The Living World

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The Living World
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Nutrient Cycles

• Carbon
• Water
• Nitrogen
• Phosphorous
• Sulfur

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General Nutrient Cycles

• Burning of fossil fuels
• Weathering, erosion
• Sedimentation
• Respiration, decomposition,excretion
• Assimilation, photosynthesis
• Fossilization

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General Nutrient Cycling
5
Carbon Cycle

• Processes Increase or Decrease?
• Cellular Respiration
• Photosynthesis
• Combustion of Fossil Fuels
• Formation of Coral Reefs
• Decomposition

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Carbon Cycle

• Processes Increase or Decrease?
• Cellular Respiration
• Photosynthesis
• Combustion of Fossil Fuels
• Formation of Coral Reefs
• Decomposition

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Nitrogen Cycle
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Nitrogen Cycle Processes

• Ammonification
• Nitrification
• Denitrification
• Nitrogen fixation
• Assimilation
• Decomposition

• NH3 ? NO2-
• NO2- ? NO3-
• NOx ? N2
• N2 ?NH4
• Proteins ? NH4 or NOx
• NH4 or NO3- ? Proteins

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Nitrogen Cycle Processes

• Ammonification
• Nitrification
• Denitrification
• Nitrogen fixation
• Assimilation
• Decomposition

• NH3 ? NO2-
• NO2- ? NO3-
• NOx ? N2
• N2 ?NH4
• Proteins ? NH4 or NOx
• NH4 or NO3- ? Proteins

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Phosphorous Cycle
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Sources of Phosphorous

• Erosion
• Mine run off
• Fertilizer run off
• Poo
• Nutrient Upwelling
• Decomposition

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Impact of Nutrients on Ecosystems
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Impact of Nutrients on Ecosystems
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Sulfur Cycle
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Trophic Levels

• List the first four trophic levels and give an
  example for each in an aquatic system and in a
  terrestrial system.

Level Aquatic Terrestrial




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Trophic Levels

• List the first four trophic levels and give an
  example for each in an aquatic system and in a
  terrestrial system.

Level Aquatic Terrestrial
Primary Producer
Prim. Consumer
Sec. Cons.
Tert. Cons.
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Food Chains and Food Webs
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Keystone Species

• Dominant and keystone species exert strong
  controls on community structure
• In general, a small number of species in a
  community

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Figure 53.16a,b
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Importance of Keystone Species
Figure 53.16a,b
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Observation of sea otter populations and their
predation
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Ecosystem Engineers (Engineering and Foundation
Species)

• Some organisms exert their influence
• By causing physical changes in the environment
  that affect community structure

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Beaver damsCan transform landscapes on a very
large scale(engineering)
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• Foundation species act as facilitators
• That have positive effects on the survival and
  reproduction of some of the other species in the
  community

Figure 53.19
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Ecosystem Dynamics
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Trophic Level Pyramids

• Grass
• Secondary Consumer
• Tertiary Consumer
• Decomposer
• Vole
• Grasshopper
• Producer
• Snake
• Primary Consumer

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4
3
2
1
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Trophic Level Pyramids

• Grass - 1
• Secondary Consumer - 3
• Tertiary Consumer - 4
• Decomposer - 5
• Bird (insectivore) - 3
• Grasshopper 2
• Producer - 1
• Snake - 4
• Primary Consumer - 2

5
4
3
2
1
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Trophic Efficiency and Ecological Pyramids

• Trophic efficiency
• Is the percentage of production transferred from
  one trophic level to the next
• Usually ranges from 5 to 20
• Average 10

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Pyramids of Production

• This loss of energy with each transfer in a food
  chain
• Can be represented by a pyramid of net production

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Pyramids of Biomass

• One important ecological consequence of low
  trophic efficiencies
• Can be represented in a biomass pyramid

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Most biomass pyramidsShow a sharp decrease at
successively higher trophic levels
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Certain aquatic ecosystemsHave inverted biomass
pyramids
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Certain aquatic ecosystemsHave inverted biomass
pyramids
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Pyramids of Numbers
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PBJ and Turkey

• The dynamics of energy flow through ecosystems
• Have important implications for the human
  population
• Eating meat
• Is a relatively inefficient way of tapping
  photosynthetic production

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Worldwide agriculture could successfully feed
many more peopleIf humans all fed more
efficiently, eating only plant material
Figure 54.14
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Biomagnification reverse of other ecological
pyramids
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Bioaccumulation vs. Biomagnification

• Bioaccumulation
• - toxins accumulate in tissues of organism may
  or may not be passed to higher trophic levels
• Biomagnification
• - increase of the toxic levels as they are
  passed up trophic levels

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GPP and NPP

• Gross Primary Productivity total increase in
  biomass
• Net Primary Productivity change in biomass over
  a period of time (only the difference) this is
  what is passed to the next trophic level

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NPP of Various Ecosystems
(c)
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Climate and Terrestrial Biomes
Overlapping Areas of Biomes ECOTONE
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The distribution of major terrestrial biomes
Figure 50.19
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Tropical Rain forest
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Tropical Rain Forest

• Rainfall 200 400 cm/year
• Temperature 25 29 oC
• Vegetation Stratification, dense canopy,
  broadleaf evergreen trees
• Animals High animal diversity, usually smaller
  and adapted for life in canopy
• Seasonal Variations Little to none
• Other Characteristics Nutrient poor soil, high
  rate of decomposition and turn over, extremely
  high biodiversity

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Desert
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Desert

• Rainfall Less than 30 cm/year
• Temperature Wide variation both seasonally and
  daily (-30 to 50 oC)
• Vegetation Low, scattered, deeply rooted
  succulents (Cacti), dense root mats to absorb
  water, adapted to heat and low water
• Animals reptiles, insects, many nocturnal
• Seasonal Variations some have short wet periods

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Savanna
Figure 50.20
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Savanna

• Rainfall 76 150 cm/year
• Temperature Continually warm, 24 29 oC
• Vegetation Scattered trees (acacia), wide
  expanse of grasses, adapted to fires, deep roots
  
• Animals Hoofed mammals, zebras, giraffe, lions,
  hyenas
• Seasonal Variations Seasonal Drought
• Other Characteristics Frequent fires, location
  of the LION KING

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Chaparral
Figure 50.20
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Chaparral

• Rainfall 30 50 cm
• Temperature Fall, Winter, Spring ? 10 12 oC,
  Summer 30 oC
• Vegetation tough evergreen woody shrubs and
  small trees adapted to seasonal fires
• Animals Deer, goats, many small mammals,
  amphibians, birds and reptiles
• Seasonal Variations Summers are hot and dry,
  fall, winter and spring are cool and rainy

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Temperate grassland
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Temperate Grassland

• Rainfall Dry winters, Wet summers 30 to 100 cm
• Temperature Cold Winters (-10 oC), Hot summers
  (30 oC)
• Vegetation ummm.Grass
• Animals Large Grazers (buffalo), prairie dogs
• Seasonal Variations dry winters, wet summers

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Coniferous (Boreal) Forest or Taiga
Figure 50.20
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Coniferous (Boreal) Forest or Taiga

• Rainfall 30 70 cm with periodic drought some
  may receive up to 300 cm (Pacific North West)
• Temperature Cold, long winters (-70 oC in
  Siberia), summers may be hot (30 oC)
• Vegetation Cone bearing trees (pine, spruce,
  fir, hemlock), conical shape helps snow fall off
  so branches dont break
• Animals Moose, brown bears, Siberian tigers,
  lots of insects during summer
• Seasonal Variations Cold, harsh winters, warm
  summers

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Temperate broadleaf forest
Figure 50.20
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Temperate broadleaf forest

• Rainfall 70 200 cm
• Temperature 0 oC (winter) to 30 oC (summer)
• Vegetation Broadleaf Deciduous Trees (drop
  leaves in fall to prevent water loss in winter),
  conifers, shrubs and various grasses and
  herbaceous plants
• Animals Black bear, deer, squirrels, snakes,
  birds (migratory and permanent), insects
• Seasonal Variations Distinct seasons of fall,
  winter, spring and summer
• Other You live here

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Temperate Rainforest
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Temperate Rainforest

• Rainfall More than 125 cm, lots of fog
• Temperature Small amount of seasonal variation (
  3 18 oC) mild winters, cool summers
• Vegetation Conifers, lots of lichens and
  epiphytic plants
• Animals Squirrels, mule deer, elk, birds,
  amphibians and reptiles
• Seasonal Variations Mild differences in season
  due to location near coasts
• Other Low nutrient turnover due to low
  temperatures. Results in a high accumulation of
  biological detritus on forest floor

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Tundra
TUNDRA
Figure 50.20
Denali National Park, Alaska, in autumn
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Tundra

• Rainfall 20 60 cm
• Temperature Long cold winters (-30 oC), Short
  cool summers (10 oC)
• Vegetation Herbaceous (non-woody), dwarf shrubs
  and trees, lichens, moss, grasses
• Animals Ox, caribou, reindeer, Santa Claus,
  Bears, wolves, foxes, lots of insects in summer
• Seasonal Variations
• OTHER Contains permanent layer of frozen soil
  call PERMAFROST

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Evolution

• Driving forces
• Genetic variation
• Competition for resources
• Survival of the Fittest
• Microevolution vs. Macroevolution

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Species Interactions

• A biological community
• Is an assemblage of populations of various
  species living close enough for potential
  interaction

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• A communitys interactions include competition,
  predation, herbivory, symbiosis, and disease
• Populations are linked by interspecific
  interactions
• That affect the survival and reproduction of the
  species engaged in the interaction

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Competition

• Strong competition can lead to competitive
  exclusion
• The local elimination of one of the two competing
  species

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The Competitive Exclusion Principle

• The competitive exclusion principle
• States that two species competing for the same
  limiting resources cannot coexist in the same
  place

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Ecological Niches

• The ecological niche
• Is the total of an organisms use of the biotic
  and abiotic resources in its environment

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Results of Competition more specific niches

• As a result of competition
• A species fundamental niche may be different
  from its realized niche
• Resource partitioning is the differentiation of
  niches
• That enables similar species to coexist in a
  community

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Resource Partitioning
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Species Interactions

• Predation
• Predator, Prey Plant Connection
• Competition
• Herbivory
• Parasitism
• Um.gross
• Even nastier
• Disease
• Mutualism
• Ants and caterpillars
• Goby and shrimp
• Commensalism

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Predation

• Predation refers to an interaction
• Where one species, the predator, kills and eats
  the other, the prey
• EPIC PREDATION

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• Feeding adaptations of predators include
• Claws, teeth, fangs, stingers, and poison
• Animals also display
• A great variety of defensive adaptations

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Cryptic coloration, or camouflage

• Makes prey difficult to spot

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Aposematic coloration
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Batesian mimicry
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Müllerian mimicry
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Herbivory

• Herbivory, the process in which an herbivore eats
  parts of a plant
• Has led to the evolution of plant mechanical and
  chemical defenses and consequent adaptations by
  herbivores

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Parasitism

• In parasitism, one organism, the parasite
• Derives its nourishment from another organism,
  its host, which is harmed in the process

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Disease

• The effects of disease on populations and
  communities
• Is similar to that of parasites

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Mutualism
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• Commensal interactions have been difficult to
  document in nature
• Because any close association between species
  likely affects both species

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Interspecific Interactions and Adaptation

• Evidence for coevolution
• Which involves reciprocal genetic change by
  interacting populations, is scarce

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Species Diversity

• The species diversity of a community
• Is the variety of different kinds of organisms
  that make up the community
• Has two components

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• Species richness
• Is the total number of different species in the
  community
• Relative abundance
• Is the proportion each species represents of the
  total individuals in the community

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Two different communitiesCan have the same
species richness, but a different relative
abundance
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Ecological Succession

• Ecological succession
• Is the sequence of community and ecosystem
  changes after a disturbance

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• Primary succession
• Occurs where no soil exists when succession
  begins
• Secondary succession
• Begins in an area where soil remains after a
  disturbance