savanna
Desert
Temperate grassland
• Temperate woodland
and shrubland
• Temperate forest
• Northwestern
coniferous forest
• Boreal forest
• Tundra
Aquatic Ecosystems
• Determined primarily by the depth, flow,
temperature, and chemistry of the overlying
water
• Grouped according to the abiotic factors that
affect them (not geographically)
Freshwater Ecosystems
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Only 3% of Earth’s surface water is fresh water
Flowing-Water Ecosystems
Standing-Water Ecosystems
Freshwater Wetlands
Flowing-Water Ecosystems
• Rivers, streams, creeks, brooks
• Organisms adapted to rate of flow
– Ways to attach to plants or rocks
– Streamlined bodies
• Usually originate in mountains from underground
water source
– Plenty of dissolved oxygen & little plant life at source
– Sediments build up as water flows down hill & plants
establish themselves
– As it slows downstream, may find turtles, beavers,
river otters
Standing-Water Ecosystems
• Lakes and ponds
• Water circulates within (not just flowing in and
out)
– Helps distribute heat, oxygen & nutrients throughout
the ecosystem
• Plankton
– Tiny, free-floating, weakly swimming organisms
– Phytoplankton: single-celled algae; base of aquatic
food webs
– Zooplankton: feed on phytoplankton
Freshwater Pond Ecosystem
Section 4-4
Spoonbill
Frogs lay eggs in the shallow
water near shore.The eggs
hatch in the water as tadpoles
and move to the land as adults.
The shore is lined with grasses
that provide shelter and nesting
places for birds and other
organisms.
Duck
Water
Frog lilies Mosquito
Duckweed
larvae
Dragonfly
Snail
The roots of water lilies
cling to the pond bottom,
Pickerel
Diving
beetle Fish share the pond
while their leaves, on long
flexible stems, float on the
with turtles and other
surface.
animals. Many of
them feed on insects
at the water’s edge.
Trout
The bottom of the pond is
inhabited by decomposers and
Hydra
other organisms that feed on
particles drifting down from the
Snail Crayfish
surface.
Go to
Section:
Phytoplankton
Plankton and the organisms that
feed on them live near the surface
where there is enough sunlight for
photosynthesis. Microscopic algae
are among the most important
producers.
Benthic
crustaceans
Freshwater Wetlands
• wetland
– Ecosystem in which water either covers the soil or
is present at or near the surface of the soil for at
least part of the year
– May be flowing or standing
– Fresh, salty or brackish (mixture of fresh & salt)
– Very productive ecosystems
– Bogs, marshes, swamps
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Estuaries
Wetlands formed where rivers meet the sea
Mixture of fresh water & salt water
Affected by rise & fall of ocean tides
Most primary production is not consumed by
herbivores
– Instead enters the food web as detritus (particles
of organic material that provide food for
organisms at the base of the estuary’s food web)
• Support an astonishing amount of biomass
– Spawning & nursery grounds for commercially important
fishes and for shellfish
• Salt marshes, mangrove swamps
Marine Ecosystems
• Oceans
• Photic zone
– Well-lit upper layer of the oceans
• Aphotic zone
– Permanently dark layer of the oceans below the
photic zone
– Only producers here are chemosynthetic
autotrophs
Intertidal Zone
• Organisms exposed to regular & extreme
changes
– Submerged in water then exposed to air, sunlight
& temperature changes
• Competition leads to zonation
– Prominent horizontal banding of organisms that
live in a particular habitat
Coastal Ocean
• Extends from the low-tide mark to the outer
edge of the continental shelf
• Often rich in plankton & other organisms
• Kelp forests
– Named for their dominant organism: a giant
brown alga that can grow as much as 50 cm a day
Coral Reefs
• Diverse and productive environments named
for the coral animals that make up their
primary structure
• Found in warm, shallow water of tropical
coastal oceans
• Among the most diverse & productive
environments on Earth
Open Ocean
• Oceanic zone
• Begins at the edge of the continental shelf and
extends outward
• Largest marine zone
– More than 90% of the surface area of the world’s
oceans
• Low levels of nutrients, only the smallest
producers, low productivity
• Swordfish, octopus, dolphins, whales
Benthic Zone
• Ocean floor
• Benthos
– Organisms that live attached to or near the ocean
floor
• Often depend on food from organisms that
grow in the photic zone
• Most feed on detritus (dead organic material)
Figure 4-17 Zones of a Marine Ecosystem
Section 4-4
land
Coastal
ocean
Open
ocean
200m
1000m
Photic zone
4000m
Aphotic zone
6000m
Ocean
trench 10,000m
Continental
shelf
Go to
Section:
Continental slope and
continental rise
Abyssal
plain