Principles of Ecology

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Principles of Ecology

• Ecology Scientific study of the interactions
  between organisms and the surrounding environment

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Biosphere

• Consists of the portion of Earth that supports
  life.
• includes land, water, atmosphere
• Relatively small in comparison to overall size of
  earth
• if Earth were an apple, biosphere would be
  thinner than the peel!!
• Is diverse and supports many different orgs in
  many different locations
• biosphere differs in climate, soil types, plants,
  and animals present from region to region

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Abiotic vs. biotic factors

• Abiotic nonliving parts of an orgs surrounding
  environment
• Ex. Soil, moisture, light, temperature
• though nonliving, abiotic factors are an
  important part of an organisms life
• Biotic all of the living organisms that live in
  a particular area under consideration.
• Ex. Goldfish in a bowl, other goldfish, plants,
  algae

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Levels of Organization

• Individual organism Ex. One frog
• Species Ex. Bullfrogs
• group of organisms so similar to one another that
  they can breed and produce FERTILE offspring.
• Population Ex. Bullfrogs in a pond
• group of organisms of ONE species that interbreed
  and live in the same area at the same time.
• Community Ex. Bullfrogs, fish, insects, algae
  in that pond
• made up of several populations that interact in
  the same area
• Ecosystem Ex. Pond ecosystem on wall poster
• collection of ALL the animals that live in a
  particular place together with their physical
  environment
• Biome Ex. Tropical rainforest
• group of ecosystems with the same climate and
  similar dominant communities

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Levels of organization.
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Ecosystems

• Ecosystem made up of the interactions among the
  populations in a community AND the communitys
  physical factors (abiotic factors like amount of
  rainfall, temperature, soil type, etc)
• 3 major types of ecosystems
• 1. terrestrial ecosystems
• 2. aquatic ecosystems
• 3. saltwater (marine) ecosystems

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Organisms in Ecosystems

• Habitat place where an org lives its day-to-day
  life.
• habitats can change dramatically due to natural
  or man-made effects
• Ex. fire because of lightning or careless
  campers...
• Niche the role and position a species occupies
  in its habitat or location. This includes all of
  the orgs interactions with the living and
  nonliving parts of the habitat.

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Living Together species interactions

• Symbiosis relationship where there are close
  and permanent associations between orgs of
  different species.
• Types of symbiotic relationships
• a. commensalism
• b. mutualism
• c. parasitism

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Commensalism

• Symbiotic relationship where one species benefits
  and another is neither harmed nor helped
• Ex. Barnacles attached to a whale
• barnacles get a free ride to areas where food is
  available

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Mutualism

• Symbiotic relationship where both species
  involved benefit from the association.
• Ex. Ants and acacia trees
• ants get shelter and nectar from plant as food,
  plants get protection from predators
• Ex. sponges attached to crab shell
• sponges get moved to new area to filter food from
  water, crab gets portable camouflage

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Parasitism

• Symbiotic relationship where one organism
  benefits and another organism is harmed.
• Ex. Ticks on a dog
• tick gets food source, dog gets hole in
  protective skin layer and possible infection
• Ex. Tapeworms in intestine
• tapeworm absorbs nutrients in pre-digested form,
  host loses weight, and never gets the nutrition
  that he needs
• malnutrition

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Nutrition and Energy Flow

• Sunlight is the main energy source for life on
  earth -- PHOTOSYNTHESIS
• Autotrophs vs. Heterotrophs
• autotrophs make own food
• heterotrophs must consume another organism in
  order to get nutrition
• herbivores (primary consumers)
• carnivores (secondary and upper level consumers)
• Scavengers
• omnivores (primary, secondary, and upper level
  consumers)
• decomposers

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Matter and Energy Flow in Ecosystems

• Energy flows through organisms in an ecosystem.
• Scientists use models to represent these
  pathways.
• 2 models food chains and food webs
• food webs are made up of many interwoven food
  chains

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Food Chains

• Nutrients and energy move from autotrophs to
  heterotrophs to decomposers
• Food chains are drawn with arrow pointing in
  direction of energy flow org that consumes will
  have mouth to eat food source.
• grasshopper ? robin
• robin ? grasshopper
• Food chains can be made up 3 links, but seldom
  have more than 5 due to loss of energy as heat.

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Food chains (cont)

• Each organism in the chain represents a feeding
  step or TROPHIC LEVEL
• Can be represented by ecological pyramids

Top carnivores
carnivores
Herbivores
Energy Pyramid
Producers
Biomass pyramid or pyramid of numbers
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Energy Pyramid vs. Biomass Pyramid vs. Pyramid of
Numbers
Energy Pyramid Shows the relative amount of
energy available at each trophic level.
Organisms use about 10 percent of this energy for
life processes. The rest is lost as heat.
Pyramid of Numbers Shows the relative number of
individual organisms at each trophic level.
Biomass Pyramid Represents the amount of living
organic matter at each trophic level. Typically,
the greatest biomass is at the base of the
pyramid.
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Homework

• Use one full sheet of unlined paper (8.5x11).
• Draw a food web like this
• a) it must consist of 5 food chains.
• b) each food chain must have
• 1. producer
• 2. primary consumer
• 3. secondary consumer
• each consumer must be labeled as an
• herbivore, carnivore, omnivore, or
• decomposer
• c) 5 abiotic factors must be included in
  your diagram and labelled
• DUE TOMORROW AT THE BEGINNING OF CLASS!

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Cycles

• All organisms need water, minerals, and other
  life-sustaining materials to survive.
• Ex. Carbon backbone of organic compounds
• (carbs, lipids, proteins)
• Ex. Phosphorus uprights of DNA ladder
• Ex. Nitrogen needed to make amino acids
• Elements, chemical compounds, other forms of
  matter are passed from one org to another and
  from one part of the biosphere to another through
  BIOGEOCHEMICAL CYCLES.

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Water Cycle Condensation, Precipitation,
Infiltration, Runoff, Evaporation
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Water Cycle

• http//observe.arc.nasa.gov/nasa/earth/hydrocycle/
  hydro1.html

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Carbon CycleCarbon is the KEY ingredient in ALL
living things
Volcano
Decomposition
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Carbon Cycle

• How does Carbon Exist? 
• Where do biotic organisms get it?
• carbon dioxide (CO2) is found in the atmosphere
  and dissolved in water
• forming HCO3-
• In carbonate rocks
• limestone and coral CaCO3
• In deposits of coal, petroleum, and natural gas
  derived from once-living things
• In dead organic matter,
• e.g., humus in the soil

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Nitrogen CycleNitrogen is abundant in the
atmosphere, but must be fixed to get in to
living systems
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Phosphorus Cycle
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Primary Productivity

• Rate at which organic matter is created by
  producers.
• Nutrient availability often controls this, so
  farmers will add nutrients to their soils
• FERTILIZER!!!
• If a single nutrient is scarce or cycles very
  slowly, it is called a LIMITING NUTRIENT.
• -ex. Nitrogen in sea water