Ecosystems & Communities:
Organisms and their Environments
1
Ecosystems have living and nonliving components
What are ecosystems?
2
What is an Ecosystem?
• A community of biological organisms plus the nonliving components with which the organisms interact.
• Living organisms are not self-sufficient. They need
energy and raw materials.
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4
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What is an Ecosystem?
• The biotic environment consists of all the living
organisms within an area and is often referred to as
a community.
• The abiotic (aka non-living or physical) environment,
often referred to as the organisms’ habitat, consists of:
• the chemical resources of the soil, water, and air,
such as carbon, nitrogen, and phosphorus
• the physical conditions, such as the temperature,
salinity (salt level), moisture, humidity, and energy
sources
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Soil erosion on a
trail in the
Adirondack
mountains
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Which scenario below exemplifies an
ecosystem?
1.
2.
3.
4.
A group of organisms of the same species living in the
same place at the same time
Different species interacting together at the same
place and time
Different species interacting with each other at the
same time in a desert
A smaller species living on a larger species in a
mutually beneficial relationship
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Take-Home Message
• An ecosystem is all of the living organisms in a habitat
as well as the physical environment.
• Ecosystems are found not just in obvious places such as
ponds, deserts, and tropical rainforests but also in some
unexpected places, like the digestive tracts of organisms
or the shell of a beetle.
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Challenge Question
• An ecosystem is made of two components: the biotic
environment, or community, consisting of the living
organisms within an area, and the physical environment,
or the habitat in which these organisms live.
• A habitat consists of its chemical resources of the soil,
water, and air as well as its physical conditions.
• List some of the aspects that make up the physical
conditions of a habitat.
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Ecosystems have living and nonliving components
A variety of biomes occur around the
world, each determined by temperature
and rainfall.
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A variety of biomes occur around the world,
each determined by temperature and
rainfall.
•
•
•
•
What is the average temperature?
What is the average rainfall (or other precipitation)?
Is the temperature relatively constant or does it vary
seasonally?
Is the rainfall relatively constant or does it vary
seasonally?
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13
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Tropical Rain Forest
•
•
•
•
•
•
forest of tall trees in a region of year-round warmth
~ 125 to 660 cm yearly rainfall
temperature ranges from 20 °C - 34 °C
average humidity 77 - 88%
rainfall > 250 cm/year (may be a brief dry season)
almost all rain forests lie near the equator
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Tropical Rain Forest
• < 6% of Earth's land surface
• > 50% of all the world's plant and animal species live in
tropical rain forests
• produce ~40% of Earth's oxygen
• ~70% of the plants in the rainforest are trees
• ~25% of all the medicines we use come from rainforest
plants
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Tropical Rain Forest
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Indicator Species
• any biological species that defines a trait
or characteristic of the environment
• may delineate an ecoregion
• could indicate an environmental condition such as
a disease outbreak, pollution, species competition
or climate change
• can be among most sensitive species in a region;
sometimes act as early warning to monitoring biologists
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Tropical Rain Forest – Indicator Plant Species
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Tropical Rain Forest – Indicator Animal Species
Gorilla
Gorilla gorilla
Orangutan (Pongo pygmaeus)
Spider Monkey
Ateles geoffreyi
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Tropical Rain Forest – Indicator Animal Species
2-toed sloth
Cholepus
hoffmanni
Three-toed Sloth (Bradypus
variegatus) with baby - Costa Rica22
Tropical Rain Forest – Indicator Animal Species
Collared Aracari
Pteroglossus torquatus
23
Grasslands (Prairie)
• 2 different types
• tall-grass: humid & very wet
• short-grass: dry; hotter summers and colder winters
than the tall-grass prairie
• found in middle latitudes in the interiors of continents
• either moist continental climates or dry subtropical
climates
• Argentina – grasslands are known as pampas
• Russia – steppes
• grasslands in southern hemisphere tend to get more
precipitation than those in the northern hemisphere
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Grasslands (Prairie)
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Grasslands (Prairie)
• temperatures range from -40° F  70° F
• growing season and a dormant season
• growing season is when there is no frost and plants
can grow (which lasts from 100 to 175 days)
• tropical and subtropical grasslands the length of
the growing season is determined by how long the
rainy season lasts
• temperate grasslands the length of the growing
season is determined by temperature (≥ 50° F)
• dormant (not growing) season: nothing can grow
because its too cold
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Grasslands (Prairie)
• average rainfall per year ranges from 10 - 30 inches
• tropical and sub-tropical grasslands: average rainfall
per year ranges from 25 - 60 inches
• amount of rainfall is very important in determining which
areas are grasslands
• hard for trees to compete with grasses in places
where the uppers layers of soil are moist during part
of the year but where deeper layer of soil are always
dry.
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Grasslands (Prairie)
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Grasslands– Indicator Plant Species
Old Field Habitat, Ohio
Grassland, North Dakota
Ironweed
(Vernonia sp.) with
Hedge Bindweed 29
Vine (Calystegia sepium)
Grasslands– Indicator Plant Species
Ironweed (Vernonia sp.)
Joe Pye Weed
Eupatorium purpureum
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Grasslands – Indicator Plant Species
Common Teasel
Dipsacus fullonum
Queen Anne's Lace (Daucus carota)
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Grasslands – Indicator Animal Species
Bison (Bison bison) on the range,
Theodore Roosevelt National Park, North
Dakota
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Grasslands – Indicator Animal Species
Przewalski's horse (Equus caballus
przewalskii), The Wilds, Ohio
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Grasslands – Indicator Animal Species
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Taiga
•
•
•
•
•
•
Russian word for forest
largest biome in the world
Eurasia, North America
located just below the tundra biome
many coniferous trees
aka boreal forest; Boreal was the Greek goddess of the
North Wind
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Taiga
•
•
•
•
•
winter temperature range is -54 to -1° C (-65 to 30° F)
summer: -7° C (20° F) to 21° C (70° F)
summers are very short (50 - 100 frost free days)
average yearly precipitation: 30 - 85 cm (12 - 33 in)
main seasons are winter and summer
• spring and autumn are very short
• weather is either hot and humid or very cold
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Taiga
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Taiga – Indicator Plant Species
Balsam Fir
Abies balsamea
Black Spruce
Picea mariana
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Taiga – Indicator Plant Species
White Poplar
Populus alba
Jack Pine
Pinus banksiana
Paper Birch
Betula papyrifera
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Taiga – Indicator Animal Species
American Black Bear
Ursus americanus
Bald Eagle
Haliaeetus leucocephalus
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Taiga – Indicator Animal Species
Snowshoe Rabbit
Lepus americanus
Long-eared Owl
Aiso otus
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Desert
• cover about one fifth of Earth's land surface
• hot and dry: near Tropic of Cancer/Tropic of
Capricorn
• cold: near the Arctic
• temperature
• hot & dry: ~ 25° C to ~ 49° C
• cold: -2 to 4° C (winter) 21 to 26° C (summer)
• precipitation
• hot & dry: very little rainfall and/or concentrated
rainfall in short periods between long rainless periods
(< 15 cm/year)
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• cold: 15 - 26 cm/year
Desert
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Desert – Indicator Plant Species
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Desert – Indicator Plant Species
Fishhook Cactus
Mammillaria microcarpa
Saguaro Cactus
Carnegiea gigantea
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Desert – Indicator Plant Species
Trichomes
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Desert – Indicator Animal Species
Zebratail Lizard - Callisaurus draconides
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Desert – Indicator Animal Species
Rock hyrax (Procavia capensis)
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Desert – Indicator Animal Species
Bactrian Camel, Camelus bactrianus
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Temperate Deciduous Forest
• temperature: 0 - 20 C
• precipitation: ~ 50 – 200 cm/year
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Temperate Deciduous Forest
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Temperate Deciduous Forest
Indicator Plant Species
Oaks (Quercus sp.)
Dutchman's-Breeches
Dicentra cucullaria
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Temperate Deciduous Forest
Indicator Plant Species
Sassafras
Sassafras albidum
Redbud
Cercis canadensis
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Temperate Deciduous Forest – Succession
• orderly succession of communities to a climax
community (biome)
• two main types of succession:
• primary succession: begins with bare rock exposed
by geologic activity
• secondary succession: begins on soil from which
previous community has been removed (by fire,
agriculture, etc.)
• secondary succession can proceed much faster
because the soil has been prepared by the
previous community
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Temperate Deciduous Forest
Indicator Animal Species
American Toad
Bufo americanus
Box Turtle
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Temperate Deciduous Forest
Indicator Animal Species
Eastern Chipmunk
Tamias striatus
Eastern Gray Squirrel
Sciurus carolinensis
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Temperate Deciduous Forest
Indicator Animal Species
Yellow-breasted chat
Icteria virens
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Tundra
• annual average temperature < 5 C
• precipitation (mostly in the form of snow) < 100 mm/year
• summer is brief
• temperatures above freezing last only a few weeks at
most
• "warm" summer coincides with periods of almost 24
hour daylight, so plant growth can be explosive
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Tundra
Anaktuvuk Pass, Alaska
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Tundra – Indicator Plant Species
Arctic Tundra Wildflowers - Alaska
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Tundra – Indicator Plant Species
Lichen
Polytrichum Moss
(photographed in Ohio, not on the
Tundra)
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Tundra – Indicator Animal Species
Reindeer
Rangifer tarandus
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Tundra – Indicator Animal Species
Caribou On Autumn Tundra Denali National Park Alaska
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Savanna
• rolling grassland scattered with shrubs and isolated trees
• found between a tropical rainforest and desert biome
• not enough rain falls on a savanna to support forests
• found in a wide band on either side of the equator on
the edges of tropical rainforests
• warm temperature year round
• very long dry season (winter): ~ 10 cm rain; none at all
from Dec - Feb
• very wet season (summer): ~ 35-65 cm rain
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Savanna
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Savanna – Indicator Plant Species
Baobab
Adansonia digitata
Umbrella Thorn Acacia
Acacia tortillis
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Savanna – Indicator Animal Species
Savanna Elephant
Loxodonta africana
Black Mamba
Dendroaspis polylepis
Lion
Panthera leo
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Chaparral
•
•
•
•
winter: mild and moist, but not rainy
summer: very hot and dry.
annual temperature range: between -1° and 38° C
annual precipitation: ~ 25-45 cm, mostly in the winter
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Chaparral
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Chaparral – Indicator Plant Species
Blue Oak
Quercus douglasii
Common Sagebrush
Artemisia tridentata
Olive Tree
Olea europaea
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Chaparral – Indicator Animal Species
Black-tailed Jackrabbit
Lepus californicus
Golden Jackal
Canis aureus
Spotted Skunk
Spilogale gracilis
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The Freshwater Biome
• low salt concentration — usually less than 1%
• plants and animals in freshwater regions are adjusted to
the low salt content and would not be able to survive in
areas of high salt concentration (i.e., ocean)
• 3 different types of freshwater regions:
• ponds and lakes
• streams and rivers
• wetlands
72
The Freshwater Biome – Ponds and Lakes
From left: a view across Manzanita Lake toward Mt. Lassen, California; a
forest pond near Donnelly, Idaho; a Great Blue Heron; Paranagat Lake,
southeastern Nevada.
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The Freshwater Biome – Streams and
Rivers
From left: McArthur-Burney Falls State Park, California; trout; Green
River, Utah; Brooks River, Alaska.
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The Freshwater Biome - Wetlands
From left: Pescadero Marsh, California; coastal marsh at Umpqua
Dunes, Oregon; trees and bogs on Esther Island, Alaska.
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The Marine Biome
• cover about three-fourths of the Earth's surface
• marine algae supply much of the world's oxygen supply
and take in a huge amount of atmospheric carbon
dioxide
• evaporation of the seawater provides rainwater for the
land
• 3 different types of marine regions:
• oceans
• coral reefs
• estuaries
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The Marine Biome - Oceans
From left: mussels, worms, and a spider crab at a hydrocarbon seep
community in the Gulf of Mexico; a sea fan and brain coral in the Florida
Keys National Marine Sanctuary; a school of Atlantic amberjack off North
Carolina.
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The Marine Biome – Coral Reefs
From left: reef life in the Gulf of Aqaba, Red Sea; a reef at Fanning
Island atoll in the central Pacific; a reef in the Florida Keys National
Marine Sanctuary.
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The Marine Biome - Estuaries
From left: Mangrove roots, south Florida; wetlands and tidal streams
in the Ashe Island area, ACE Basin National Estuarine Research
Reserve, South Carolina; a salt marsh in Winyah Bay National
Estuarine Research Reserve, South Carolina.
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Ecological Notes
These are the biomes, in order of their productivity (highest
first)
1. estuaries and tropical rain forest (highest)
2. temperate forest
3. agricultural land
4. temperate grassland
5. lakes and streams
6. coastal zone
7. tundra
8. open ocean
9. desert (lowest)
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Ecological Notes
In order to be productive and have a lot of living material
standing around (biomass), an ecosystem has to have 4
basic necessities for plant life to thrive (if there are
enough plants, the ecosystem will also support a lot of
animals). The four things are:
1. Sunlight
2. Nutrients
3. Warm temperatures
4. Water
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Biomes Video
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Take-Home Message
• Biomes are the major ecological communities of earth,
characterized mostly by the vegetation present.
• Different biomes result from differences in temperature
and precipitation, and the extent to which they vary from
season to season.
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Challenge Question
• Terrestrial biomes are determined by the temperature
and precipitation amounts as well as whether those
factors are constant or vary by season.
• By contrast, how are aquatic biomes determined?
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Energy and chemicals flow within
ecosystems
Energy flows from producers to
consumers.
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86
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First Stop: Primary Producers
• ecosystem: producers or consumers
• primary producers: plants, algae (some), bacteria
• convert light energy from sun into chemical energy
through photosynthesis
• chemical energy = food
• consumers eat or absorb their food
• energy stored in chemical bonds of carbohydrate,
protein, and lipid molecules is captured and
harnessed for consumers’ own movement,
reproduction, and growth
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Food Chain
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Food Web
90
Food Web
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Food Chains & Food Webs
• A change in one link in a food chain will affect the other
links.
• The table on the next slide gives one example of a food
chain and the trophic levels represented in it:
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Food Chains & Food Webs
GRASS

GRASSHOPPER

TOAD

SNAKE

HAWK

BACTERIA
IN GENERAL,
AUTOTROPHS
(PRODUCERS)

HERBIVORES
(PRIMARY
CONSUMERS)

CARNIVORES
(2, 3, ETC.)

DECOMPOSERS
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Chain Reaction Game
94
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Energy Flows through a Food Web
•
Losses at every “step” in a food chain
•
Inefficiency of energy transfers
96
Energy flow through a food chain
Energy flow refers to the way that energy is transformed through
a food chain (pictured here) containing a series of levels,
including plants, consumers, predators, and decomposers. 97
Amount of energy available at each of the
four levels of an ecosystem
Ecological pyramids illustrate the amount of energy
available at each of the four levels of an ecosystem.
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Ecological Pyramid
99
A grasshopper eats a plant. A mouse eats the
grasshopper. A snake eats the mouse. A hawk
could eat the snake or the mouse. In this food
web, how would we categorize the hawk?
1.
2.
3.
4.
5.
6.
Producer
Primary consumer
Secondary consumer
Tertiary consumer
Quaternary consumer
4 and 5
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Take-home message
•
•
•
Energy from the sun passes through an ecosystem in
several steps.
First, it is converted to chemical energy in
photosynthesis.
Herbivores then consume the primary producers, the
herbivores are consumed by carnivores, and the
carnivores, in turn, may be consumed by top carnivores.
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Take-home message
•
•
Detritivores and decomposers extract energy from
organic waste and the remains of organisms that have
died.
At each step in a food chain, some usable energy is lost
as heat.
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Energy and chemicals flow within
ecosystems
Energy pyramids reveal the inefficiency of
food chains.
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Biomass
• biomass: total weight of all living organisms in a given
area
• only about 10% of the plants in an ecosystem is
converted into biomass
• Food Energy Pyramid
• flow of energy through a food chain
• trophic level: position that an organism occupies in a
food chain - what it eats, and what eats it
• African savannas and grasslands sustain more species
of higher-order carnivores than any other terrestrial
ecosystem
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Food Energy Pyramids
•
•
flow of energy through a food chain
trophic level: position that an organism occupies in a
food chain - what it eats, and what eats it
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107
108
You go out to eat at a fancy restaurant. You
have a salad, salmon, and for dessert ice
cream! Which part of the meal was the most
energy efficient food for you to eat?
1.
2.
3.
4.
Salad
Salmon
Ice cream
2 and 3
109
Take-home message
•
•
•
•
Energy from the sun passes through an ecosystem in
several steps known as trophic levels.
Energy pyramids reveal that the biomass of primary
producers in an ecosystem tends to be far greater than
the biomass of herbivores.
The biomass transferred at each step along the food
chain tends to be only about 10% of the biomass of the
organisms being consumed, due to energy lost in cellular
respiration.
As a consequence of this inefficiency, food chains rarely
exceed four levels.
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Energy and chemicals flow within
ecosystems
Essential chemicals cycle through
ecosystems.
111
Chemical Reservoirs
•
Each chemical is stored in a non-living part of the
environment.
•
Organisms acquire the chemical from the reservoir, a
non-living part of the environment.
•
The chemical cycles through the food chain
(biogeochemical cycles).
•
Eventually, the chemical is returned to the reservoir.
112
Hydrologic Cycle and the Florida Springs
•
Click here for a description of how falling rain feeds
underground aquifers in Florida and forms springs.
113
The Most Important Chemical Cycles
1)
2)
3)
4)
Carbon
Nitrogen
Phosphorus
Sulfur
114
The
Carbon
Cycle
115
The Carbon Cycle
116
Keeping Up With Carbon
NASA video provides key information on the
carbon cycle.
117
Carbon Cycle Game
118
Fossil Fuels
•
•
•
created when large numbers of organisms die and are
buried in sediment lacking oxygen
In absence of oxygen, at high pressures, and after very
long periods of time, organic remains are ultimately
transformed into coal, oil, and natural gas
burning coal, oil, and natural gas releases large amounts
of carbon dioxide
• increases average CO2 concentration in the
atmosphere
• current level of CO2 in the atmosphere is the highest it
has been in almost half a million years
119
Global CO2 levels are rising in
general, but they also exhibit a
sharp rise and fall within each
year – why?
120
The Nitrogen Cycle
121
The Nitrogen Cycle
122
Fertilizers
• Because it is necessary for the production of every plant
protein, and because all nitrogen must first be made
usable by bacteria, plant growth is often limited by
nitrogen levels in the soil.
• For this reason, most fertilizers contain nitrogen in a
form usable by plants.
123
124
125
126
Oxygen reduction downstream of a source of
organic pollution
127
Algal growth and eutrophication in an Australian
outback waterway
128
129
Sulfur Cycle
•
•
•
•
component of protein
cycles in both a gas and sedimentary cycle
source : earth's crust
enters the atmosphere as hydrogen sulfide (H2S)
during fossil fuel combustion, volcanic eruptions,
gas exchange at ocean surfaces, decomposition
130
Sulfur Cycle
•
•
•
H2S is immediately oxidized to sulfur dioxide (SO2)
SO2 + water vapor  H2SO4 (falls to earth in rain)
sulfur in soluble form is taken up by plant roots,
incorporated into amino acids such as cysteine
•
travels through food chain
•
eventually released through decomposition
131
How is carbon recycled back to the
atmosphere in the carbon cycle?
1.
2.
3.
4.
5.
It is “fixed” by bacteria.
It is a product of cellular respiration.
Burning of fossil fuels.
2 and 3.
All of the above.
132
Why do commercial fertilizers usually
contain usable forms of nitrogen and
phosphorous?
1. These chemicals are not efficiently recycled in
the soil.
2. Nitrogen and phosphorous need to be “fixed”
by bacteria or the plant.
3. Nitrogen and phosphorous are found at high
levels in the atmosphere but not in the soil.
4. Nitrogen and phosphorous only enter the soil
through erosion.
133
Take-home message
•
•
•
Chemicals essential to life—including carbon,
nitrogen, and phosphorus—cycle through
ecosystems.
They are usually captured from the atmosphere,
soil, or water by growing organisms; passed from
one trophic level to the next as organisms eat other
organisms; and returned to the environment through
respiration, decomposition, and erosion.
These cycles can be disrupted as human activities
significantly increase the amounts of the chemicals
utilized or released to the environment.
134
Symbiotic Relationships
•
•
•
•
•
•
•
Symbiosis: close relationship between organisms of
two different species
At least one participant gains some sort of benefit
(usually nutritional)
Types of symbiosis:
Parasitism
Commensalism
Mutualism
Predation
135
Symbiotic Relationships in the
Ocean
•
Click here for an explanation of the
relationships of marine animals,
including sharks, rays, and various
fishes.
136
Parasitism
•
•
Parasite derives nutrition from the host
This harms the host but a true parasite does
not usually kill its host (directly)
137
Ectoparasites
Remain outside the host
Ticks, fleas, leeches
138
Endoparasites
Live inside the host’s body
Tapeworms, malarial parasites
139
Parasite Transmission
•
•
Many parasites live on or in a single organism
Some will alternate between 2 or more host species
•
Vertical transmission – from mother  offspring
•
Horizontal transmission – between members of a
population
•
Direct contact (head lice)
•
Vectors (mosquitos)
140
141
Commensalism
•
•
•
•
Neither species is totally dependent on the other
One benefits – no effect on the other
Feeding or protection
Porcelain anemone crabs and anemones
142
Mutualism
•
•
•
•
•
•
•
•
•
Both species benefit
Food or shelter
Examples:
Plants and microbes (rhizobium in root nodules)
Plants and fungi (orchids and mycorrhizae)
Protists and fungi (lichen)
Plants and insects (pollination)
Animals and bacteria (ruminants)
Animals and other animals (crocodiles and
plover birds)
143
Mutualism, shrimp and moray
Cleaner shrimp cleaning a zebra moray eel. Mutualistic
relationships such as these promote the well-being of the
host fishes and provide food for those that do the cleaning.144
Rhizobium
Rhizobium in root nodules of certain plants convert
nitrogen in soil to usable form.
145
Orchid/ Mycorrhizae
Fungi aid the plant in the uptake of nutrients.
Fungi ingest some of the food from plant
photosynthesis
146
Lichen
Most of the lichen is composed of fungal filaments,
but living among the filaments are algal cells,
usually from a green alga or a cyanobacterium.
The lichen fungus provides its partner(s) a benefit
(protection) and gains nutrients in return.
147
Ruminants
Ruminants are characterized by their four-chambered
stomach and "cud-chewing" behavior. Cud is a food bolus
that is regurgitated, rechewed, and reswallowed. The
rumen is a large fermentation vat containing billions of
microorganisms, including bacteria and protozoa, which
allow ruminants to digest fibrous feeds such as grass and
hay that other animals cannot efficiently utilize.
148
Crocodiles &
Plover Birds
The bird gets into the crocodile's mouth and picks out
the tiny bits of food stuck in his teeth, then eats it (the
tiny bits).
This cleans the crocodile's teeth and keeps his mouth
fresh and free from infections.
149
Predation
•
Consumption of one living organism by
another
• Predators must have offensive strategies
• ways of finding, catching, and eating
their prey
• Prey organisms must have defensive
strategies
• ways of avoiding or discouraging this
activity
150
Predation
•
Encompasses all levels within an
ecological food chain/web
• plant-herbivore systems
• herbivore-carnivore systems
• three-way interactions of
interdependent plant-herbivorecarnivore systems
151
This goshawk is the tertiary consumer in his ecosystem,
and the mouse in his beak is the secondary consumer.
Beneath the mouse on the ecological pyramid lies his
foodsource, likely a worm, which fed on the primary
producer, leafy plants.
152
Ecosystem of Life in Florida's
Springs
•
Click here for a close-up look of life
in Florida's springs and the various
predator-prey interactions there.
153