II. The Living World

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II. The Living World
2

• A. Ecosystem Structure
• Biological populations and communities
  ecological niches interactions among species
  keystone species species diversity and edge
  effects major terrestrial and aquatic biomes
• B. Energy Flow
• Photosynthesis and cellular respiration food
  webs and trophic levels ecological pyramids
• C. Ecosystem Diversity
• Biodiversity natural selection evolution
  ecosystem services
• D. Natural Ecosystem Change
• Climate shifts species movement ecological
  succession
• E. Natural Biogeochemical Cycles
• Carbon, nitrogen, phosphorus, sulfur, water,
  conservation of matter

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THE NATURE OF ECOLOGY

• Ecology is a study of connections in nature.
• How organisms interact with one another and with
  their nonliving environment.

Figure 3-2
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Species Diversity and Niche Structure Different
Species Playing Different Roles

• Species diversity the number of different
  species it contains (species richness) combined
  with the abundance of individuals within each of
  those species (species evenness).

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Indicator Species Biological Smoke Alarms

• -early warnings of damage to a community or an
  ecosystem.
• Ex. Presence or absence of trout species because
  they are sensitive to temperature and oxygen
  levels.

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Keystone Species Major Players

• -determine the types and numbers of other species
  in a community, helping to sustain it.

Figures 7-4 and 7-5
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Foundation Species Other Major Players

• -can create and enhance habitats which benefits
  other species in a community.
• Ex. Elephants push over, break, or uproot trees,
  creating forest openings promoting grass growth
  for other species to utilize.

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Population

• -A group of the same species living w/in a
  particular area.

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Community

• -All the population s in an area.

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Ecosystem

• - All nonliving (abiotic) and living (biotic)
  components

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Universe
Galaxies
Biosphere
Solar systems
Planets
Earth
Biosphere
Ecosystems
Ecosystems
Communities
Populations
Realm of ecology
Organisms
Communities
Organ systems
Organs
Tissues
Cells
Populations
Protoplasm
Molecules
Atoms
Organisms
Subatomic Particles
Fig. 3-2, p. 51
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Habitat

• The place where an organism or a population lives.

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Niche

• The total way of life or role of a species in an
  ecosystem.
• All the physical, chemical, and biological
  conditions a species needs to live reproduce in
  an ecosystem.

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Species InteractionsSymbiosis

• Parasitism when 1 species (parasite) feeds on
  part of another species (host) by living on or in
  it
• Commensalism benefits one species but doesn't
  harm or help the other
• Mutualism both species benefit

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Parasites Sponging Off of Others

• Although parasites can harm their hosts, they can
  promote community biodiversity.
• Some parasites live in host (micororganisms,
  tapeworms).
• Some parasites live outside host (fleas, ticks,
  mistletoe plants, sea lampreys).
• Some have little contact with host (dump-nesting
  birds like cowbirds, some duck species)

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Mutualism Win-Win Relationship

• Two species can interact in ways that benefit
  both of them.

Figure 7-9
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Commensalism Using without Harming

• -helps one species but has little or no effect on
  the other.

Figure 7-10
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Predator

• An organisms that captures feeds on parts or
  all of another animal.

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Prey

• An organisms that is captured serves as a
  source of food for another animal.

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Cycle

• See graph (page 203 and 204)

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Decomposition

• -When organisms die or release waste Bacteria
  break down and return the chemicals back to the
  soil.

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BIOMES CLIMATE AND LIFE ON LAND
Figure 5-9
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BIOMES CLIMATE AND LIFE ON LAND

• Biome type is determined by precipitation,
  temperature and soil type

Figure 5-10
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PhotosynthesisProducers Basic Source of All Food

• producers capture sunlight to produce
  carbohydrates by photosynthesis

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First Trophic Level
Second Trophic Level
Third Trophic Level
Fourth Trophic Level
Tertiary consumers (top carnivores)
Producers (plants)
Secondary consumers (carnivores)
Primary consumers (herbivores)
Heat
Heat
Heat
Solar energy
Heat
Heat
Heat
Heat
Detritivores (decomposers and detritus feeders)
Heat
Fig. 3-17, p. 64
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Food Webs/Chains

• -how energy nutrients move through the
  ecosystem
• Arrows point from the producer to the consumer

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Energy Flow in an Ecosystem Losing Energy in
Food Chains and Webs

• Ecological efficiency percentage of useable
  energy from one trophic level to the next.

Figure 3-19
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10 Rule

• We assume that 90 of the energy at each energy
  level is lost because the organism uses the
  energy. (heat)
• It is more efficient to eat lower on the energy
  pyramid. You get more out of it!
• This is why top predators are few in number
  vulnerable to extinction.

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Producers

• -use photosynthesis or chemosynthesis (some
  bacteria) to manufacture its food.

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Primary Consumer (herbivore)

• -feed directly on all or parts of plants.

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Secondary Consumer (carnivore)

• -feed only on primary consumers. Most are
  animals, but some are plants (Venus fly-trap).

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Tertiary Consumer (carnivore)

• -feed on animal-eating animals. Ex. hawks,
  lions, bass, and sharks.

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Quaternary Consumer (carnivore)

• -feeds on tertiary consumers. Ex. humans.

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Decomposers and Detrivores

• Decomposers Recycle nutrients in ecosystems.
• Detrivores Insects or other scavengers that feed
  on wastes or dead bodies.

Figure 3-13
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Biodiversity

• -the many forms of life found on the Earth.
  Wildness
• Genetic Diversity the variety of genetic
  make-up w/in a single species
• Species Diversity the variety of species in
  different habitats on the Earth

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Biological Evolution

• -has led to the variety of species we find on the
  earth today.

Figure 4-2
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EVOLUTION, NATURAL SELECTION, AND ADAPTATION

• - the change in a populations genetic makeup
  through successive generations.
• genetic variability
• Mutations random changes in the DNA that can be
  inherited by offspring.

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Succession

• -process where plants animals of a particular
  area are replaced by other more complex species
  over time.

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Primary Succession

• -begins with a lifeless area where there is no
  soil (ex. bare rock). Soil formation begins with
  lichens or moss.

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Stages

• Land rock ? lichen ? small shrubs ? large
  shrubs ? small trees ? large trees

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Water bare bottom ? small/few underwater
vegetation ? temporary pond and prairie ? forest
and swamp
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Secondary succession - begins where the natural
community has been disturbed, removed, or
destroyed, but soil or bottom sediments remain.
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Pioneer Communities

• Lichens and moss.

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Climax Communities

• -area dominated by a few, long-lived plant
  species.

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Biosphere
Nitrogen cycle
Phosphorus cycle
Carbon cycle
Oxygen cycle
Water cycle
Heat in the environment
Heat
Heat
Heat
Fig. 3-7, p. 55
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CARBON CYCLE
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Effects of Human Activities on Carbon Cycle

• -We add excess CO2 to the atmosphere through
• Burning fossil fuels.
• Clearing vegetation faster than it is replaced.

Figure 3-28
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Phosphorous Cycle
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Effects of Human Activities on the Phosphorous
Cycle

• 1. We remove large amounts of phosphate from the
  earth to make fertilizer.
• 2. We reduce phosphorous in tropical soils by
  clearing forests.
• 3. We add excess phosphates to aquatic systems
  from runoff of animal wastes and fertilizers.

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Nitrogen Cycle
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Effects of Human Activities on the Nitrogen Cycle

1. Adding gases that contribute to acid rain.
2. Contaminating ground water from nitrate ions in
   inorganic fertilizers.

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Nitrogen Fixation

• - bacteria convert N2 gas to ammonia (NH3) that
  can be used by plants.

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Nitrification

• - Ammonia is converted to nitrite (NO2), then to
  nitrate(N03)

Assimilation
- Plants use N02 and NO3 to make DNA, amino acids
and proteins.
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Ammonification

• - decomposing bacteria convert wastes, and dead
  bodies into ammonia.

Denitrification
-Nitrate ions and nitrite ions are converted into
nitrous oxide gas and nitrogen gas by
denitrifying bacteria
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The Sulfur Cycle
Figure 3-32
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Effects of Human Activities on the Sulfur Cycle

• We add sulfur dioxide to the atmosphere by
• Burning coal and oil
• Refining sulfur containing petroleum.
• Convert sulfur-containing metallic ores into free
  metals such as copper, lead, and zinc releasing
  sulfur dioxide into the environment.

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Water cycle