ECOSYSTEMS AND CYCLES

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ECOSYSTEMS AND CYCLES
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EVERYTHING IS CONNECTED

• Ecology is the study of the interactions between
  living things and their environment
• Living things are known as biotic
• Non living things are abiotic

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The environment is organized into 5 layers

• Organism
• Single living thing
• Population
• All the same kind of organism in one place at one
  time
• Community
• All the different populations living in the same
  place at the same time
• Ecosystem
• The community AND the abiotic parts of the
  environment
• Biosphere
• All of the ecosystems throughout the Earth

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LIVING THINGS NEED ENERGY

• The sun is the ultimate source of energy in
  almost all ecosystems
• Energy is passed from organism to organism
• A balanced ecosystem has organisms in all of the
  following roles
• Producers
• Consumers
• Decompsers

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Producers

• Most producers use sunlight, carbon dioxide and
  water to make food for other organisms through
  the process of photosynthesis.
• Plants and algae are main producers
• A few producers use chemosynthesis where
  chemicals in the environment are used to make
  food without light

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Consumers

• Consumers are organisms that eat (consume) other
  organisms
• Herbivores eat plants (primary consumers)
• Carnivores eat other consumers (secondary
  consumers)
• Omnivores eat both plants and animals (are both
  primary and secondary consumers)
• Scavengers feed on the bodies of already dead
  animals (secondary consumers)

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Decomposers

• Breakdown the remains of dead organisms into
  simple nutrients (water, CO2, etc.) and return
  them to the soil or atmosphere
• Bacteria and Fungi are decomposers

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Food chains and food webs

• Both are models that show how energy moves, in
  the form of food molecules, from one organism to
  the next
• Food chains are simple and show ONE route for the
  energy to move
• Food webs are complex and show multiple (and
  possibly ALL) paths for the energy to move like
  overlapping food chains.

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Energy pyramids

• Model that shows HOW MUCH energy is at each level
  of the ecosystem
• Producers are at the bottom showing that the
  number of organisms and the amount of energy are
  the greatest there

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ENERGY PYRAMIDS 2

• The herbivores are next because they get the
  energy directly from producers
• Then carnivores
• Then scavengers
• At each level the number of organisms decreases
  since there is less energy available to them to
  sustain life

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Wolvesstay or go?

• One hundred years ago wolves were eliminated from
  Yellowstone National Park

• Why would people do this intentionally?
• What would be some advantages or disadvantages of
  taking them out?
• DISCUSS

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Wolves and the energy pyramid(When reintroduced
into Yellowstone)

• Wolves are top carnivores in the ecosystem
• Reduced the number of large unhealthy, weak, old
  herbivores
• Increased number of smaller herbivores
• Improved balance of ecosystem

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Types of interactions

• Interactions in the environment
• Limiting factors
• those resources that prevents the population from
  getting too large such as food, space, water, and
  for plants sunlight.
• Any single resource can be a limiting factor to
  population size
• Carrying capacity
• Is the largest a population can be in an
  environment.
• Limiting factors determine what the carrying
  capacity is.

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Types of interactions-continued

• Competition
• Occurs when two or more species try to use the
  same limited resource
• Food
• Space
• sunlight
• Can occur between populations of different
  organisms or within the same population

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Types of interactions-continued

• Predators and prey
• Predators are carnivores that have developed
  adaptations to help them catch other animals to
  eat them
• Vision
• Speed
• Camouflage
• Others?
• Prey are animals that are adapted to survive so
  that even though their species is being killed by
  predators enough of them survive for their
  population lives on
• Vision
• Speed
• Camouflage
• Others?

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Types of interactions-continued

• Symbiosis long term association between two or
  more species
• Mutualism both types of organism benefit
• Commensialism one organism benefits and the
  other organism is unaffected
• Parasitism one organism benefits and the other
  is harmed or killed
• Coevolution is a long term change that has
  occurred because of the close relationship
  between two species.

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CYCLES OF MATTER

• Matter is anything that has mass and occupies
  space
• Certain types of matter is constantly reused and
  recycled in nature
• Examples studied in 7th grade
• Water
• Carbon
• Nitrogen

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Cycles in Nature

• Water cycle
• Precipitation liquid water falls to earth in
  four forms rain, sleet, snow, hail
• Evaporation liquid water becomes water vapor
• Ground water liquid water seeps into the earth
  and is stored under the ground

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Cycles in Nature

• Other processes
• Run-off water flows along the ground and
  collects in streams, rivers, lakes, and oceans
• Transpiration water vapor is released from
  plants
• Condensation water vapor cools, becomes liquid
  water

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Carbon cycle - part of all living things.

• move carbon from the atmosphere into the
  organisms and back to the atmosphere.
• Photosynthesis plants use carbon dioxide and
  water to make sugar
• ( food)
• Respiration organisms use the food and it is
  broken down to produce energy for the organism
  carbon dioxide and water are released

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Carbon Cycle

• Other processes that put carbon back into the
  atmosphere
• Combustion coal, oil and natural gas contains
  high amounts of carbon. When burned carbon is
  released
• Decomposition breakdown of dead organisms
  releases the carbon stored in their bodies back
  into the environment.

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Cycles in Nature

• Nitrogen Cycle nitrogen is essential to life
  because it is the main ingredient in proteins,
  which build muscles and is in DNA.
• The nitrogen cycle has two processes
• Fixation
• decomposition

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Cycles in Nature

• Nitrogen cycle continued
• Fixation the atmosphere is 78 nitrogen but it
  is not in a form organisms can use.
• Nitrogen must be fixed so it can be absorbed by
  plants and then passed onto animals.
• Nitrogen is fixed by bacteria and lightning
• Decomposition when organisms die nitrogen
  stored in their bodies is released into the
  environment to be used again

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Succession

• Succession is a series of slow gradual,
  predictable steps in the development of a
  community. There are two types.
• Primary occurs in an area where there is no
  soil or life of any kind. Soil must be formed
  first so it takes a VERY long time (hundreds or
  thousands of years)
• Secondary occurs in an area where the existing
  life had been destroyed by a natural disaster
  such as a flood or a forest fire. Soil is already
  present so it takes place over a shorter period
  of time (100 years)