Transcript Document 7574930

5 Levels of Ecological
Organization
 Species- organisms that can
interbreed and produce fertile
offspring
 Population- all the members of 1
species in an area
 Community- every species in an area
 Ecosystem- many communities
 Biosphere- The entire region of Earth
where living things can be found
(many ecosystems)
What is Ecology?
 Study of the interaction between
organisms and their environment
 Within an ecosystem there are two
main components.
habitat- place where organism
lives
community- ALL the species in
habitat
Species Interaction
 Many interactions take
place between species in
a community.
i.e.) predator and
prey
 Each organism plays a
certain role in the
community.
 Niche- role of organism
in which it interacts
with other species and
its environment (i.e. its
job)
Abiotic vs. Biotic Factors
 Abiotic- “non-living”
components
-ex) temperature, light,
water, nutrients, boats
 Biotic- “living” species
-ex) sea turtle, sea grass,
coral, fish, humans
Biodiversity
 Biodiversity-The
number of
different species
in an ecosystem.
 More plants =
more animals
 More biodiversity
= healthier
ecosystem.
What Determines Biodiversity
of Ecosystem?
 Size
 Latitude – Closer to
equator more diverse.
a) More sunlight and
longer growing season
b) More producers
(plants)
Why do we call plants
producers?
c) More producers =
more consumers
 Precipitation (i.e. rainfall)
Conditions for Life
 For an ecosystem to sustain life, it
must have:
1) Constant source of energy (sun).
2) Living system that converts sun’s
energy into organic molecules.
-Producers (plants) Why?
3) Cycling of nutrients between
organisms and environment (water,
carbon dioxide, nitrogen, oxygen).
4) Decomposers return unused
nutrients to the environment.
Photosynthesis Equation
KNOW THIS EQUATION!
Producers are considered autotrophs, or “selffeeders” because they can make their own
“food.”
Consumers are considered heterotrophs, or
“other-feeders” because they have to consume
their food.
Nutritional Interactions
 All ecosystems must have
interactions between
producers, consumers, and
decomposers.
 Producers (autotrophs)
 Consumers (heterotrophs)
-herbivores
-carnivores
-omnivores
-decomposers
Energy flow in an
ecosystem
 Energy flows through an
ecosystem from the sun to
producers to consumers.
 ***Arrows show the way the
energy flows.
“Who Eats Who”…
 Food chain- straight line
sequence shows simple
feeding relationships
 Notice the direction of
the arrows!
 Sun
 Producers
 Primary consumers
 Secondary Consumers
 Tertiary Consumers
 Food webillustrates how the
many food chains in
an ecosystem are
related
 Primary consumers?
 Secondary
consumers?
 Tertiary consumers?
 Where would
decomposers fit in
this food web?
How many trophic levels
are possible…?
 Trophic means “feeding”
 Trophic levels -levels of feeding from
producers (plants) to the consumers
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Few ecosystems have more than 4 or 5 trophic
levels
Energy diminishes at each level because it is
used for life’s processes.
 Energy pyramids- show amount of energy
at each trophic level.
 These are not food pyramids!!
Pyramid of Energy
Which level has the most energy
AVAILABLE?
 TROPHIC
LEVELS
 Producers (most
energy available)autotrophs
 Primary consumersherbivores
 Secondary consumerssmall carnivores
 Tertiary consumerlarge carnivores
 Energy is given off at
every level as waste
heat by the organisms
as they survive.
How do organisms obtain
nutrients?
 Although energy moves through
ecosystems in a one-way direction,
nutrients are recycled.
 Three basic nutrient cycles are
present in all ecosystems allowing
organisms to obtain needed
nutrients to function effectively.
Nitrogen Cycle
The atmosphere contains
80% nitrogen gas (N2).
However, this nitrogen can
not be used by most living
things.
Bacteria are the only
organisms that use nitrogen
gas directly from the
atmosphere.
They can fix nitrogen for
plants to use by converting it
into ammonia.
N2
DNA and proteins
Nitrogen Cycle
Terminology
N2
Nitrogen fixation- nitrogen gas
in atmosphere converted to
ammonia (bacteria in soil,
Nitrogen fixation
lightning)
Nitrification- bacteria
converting ammonia to nitrate
NH3
(another form of nitrogen)
Assimilation- absorption of
ammonia and nitrate by plants
YUMMY!
Assimilation
Nitrogen Cycle
Terminology
 Ammonificationdecomposers (bacteria
and fungi) break down of
dead organisms and waste
and return nitrogen to soil
as ammonia.
 Denitrificationconversion of ammonia
back to nitrogen gas
(decomposers).
N2
Denitrification
Ammonification
NH3
Nitrogen Cycle
Why is the nitrogen cycle
important?
 Why is nitrogen important to living
things?
 How do plants obtain nitrogen?
 Why are bacteria SO important to
the nitrogen cycle?
 How do we obtain nitrogen?
 Nitrogen cycle movie with QUIZ
Water Cycle
 Driving force is the sun and gravity.
 Consists of the alternation between
evaporation and precipitation.
 Most water returned to the
atmosphere comes from evaporation
from the oceans.
Water Cycle Terminology
 Water vapor- gaseous form of water in
atmosphere
 Evaporation- liquid water from bodies of
water becomes gas returned to
atmosphere.
 Transpiration- loss of water by land plants
 Condensation- process which water
molecules gather in atmosphere “change
from gas to liquid” when cooled.
 Precipitation- water falls from
atmosphere to ground (rain, snow, sleet,
or hail)
Water Cycle
What is missing here?
Why is the water cycle
important?
 Water is the most important
nonliving (abiotic) component of an
ecosystem.
 Water essentially determines what
organisms we find in an ecosystem.
 What is the major difference
between the tropical rainforest and
the desert? Why?
Carbon Cycle
 Carbon cycles between the living
organisms and the non-living
components of ecosystem.
 Plants are of great importance to
the carbon cycle!!--photosynthesis
 Carbon exists in the atmosphere as
carbon dioxide (CO2)
 Why do living things need carbon?
Carbon Cycle
Carbon Cycle Terminology
 Photosynthesis- process where sunlight, CO2 and
H2O is used to make carbs.
CO2 + H2O + sunlight (energy)  glucose (carb) + O2
 Respiration- process by which animals use carbs,
taking in O2 given off by plants and give off CO2
***THE OPPOSITE OF PHOTOSYNTHESIS!
glucose (carb) + O2  CO2 + H2O + energy to live
 Decomposition—breakdown of dead organisms and
waste, returning carbon to the soil and atmosphere
 Fossil fuels- formed by pressure applied to dead
organisms that are buried in sediment. They are
carbon and release CO2 when burned.
 Combustion- burning of fossil fuels
 Carbon cycle video with QUIZ
Why is the carbon cycle important?
 Organic macromolecules -energy for living
organisms (carbohydrates), cell membranes
(lipids), DNA/RNA, and proteins.
 ***Humans in the United States are altering
this cycle
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Deforestation
CO2 is a greenhouse gas
Burning too many fossil fuels releases extra CO2
into the atmosphere creating global warming due
to increased greenhouse effect.
 The greenhouse effect is normal. Global
warming is abnormal amounts of the
greenhouse effect.
 Greenhouse effect video clip
How competition effects
ecosystems
 Sometimes two species will compete.
 No two species can occupy the exact same niche
(job) for a long period time.
 Only one species wins. This is called competitive
exclusion.
What if no one wins?
 In some species interactions,
neither species wins.
 This results in close, long term
associations within an ecosystem
called symbiotic relationships.
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3 Kinds Symbiotic
Relationships
+=helped
- = harmed
0=neither
Parasitism (+/-)
 Commensalism (+/0)
 Mutualism (+/+)
Evolution and Ecology
 Symbiotic relationships
cause species to evolve
in response to each
other.
 Ex) Flowers pollinated
by nocturnal moths.
 This is called
coevolution.
 Ant and Fungus
Symbiosis
Changing Ecosystems
• Changes are a natural part of any ecosystem.
• Succession: regular development of an ecosystem
which leads to gradual replacing of species in a
community by others.
• Succession
Ecosystem Stability
 Does succession ever end?
 Climax community
 Stability - ability of an ecosystem to
resist change when a disturbance
occurs.
 Biodiversity tends to promote
stability.
Ecosystem Stability
 Keystone speciesspecies that are
crucial to the
stability of an
ecosystem.
 If members of a
keystone species die,
then the entire
ecosystem can
collapse.
 i.e. sea otters- keep
sea urchins in check,
which would take
over the kelp beds
without the otters
Ecosystem Stability
 Invasive/introduced
species destroy
ecosystems.
 They are species that are
brought by humans
accidentally or
purposefully from other
places and take hold
 They multiply unchecked
due to lack of predators
in new place they are
moved to.
 Ex: Asian longhorn beetle,
Zebra mussels
SEA LAMPREY
Population Dynamics
World Populaton Clock
 Population-a group of organisms of the
same species that occupy a given area.
 Living things reproduce.
 If environmental conditions are
“favorable,” then the number of
individuals in population should increase
from one generation to next.
Biotic Potential
 Under favorable conditions,
a species may reach its biotic
potential.
 Biotic potential- highest
reproduction rate possible
for a species under “ideal”
conditions.
Ex) Houseflies
-lay over 100 eggs at once
-can reproduce at 1 month
old
-after 7 generations,
one fly = 15 billion flies!!!
Exponential Growth
 Population
grows rapidly
to infinitely
high number.
 Represented by
“J curve”
 This does NOT
describe
real-life.
biotic
potential
Logistic Growth
 Real populations
can only grow
exponentially for
short spans.
 Environmental
resistance limits
size of a
population.
 Logistic curvereal population
growth looks like
this and is“S”
curve
Carrying Capacity
 Population grows
slowly, increases,
levels off.
 Carrying capacitytotal # of individuals
that can be
supported by the
environment in a
particular area
 Earth has 6.6 billion
people…how many
more can it support?
 Population Crash
Population Size- Growth Rate
Birth rate- # individuals born
Death rate- # individuals die
Immigration- # individuals move in
Emigration- # individuals move out
If…
BR + I = DR + E EQUILIBRIUM
BR + I > DR + E INCREASING
BR + I < DR + E DECREASING
 Population growth video clip
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Factors Affect Growth Rate
Size of Population
 Environmental resistance- “limiting
factors” stop population from reaching
biotic potential
 Population density -the number of
individuals in a population for a certain
area.
Types of limiting factors:
 Density independent factors- don’t depend on
the density of individuals
i.e.) usually abiotic- natural disasters, pollution
Types of limiting factors:
 Density dependent factors – factors that affect
a population as it increases in density
i.e.) Disease (flu/colds winter)
Predation
Competition—
interspecific ( between different species)
intraspecific ( within same species)
Problems with Overpopulation
 Humans, more than anything else, are affecting the
stability of Earth.
 1.) Decrease in food supply
-over fishing
-agricultural land/residential
 2.) Energy shortage- renewable/nonrenewable resources
 3.) Destruction natural resources
-topsoil, groundwater, species
 4.) Pollution
-water
-air (acid rain, ozone depletion due to
CFC’s in aerosol cans, global warming due to
burning and deforestationCO2
-production of tons of solid waste
Ozone Shield:
• Ozone (O3) in the atmosphere
absorbs harmful UV light.
• Since the late ‘70s, scientists
have discovered that the
ozone layer over Antarctica
has decreased by as much as
60 %
• Ozone: Good Up High, Bad
Near By
Human inputs?
• chlorofluorocarbons(CFCs)
Problems?
• UV light is a mutagen, which
can cause skin cancer
• Cataracts
b) CFCs
Biomes
 Biomes are groups of terrestrial ecosystems that
have the same climate and dominant
communities.
 3 types of biomes:
 Temperate: seasonal
 Tropical: by equator and hot year round
 Arctic: far from equator and cold year round
 You have forests, deserts and grasslands in these
different areas
Biomes
 Biomes:
 Temperate forests
(deciduous)
 Grasslands
 Tropical forest
 Tropical desert
 Tropical grassland
(called savannahs)
 Arctic forests
(taiga)
 Arctic grasslands
(tundra)
Aquatic Lifezones
 Aquatic lifezones are aquatic ecosystems.
 Freshwater or saltwater.
 Freshwater
 Wetlands are very important ecosystems.
 Bogs, swamps or marshes.
 Rivers
 Ponds
 Estuaries (wetlands where river meets sea)
 Mangrove swamps
 Saltwater (Marine)
 Coral Reefs
 Intertidal zone
 Open ocean
 Biomes-22min