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Ecology
The first law of ecology is that everything is
related to everything else.
~Barry Commoner
Warm-Up
• Do this on your OUTPUT side!
• Think of your favorite outdoor spot.
• List all of the living things that exist there.
• List all of the non-living aspects of your
experience there.
The Biosphere
Chapter 34
Concept 34.1
• The biosphere is the global ecosystem.
• Key Terms
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Ecology
Biotic factor
Abiotic factor
Population
Community
Ecosystem
Biosphere
Habitat
The Study of Ecology
• Ecology
• Study of
interactions
among organisms
and their
environments
• Biotic vs. Abiotic
Ecological Relationships
• Classified by broad levels:
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Organisms
Populations
Communities
Ecosytems
Biosphere
Individual Organisms
• Smallest unit of
ecological study
• Ecologists ask
questions about the
adaptations that enable
individuals to meet the
challenge of their
environment
Populations
• Group of the individual
organisms of the same
species living in a
particular area
• Ecologists often ask
questions about factors
that affect the size and
growth of a population
Communities
• All of the organisms
inhabiting a particular
area
• Ecologists investigate
interactions among all
of the organisms in a
community
Ecosystems
• Includes the biotic and
abiotic factors in an area
• Questions at the
ecosystem level may
relate to the flow of
energy and chemicals
Biosphere
• Broadest of all levels of
ecological study
• Sum of all of the Earth’s
ecosystems
• Questions at the biosphere
level involve global issues,
such as investigating the
effects of climate change on
living things
Patchiness of the Biosphere
• Differences in the abiotic factors of a
location leads to a “patchy” appearance
like a quilt
• Each of these “patches” are different
habitats for organisms to live in
Chlorophyll Concentrations
Key Abiotic Factors
• Sunlight
• Provides light and
warmth and is an energy
source for all ecosystems
• Water
• Essential to all life on
Earth – all organisms
contain water
• Temperature
• Life exists at a very
narrow range of
temperatures (0-50°C)
• Soil
• Product of abiotic
forces and the actions
of living things
• Wind
• Can affect the
distribution and
activities of organisms
• Severe Disturbances
• Naturally affect the
ecosystems – fire,
hurricanes, droughts,
Concept 34.2
• Climate determines global patterns in the biosphere.
• Key Terms
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Tropics
Polar zones
Temperate zones
Current
Microclimate
Uneven Heating of the Earth’s Surface
• The angle that the
sun’s rays hit the
Earth causes different
temperature gradients
• Tropics
• Polar Zones
• Temperate Zones
Wind, Precipitation & Ocean Currents
• Global wind patterns and Earth’s
rotation create warm and cold surface
currents in the oceans
• These surface currents affect the climate
on the continents
Local Climate
• Local climate
can be
affected by:
• Bodies of
Water
• Mountains
Microclimate
• Climate in a specific area that
varies from the surrounding
climate region
• Microclimates can be created by:
• Shade
• Snow cover
• Windbreaks
Concept 34.3
• Biomes are the major types of terrestrial ecosystems.
• Key Terms
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Biome
Tropical rain forest
Savanna
Desert
Chapparral
Temperate grassland
Temperate deciduous forest
Coniferous forest
Tundra
Permafrost
What is a Biome?
• Major types of terrestrial ecosystems that
cover large areas of Earth
• Biomes are characterized by communities of
plants and other organisms that are adapted to
its climate and other abiotic factors
Tropical Rainforest
• Characterized by tall
trees
• Treetops = Canopy
• Contain epiphytes
• Don’t get enough sunlight
at the floor of the
rainforest
• Often live on the branches
of tall trees
• Not parasitic because they
make their own food
Tropical Rainforest
• Highest species richness
• 1 Hectare = 300 species
• Temperate forest
• 1 Hectare = 10 species
• Animals:
• Sloth, colorful birds,
monkeys, snakes, and
lizards
• Maybe be 8 million
species of beetles in the
rain forest
Savanna
• Tropical or subtropical
grasslands with
scattered trees and
shrubs
• Alternating wet and
dry seasons
• More rain than deserts
• Less rain than
rainforests
Savanna
• Animals:
• Zebras, giraffes,
and gazelles
• Lions, leopards,
and cheetahs
Desert
• Receive less than 25
cm of rainfall per year
• Deserts are NOT hot
all the time
• Desert vegetation is
often sparse and
consists of plants that
have adapted to the
dry climate
Desert
• Plant adaptations:
• Waxy coating
• Protective spines
• Plants and animals
have adaptations to
conserve what little
water they receive
• Animals:
• Kit foxes, snakes, and
lizards
Chaparral
• Dominated by dense
evergreen shrubs
• Dry climate consists
of mild, rainy winters
and hot, dry
summers
Chaparral
• Chaparral’s dry,
woody shrubs
often ignite by
lightning and are
adapted to survive
periodic brushfires
Temperate Grassland
• Form in the interior of
continents, at about the
same latitude of
temperate deciduous
forests
• Known by different
names in different
places:
• Prairie = N. America
• Steppes = Asia
• Pampas = S. America
• Veldt = Africa
Temperate Grassland
• Because of its rich soil –
grasslands have been
transformed into
farmland for crops such
as wheat and corn
• Very little undisturbed
portions of the
grasslands in the world
Temperate Deciduous Forest
• Characterized by
trees who lose their
leaves in the fall
• These regions have
pronounced seasons,
with precipitation
throughout the year
Temperate Deciduous Forest
• Animals:
• Deer, foxes, squirrels,
and raccoons
• Large areas of temperate
deciduous forests have
been cut down for timber
or cleared to make room
for farms, towns, and
cities
Coniferous Forest / Taiga
• South of the tundra
• Dominated by conebearing trees (pines,
firs, hemlocks, and
spruce)
• Plants in the taiga are
adapted to long and cold
winters, short summers,
and nutrient-poor soils
Coniferous Forest / Taiga
• Typical animals:
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Moose
Bears
Wolves
Lynx
• Some animals stay in the
forest year-long
• Many species hibernate
6-8 months of the year
Tundra
• Cold and largely
treeless, surface
covered with
permafrost
(permanently
frozen soil)
• Receives little
precipitation
Tundra
• Tundra plants are
usually small and
grow slowly
• Grasses, sedges, and
mosses
• Animals
• Caribou, musk oxen,
snowy owls, artic
foxes, lemmings, and
snowshoe hairs
Concept 34.4
• Aquatic ecosystems make up most of the biosphere.
• Key Terms
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Photic zone
Phytoplankton
Aphotic zone
Benthic zone
Estuary
Pelagic zone
Intertidal zone
Neritic zone
Oceanic zone
Zooplankton
Hydrothermal vent
Aquatic Ecosystems
• Water covers ¾ of the Earth and is home to
a variety of organisms
• Freshwater zones
• Lakes and ponds
• Rivers and streams
• Estuaries
• Ocean zones
• Intertidal zone
• Neritic zone
• Oceanic zone
Freshwater Zones
• Low levels of salt (0.0005% salinity)
• Freshwater ecosystems include:
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Lakes
Ponds
Streams
Rivers
Lakes and Ponds
• Freshwater Lakes and Ponds support:
• Otters, Muskrats, Birds (Ducks and Loons), and Fish
• Eutrophic
• Rich in organic matter and vegetation
• Water is relatively murky
• Oligotrophic
• Very little organic matter
• Water is much clearer, bottom is usually sandy or
rocky
Lakes and Ponds
Rivers and Streams
• Body of water that flows down a gradient towards its
mouth
• Water flows swiftly down steep gradients, organisms
are adapted to withstand powerful currents
• Brook trout face upstream to catch passing drifting
invertebrates
• Slow-moving rivers and backwaters are richer in
nutrients and support more life
• Rooted plants and fishes are adapted to weaker currents in
slow-moving rivers
Rivers and Streams
Estuaries
• Place where freshwater meets sea water
• Examples:
• Bays
• Mud flats
• Salt marshes
• Inhabitants are adapted for frequent changes
• Mangrove trees have salt glands that secrete salt
from salt water
Estuaries
Ocean Zones
• The ocean covers 70% of the Earth’s surface,
with an average depth of 3.7 km
• At the deepest parts the depth is 11km deep
• Different Oceanic Zones
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Aphotic – cold and dark, no sunlight
Photic – receives sunlight
Intertidal – along the oceanic shore, tides rise and fall
Neritic – relatively shallow, just beyond the intertidal
zone
• Pelagic – open ocean
• Benthic – ocean bottom
Ocean Zones
Oceanic Zones
Intertidal Zone
• Organisms in this zone are adapted to
periodic exposure to air during low tide
• Crabs avoid dehydration by burrowing into the
sand or mud
• Organisms in this zone must be able to
withstand the force of crashing waves
• Sea anemones cling to rocks
• Sea stars use tube feet to adhere to surface
Intertidal Zone
Neritic Zone
• Most productive zone of the ocean
• Waters are rich in plankton
• Coral reefs are productive and rich in species
• Animals:
• Many species of fish
• Crustaceans
• Mollusks
Neritic Zone
Oceanic Zone
• Fewer species than neritic zone
• Half of the photosynthesis that occurs
on Earth takes place in oceanic zone
• Producers of the upper parts are
protists and bacteria in the plankton
Oceanic Zone
• In the aphotic zone, animals feed mostly on
sinking plankton and dead organisms
• Deep-sea organisms must cope with the near
freezing temperature and crushing pressure
• Deep sea vents lead to adaptations from
organisms -> Deep sea tube worms
Oceanic Zone
Population and
Community Ecology
Chapter 35
WARM - UP
How many
species are
there?
Concept 35.1
• A population is a local group of organisms
of ONE species.
• Key Terms
• Population density
What is a Population?
• Alligators living in a
swamp make up a
population—members of
the same species living in
a specific geographic area.
• Other populations in the
swamp include diverse
species of trees, egrets and
other birds, and the
various species of fishes,
algae, and microorganisms
in the swamp water.
Defining Populations
• Several factors influence a
population's size and how much it
changes over time. They include
the availability of food and space,
weather conditions, and breeding
patterns.
• In studying how these factors
affect a population, ecologists need
to define the population's
geographic boundaries.
• Natural
• Artificial
Population Density
• Population density is the number of individuals of
a particular species per unit area or volume.
• The number of alligators per square kilometer of
swamp, the number of bacteria per square centimeter of
an agar plate, and the number of earthworms per cubic
meter of soil are all examples of population density
measurements.
Population density = Individuals = 1000 trees = 20 trees
Unit area
50 km2
1 km2
Sampling Techniques
• It usually isn't practical to count every member of a
population. There may be too many individuals, or
they may move around too quickly to be counted
accurately, as with many species of insects, birds,
and fish.
• In such cases, ecologists use a variety of sampling
techniques to estimate the size of the population.
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Quadrats
Indirect Counting
Mark-Recapture
Limits to Accuracy
Sampling Techniques
• Quadrats
• One method is to mark off a
particular area, then count the
number of a particular species
within this boundary
• After repeating this procedure
in several locations within the
ecosystem, ecologists average
their results to estimate the
population density of this
species in the ecosystem
Sampling Techniques
• Indirect Counts
• A sampling technique
for organisms that move
around a lot or are
difficult to see is
indirect counting
• This method involves
counting nests, burrows,
or tracks rather than the
organisms themselves
Sampling Techniques
• Mark-Recapture
• The biologist traps animals in the study area and marks
them, such as with a drop of colored dye.
• The researcher then releases the marked individuals.
• After a period of time, the researcher again captures
animals from the population and counts the marked and
unmarked individuals in the second sample.
Total population =
# in 1st capture * # in 2nd capture
# of marked animals recaptured
Mark-Recapture
Limits to Accuracy
• Most sampling techniques involve making some
assumptions about the population being studied. If
these assumptions are not valid, then the estimate
will not be accurate.
• For example, the quadrat method assumes that organisms
are distributed fairly evenly throughout the study area.
• The mark-recapture technique assumes that both marked
and unmarked animals have the same chance of surviving
and of being caught in the second capture.
Warm-Up
• Charles Darwin
calculated that a single
pair of elephants could
increase to a population
of 19 million
individuals within 750
years.
• Why isn’t the world
overrun with elephants?
• What type of factors may
have influenced the
population growth of the
elephants?
Concept 35.2
• There are limits to population growth.
• Key Terms
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Exponential growth
Limiting factor
Carrying capacity
Density-dependent factor
Density-independent factor
Population Dispersion
• Spatial distribution of organisms (spacing)
• Clumped
• Even
• Random
Clumped Distribution
• Individuals are clustered
together
• Occurs when resources
such as food and living
space are clumped
together
• Occurs also with social
behavior
• Fish in schools
• Birds in flocks
Even Distribution
• Results from social
interactions where
individuals are trying
to get as far away
from each other as
possible
• Gannets staking claim
on a specific area of
the coast from its
neighbors
Random Distribution
• Results from seed
dispersal by the
wind or birds
• Forests
• Wildflowers
Population Dynamics
• All populations are dynamic – they change
in size and composition over time
• In order to understand these changes – you
need to look at:
• Birth rate
• Death (Mortality) rate
• Life Expectancy
Birth vs. Death (Mortality) Rates
• Number of births occurring in a period of time
• In the United States there are 4 million births per year
• Number of deaths occurring in a period of time
• In the United States there are 2.4 million deaths per year
• The average length an individual is expected to live
• In the United States in 1996, the life expectancy for a man
was 72 years, and for a woman is was 79 years
Patterns of Mortality
• The mortality rate of different species tend
to conform to one of three curves on a graph
• These curves are called “survivorship
curves” because they show the likelihood of
survival at different ages throughout the
lifetime of an organism
Survivorship Curves
• Red = Type I
• Likelihood of dying is small until
later in life
• Humans & elephants
• Green = Type II
• Probability of dying does not
change, is constant
• Bird species
• Blue = Type III
• Many organisms die young, the
few who survive live long lives
• Oysters, salmon, and insects
Population Growth Rate
• Demographers = scientists who study population
dynamics
• Growth rate of a population = the amount by which a
population’s size changes in a given time
• Whether a population grows, shrinks, or remains the
same size depends on four processes.
• Birth, Death, Immigration, and Emigration
Population Growth Processes
• Birth and Immigration add to a population
• Death and Emigration subtract individuals
from a population
• Birth rate – Death rate = Growth rate
Exponential Growth (J-shaped)
• Population increases rapidly after
only a few generations; the larger a
population gets, the faster it grows
• We can predict that the population
will grow indefinitely and at an
increasingly rapid rate based on this
model
• Limitations = populations can only
grow indefinitely with unlimited
resources
Logistic Model (S-shaped)
• Builds on the Exponential
Model by accounting for the
influence of limiting factors
• Employs K (carrying
capacity)
• The number of individuals the
environment can support over a
long period of time
Limiting Factors
• Factors that restrain the
growth of a population
• Resources depleted or
shrinking
• Waste build-up
• Competition among
individuals
2 Types of Limiting Factors
• Density-independent
• Reduces the population by the same proportion,
regardless of the population’s size
• Examples: weather, flood, fires
• Density-dependent
• Resource limitations (such as food shortages or
nesting sites) are triggered by increasing
population density
Population Fluctuations
• Population
fluctuations are
linked to
environmental
changes.
• Lynx and
Snowshoe hares
Perils of Small Populations
• Rapidly growing human
population has caused
extreme reductions in the
populations of some other
species and subspecies
• Siberian tigers – less than 200
left in the wild due to over
hunting and habitat
destruction
• California condors – by the
1980’s, the condor’s wild
population was down to 9
individuals
More Perils of Small Populations
• Small populations are
more vulnerable to
extinction due to:
• Environmental
disturbances (storms,
fires, floods, or diseases)
• Inbreeding – lack of
genetic variability
• More susceptible to
diseases and have a
shorter life span
• Example: Cheetahs
Concept 35.3
• Biologists are trying to predict the impact of
human growth on the world.
• Key Terms
• Age Structure
Age Structure
• The distribution of individuals among different
ages in a population
• Populations with a high percentage of young
individuals have a greater potential for rapid
growth
Population Age Structures
History of Human Population Growth
• Until 10,000-12,000 years
ago the human population
grew very slowly
• Hunter-gatherer lifestyle
• Low population
growth rate due to
small populations and
high mortality rates
• Infants and young
children rarely reached
reproductive maturity
Development of Agriculture
• Humans learned how to
domesticate animals and cultivate
plants for food
• Change from hunter-gatherer to
agriculturists
• Called the Agricultural
Revolution
• Increase in available food supply
• Human population grew faster
Population Explosion
• Human population growth accelerated after
1650 because of a sharp decline in death rates
• Reason for decline:
• Better sanitation
• Increased availability of food
• Improved economic conditions
Human Population Growth
• It took most of human
history for the
population to reach 1
billion (1800),
however it only took
27 years (1960-1987)
for the population to
grow from 3 billion to
5 billion
Population Growth Today
• Even though birth rates have decreased, the
population is still increasing
• 20% of the population live in developed countries
• U.S., Japan, Germany, France, United Kingdom,
Australia, Canada, and Russia
• Better educated, healthier, and live longer
• 80% of the population live in developing countries
• Central America, South America, Africa
• Poorer, populations grow much faster
The Future of the Human Population
• Human population growth will
eventually stop, however we do
not know when
• How large will the population be?
• Will the planet be able to support
the population over a long period
of time?
• The answer to these questions
will depend on whether we use
our resources wisely
Human Populations Lab
Demographics Lab
You can look
at cemeteries
in order to
document
trends in
human
populations
In this lab you will
calculate the age of
individuals located
in 4 different plots
in a cemetery
After calculating the
ages, you will
document the data
on a data table and
graph your results
Concept 35.4
• Species interact in biological communities.
• Key Terms
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Interspecific competition
Competitive exclusion
Niche
Predation
Symbiotic relationship
Parasitism
Mutualism
Commensalism
Symbioses
• 5 Major Types of Close Interactions
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Predation
Parasitism
Competition
Mutualism
Commensalism
Predation
• Predators capture, kill, and consume another
individual, the prey
• Natural Selection favors adaptations that
improve the efficiency of predators in finding,
capturing, and consuming their prey
• Natural Selection favors adaptations that allow
prey to avoid, escape, or ward off predators
Predators & Prey
• Example:
• Rattlesnakes have
adaptations for
locating their prey
(frogs, etc) with an
acute sense of smell
and with specialized
heat sensitive pits
located below each
nostril
Mimicry
• Deception is important in anti-predator
defenses
• Two types of Mimicry
• A harmless species resembles a poisonous
or distasteful species
• Two or more dangerous species look
similar so that when a predator encounters
one it will avoid similar individuals
Mimicry in action…
• Can you see the
mantis in the pictures?
Mimicry in action…
• The scarlet king snake
(top) mimics the
pattern of the eastern
coral snake (bottom)
so that predators will
avoid it
• Scarlet King Snake =
non-poisonous
• Eastern Coral Snake =
poisonous
Toxic Prey
• This poison arrow
frog escapes
predation
because its bright
colors signify a
toxic taste
Plant vs. Herbivore Interactions
• Some plants develop adaptations to avoid
animals that eat plants (herbivores)
• Physical defenses – sharp thorns, spines, sticky
hairs, and tough leaves
• Chemical defenses – secondary compounds
that are poisonous, irritating, or bad-tasting
• Strychnine and nicotine (toxic to insects)
• Poison ivy and oak produce a skin-irritating substance
• Drugs like morphine, atropine, codeine, taxol, and quinine
are derived from secondary compounds
Parasitism
• Species interaction that resembles predation,
where one individual is harmed and the other
benefits; however, the parasite feeds on the
other individual (the host)
• While most forms of predation removes an
organism from the population, parasitism does
not result in the immediate death of the host
• Often the parasite feeds off of the host for a long
time instead of killing it
Ectoparasites
• External parasites – live
ON their host and do not
enter the host’s body
• Examples:
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Ticks
Fleas
Lice
Lampreys
Leeches
Mosquitoes
Endoparasites
• Internal parasites – live
INSIDE the host’s body
• Examples:
• Disease-causing bacteria
• Protists (like malaria
parasites)
• Tapeworms
Parasite Adaptations
• Parasites have specialized anatomy and
physiology
• Example: The tapeworm doesn’t even have a
digestive system – instead they absorb nutrients
through their skin
• Host Adaptations:
• Skin is an important defense against parasites
• Openings (eyes, mouth, and nose) are defended
chemically by tears, saliva, and mucus
Competition
• Results from a niche overlap – where resources
are used by two or more species
• Interspecific Competition – species compete for
the same resources
• Savanna Grasslands
• First studies on competition were performed by
G.F. Gause on two species of paramecia
Competitive Exclusion
• Joseph Connell’s study on barnacles
(Balanus and Chthamalus)
• Two species of barnacles competing for
space on the rocks
• Balanus crowded out the Chthamalus in
the lower tidal zone
Competitive Exclusion
• The composition of a community may change
through competitive exclusion
• Competitors may adapt niche differences or
anatomical differences that lessen the
intensity of competition
• These differences are often greatest where the
ranges of potential competitors overlap
• Called character displacement
Adaptive Radiation
• Darwin’s Finches
• Example of character
displacement because
their beak differences
allow for them to feed on
different foods and in
turn reduce competition
• Resource Partitioning
Mutualism
• Cooperative relationship in which both species
derive some benefit from the relationship
• Some mutualistic relationships are so close that
neither species can survive without the other
• Pollination is a mutualistic relationship
• Animals feed on the flower
• Animal is covered with pollen and carries it to other
flowers and pollinates them
Mutualism
• Lichens
• Made up of a
fungi and an
algae
• Coral polyps
contain
dinoflagellates
Commensalism
• Commensalism is an
interaction in which
one species benefits
and the other is not
affected
• Example:
• Clown Fish and Sea
Anemone
Concept 35.5
• Disturbances are common in communities.
• Key Terms:
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Ecological succession
Primary succession
Secondary succession
Introduced species
Species Richness vs. Diversity
• Species Richness
• The number of species a community contains
• Counts the species in a community
• Species Diversity
• The number of species in a community and the
relative abundance of the species in the
community
• Suggests the species’ importance because it takes
into account how common the species is in the
community
Patterns of Species Richness
• Varies with Latitude
• The closer to the Equator = more species
• Hypotheses:
• Temperate habitats are younger, due to the ice age
• Climate is more stable in the tropics
• Plants can photosynthesize all year long in the
tropics, allowing more food to support more
organisms
Species/Area Effect
• Larger areas contain more species
than smaller areas
• Larger areas usually contain a greater
diversity of habitats and can support
more species
Reducing the size
of the habitat
reduces the number
of species is can support
Species Interaction and
Species Richness
• Interactions among species (Symbioses)
promote species richness
• Predators can prevent competitive
exclusion
• Example:
• Pisaster
Pisaster vs. Mytilus
Community Stability
• Community Stability = A community’s
resistance to change
• Species richness improves community stability
• Grass plots with more species took less time to
recover from drought
• Grass plots with more species lost a smaller
percentage of land mass than plots with less species
Succession
• Disturbances such as fires, landslides,
hurricanes, and floods trigger a
sequence of changes in communities
• The gradual, sequential re-growth of
species in an area is called succession
Disturbances to Communities
• Large scale
• Small scale
Primary Succession
• Development of a community in an area that
has NOT supported life previously, such as bare
rock, sand dunes, or an island formed by
volcanic eruptions
• Proceeds very slowly because minerals
necessary for plant growth is unavailable
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•
•
•
Lichens
Plants
Trees
Pine, Balsam, and Spruce Forests
Secondary Succession
• Sequential replacement of species that follow
disruption of an existing community
• May stem from a natural disaster (forest fire or a strong
storm)
• Could happen following human activities (farming, logging,
and mining)
• Commonly takes about 100 years for the original
ecosystem to return through a series of well-defined
stages
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•
•
•
Annual grasses (dandelions, grasses)
Perennial grasses and shrubs
Trees
Deciduous forest
Pioneer Species vs. Climax Community
• Pioneer Species
• The species that predominates early in succession
• Tends to be small, fast-growing, and fastreproducing
• Climax Community => Stable End Point
• The organisms in each stage alter the physical
environment in ways that make it less favorable for
their own survival, but more favorable for the
organisms that succeed them
Human Activities &
Species Diversity
• Clearing the Land
• Forests cleared for
farmland or housing
• Introduced Species
• Kudzu – introduced to
help stop erosion
• Grew out of control
and took over the
landscape
Ecosystems and
Conservation Biology
Chapter 36
Concept 36.1
Feeding relationships determine the path of
energy and chemicals in the ecosystems.
• Key Terms
•
•
•
•
•
•
Producer
Consumer
Decomposer
Trophic level
Food chain
Herbivore
•
•
•
•
•
•
•
Carnivore
Omnivore
Primary consumer
Secondary consumer
Tertiary consumer
Detritus
Food web
Energy Flow & Chemical Cycling
Concept 36.2
• Energy flows through ecosystems.
• Key Terms
•
•
•
•
•
Biomass
Primary productivity
Energy pyramid
Biomass pyramid
Pyramid of numbers
Energy Flow
• Energy is passed from one organism to
another in the ecosystem
• In order to follow the energy flow we
group organisms based on how they
obtain energy
• Trophic Levels
Trophic Level
• The organism’s position in the
sequence of energy transfer
• Most ecosystems contain only 3-4
trophic levels
Energy Transfer
• Food Chain
• Single pathway of feeding relationships
• Ex. Grass seeds -> Mouse -> Snake -> Hawk
• Food Web
• Linking of 2 or more food chains
Food
Chains
Food
Webs
Energy Pyramid
Biomass Pyramids
Output Assignment
• Design 3 Food Chains
• Must have at least 3 individual organisms
• Incorporate those 3 Food Chains into a
Food Web
• Create a meal for a human that
incorporates 2 different Trophic levels
Concept 36.3
• Chemicals cycle in ecosystems.
• Key Terms
• Nitrogen Fixation
• Nitrification
• Transpiration
KWLH Chart – Output WarmUp
• Before Taking Notes:
• Write down 3 things you KNOW about any of
the biogeochemical cycles
• Write down 3 things you WANT to find out
about the biogeochemical cycles
Ecosystem Cycles
• Energy flows through the ecosystem and is
recycled and reused
• Each substance travels through a
biogeochemical cycle
•
•
•
•
Water Cycle
Carbon Cycle
Oxygen Cycle
Nitrogen Cycle
Basic Pattern of Chemical Cycling
• Producers incorporate chemicals from the nonliving environment into organic compounds
• Consumers feed on the producers, incorporating
some of those chemicals into their own bodies and
releasing some back into the environment as waste
products
• As organisms die, decomposers break them down,
further supplying the soil, water, and air with
chemicals in inorganic form
Water Cycle
• Cells contain 70-90% water
• Found in a number of places in the
environment
• Cells
• Ground water
• Water vapor in the atmosphere
• Evaporation
• Adds water to the atmosphere as water vapor
• Heat causes water to evaporate from bodies of water,
the soil, and living things
• Transpiration
• Plants take in water through their roots and it is
released from their leaves into the atmosphere
• Animals drink water and then release it when they
breathe, sweat or excrete
• Precipitation
• Water is leaving the atmosphere via rain, snow, sleet,
hail or fog
Carbon-Dioxide & Oxygen Cycles
• Two processes...
• Photosynthesis
• Plants and other autotrophs use carbon dioxide
with water and sunlight to make carbohydrates
• Cellular Respiration
• Autotrophs and Heterotrophs use oxygen to break
down carbohydrates into water and carbon dioxide
Human Influence on the Carbon Cycle
Burning fossil fuels adds carbon dioxide
into the atmosphere
+
Destruction of vegetation (clear-cutting)
=
Less carbon cycling
Nitrogen Cycle
• All organisms need nitrogen to make
proteins and nucleic acids
• Plants absorb nitrates from the soil
• Animals obtain nitrogen by eating plants
and digesting the proteins and nucleic
acids
• 78% of the atmosphere = Nitrogen
Nitrogen Cycle…
• Nitrogen Fixation
• Converts nitrogen gas to nitrate
• Nitrogen-fixing bacteria convert N2 gas into
ammonia, then nitrite, then nitrate, which
plants can use
• Ammonification
• Decomposers break down the corpses and
wastes of organisms and release the
nitrogen that they contain as ammonia
Nitrogen Cycle…
• Nitrification
• Bacteria in the soil take up ammonia and
oxidize it into nitrites and nitrates
• Denitrification
• Anaerobic bacteria break down nitrates and
release nitrogen gas back into the
atmosphere
KWLH Chart – Output WarmUp
• After Taking Notes:
• Write down 3 things you LEARNED about the
biogeochemical cycles
• Write down 3 ideas of HOW we can learn
more about the biogeochemical cycles
Concept 36.4
• Human activities can alter ecosystems.
• Key Terms
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•
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Deforestation
Greenhouse effect
Global warming
Eutrophication
Acid rain
Pollution
Biological magnification
Ozone
Impact on Chemical Cycles
• Human activities can affect chemical cycles by
moving the nutrients from place to place
• Deer – eats plants in a forest and returns the
waste to the same location
• Humans – eat a salad and then their waste may
be carried out to the ocean
Carbon Cycle Impacts
• Burning of wood and fossil fuels increase carbon
dioxide in the atmosphere
• Deforestation – eliminated plants that use carbon
dioxide for photosynthesis
• Greenhouse effect – process in which atmospheric
gases trap heat
• Global warming – overall rise in Earth’s temperature
Greenhouse Effect
Nitrogen Cycle Impacts
• Human activities move large portions of nitrogen
into the water or air
• Eutrophication
• Fertilizer runs off into a water source causing algae
blooms
• Acid Rain
• Nitrogen and Sulfur combine to create acid rain in the
atmosphere
Eutrophication
Acid Rain
Water Cycle Impact
• Deforestation – Removes trees that
return water to the atmosphere through
transpiration, reduces the amount of
water vapor and changes precipitation
patterns
Other Effects of Pollution
• Pollution – addition of substances to the
environment that results in negative
effects
• Biological Magnification
• Damage to the Ozone Shield
Biological Magnification
• Gradual accumulation of chemicals inside
of an organism because it cannot excrete
the pollutants
• DDT
• Used to combat mosquitoes
• Accumulates in fat cells (lipids) and is
magnified through the food chain
PCB’s & DDT
Damage to the Ozone
• Some pollution affects a gas called
ozone (O3) to break down
• A major contributor to the destruction
of the ozone are chloroflurocarbons
(CFCs) released from aerosol cans,
refrigeration units, and manufacturing
processes
Ozone Hole
& CFC’s
DDT Debate
Are the benefits of DDT worth the costs?
Roles of the debater:
1.
Environmentalist - environmental stance on DDT use
2.
Govt. Official in charge of Environmental Policy
3.
World Health Organization investigating Malaria and
other mosquito-based disease Prevention
Warm-Up
• Brainstorm 3-5 past/present
products that are derived from
threatened species.
• Ex. Taxol, a cancer drug, derived
from yew trees threatened by
deforestation
• Ex. Ivory for piano keys or
jewelry, comes from elephants
threatened by overhunting
• Step beyond blaming humans for
evil/greed:
• Why can protecting threatened
species be a tough issue to
solve?
Concept 36.5
• Conservation biology can slow the loss of
biodiversity.
• Key Terms
•
•
•
•
•
•
Biodiversity
Overexploitation
Conservation biology
Zoned reserve
Buffer zone
Sustainable development
Conservation & Biodiversity
• Conservation = protecting and sustaining resources for
the future
• Biodiversity =
• Variety of life on Earth
• Variety of ecosystems in the biosphere
• Genetic variety among individuals in a species
• Why does it matter?
• Because EVERYTHING is connected!
• If one species was to disappear – it would affect the
entire ecosystem!
Biodiversity:
Importance to Humans
• Source of beauty/inspiration
• Oxygen, food, clothing, and shelter
• Aids in the development of medicines
• 25% of medicine in the U.S. contain substances from plants
• Possibility of discovering new products for human use
• Rosy periwinkle – yields a medicine used to treat 2 forms of
cancer (childhood leukemia & Hodgkin’s disease)
• Deforestation in Madagascar threatens this species
Mass Extinctions
• There are periods in Earth’s history
where mass extinctions caused a
number of species to become extinct
• Signs of another mass extinction taking
place:
• ~11% of the 9,040 known bird species in
the world are endangered
• Of the ~20,000 known plant species in the
U.S., at least 680 species are endangered
• ~20% of the world’s freshwater fish have
either become extinct or are endangered
Threats to Biodiversity
• Conservation Biologists use the acronym
HIPPO to summarize global threats to
biodiversity
•
•
•
•
•
H = Habitat Destruction
I = Introduced Species
P = Pollution
P = Population Growth
O = Overexploitation
Habitat Destruction
• As the human population grows –
more land is needed for agriculture,
roads, and communities
• If an organism that required that
habitat does not adapt or move - it
will not survive
• Some changed to a habitat causes it
to be fragmented (building a road
through a forest) preventing species
from using resources in all parts of
the forest
Introduced Species
• Introduced (non-native)
species often prey on native
species or compete with them
for resources
• Starlings and House Sparrows
competing with native
Bluebirds
Overexploitation
• The practice of
harvesting or hunting to
such a degree that the
small number of
remaining individuals
may not be able to
sustain the population
• Examples:
• Over-fishing
• Poaching
Conservation Biology Approaches
• Goals of Conservation Biology
• Finding solutions
• Carrying out the solutions
• Possible Approaches
•
•
•
•
Focusing on hot spots
Understanding an organism’s habitat
Balancing demands for resources
Planning for a sustainable future
Hot Spots
• Earth’s biodiversity “hot spots” are home to an
enormous variety (2/3 of ALL plant and
vertebrate) of species, many of which are
endangered.
• Biodiversity hot spots also tend to be “hot
spots” for extinction – this makes them a top
priority with conservation biologists, lawmakers,
and local communities working together to
preserve those locations.
Understanding Habitats
• Understanding the
habitat requirements
of a species can help
biologists manage its
existing habitat or
create new habitat
areas
• Red-Cockaded
Woodpecker
Balancing Demands for Resources
• In many cases a tug-of-war exists between
efforts to save species and the economic and
social needs of people
• Should a wooded habitat be conserved in an effort to
save an owl population if it means putting hundreds
of loggers out of work?
• Remember the DDT debate?
• Politicians, townspeople, and conservation
biologist can reach resolutions by reviewing
scientific data, weighing costs and benefits,
looking for alternative solutions, and casting
their votes.
Planning for a Sustainable Future
• Costa Rica has established
8 zoned reserves in an
effort to conserve
biodiversity while meeting
the needs of humans
• People live and work in
the buffer zones
surrounding the park
reserves
Planning for a Sustainable Future
• Many nations, scientific organizations, and
private foundations are working toward a goal of
sustainable development – developing natural
resources so that they can renew themselves
and be available for the future.
• The challenge for individuals and nations is to
find a way to meet the needs of Earth’s human
population, while conserving ecosystems and
resources for the planet’s other populations as
well.
Output – Conclusion
• What types of things could you do in
your life that will impact the
environment in a positive way?