Ecosystems and Communities
Chapter 4
Weather
Day-to-day conditions of Earth’s
atmosphere.
Climate
Average conditions over long periods.
Regional climate
Year-after-year patterns of
temperature and precipitation
Microclimates
Environmental conditions that can vary over
small distances
e.g. south- facing side of trees and buildings
receive more sunlight, and are often warmer
and drier than north-facing sides.
Factors That Affect Climate
• Solar energy trapped in the biosphere
– Greenhouse Effect
• Latitude
• Transport of Heat by winds
• Ocean Currents
Solar Energy
• Main force that affects climateSolar Energy (sunlight)
• Reflected back into space
• Absorbed
• Converted into heat
Earth’s average temperature
Balance b/w heat that stays in
biosphere and heat lost to space
Balance controlled by
concentrations of:
• Carbon Dioxide
• Methane
• Water Vapor
Greenhouse Gases-Function
like glass in a greenhouse;
allow visible light to enter but
trap heat.
Greenhouse Effect
Process in which gases trap sunlight
energy in Earth’s atmosphere as heat.
Heat trapped-temps to rise
Heat escapes-temps cool
Latitude
A measure of relative position north or south
on the Earth's surface, measured in degrees
from the equator, which has a latitude of 0°,
with the poles having a latitude of 90° north
and south.
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Solar Energy
• Equator-Sun almost directly overhead at noon
all year long-generally warm
• Poles-Receive less intense solar energy, less
heat-cooler
• Differences in heat distribution create climate
zones (tropical, temperate, and polar).
Tropic Zone
• Equator
• B/w 23.5° North and 23.5 ° South Latitudes
• Direct sunlight all year
Temperate Zone
• B/w 23.5°and 66.5 ° North and South
Latitudes
Polar Zone
• B/w 66.5°and 90 ° North and South Latitudes
Climates
• Varied amounts of solar energy at different
times of year because of Earth’s axis is tilted
• As earth revolves around sun, solar radiation
strikes different regions at angles that vary
from summer to winter.
• Winter-sun lower in sky; shorter days and
solar energy less.
Heat transport in the biosphere
• Unequal distribution of heat across
globe create winds and ocean
currents; transport heat and
moisture
Creation of winds
• Warm air less dense and rises
• Cool air more dense and sinks
• Air heated by warm area of Earth’s Surface
(equator) rises.
• Warm air rises-spreads north and south, losing
heat along way. Cool air sinks
Creation of Winds
• (Same time) Cooler regions (poles)-chilled air
sinks towards earth surface; pushing air at
surface outward
• Air warms as travels over surface; as warms it
rises.
• Upward and downward movement of air
creates winds.
Winds
•
•
•
•
Winds transport heat
Warm air rises
Cool air sinks
Earth’s rotation causes winds to blow
generally from
• west to east-temperate zones
• East to west over tropics and the poles
Heating and Cooling in Oceans
• Surface water pushed by winds.
• Currents carry lots of heat
• Warm surface currents add moisture and
heat to air; Cool surface currents cool airaffecting climate and weather of nearby land.
Currents
Deep ocean currents caused by cold water near the
poles sink and flowing along ocean floor.
Water rises in warmer regions through a process
called upwelling.
Niches and Community
Interactions
Species Success
• Each species has a range of conditions
under which it can grow and reproduce.
• Conditions define where and how an
organism lives.
Tolerance
Species ability to survive and
reproduce under a range of
environmental circumstances.
(RANGE)
Tolerance Graphs
Shows the response of
an organism to different
values of a single
environmental variable
Tolerance Graphs
Zone of Tolerance
• Optimal Range (center) organisms most likely
to be most abundant
• Physiological stress zone (edges of curve)
organisms stressed and numbers decline
– Expend more energy to maintain homeostasis
– Less energy available for growth and reproduction
Zone of Intolerance
• Outside tolerance zone; No organisms
Intolerance Zone
Habitat
• General place where an organism lives.
• Determined by species tolerance for specific
environmental conditions
Niche (organisms occupation)
The range of physical and biological
conditions in which a species lives and
the ways the species obtains what it
needs to survive and reproduce.
Aspect = parts
Two aspects of an organism’s niche
• Physical
• Biological
Niches
• Resources – Necessity of life such as food, water,
light, nutrients or space.
– Plants- sunlight, water and soil nutrients
– Animals- nesting, space, shelter, food, places to feed
• Physical Aspects – Abiotic factors it requires for
survival. E.g amphibians lose and absorb water
through skin::must live in moist places.
• Biological – Biotic factors required for survival.
E.g. when/how reproduces, food it eats, way
obtains food.
Competition
• Community-more than one kind of organism
attempting to use various essential resources.
• Same resources at same time and place =
competition
• Intraspecific competition-same species
competing
• Interspecific competition- competing
b/w different species.
What do you think these two males
are fighting over?
Direct Competition
• Competition = almost always a winner and
loser (losing species dies out)
Competitive Exclusion Principle
States no two species can
occupy exactly the same niche
in exactly the same habitat at
exactly the same time.
Species with same niche
One species will be better at
competing for limited resources and
will eventually exclude other species.
Dividing Resources
• Instead of competing resources divided
• By causing species to divide resources,
competition helps determine the number and
kinds of species in a community and the niche
each species occupies.
What would happen if two of the warlber species tried to occupy the same
niche in the same tree at the same time?
Predation, Herbivory, and Keystone
Species
Predation
An interaction in which one animal
(the predator) captures and feeds on
another animal (the prey)
Predation
• Predators can affect prey population in a
community
• Can determine the places prey can live and
feed.
– E.g. birds can play important role in regulating
mouse population sizes
Herbivore-Plant Relationship
An interaction in which one animal
(herbivore) feeds on producers
(plants) is called HERBIVORY
Herbivores
• Affect size and distribution of plant
populations in a community
• Determine the places that certain plants can
survive and grow
• E.g- Very dense populations of white-tailed
deer are eliminating their favorite food plants
across US.
Keystone Species
A change in a single species that can
cause a dramatic change in the
structure of a community
Keystone Species
• E.g.- Sea otters devour large amounts of sea
urchins; Urchins are herbivores that eat kelp
(giant algae that grows undersea “forests”.
• Sea otters almost eliminated by hunting; urchins
population increased; devoured kelp.
• Other organisms also disappeared.
• Sea otters went on endangered species,
populations recovered
Symbioses
Any relationship in which two species
live closely together
(Three main classes: mutualism,
parasitism, and commensalism)
Mutualism
• Relationship in which both species benefit
• E.g. – Sea anemone (sting functions-capture
prey and protect anemone from predation)
and clownfish (immune to stings)
Sea anemone-offers shelter; clownfish darts out
and chases other fish away (protects for
preditors)
Parasitism
A relationship in which one organism
lives inside or on another organisms
and harms it.
parasites
• E.g. Tapeworms live in the intestines of
mammals; absorb large amounts of hosts food
• E.g. Fleas, ticks and lice live on mammals
feeding on blood and skin.
• Parasites obtains all or part of its nutritional
needs
• Parasites weaken but generally do not kill
hosts.
Commensalism
Relationship in which one organism
benefits and another organism is
neither harmed or helped
Commensalism
• E.g. Grey whale and barnacles– Grey whale not harmed and no benefits
– Barnacles- benefit from flow of water from
moving whale that provides food
Sloth and lichen,
what type of
relationship?
Succession
Succedere (latin) “to come after”
Ecological Succession
Ecosystems change over time, especially
after disturbances, as some species die
out and new species move in.
Primary Succession
Succession that occurs in an area in which no
trace of a previous community is present.
(newly exposed surfaces)
Primary Succession
• Must create soil
• Occurs over a long period of time
Pioneer Species
1st species to colonize barren areasnamed after rugged human pioneers
who first settled the wilderness.
Eg. Lichen (on rock)
Lichen
• Lichen (mutualistic-algae and fungus) converts
nitrogen from atmosphere to into useful
nitrogen for other organisms
• break down rock
• Add organic material to form soil
Secondary Succession
Type of succession that occurs in a n
area that was only partially destroyed
by disturbances.
Secondary Succession
• Soil already established :: more rapid growth
• E.g of causes-wildfire, hurricane, or other
natural disturbance.
• Note-Fires are necessary for some species
survival; certain trees need them for seeds to
germinate.
• Could have different pioneer species
Why Succession Occurs?
• Every organism changes the environment it
lives in.
• As one species alters its environment; other
species find it easier to find resources and
survive.
• Lichen-add organic matter, form soil- other plants can
colonize and grow; more species move in and further
change environment; Over time, more and more
species find niches and survive.
Climax Communities
Traditional Definition/view point
An ecological community in which
populations of plants or animals remain
stable and exist in balance with each
other and their environment. A climax
community is the final stage of
succession, remaining relatively
unchanged until destroyed by an event
such as fire or human interference.
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Modern Idea of a Climax Community
• Succession doesn’t always follow same path
• Often reproduces original climax community.
• Are not always uniform and stable (disturbed so often)
Human-Caused Disturbances
• E.g - Farming
• Ecosystems may or may not recover from
extensive human-caused disturbances
• E.g farming a Tropical rain forests can change
microclimate and soil enough to prevent
regrowth of original community.
Studying patterns of succession
• compare different cases
• look for similarities and differences
• Eg. Mount Saint Helens and Krakatau (volcanoes)
– Both places primary succession proceeded through
predictable stages
– Hardy pioneer species helped stabilize loose volcanic
debris
– Confirmed early stages of primary succession are slow
and that chance can play a large role in determining
which species colonize at different times.
THINK ABOUT IT
– Why does the character of biological
communities vary from one place to another?
– Why, for example, do temperate rain forests
grow in the Pacific Northwest while areas to
the east of the Rocky Mountains are much
drier?
– How do similar conditions shape ecosystems
elsewhere?
The Major Biomes
Biomes are described in terms of
– abiotic factors like climate and soil type
– biotic factors like plant and animal life.
Global Climate
– Latitude and the heat transported by winds are
two factors that affect global climate.
– Area’s proximity to an ocean or mountain
range
Regional Climates
– In Oregon, cold currents that flow from north
to south have the effect of making summers in
the region cool relative to other places at the
same latitude.
Regional Climates
– Oregon borders the Pacific Ocean, and moist
air carried by winds traveling west to east is
pushed upward when it hits the Rocky
Mountains.
– This air expands and cools, causing the
moisture in the air to condense and form
clouds.
Regional Climates
– The clouds drop rain or snow, mainly on the
upwind side of the mountains.
– As the air sinks on the downwind side of the
mountain, it expands, warms, and absorbs
moisture.
– As a result, west and east Oregon have very
different regional climates, and different climates
mean different plant and animal communities.
Defining Biomes
–
Ecologists classify Earth’s terrestrial ecosystems into at least
ten different groups of regional climate communities called
biomes.
–
Biomes are described in terms of abiotic factors like climate
and soil type, and biotic factors like plant and animal life.
–
Major biomes include
•
•
•
•
•
•
•
•
•
•
tropical rain forest
tropical dry forest
tropical grassland/savanna/shrubland
Desert
temperate grassland
temperate woodland and shrubland
temperate forest
northwestern coniferous forest
boreal forest
tundra.
Defining Biomes
– The map shows the locations of the major
biomes.
Defining Biomes
–
Each biome is associated
with seasonal patterns of
temperature and
precipitation that can be
summarized in a graph
called a climate diagram.
–
A climate diagram shows
the average temperature
and precipitation at a given
location during each month
of the year. On this climate
diagram, temperature is
plotted as a red line, and
precipitation is shown as
vertical blue bars.
Defining Biomes
–
Organisms within each biome can be characterized by
adaptations that enable them to live and reproduce
successfully in the environment.
–
However, even within a defined biome, there is often
considerable variation among plant and animal
communities.
–
These variations can be caused by differences in
exposure, elevation, or local soil conditions.
–
Local conditions also can change over time because of
human activity or because of community interactions.
TROPICAL RAIN FOREST
– More species than all the other biomes
combined
– Rain forests get at least 2 meters of rain a
year!
TROPICAL RAIN FOREST
– Tall trees form a dense, leafy covering called a canopy
from 50 to 80 meters above the forest floor. In the shade
below the canopy, shorter trees and vines form a layer
called the understory.
– Organic matter on the forest floor is recycled and reused
so quickly that the soil in most tropical rain forests is not
very rich in minerals.
TROPICAL RAIN FOREST
Abiotic Factors:
– Rain forests are hot and wet year-round.
– They have thin, nutrient-poor soils that are
subject to erosion.
TROPICAL RAIN FOREST
– Biotic Factors – Plant Life
– Understory plants compete for sunlight, so
most have large leaves that maximize capture
of limited light.
TROPICAL RAIN FOREST
– Tall trees growing in
poor shallow soil often
have buttress roots for
support.
TROPICAL RAIN FOREST
– Epiphytic plants grow on the branches of tall
plants as opposed to soil. This allows the
epiphyte to take advantage of available
sunlight while obtaining nutrients through its
host.
TROPICAL RAIN FOREST
– Biotic Factors – Animal Life
– Animals are active all year
– Many animals use camouflage to hide from
predators
– Some change color to match their
surroundings.
TROPICAL RAIN FOREST
– Biotic Factors – Animal Life
– Animals that live in the canopy have
adaptations for climbing, jumping, and/or
flight.
TROPICAL
DRY FOREST
– Tropical dry forests grow in areas where
rainy seasons alternate with dry seasons.
– In most places, a short period of rain is
followed by a prolonged period of drought.
TROPICAL DRY FOREST
– Abiotic Factors
– Warm year-round, with alternating wet and
dry seasons.
– Rich soils are subject to erosion.
TROPICAL DRY FOREST
– Biotic Factors – Plant Life
– Adaptations to survive the dry season include
seasonal loss of leaves.
– A plant that sheds its leaves during a particular
season is called deciduous.
–
– Some plants also have an extra thick waxy layer
on their leaves to reduce water loss, or they store
water in their tissues.
TROPICAL DRY FOREST
– Biotic Factors – Animal Life
– Many animals reduce their need for water by
entering long periods of inactivity called
estivation.
– Estivation is similar to hibernation, but typically
takes place during a dry season.
– Other animals, including many birds and
primates, move to areas where water is available
during the dry season.
TROPICAL
GRASSLAND/SAVANNA/SHRUBLAND
– More seasonal rainfall than deserts but less
than tropical dry forests.
– Grassy areas are spotted with isolated trees
and small groves of trees and shrubs.
TROPICAL
GRASSLAND/SAVANNA/SHRUBLAND
– compacted soils
– fairly frequent fires
– action of large animals prevent some areas
from turning into dry forest.
TROPICAL
GRASSLAND/SAVANNA/SHRUBLAND
Abiotic Factors
– Warm, with seasonal rainfall.
– Soil is compact-frequent fires set by
lightning.
TROPICAL
GRASSLAND/SAVANNA/SHRUB
LAND
Biotic Factors – Plant
Life
– Adaptations include waxy
leaf coverings and
seasonal leaf loss.
TROPICAL
GRASSLAND/SAVANNA/SHRUBLAND
Biotic Factors – Plant Life
– Some grasses have a high silica content that
makes them less appetizing to grazing
herbivores
– Unlike most plants, grasses grow from their
bases, not their tips, so they can continue to
grow after being grazed.
TROPICAL
GRASSLAND/SAVANNA/SHRUBLAND
Biotic Factors – Animal Life
– Many animals migrate during the dry season in
search of water.
– Some smaller animals burrow and remain
dormant during the dry season.
DESERT
– Less than 25 centimeters of precipitation
annually, but otherwise vary greatly,
depending on elevation and latitude.
– Many deserts undergo extreme daily
temperature changes, alternating between hot
and cold.
DESERT
Abiotic Factors
– Low precipitation and variable temperatures.
– Soils are rich in minerals, but poor in organic
material.
DESERT
Biotic Factors – Plant Life
– Many plants, including cacti, store water in
their tissues, and minimize leaf surface area
to cut down on water loss. Cactus spines are
actually modified leaves.
DESERT
Biotic Factors – Plant Life
– Modified photosynthesis in some plants
requires leaf pores to open only at night,
enabling plants to conserve moisture on hot,
dry days.
DESERT
Biotic Factors – Animal Life
– Many desert animals get the water they need
from the food they eat.
– To avoid the hottest parts of the day, many
animals are nocturnal—active only at night.
DESERT
– Large or elongated ears and other extremities
often have many blood vessels close to the
surface to help the animal lose body heat and
regulate body temperature.
TEMPERATE GRASSLAND
– Plains and prairies once covered vast areas
of the mid-western and central United States.
– Periodic fires and heavy grazing by
herbivores maintained grassland plants.
– Today, most have been converted for
agriculture because their soil is so rich in
nutrients and is ideal for growing crops.
TEMPERATE GRASSLAND
– Warm to hot summers and cold winters, with
moderate seasonal precipitation.
– Soil is fertile and there are occasional fires.
TEMPERATE GRASSLAND
Biotic Factors – Plant Life
– Grassland plants—especially grasses, which
grow from their base—are resistant to grazing
and fire.
TEMPERATE GRASSLAND
Biotic Factors – Plant Life
– Wind dispersal of seeds is common in this
open environment.
– Root structure and growth habit of grassland
plants help establish and retain deep, rich,
fertile topsoil.
TEMPERATE GRASSLAND
Biotic Factors – Animal Life
– Because temperate grasslands are such
open, exposed environments, predation is a
constant threat for smaller animals.
– Camouflage and burrowing are two common
protective adaptations.
TEMPERATE WOODLAND AND
SHRUBLAND
– In open woodlands, large areas of grasses
and wildflowers are interspersed with oak and
other trees.
– Communities that are more shrubland than
forest are known as chaparral.
– Dense low plants that contain flammable oils
make fire a constant threat.
TEMPERATE WOODLAND AND
SHRUBLAND
Abiotic Factors
– Hot dry summers and cool moist winters.
– Thin, nutrient-poor soils and experience
periodic fires.
TEMPERATE WOODLAND AND
SHRUBLAND
Biotic Factors – Plant Life
– Woodland plants have adapted to drought.
– Woody chaparral plants have tough waxy
leaves that resist water loss.
TEMPERATE WOODLAND AND
SHRUBLAND
Biotic Factors – Plant Life
– Fire resistance is important, although the
seeds of some plants need fire to germinate.
TEMPERATE WOODLAND AND
SHRUBLAND
Biotic Factors – Animal Life
– Varied diets of grasses, leaves, shrubs, and
other vegetation.
– In exposed shrubland, some camouflage
TEMPERATE FOREST
– Mostly deciduous and
evergreen coniferous
trees.
– Coniferous trees, or
conifers, produce seedbearing cones
– most needle-shaped
leaves coated in a waxy
substance (reduce water
loss)
TEMPERATE FOREST
– Cold to moderate winters, warm
summers
– Autumn-shed their leaves
– Spring-small plants burst from the
ground and flower
– Fertile soils (humus-a material formed
from decaying leaves and other organic
matter)
TEMPERATE FOREST
TEMPERATE FOREST
– Biotic Factors – Plant Life
– Deciduous trees drop their leaves and
dormant in winter.
– Conifers have needlelike leaves
TEMPERATE FOREST
– Biotic Factors – Animal Life
– Changing weather
• some animals hibernate
• migrate to warmer climates.
• camouflaged to escape predation in the winter,
when bare trees leave them more exposed.
NORTHWESTERN CONIFEROUS
FOREST
– Mild moist air from the Pacific Ocean
influenced by the Rocky Mountains provides
abundant rainfall to this biome.
NORTHWESTERN CONIFEROUS
FOREST
– The forest includes
• a variety of conifers
• flowering trees and shrubs such as dogwood and
rhododendron
• Moss often covers tree trunks and the forest floor
• Because of its lush vegetation, the northwestern
coniferous forest is sometimes called a “temperate
rain forest.”
NORTHWESTERN CONIFEROUS
FOREST
Abiotic Factors
– Experience mild temperatures
– Abundant precipitation in fall, winter, and
spring.
– Summers are cool and dry
– Soils are rocky and acidic
NORTHWESTERN CONIFEROUS
FOREST
– Seasonal temperature variation
– less diversity in this biome than in tropical rain
forests
– ample water and nutrients support lush,
dense plant growth.
NORTHWESTERN CONIFEROUS
FOREST
– Adaptations that enable plants to obtain
sunlight are common.
– Trees here are some world’s tallest.
Northwestern Coniferous Forest
Biotic Factors – Animal Life
– Camouflage helps avoid predation
– Many animals are browsers—they eat a
varied diet—an advantage in an environment
where vegetation changes seasonally.
BOREAL FOREST
– Dense forests of coniferous evergreens along
the northern edge of the temperate zone are
called boreal forests, or taiga.
– Winters are bitterly cold
– Summers are mild and long enough to allow
the ground to thaw.
– Occur mostly in the northern part of the
Northern Hemisphere.
– The word boreal comes from the Greek word
for “north.”
BOREAL FOREST
Abiotic Factors
– Moderate precipitation
– High humidity
– Soil is acidic and nutrient-poor.
BOREAL FOREST
Biotic Factors – Plant Life
– The conical shape of conifers sheds snow,
leaves prevent water loss, making conifers
well suited to the boreal forest environment.
– Dark green color of most conifers absorbs
heat energy.
BOREAL FOREST
Biotic Factors – Animal Life
– Staying warm is the major challenge for
boreal forest animals.
– Small extremities and extra insulation in the
form of fat or downy feathers.
– Some migrate to warmer areas in winter.
TUNDRA
– Characterized by permafrost, a layer of
permanently frozen subsoil.
– Short cool summer-ground thaws to a depth
of a few centimeters and becomes soggy.
– In winter, the top layer of soil freezes again.
– Thawing and freezing-rips and crushes plant
roots (one reason that tundra plants are small
and stunted)
TUNDRA
– Cold temperatures
– high winds
– short growing season
– humus-poor soils-limit plant height.
TUNDRA
Abiotic Factors
– Strong winds and low precipitation.
– Summers are short and soggy, and the
winters are long, cold, and dark.
TUNDRA
Abiotic Factors
– Permafrost- permanently frozen subsoil.
TUNDRA
Biotic Factors – Plant Life
– By hugging the ground, mosses and other
low-growing plants avoid damage from
frequent strong winds.
– Seed dispersal by wind is common.
TUNDRA
Biotic Factors – Plant Life
– Adapted to growth in poor soil,
• E.G. legumes, which have symbiotic bacteria on
their roots that fix nitrogen.
TUNDRA
Biotic Factors – Animal Life
– Migrate to avoid the long harsh winters.
– Year-round-display adaptations such as
natural antifreeze, small extremities that limit
heat loss, and a varied diet.
Other Land Areas
– What areas are not easily classified into a
major biome?
– Not a typical community of plants and animals
– E.g. mountain ranges and polar ice caps
Mountain Ranges
– All continents and in many biomes.
– Temperature, precipitation, exposure to wind,
and soil types all change with elevation, and
so do organisms.
Polar Ice Caps
– Polar regions border the tundra and are cold
year-round.
– Plants are few
– Some algae grow on snow and ice.
– Rocks and ground are exposed seasonally,
mosses and lichens may grow.
– Marine mammals, insects, and mites are the
typical animals.
Polar Ice Caps
– In the north, where polar bears live, the Arctic
Ocean is covered with sea ice
– ice is melting each summer.
– In the south, the continent of Antarctica is
covered by ice nearly 5 kilometers thick in
places.
Aquatic Ecosystems
Factors that effect aquatic
ecosystems
•
•
•
•
•
Water’s depth
Temperature
Flow
Amount of dissolved nutrients
Runoff-Distance from the shore
Water Depth
• Sunlight penetrates only a relatively short
distance through water
• Photic Zone-sunlit region
– photosynthesis can occur
– Up to 200 meters in tropics
– Phytoplankton-photosynthetic algae
– 1st step in many aquatic food webs
• Aphotic Zone-Below photic zone; no
photosynthesis
Benthos
Organisms that live on, or in, rocks and
sediments on the bottoms of lakes,
streams, and oceans-habitat is the
benthic zone
Benthic Zone
• Water is shallow enough for photic zone
– Algae and rooted aquatic plants can grown
• Below photic zone
– Chemosynthetic autotrophs are the only primary
producers
Temperature and Current
• Warmer near equator; colder near poles
• Temps vary w/ depth; deepest often colder
• Lakes and oceans-Current carry water that is
significantly colder or warmer than would be
typical for any given latitude, depth, distance
from shore
Nutrient Availability
• Organisms needs substances to live-oxygen,
nitrogen, potassium and phosphorus
• Type and availability of dissolved substances
vary w/I and b/w bodies of water, greatly
affect types of organisms that can survive
there.
Freshwater Ecosystems
• 3 categories: River and streams, lakes and
ponds, freshwater wetlands.
• 3% of Earths surface water
• Terrestrial Organisms- Source of drinking
water, food and transportation
River and Streams
creeks, and brooks
• Often originate from underground water sources in
mountains or hills
• Near source-plenty dissolved oxygen; little plant life
• Downstream-sediment and plants
• Animals depend on terrestrial plants and animals along
banks for food.
Lakes and ponds
• Food webs based on plankton and attached
algae and plants.
• Plankton-general term for phytoplankton and
zooplankton
• Water-flows in and out and circulates b/w
surface and benthos
• Circulation distributes heat, oxygen, and
nutrients.
Wetlands
• Ecosystem in which water either covers the soil or
is present at or near the surface for at least part
of the year.
• Nutrient-rich, highly productive, breeding
grounds for many organisms.
• Environmental Functions
– purify water by filtering pollutants
– Prevent flooding by absorbing large amounts of water
and slowing releasing it.
• Bog, Marsh, Swamp
Estuaries
• Special wetland-river meets
the sea
• Mix of fresh and salt water
• Effected by rise and fall of
tides
• Many shallow-sunlight
reaches benthos to power
photosynthesis
• Support great amount of
Biomass-although contain
few species than freshwater
or marine.
Estuaries
• Spawning and nursery grounds for
many ecological/commercially
important fish and shellfish
(bluefish, bass, shrimp and crabs)
• Salt marshes– Temperate conditions
– Salt-tolerant grasses above the lowtide line and seagrasses below the
water.
– One of largest-Chesapeake Bay in
Maryland
Estuaries
• Mangrove Swamps
– Tropical estuary
– Salt-tolerant trees-collectively mangroves
– Largest-Florida’s Everglade National Park
Marine Ecosystems
• Occupy specific areas w/I the ocean
• Ocean zones
– Intertidal zone
– Coastal zone
– Open Ocean
Intertidal Zone
• Submerged high tide;
air and sunlight low
tide
• Subjected to regular
and extreme changes
in temps
• Battered by waves and
currents
• Barnacles and
seaweed attached to
rocks.
Coastal Ocean
• Low tide mark to
outer edge of
continental shelf
• Water brightly lit
• Nutrients from runoff
• Highly productive
• Kelp forests and coral
reefs
Open Oceans
• Edge of the continental shelf and extends
outward
• 90 % of world’s ocean
• 500 meters (shelf) to 10,000 meters in ocean
trenches
• Photic and aphotic zones
Open Ocean-Photic Zone
• Low nutrient
levels
• Supports only
small
phytoplankton
• Most
photosynthesis
occurs in top 100
meters
Open Ocean-Aphotic Zone
• Permanently dark zone; deepest parts of
ocean
• Food webs based on photic zone or
chemosynthetic primary producers
• High pressure, frigid temperatures and total
darkness
• Islands of high productivity
• Deep-sea vents, superheated water boils out
of cracks