Introduction to Ecology

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Chapter 50

• Introduction to Ecology

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• Study of the interactions between organisms and
  their environment
• Ecology and evolutionary biology are closely
  related
• Darwins observations of the distribution of
  organisms and their adaptation to specific
  environments led him to propose that
  environmental factors interacting with variation
  within populations could cause evolutionary change

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• Organismal ecology concerns how an organisms
  structure, physiology, and behavior meet the
  challenges posed by the environment
• The environment has two components
• Biotic
• Abiotic

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Subdivisions of Ecology

• Species
• Population
• Community
• Ecosystem
• Biosphere

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• Biogeography
• Species dispersal contributes to geographic
  isolation and patterns of distributions
• Most species have small geographical ranges
• Factors affecting organism distribution
• Behavior and habitat selection
• Biotic factors
• Abiotic factors

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• Biomes are major ecosystems that occupy broad
  geographical ranges
• Differ in temp and rainfall
• Coniferous forests, deciduous forests, chaparral
  rainforests, grasslands, tundra, savanna, desert
  and aquatic biomes
• Climates vary globally and may be seasonal or
  long term
• Climates also vary on a very small scale
• Microclimate

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• Aquatic Biomes
• Occupy the largest part of the biosphere
• Cover 75 of the Earths surface
• Many display vertical stratification due to
  changes in physical chemical parameters
• Photic zone
• Aphotic zone
• Thermocline
• Benthic zone
• Occupied by organisms called benthos
• Major source of food is dead organic matter
  called detritus

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• Fresh water systems may be free standing (lakes,
  ponds) or free moving (streams, rivers)
• Littoral zone
• Limnetic zone
• Profundal zone
• Benthic zone
• Lakes are usually classified by production of
  organics
• Oligotrophic lakes
• Eutrophic lakes
• Mesotrophic lakes

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• Wetlands areas covered with water and able to
  support aquatic plants
• Swamps, bogs marshes
• Among the richest of the biomes
• diverse community of invertebrates supporting a
  wide variety of birds
• Provide storage basins that reduce flooding and
  filter water improving quality
• Sources of mosquitoes flies, foul odors

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• Estuaries the area where a freshwater ecosystem
  merges with the ocean
• Often bordered by costal wetlands (mudflats
  salt marches)
• One of the most biologically productive biomes
• Support a wide variety of commercially valuable
  species
• Prime locations for real estate developments

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• Marine communities are distributed according to
  depth, light penetration and distance to shore
• Intertidal zone
• Neritic zone
• Oceanic zone
• Pelagic zone
• Benthic zone
• Neteric benthos are highly productive and consist
  of bacteria, fungi, algae, seaweed, invertebrates
  and fishes
• In deep abyssal zone deep-sea hydrothermal vent
  communities have been discovered

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• The geographical distribution of terrestrial
  biomes is based mainly on regional variations in
  climate
• Temp and water are the most important factors
• Terrestrial biomes are usually named for major
  physical or climatic features or predominant
  vegetation
• Vertical stratification is an important feature
• Tropical, Coniferous and Temperate broadleaf
  forests Deserts Tundra Grasslands Savanna
  Chaparral

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