Ecology I

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Ecology I

• Notes

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Ecology

• This is the scientific study of interactions
  between organisms and their environments
• There is a relationship between the living and
  nonliving parts of the world

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Biotic and Abiotic Factors

• Biotic factors all of the living organisms that
  inhabit an environment
• Abiotic factors all of the nonliving parts of
  the environment such as, air currents,
  temperature, moisture, light, minerals in the
  soil topography, etc.

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Levels of Biological Organization

• Organism an individual living thing.
• Population interbreeding individuals of one
  species that compete for food, water, shelter,
  and mates and live in the same place at the same
  time.

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.

• Community several interacting populations that
  inhabit a common environment and are able to
  function because each organism within the
  ecosystem depends on other organisms.

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..

• Ecosystem a biological community plus all of
  the abiotic factors influencing that community
• Biosphere the area of the Earth where all life
  exists.

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Habitat vs. Niche

• Habitat - the physical area in which an organism
  lives.
• Niche the environmental factors that influence
  the growth, survival, and reproduction of a
  species.

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Different ways organisms interact

• Autotrophs organisms that use energy from the
  sun or energy stored in chemical compounds to
  manufacture their own food. Examples would be
  green plants that are also called producers all
  other organisms in the community depend on the
  producers

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• Heterotrophs these are organisms that depend on
  other organisms for their source of food and
  energy. They are known as consumers, those that
  feed on plants are called herbivores, those that
  kill and feed on other animals are called
  carnivores, and those that feed on organisms that
  they did not kill are known as scavengers. Deer
  are herbivores, coyotes and bobcats are usually
  carnivores, and vultures are usually scavengers

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• Omnivores are organisms that eat either plants
  or animals when they feed. However, they are
  herbivores when they eat plants and carnivores or
  scavengers when they eat animals. Bears, coyotes,
  and humans are usually considered omnivores
  because they sometimes eat producers and at other
  times they are carnivores or scavengers.

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• Decomposers are organisms that break down and
  absorb nutrients from dead organisms or waste
  products from organisms. These are many of the
  bacteria, some protozoan, and most fungi. These
  organisms break down the dead organisms so that
  their nutrients can be recycled back into the
  ecosystem.

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Symbiosis

• Symbiosis - the close association between two
  dissimilar organisms

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Types of Symbiosis

• Commensalisms a relationship where one species
  is benefits and the other is neither harmed nor
  benefits. An example would be a bird nest in a
  tree. The bird is benefited and the tree is
  neither harmed nor benefited.

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• Mutualism a relationship where both species
  benefit. An example is the ant and the acacia
  tree. The ant keeps other herbivores from feeding
  on the tree and kills other plants that try to
  come near the acacia tree while the tree provides
  a home for the ant and acacia for the ants to
  eat.

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• Parasitism a relationship where one organism is
  harmed and the other organism benefits. An
  example is fleas on a dog.

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Energy

• Energy enters an ecosystem from the sun and flows
  between organisms as one eats another
• Trophic Levels - the flow of energy through an
  ecosystem. Energy is always lost from one trophic
  level to the next.

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Trophic Levels

• Producers - plants
• Primary consumers (herbivores) - eat primary
  producers
• Secondary consumers (carnivores) - eat primary
  consumers
• Tertiary consumers (carnivores) - eat secondary
  consumers

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10 Rule in Food Chain

• 10 of the original energy is transferred from
  one trophic level to the next, 90 of the energy
  is lost as heat to the environment.

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Food Chain

• food chain shows the simple relationship of
  what organism consumes what organisms. This
  relationship very seldom exists in nature since
  it represents only one way that energy can be
  transferred in an ecosystem. There are two rules
  that must be followed when making a food chain or
  food web.

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Rules to Food Chain

• 1.  Always start with a producer organism.
• 2.  The arrows always go in the directions of
  energy flow.

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Simple Food Chains

• Grass?Grasshopper?Shrew?Rat Snake

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Food Webs

• food webs tries to explain all of the feeding
  relationships at each trophic level in a
  community. A food web is more realistic than a
  food chain since most organisms feed on more than
  one organism.

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Limiting Factors

• Any biotic or abiotic factor that restricts the
  existence, numbers, reproduction, or distribution
  of organisms
• Examples are environmental factors, such as food
  availability and temperature that affect an
  organisms ability to survive in its environment.

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Ecological Pyramid
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Ranges of Tolerance

• Gives the effect of an environmental factor on
  the number of organisms in a population.
• The ability to withstand fluctuations in biotic
  and abiotic environmental factors is known as
  tolerance.

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Ranges of Tolerance
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Succession

• Succession are orderly, natural changes that
  take place in the community of an ecosystem.
• Succession eventually ends up in what is called a
  climax community. Climax community a stable,
  mature community that undergoes little or no
  succession the new trees (plants) that are
  coming up under the old trees are the same
  species as the old trees.

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Stages of Succession

• Primary Succession changes that occur on soil
  that has never supported plant life.
• Examples lava from volcanoes, glaciers
  retreating, etc.

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• Secondary Succession changes that occur on soil
  that has supported plant life.
• Examples are plants coming back after some
  natural disaster such as a forest fire. Plants
  coming back after land has been abandoned.
• Secondary succession is much faster than primary
  succession because in primary succession, soil
  must be formed before plants can grow.

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Photic Zone

• Photic Zone that area of the marine biome where
  sunlight can penetrate. It is the most productive
  region because sunlight can penetrate which
  allows algae and other plant life to grow.
• Many of the the nutrients come from runoff from
  the rivers into this shallow area which also
  contributes to the growth of plant life. The
  producers are called photoplankton because they
  carry on photosynthesis. They produce most of the
  oxygen on the surface of the earth. The tiny
  consumers are called zooplankton which are
  heterotrophic and are lowest level of consumer in
  the photic zone.

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Aphotic Zone

• Aphotic Zone that area of the marine biome
  where sunlight does not penetrate.
• Most of the organisms in this biome are
  heterotrophs and are adapted to living in total
  darkness and at great pressures. Most of these
  organisms rely on photoplankton for their food
  source in an indirect way because they eat
  organisms in the food chain that can be traced
  back through the food chain to an autotroph.

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Terrestrial Biomes

• There are six major which are grouped using
  general geographic distribution, temperature,
  precipitation, and the main plants and/or animals
  present.
• The two primary factors affecting terrestrial
  biomes terrestrial biomes are precipitation and
  temperature.

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