Ecology

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Ecology
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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 and their environment
• Biosphere- the entire region of Earth where
  living things can be found (many ecosystems)

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What is Ecology?

• 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

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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

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Biomes
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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

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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 an organism in which it interacts
  with other species and its environment (i.e. its
  job)

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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

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Biotic Factors

• Two categories of life based on how they get
  energy
• All life is either a
• Producer OR
• Consumer

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Biotic Factors

• Producers- organisms that are capable of
  producing their own energy source
• Photosynthetic (plants that take light to make
  carbs)
• Chemosynthetic (some bacteria that can take
  chemicals to make their carbs)
• All producers are autotrophs or self-feeders

KNOW THIS EQUATION!
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Biotic Factors

• Consumers- organisms that cant produce their own
  energy source, but have to consume it from
  another source
• All consumers are heterotrophs or other feeders
• Many different types of consumers (heterotrophs)
• -Herbivores
• -Carnivores
• -Omnivores
• -Decomposers

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Look at each of the pictures and write in
the space below it whether it is a producer or a
consumer
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Conditions for Life

• For an ecosystem to sustain life, it must have
• 1) Constant source of energy (sun).
• 2) Living system that converts suns energy into
  organic molecules. Plants!
• 3) Cycling of nutrients between organisms and
  environment (water, carbon dioxide, nitrogen,
  oxygen).
• 4) Decomposers- bacteria and other small
  organisms that breakdown and return unused
  nutrients to the environment.

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Biodiversity

• Biodiversity- The number of different species in
  an ecosystem
• More plants more animals
• More biodiversity healthier ecosystem

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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)

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Nutritional Interactions

• All ecosystems must have interactions between
  producers, consumers, and decomposers
• These interactions transfer nutrients and energy
  throughout the ecosystem

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Energy flow in an ecosystem

• Energy flows through an ecosystem from the sun to
  producers to consumers
• Arrows show the direction the energy flows

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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

OWL Quaternary consumer
FLOWER Producer
FROG Secondary consumer
SNAKE Teriary consumer
CATERPILLAR Primary consumer
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• Food web- illustrates how many food chains in an
  ecosystem are related
• Primary consumers?
• Secondary consumers?
• Tertiary consumers?
• Where would
• decomposers fit in
• this food web?

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How many trophic levels are possible?

• Energy pyramids- show amount of energy at each
  trophic level
• These are not food pyramids!!
• Trophic levels -levels of feeding from producers
  (plants) to the consumers
• Few ecosystems have more than 4 or 5 trophic
  levels
• Energy diminishes at each level because it is
  used for lifes processes

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Pyramid of Energy

• Which level has the most energy AVAILABLE?

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• Trophic levels
• Producers have the most energy available
• Primary consumers are all herbivores
• Secondary consumers are small carnivores
• Tertiary consumers are large carnivores
• Part of the original energy from the sun is used
  at every level by the organisms for survival

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Nutrient Cycles
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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

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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
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Nitrogen Cycle Processes

• Nitrogen fixation- nitrogen gas in atmosphere
  converted to ammonia, NH3
• (bacteria in soil, lightning)
• Nitrification- bacteria converting ammonia to
  nitrate (another form of nitrogen)
• Assimilation- absorption of ammonia and nitrate
  by plants

N2
YUMMY!
Nitrogen fixation
Assimilation
NH3
Nitrification
Nitrate
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Nitrogen Cycle Processes
N2

• Ammonification- decomposers (bacteria and fungi)
  break down of dead organisms and waste and
  return nitrogen to soil as ammonia
• Denitrification- conversion of ammonia back to
  nitrogen gas (decomposers)

Denitrification
Ammonification
NH3
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Nitrogen Cycle
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Review Nitrogen Importance

• 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

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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

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Water Cycle Processes

• 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

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Water Cycle Processes

• 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 )

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Water Cycle
What is missing here?
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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
• Tropical rainforest vs. desert

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Carbon Cycle

• Carbon cycles between the living organisms and
  the non-living components of ecosystem
• Carbon exists in the atmosphere as carbon dioxide
  (CO2)
• Plants are of great importance to the carbon
  cycle!!photosynthesis takes carbon from the air
  and creates glucose for all consumers to use
• Why do living things need carbon?

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C
Carbon
12.011
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Carbon Cycle Processes

• 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

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Respiration

• The energy for lifes processes comes from
  cellular respiration, which occurs in your
  mitochondria
• glucose (carb) O2 ? CO2 H2O ATP energy

• Carbon that you eat is used to build other
  organic macromolecules or is exhaled

• This carbon that you exhale is from the food you
  eat

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Carbon Cycle Processes

• Decompositionbreakdown 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

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Carbon Cycle
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Why is the carbon cycle important?

• Organic macromolecules carbon compounds used
  for energy for living organisms (carbohydrates),
  cell membranes (lipids), DNA/RNA, and proteins.
• Humans are altering this cycle
• Deforestation releases stored carbon
• CO2 from burning is a greenhouse gas which warms
  the planet

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Why is the carbon cycle important?

• Burning too many fossil fuels releases extra CO2
  into the atmosphere
• This creates climate change due to increased
  greenhouse effect
• The greenhouse effect is normal
• Climate change is due to abnormally high levels
  of the greenhouse effec
• Greenhouse effect video clip

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What is the Scientific Consensus?
1979--NASA
Mean global temperature rose about 0.6º C (1.5º
F) since 1880 Increase is real, not explained
by natural variation in solar radiation Warming
greater at poles than equator, greater at night,
mostly troposphere September sea ice level
animation
2003--NASA
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Populations
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How competition effects ecosystems

• Sometimes two species will compete
• Competitive exclusion- no two species can occupy
  the exact same niche (job) for a long period time
• Only one species wins

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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 of Symbiotic Relationships

• helped
• - harmed
• 0neither
• Parasitism (/-)
• Commensalism (/0)
• Mutualism (/)

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Evolution and Ecology

• Symbiotic relationships cause species to evolve
  in response to each other
• Ex) Flowers pollinated by nocturnal moths
• Coevolution- evolution of two or more species in
  response to one another
• Ant and Fungus Symbiosis

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Changing Ecosystems

• Infer.what do you think is the story behind the
  picture?
• 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 and the Mount

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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

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Ecosystem Stability

• Keystone species- species 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

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Ecosystem Stability

• Invasive, or introduced species- those that are
  brought by humans accidentally or purposefully
  from other places
• Invasive/introduced species can take hold and
  destroy ecosystems.
• They multiply out of control due to lack of
  predators in new place they are moved to.
• Ex Asian longhorn beetle, Zebra mussels

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SEA LAMPREY
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Population Dynamics

• 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

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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 gt DR E INCREASING
• BR I lt DR E DECREASING
• Population growth video clip

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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!!!

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Exponential Growth

• Exponential growth- starts out slowly but then
  grows rapidly to infinitely high numbers
• Represented by J curve
• This does NOT describe real populations forever
• Something always limits growth eventually

biotic potential
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Factors Affect Growth Rate Size of Population

• Environmental resistance- limiting factors that
  stop populations from reaching their biotic
  potential
• Space
• Water
• Nutrients
• Competition
• Disease
• Natural disasters

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Logistic Growth

• Real populations can only grow exponentially for
  short spans.
• Environmental resistance limits size of a
  population.
• Logistic curve-population growth that levels off
  due to environmental resistance
• S curve

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Carrying Capacity

• Carrying capacity- total of individuals that
  can be supported by the environment in a
  particular area
• Earth has over 7 billion peoplehow many more can
  it support?
• Population Crash

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The Human Population World Populaton Clock

• The human population is growing exponentially at
  1 a year
• Adding 1 million people every 5 days
• Remember that exponential growth cannot continue
  forever
• Humans are subject to the same laws of nature as
  all other species

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Problems with Overpopulation

• Humans, more than anything else, are affecting
  the stability of Earth
• 1.) Food supply increased over past few decades,
  but amount per person has decreased
• Many people starving, and this will continue to
  get worse as over 90 of future population growth
  is expected to occur in less developed nations
• Over-fishing
• Erosion and pollution of agricultural land

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Problems with Overpopulation

• 2.)Energy shortage
• Nonrenewable resources are limited and we are
  using them faster than ever before
• Less developed nations who are developing will
  continue to use more fossil fuels
• The U.S., with 5 of the worlds population, uses
  25 of the worlds energy resources
• Pollutants are increasing as well as climate
  change

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Problems with Overpopulation

• 3.)Destruction and abuse of natural resources
• Topsoil
• Forests
• Freshwater supplies diminished
• Species extinction

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Problems with Overpopulation

• 4.)Pollution
• Production of tons of unnecessary solid waste
• Water
• Air
• Climate change due to burning and deforestation
  increasing carbon dioxide levels
• Acid rain
• Ozone depletion

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Ozone Layer Depletion

• Ozone shield
• Ozone (O3) in the atmosphere protects us by
  absorbing harmful UV light
• 1970s scientists discovered the ozone layer over
  Antarctica has decreased by as much as 60
• Problems?
• UV light is a mutagen, which can cause skin
  cancer
• Cataracts