ECOLOGY

1
ECOLOGY

• Definition
• Interaction of organisms and the living and
  nonliving components of their environment

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ECOLOGY

• Our Environment
• Human Population is Exploding
• 1. 2 billion in 1930
• 2. 6 billion in 1999
• 3. 8 billion by 2020
• (estimate)
• How many people can the earth support??

3
ECOLOGY

• C. Mass Extinction
• 1. 5 previous mass extinctions
• a. 65 mya
• 2. Extinction rate today is faster
• 20 by 2050

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ECOLOGY

• Our Atmosphere is changing
• A. Ozone Hole
• 1. Antarctica
• 2. Caused by CFCs
• 3. Rain Forest cutting?
• 3O2 gtgt 2O3
• UV

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ECOLOGY

• Ozone Thickness

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ECOLOGY

• Climate Changes
• Greenhouse effect
• a. CO2 absorbs heat
• b. Increased CO2 from burning fossil fuels is
  leading to Global Warming
• Acid Rain
• a. CO2 and NO3 mix with water
• b. Rainfall is acidic

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ECOLOGY

• Levels of Organization
• The Biosphere
• 1. All areas on earth that support life
• 2. Deep Ocean to Mountains
• 3. Includes all Ecosystems

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ECOLOGY

• Levels of Organization
• Ecosystems
• 1.Includes all organisms and nonliving items in a
  location
• a. The Ocean
• Whales
• Fish
• Plankton
• Minerals
• Water

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ECOLOGY

• Levels of Organization
• C. Communities
• 1. Includes all living species in a location
• a. Foothill Woodland
• b. Deciduous Forest

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ECOLOGY

• Levels of Organization
• Populations
• 1. Includes all individuals of a single species
  in a location
• a. Acorn Woodpeckers
• b. Mule Deer
• c. Grizzley Bears

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ECOLOGY

• Levels of Organization
• Organism
• 1 individual

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ECOLOGY

• Populations
• a group of individuals of the same species
  living in the same place
• Population Size
• the number of individuals it contains
• B. Population Density
• how crowded a population is

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ECOLOGY

• Populations
• C. Population Dynamics
• All Populations change over time
• Birth Rate
• of Births over time
• Mortality Rate (Death Rate)
• of deaths over time
• 3. Life Expectancy
• how long an individual is expected to live

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ECOLOGY

• Populations
• D. Survivorship Curves

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ECOLOGY

• Populations
• E. Population Growth Rates depend on 4 factors
• Birth Rate
• Mortality Rate
• Immigration
• -rate at which individiuals enter a population
• Emmigration
• -Rate at which individuals leave

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ECOLOGY

• Populations
• F. 2 Models of Population Growth
• Exponential
• -Short period of rapid growth
• -Populations rise and fall rapidly

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ECOLOGY

• Populations
• F. 2 Models of Population Growth
• 2. Logistic
• -Carrying Capacity is reached
• -Long periods of Stability

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ECOLOGY

• Energy Flow
• A. The Sun is the ultimate source of all energy
  in living systems
• 1.Producers (plants) carry out photosynthesis
• -producer trophic level provides energy for all
  other trophic levels.
• B. Results in pyramids of energy, biomass and
  numbers
• C. Energy Only Flows One Way Through Ecosystem

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ECOLOGY

• Nutrient Cycles
• All Nutrients must be recycled
• All life requires certain nutrients
• Decomposers break down dead organisms from all
  other trophic levels
• Inorganic processes also release nutrients
  essential for life.

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ECOLOGY

• Nutrient Cycles
• The Water Cycle
• Water enters atmosphere via evaporation and
  transpiration
• a. powered by sun
• Clouds release water via precipitation

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ECOLOGY

• Nutrient Cycles
• The Carbon Cycle
• Producers absorb CO2 during photosynthesis to
  produce sugars
• Consumers, decomposers and producers all process
  sugars during respiration and release CO2

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ECOLOGY

• Nutrient Cycles
• The Nitrogen Cycle
• 1. All organisms require nitrogen for protein
  production
• 2. Nitrogen makes up 78 of atmospheric gases
• 3. Most organisms cannot use nitrogen N2 directly

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ECOLOGY

• Nutrient Cycles
• The Nitrogen Cycle
• Bacteria living in roots of legumes (symbiosis)
  convert N2 to nitrates and nitrites
• Nitrogen Fixation