Ecology%20Intro

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Ecology Intro

• Ch.18

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(18-1) Ecology

• Study of interactions b/w the living nonliving
  parts of the environment
• Collect info about organisms environments, look
  for patterns, try to explain those patterns

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Todays Issues

• Survival used to depend on practical knowledge
• Humans have changed the environment more than
  ever in the past few decades

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Exploding Human Population

• Rapid increase of humans on Earth
• Downfalls severe crowding, requires more E,
  food, space for waste disposal

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6th Mass Extinction

• As humans increase, the of species decrease
• Species disappearing at a faster rate now than
  last mass extinction (dinosaurs)
• Estimated that 1/5 of species may disappear in
  the next century

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Thinning Ozone Layer

• Ozone protects Earth from the suns UV light
• CFCs other chemicals are destroying it
• Hole over Antarctica

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Climatic Changes

• Greenhouse effect inc. in CO2 caused inc. in
  reflected heat towards Earth
• CO2 from burning fossil fuels
• Causing global warming

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Key Theme

• Interconnectedness (interdependence)
• No organism is isolated
• Survival depends on interactions
• Disturbances can effect the entire network

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Ecological Models

• Visual, verbal, or mathematical
• Ecosystems are complex difficult to study
• Use to help understand make predictions

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5 Levels of Organization

• Biosphere
• Earth atmosphere that supports life
• Broadest, most inclusive

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5 Levels (cont.)

• 2. Ecosystem
• All organisms the nonliving found in a
  particular place
• Ex pond - fish, algae,
• bacteria, O2, CO2, pH

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5 Levels (cont.)

• Community
• All interacting organisms living in an area
• No nonliving parts
• Population
• All members of a species that live in 1 place at
  1 time

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5 Levels (cont.)

• Organism
• Simplest level
• Study the adaptations that organisms develop to
  survive

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(18-2) Factors

• Biotic living
• Abiotic nonliving
• Temp., humidity, pH, sunlight, O2
• Habitat where organism lives

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Tolerance Curve

• Performance vs. environmental variable (ex
  temp.)
• Organism cant live in areas outside its
  tolerance curve

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Acclimation

• Adjust tolerance to abiotic factors
• Ex adjust to higher elevation
• Occurs w/in an organisms lifetime
• Adaptation genetic change in a species or pop.
  that occurs over many generations

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Control of Internal Conditions

• Conformers do not regulate their internal
  conditions change as their external environment
  changes
• Ex lizard body temp.
• Regulators use E to control some of their
  internal conditions
• Ex human body temp.

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Escape from Unsuitable Conditions

• Dormancy reduced activity
• Ex reptiles amphibians hide in winter
• Migration move to more favorable habitat
• Ex seasonal movements of birds

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Resources

• E materials the species needs
• Ex food, E, nesting sites, water, sunlight

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Niche

• Way of life role the species plays in the
  environment
• Fundamental niche all conditions a species can
  tolerate resources it can use
• Realized niche range of resources it actually
  uses
• Avoid predators, competition

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Niche Differences

• Generalists species w/ broad niches
• Ex opossum, rat
• Specialists species w/ narrow niches
• Ex koala

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(18-3) E Transfer

• Goals
• Contrast b/w producers consumers
• Explain the important role of decomposers in an
  ecosystem
• Contrast a food chain w/ a food web
• Explain why an ecosystem
• usually contains only a few
• trophic levels

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Energy

• Need E to maintain homeostasis, grow, reproduce,
  etc.
• Determines how many what kind of organisms live
  in an ecosystem

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Producers

• Sun is the ultimate source of E
• Producers use sun E to make food E for
  themselves for the consumers
• Chemosynthesis produce carbs by using E from
  inorganic molecules
• bacteria

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Measuring Productivity

• Gross primary productivity rate at which
  producers capture E
• Net primary productivity rate at which biomass
  (organic material) accumulates
• Varies from 1 ecosystem to another

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Consumers

• Herbivores eat producers
• Antelope, deer
• Carnivores eat other consumers
• Lions, bald eagles, cobras
• Omnivores eat both
• producers consumers
• Grizzly bear

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Consumers (cont.)

• Detrivores feed on garbage of ecosystem
• Vulture
• Decomposers cause decay by breaking down dead
  tissues wastes
• Bacteria, fungi

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E Flow

• Trophic level organisms position in the
  sequence of E transfers
• 1st producers (autotrophs)
• Largest
• 2nd herbivores
• 3rd above all other consumers
• Smallest

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Ecosystem Implications

• 10 of the total E consumed in 1 trophic level
  is passed on to the next level
• Usually no more than 4 or 5 levels

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Food Chain

• Single pathway of feeding relationships in an
  ecosystem

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Food Web

• Diagram of the interrelated food chains in an
  ecosystem
• More accurate description of the ecosystem

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Can you now answer these questions?

1. Contrast b/w producers consumers
2. Explain the important role of decomposers in an
   ecosystem
3. Contrast a food chain w/ a food web
4. Explain why an ecosystem usually contains only a
   few trophic levels

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(18-4) Ecosystem Recycling

• Biogeochemical cycle process where nutrients are
  circulated through the environment

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Water Cycle

• Evaporation
• Transpiration plants take in H2O through their
  roots release H2O take in CO2 through stomata
• Condensation cloud formation
• Precipitation
• Returned back into the cycle

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Water Cycle
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Carbon Cycle

• Cellular respiration
• Photosynthesis
• Combustion
• Death decomposition

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Nitrogen Cycle Terms

• Nitrogen fixation converting N2 gas to ammonia
• N-fixing bacteria
• Denitrification N compounds are broken down N2
  gas is returned to atmosphere

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Nitrogen Cycle
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Phosphorus Cycle

• Needed by animals to form bones, teeth, RNA,
  DNA
• Plants get it from soil water
• Animals get it from eating plants

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