Ecology and the Biosphere Chapter 50

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Ecologyand theBiosphereChapter 50

• Ecology is the scientific
• study of the interactions between
• organisms and their environment

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Emphasis

• scientific study
• interactions
• environment

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Environmental Components

• Abiotic Components
• (non-living chemical and physical factors)
• Temperature Light Water Nutrients
• Biotic Components
• (other organisms)
• Predators and their Prey
• Pathogens and their Hosts
• Competitors same species or other
• Organisms that modify the environment

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Broad Range of Research

• Adaptatons of Organisms
• Ecosystem Dynamics

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Four Major Sub disciplines
adaptations of individuals to their environment

• Organismal Ecology
• Population Ecology
• Community Ecology
• Ecosystem Ecology

all of the individuals of a species in a site
Increasing complexity
all of the populations in a site
all of the biotic (community) and abiotic factors
in a site
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Ecology
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Biomes of the Biosphere
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Abiotic factors of Biosphere

• Temperature
• Water
• Sunlight
• Wind
• Substrate Rocks and soil
• Disturbances

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Temperature

• Temperature influences biological processes
  chemistry and physiology
• freezing can rupture cells
• high temperatures denature proteins NAs
• Organisms can only regulate body temperatures
  within narrow ranges of temperature
• metabolism slows down at low and high
  temperatures
• endotherms and extreme specialists are
  exceptions, but still operate within ranges of
  acceptable temperatures

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Water

• Aquatic and marine organisms face challenges of
  maintaining osmotic balance
• Terrestrial organisms confront the problem of
  dessication, which has been an vital factor in
  the evolution of many lineages

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Sunlight

• Virtually all ecosystems rely on sunlight for
  energy
• But sunlight is not the prime determinent of
  plant distribution
• Light can be limiting under canopies and in
  aquatic environments both are shade conditions
• Sunlight heats the earth uneavenly, resulting in
  climate variation

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Wind

• Wind chill exacerbates cold temperatures
• Wind can exacerbate water loss by increasing
  evaporation
• Wind moves air masses and moisture, influencing
  the distribution of temperature and moisture
  variation

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Rocks and Soil

• physical structure, pH, nutrient content
• limits the distribution of plants and the animals
  that feed on them resulting in patchiness of
  biotic communities

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Disturbance

• Fires, extreme stroms, volcanic eruptions
• Disturbance can devastate biota
• Resets community, resulting in succession
• Succession of biota, emphasizing disperal early,
  then competitive ability later major trade-off

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Climate

• Sunlight
• Temperature
• Water
• Wind

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Climograph of Biomes (major ecosystems)
overlap indicates that other factors are involved
too
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Climograph of Biomes (major ecosystems)
identify at least three patterns in this
climograph
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Biomes of the Biosphere
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Causes of Global Climate Patterns
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Causes of Global Climate Patterns
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Causes of Global Climate Patterns

• Solar energy incident to planet's surface
• Movement of planet through space

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Solar Energy

• Half of the solar radiation is aborbed in the
  atmosphere, especially high energy wave lengths
  (e.g., UV radiation absrobed by ozone)
• Solar radiation heats the planet's surface
  unevenly
• Which creates patterns of atmospheric activity
• Which influences where moisture is captured or
  deposited

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Why does the falling air at 30 move to the west
if it moves toward the equator, and to the east
if it moves to the poles?
90
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0
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90
60
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BiomeDistributions
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Effects of Mountains

• Rain shadows
• Slopes facing the equator are warmer
• Increases in altitude mimic increases in
  latitude
• 6 C per
• 1000m altitude
• or
• 880 km latitude

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Aquatic Biomes
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Turnover mixes stratified lakes and ponds,moving
oxygen down and nutrients up
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Biotic Zonation in Lakes and Ponds
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Nutrient Conditions

• Deep lakes are often nutrient poor
• oligotrophic
• Lakes in between are
• mesotrophic
• Shallow lakes are often nutrient rich
• eutrophic

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Zonation in Marine Communities
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Organismal Ecology Concepts
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Regulators Conformers

• Regulators use physiological behavioral
  mechanisms to achieve homeostasis in variable
  environments
• e.g., Salmon marine/aquatic conditions,
  osmoregulation
• Conformers allow body conditions to vary with
  those of external environment, usually in stable
  environments
• e.g., spider crabs (Libinia) doesn't
  osmoregulate

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Tradeoffs

• Energy is the limiting currency
• Competing functions

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Regulators and Conformers
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RegulatorsandConformers
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Principle of Allocation

• Organisms have limited energy to invest in
  competing needs
• ? growth, survival reproduction (maintenance)
• ? homeostasis
• Homeostasis is costly
• ? grasshoppers (moderately active ectotherms)
  70/30
• ? weasel (active endotherms) 97.5 versus 2.5
  
• ? wren (very active endotherms) 99.5 versus
  0.5
• Results in Tradeoffs
• ? Regulators
• Generalists with broad distributions over
  variable conditions
• ? Conformers
• Specialists with narrow distributions under
  stable conditions

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Responses to Environmental Change

• Physiological
• Morphological
• Behavioral

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Physiological Responses Tolerance and Acclimation
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Morphological Responsessometimes
reversibleoccurs over developmental time
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Behavioral Responses

• Can be almost instantaneous, often reversible
• Examples
• ? desert animals that burrow in the day to
  escape heat
• ? seasonal migration
• ? hibernation
• ? honey bees cool their hives by fanning their
  wings or heat
• them up by through their activity