ECOSYSTEM ORGANIZATION AND ENERGY FLOW

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CHAPTER 14 ECOSYSTEM ORGANIZATION AND ENERGY
FLOW
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ECOLOGY AND ENVIRONMENT

• Ecology the branch of biology that studies the
  relationships between organisms and the
  environment
• The environment is anything that affects an
  organism during its lifetime
• Organisms are affected by both biotic (living)
  and abiotic (nonliving) factors of the environment

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ORGANIZATION OF ECOLOGICAL SYSTEMS

• Ecologists study ecological relationships at
  different levels of organization
• Organism smallest, independent living unit
• Ex one leopard frog
• Population - members of the same species living
  in a particular area
• Ex leopard frogs in a pond
• Community - populations of different species
  living in the same area
• Ex pond community (frogs, fish, plants, etc.)

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ECOLOGICAL SYSTEMS

• An ecosystem - all interacting organisms in an
  area and how they interact with their abiotic
  surroundings.
• Living things can be organized into energy
  relationships.
• Producers trap sunlight, carry out
  photosynthesis
• Consumers feed on producers
• Trophic levels describe how energy flows
  through an ecosystem
• Producers occupy the first trophic level
• Arranged like a pyramid

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ECOLOGICAL SYSTEMS

• Consumers can be divided into
• primary consumers
• secondary consumers
• Primary consumers feed directly on plants are
  known as herbivores (mouse)
• Second trophic level
• Secondary consumers feed on other animals and are
  called carnivores (snake)
• Third trophic level
• Animals that feed on carnivores are fourth
  trophic level consumers (hawk)

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TROPHIC LEVELS
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ECOLOGICAL SYSTEMS

• Omnivores feed on both plants and animals
• Can occupy different trophic levels
• Decomposers feed on dead organisms as their
  source of energy
• Includes bacteria and fungi
• Convert organic matter into inorganic matter that
  can be used by producers

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COMMUNITY INTERACTIONS

• All consumers depend on producers for their
  energy (directly or indirectly).
• One way to study interactions among communities
  involves analysis of the various food chains.
• Show linear feeding patterns
• Organisms can be involved in several food chains
  at the same time forming a food web.
• Show complex feeding patterns

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COMMUNITY INTERACTIONS

• Changes in the population size of one species can
  influence population sizes of other species.
• Insecticide use may decrease the population size
  of organisms that feed on insects.
• Population sizes may change due both biotic and
  abiotic factors

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WORLD BIOMES
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TEMPERATE DECIDUOUS

• Found in areas with moderate rainfall (75-130 cm
  per year)
• Long summers (130-160 days)
• Colonized by many large deciduous trees
• Typical animals include
• leaf eating animals, insects
• Birds, skunks, deer
• mosquitoes , etc.

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GRASSLAND

• Also known as a prairie
• Average rainfall amount is 30-85 cm per year
• Not adequate to support the growth of trees
• Mostly grasses and wildflowers
• Good for agricultural crops (corn, wheat)
• Experience long periods of drought
• Common animals include
• Grazing mammals
• Small insects
• Rodents
• Carnivores

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SAVANNA

• Similar to a prairie
• Receive about 100 cm of rainfall per year
• Home to many grazing animals
• Have a dry season and a rainy season
• During the rainy season, trees produce leaves and
  the grass grows rapidly
• In the African savanna, migration is typical.

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DESERT

• Very dry areas found all over the world
• Receive less than 25 cm of rainfall per year
• Plants are adapted for conserving water
• Scattered, thorny plants
• Many animals can live here, most are nocturnal

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BOREAL CONIFEROUS FOREST

• Include the evergreen areas
• Annual rainfall of 40-100 cm per year
• Growing season is less than 102 days
• Trees must withstand long cold winters
• Animals include mice, bears, wolves, moose, and
  flies

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TUNDRA

• Long, severe winters and short summers of less
  than 100 days
• Little rainfall (10-25 cm per year)
• Deep layers of soil are permanently frozen
  (permafrost)
• Supports very few forms of animals and plants.
• No trees can live in this biome.

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TEMPERATE RAINFOREST

• Receive about 200 cm of rain per year
• Found in fertile and mild temperatures with lush
  plant growth.
• Undisturbed areas have 800-year-old trees nearly
  100 meters tall
• Many are covered with mosses and ferns
• Over 90 of the original temperate rainforests
  have already been logged.
• Found near coastal areas of Pacific northwest
• Northern California, Oregon, Washington, Canada,
  Alaska

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TROPICAL RAINFOREST

• Found primarily in the equatorial regions.
• Considered the richest biome
• Warm temperatures year round, and rain falls
  almost daily (200-1000 cm a year)
• Thousands of species of plants in very small
  areas
• Many species of animals

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SUCCESSION

• Communities are relatively stable when left
  undisturbed
• Known as climax communities
• Succession is the process of changing from one
  type of community to another
• Two types
• Primary succession - occurs in areas where
  plants and animals didnt exist before (volcanic
  areas)
• Secondary succession occurs when a community is
  disturbed by natural or human action, and it
  returns to a previous stage in the succession
  (forest fires, clear cutting)

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PRIMARY SUCCESSION
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SECONDARY SUCCESSION
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CHAPTER 14 ECOSYSTEM ORGANIZATION AND ENERGY
FLOW
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KINDS OF INTERACTIONS

• Predation a predator captures prey, kills it,
  and eats it.
• Elimates poorly adapted individuals
• Parasitism the host is harmed and the parasite
  benefits
• Parasites can live inside or outside the host.
• Mistletoe, tapeworms, fleas
• Vectors are organisms that can spread parasites.
• Mosquitoes, ticks

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KINDS OF INTERACTIONS

• Commensalism one organism benefits and the
  other is not affected.
• Remoras and sharks
• Tree mosses
• Mutualism both organisms benefit from one
  another
• E.coli and humans
• Bees and flowering plants
• Competition an interaction between organisms
  in which both organisms are harmed to some
  extent.
• Weeds and garden plants
• Occupying different niches helps reduce
  competition

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PRIMARY SUCCESSION
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SECONDARY SUCCESSION
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