Ecology

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Ecology

• Ch 3, 4, 5, 6

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Organization of Life

• Molecules carbohydrates, nucleic acids,
  proteins, lipids, water, and other molecules
  necessary for life
• Cells basic building block of life.
• Tissues similar cells with similar functions
  grouped together.
• Organs and Organ systems Tissues that form a
  specific function for the organism.

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Organization of Life - Ecology

• Individual one organism
• Population one species in a defined area
• Community all biotic factors in a defined area
• Ecosystem all biotic and abiotic factors in a
  defined area
• Biosphere all biomes and ecosystems (EARTH)

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Ecosystem Structure

• An ecosystem is based on energy and nutrients
  available. One way flow.
• Inputs sun, dissolved minerals
• Outputs heat, loss of minerals
• Order of feeding relationships trophic levels.
• Some organisms are in one specific level, others
  can be multilevel.

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Ecosystem Structure

• Main Energy Source Sunlight
• 1) Primary Producers (Autotrophs)
  Photosynthesizing Organisms convert radiant
  energy to chemical energy.
• CO2 H2O ? C6H12O6 O2

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Ecosystem Structure

• 1)Primary Producers
• Chemiosynthesis a process of generating organic
  molecules from inorganic substances (Nitrogen and
  Sulfur compounds)
• Few bacteria nitrogen fixing bacteria and
  archaebacteria

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Ecosystem Structure
decomposers fungi and bacteria that eat on
dead material All feed on producers

• 2) First Level Consumers (heterotrophs)
• herbivores animals that eat plants (gophers,
  squirrels)
• parasites insects that harm plants (grubs)
• detrivores animals that eat decaying organic
  matter. (earthworms)
• !

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Ecosystem Structure

• 3) Second Level Consumers (heterotrophs)
• Carnivores
• Omnivores
• Parasites
• Detritivores
• Decomposers
• All feed on first level consumers!

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Ecosystem Structure

• 4) Third Level Consumers (heterotrophs)
• Carnivores
• Omnivores
• Parasites
• Detritivores
• Decomposers
• All feed on Second Level Consumers!

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Ecosystem Structure

• 5) Fourth Level Consumers (heterotrophs)
• Top Carnivores
• Parasites
• Detritivores -
• Decomposers
• All feed on Third Level Consumers!

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Food Web VS. Food Chain?

• Food Chain A straight sequence from producer to
  4th level consumer.
• Food Web several food chains cross connecting
  with each other.

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Energy Flow

• Energy flows from producers to top level
  carnivores.
• Energy transfer is never 100. Some is lost as
  heat.
• Ecosystems will never be more than 4 or 5 trophic
  levels.
• Energy transfers are only one way.

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Warm Up

1. Give an example of an organism in each trophic
   level
2. Primary producer, primary consumer, secondary,
   tertiary, and quartinary consumers
3. Explain how decomposers, detrivores, and
   parasites fit into the ecosystem.
4. What is the primary source of energy and is it
   cyclic or one-way flow?

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Ecological Pyramids

• Biomass depicts the mass of organisms at each
  trophic level for an ecosystem.
• Can be an upside down in an aquatic ecosystem due
  to primary producers having less biomass (algae
  or phytoplankton)

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Ecological Pyramids

• Energy shows how energy changes from each
  trophic level. Only 10 of energy will be
  transferred. The rest is lost as heat. Always a
  traditional pyramid shape.
• Numbers shows how many organisms are at each
  level. Will not always be a traditional pyramid
  shape.

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Energy Pyramid
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Biomass Pyramid
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Numbers
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Biogeochemical Cycles
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Biogeochemical Cycles
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Water Cycle
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Carbon Cycle
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Nitrogen Cycle
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Sedimentary Cycles
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Success of an Ecosystem

• Primary Productivity
• Limiting Nutrients
• Example Nitrogen cause algal blooms

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Community Interactions and The Biosphere
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Ecosystem

• Biotic Factors all living organisms in an
  ecosystem.
• Abiotic Factors all nonliving substances in an
  ecosystem
• These determine survival and growth of an
  organism and the productivity of the ecosystem.

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Warm-UP

• Describe a commenalistic, parasitic, and
  mutualistic relationship

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• Habitat place where an organism lives.
• Several organisms may have the same habitat.
• Niche activities, relationships, and resources
  needed for survival and reproduction.
• EX temperature needed, pH levels, place in the
  food web, competition, time of the year it
  reproduces, time of the year it hibernates or
  migrates, and any other characteristic for the
  survival of the organism.

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Competition

• When organisms of the same or different species
  attempt to use the same ecological resource.
• Adaptations occur to help organisms compete in
  the same ecosystem. Ex Resource Partitioning.
• Can suppress growth of populations.

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Competitive Exclusion Principle

• No two species can occupy the same niche in the
  same habitat at the same time.

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Interactions

• Commensalism one species benefit, the other
  neither helped or harmed.
• Mutualism both species benefit
• Parasitism one species benefit, the other is
  harmed.

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Interactions

• Predator / Prey one consumer hunts another
• May control population size of prey.
• Unique defense adaptations of prey.
• Unique adaptations of predators.Horned Toad
  (Short-Horned Lizard) -- Animal Videos --
  National Geographic

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Succession

• Ecosystems change in response to natural and
  human disturbances.
• Ecosystems begin with pioneer species
• colonizers of vacant habitats, high dispersal
  rates, grow fast, and have high reproduction
  rates. Ex Lichens
• Stronger competitor species come to replace
  pioneer species.

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Succession

• Primary Succession pioneer species inhabit a
  barren habitat. Ex new volcanic island, new land
  after glacier retreat.
• Pioneer species break rock, release nutrients to
  make way for grasses and flowering plants.
• Soon more species of seeds arrive some with
  nitrogen fixing bacteria.
• Over time wastes and dead material accumulate to
  add nutrients.

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Mt. St. Helens after disaster and during
recovery.
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Succession

• Secondary Succession a disturbed area within a
  community recovers and moves toward a climax
  state. Ex abandoned fields, burned forests.
• Climax pattern model a community is adapted to
  many environmental factors topography, climate,
  soil, wind, interactions, common disturbances.

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Populations
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How Populations Grow

• There are three important characteristics of a
  population
• 1. Geographic Location
• 2. Density
• 3. Growth rate

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How Populations Grow

• Population Density ? the number of individuals
  per unit area
• Geographic location ? where are they
• Growth rate ? how fast are they growing

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Population Growth

• Three factors that affect population size
• 1. The number of births
• 2. The number of deaths
• 3. And the number of individuals that enter or
  leave the population

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Population Characteristics

• Immigration ? the movement of individuals into an
  area
• Emigration ? the movement of individuals out of
  an area

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Types of Growth

• Exponential Growth ? occurs when the individuals
  in a population reproduce at a constant rate.
• Under ideal conditions with unlimited resources,
  a population will grow exponentially
• J - curve

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Types of Growth

• Logistic growth ? occurs when a populations
  growth slows or stops following a period of
  exponential growth
• As resources become less available, the growth of
  a population slows or stops
• S - curve

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Types of Growth

• Carrying capacity ? the largest number of
  individuals that a given environment can support

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Population Characteristics

• Limiting Factor something that causes
  populating growth to decrease.
• Two types density dependent factors and density
  independent factors.

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Density Dependent Factors

• These factors are limiting only when the
  population density reaches a specific level.
  (too many for ecosystem to support)
• Competition, predation, parasitism, and disease

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Density Independent Factors

• These factors are limiting on all populations
  regardless of size.
• Unusual weather, natural disasters, seasonal
  cycles, human activity.

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Human Population Growth

• Increases over time yet showing exponential
  growth
• Most advanced countries have shown demographic
  transition death rate and birth rate are equal
  no population growth
• Can analyze a population using an age structure
  diagram.

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Humans and the Biosphere
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Biodiversity

• All different organisms of this biosphere.
• Human activity can reduce biodiversity by
  altering habitats, hunting species to extinction,
  introducing toxic compounds into food webs, and
  introducing foreign species to new environments.

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Habitat Alteration

• Land development destroys habitats.
• Habitat fragmentation splits ecosystems to
  several sections. Reduces number and variety of
  organisms that can survive.

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Pollution

• Organism can ingest toxic compounds if they are
  introduced into the water or soil of an ecosystem
• Biological magnification concentrations of a
  harmful substance increases in organisms at
  higher trophic levels in a food chain or food
  web.
• DDT, Hg

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Introduced Species

• Invasive species rapidly reproducing species of
  organisms that are not indigenous to the
  ecosystem.
• Has no natural predators to keep them in check.
• Nutrias, zebra mussels, leafy spurge

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Conservation Biology

• The application of wise management of natural
  resources, including the preservation of habitats
  and wild life.
• Protecting entire ecosystems as well as
  individual species.
• Focus on hot spots places where large numbers
  of habitats and species are in immediate danger
  of extinction due to humans

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Questions for thought.

• What is our role as a species in this biosphere?
• Do we have the right to use the natural resources
  and destroy ecosystems?
• Find an article that deals with conservation
  Biology