The scientific study of how organisms interact with their environment
 and all the other organisms that live in that environment.

 All the living and nonliving things that interact in a particular area.
    ( Ecosystems can be as small as a pond or a large as a desert.)

The place where an organism lives and that provides the things the organism needs.
A single ecosystem might contain many habitats. Organisms live in different habitats because
they have different requirements for survival.

Each organism has a role to play in the habitat, a role which is referred to as its Niche.
The Niche an organism fills in a habitat is not limited to its place in a food web.  Plants  provide nesting sites as well as food.   Generally, no two species will fill exactly the same niche in a habitat     
Organism-  A single individual animal, plant, fungus or other living thing.

Population-All the members of one species in a particular area .

The maximum number of individuals in a population that an ecosystem can support
 is called  Carrying Capacity.

Community -Most ecosystems contain more than one type of organism.
A community is a group of different populations that live close enough together to interact.
One way they might interact is by using the same resources, such as food and shelter.

Biome-A biome describes in general terms the climate and types of plants found in similar places around the world.
Limiting Factors
Environmental factors that prevent a population from increasing. 
Some limiting factors for populations are food, space and weather conditions.  ALSO,  air, light and water. 
Other limiting factors might be the number of other organisms of the same population living in an area.  

Biotic Factors
- are the living parts of an ecosystem.

Abiotic Factors-
are the nonliving parts of an ecosystem.
         (Water, Sunlight, Oxygen, Temperature, Soil)

                          All living things need water.
                             Plants need it and sunlight to carry out photosynthesis,
                             Animals need it to digest food and release energy stored in food.  
                          Ecosystems with a lot of water can support a large number of plants,                                        and these plants can support a large number of different types of                                        animals.

                        It’s necessary for photosynthesis. 
                            If the plants don’t get it they can’t survive. 
                                The strength ofthe sunlight and amount of sunlight
                                 will determine the type of plants that can survive
                            No plants means no food for other organisms. 
                        It also warms the Earth’s surface. 
                        It’s also a factor in ocean ecosystems because the deeper the water, the                                less light will be available.
                       In shallow water near the shore there will be more plant growth and                                     therefore more food than in deeper parts of the ocean.

                         Most living things require oxygen to carry out their life processes.

                          The temps that are typical of an area determines the types of organisms                              that can live there.
                  Soil is a mixture of small rock and mineral particles,  nutrients, air, water and                    the decaying remains of living things.  The type of soil influences the kind                      of plants that can grow in an ecosystem.  Some animals use the soil as a                             home.  Billions of microscopic organisms such as bacteria may also live in                       Vthe soil.

Matter Cycles Through Ecosystems

Cycle-  A series of events that happens over and over again.

The Water Cycle
  Water is stored in lakes, rivers and oceans.  Water is found underground in the spaces between soil particles and cracks in rocks.  Water is stored in glaciers and polar ice sheets.  Water is also part of the bodies of living things.  

Water isn’t just stored.  It’s constantly moving among these areas.  This movement ofwater through the environment is called the Water Cycle. The Hydrologic Cycle (Water Cycle) is also responsible for purifying Earth's water supplies.  The process of Evaporation occurs when liquid water turns to water vapor.  This happens when heat is added to liquid water.  When water evaporates, ONLY the H2O turns to water vapor.
Anything else (impurities, salt, whatever...) is left behind.  Water vapor returns to liquid state when it LOSES HEAT.  This process is called Condensation.  Finally, the liquid, or frozen water falls to the Earth as Precipiation.  This precipitation may flow over Earth's surface as Surface Runoff.  Surface Runoff often follows the same path, and when this happens, it forms Rivers and Streams.  Precipitation may also sink into the pore spaces found between particles of soil.  When this happens, it's called Groundwater.  Both Surface Runoff and Groundwater eventually makes it way back to the sea, where it will eventually be evaporated into the atmosphere once again.  Perhaps instead it evaporates somewhere along the way back into the atmosphere, perhaps it's  used by other living things along the way, or perhaps used by plants and returned to the atmopshere through Transpiration.  This process has been going on since water first formed on  Earth, nearly five billion years ago!  Think of it...the water that you use today, has undoubtedly been used many, many times before, by many, many creatures which existed on Earth before you came along.  Wouldn't it be interesting to know what, or who, previously used those very same water molecules that you just consumed?  You're not the first to use those same molecules, and you certainly won't be the last.  With every sip you take, you're part of a very old series of events indeed.  Events that have gone on, and will continue, well beyond the short number of years you're here on Earth.

The Carbon Cycle

All living things on Earth are built with the Carbon atom.  We're carbon based life forms!  This important atom called Carbon is also recycled here on Earth.  If it were not, you wouldn't be here reading this right now, since all the carbon would have been used up long, long ago.

The carbon cycle involves two important processes.  Photosynthesis and Respiration.  Photosynthesis is the process that green plants use to make food.  Remember that the major difference between plants and animals is just that...Plants can make their own food using the process of Photosynthesis.  Animals have to find their food and eat it.  Using sunlight, and some water, and a few compounds like Chlorophyll, plants are able to basically break a CO2 molecule into a Carbon atom, which is used to build starches and sugars by the plant, and a pair of Oxygen atoms, which are pretty much given off as a waste product.  Good thing for us.   Animals, like Lions and Tigers and Bears and I, eat food made of long chains of Carbon Atoms and we breathe in 0xygen.  We use the Oxygen to burn the Carbon-based food we consumed, and we get the energy we need to run our bodies.  This process, called Respiration, provides the energy we need, and the Carbon atoms are now bonded to the Oxygen atoms, in the form of Carbon Dioxide .  The Carbon Dioxide is exhaled by animals like us, as a waste product.  This same Carbon Dioxide is then absorbed by some lucky, hungry, photosynthesizing plant somewhere.  The cycle goes on and on, forver and ever.  It always has, and it always will, so long as there are plants and animals here on Earth.

Carbon is also stored underground.  Remains of plants and animals buried for millions of years decay slowly and change into fossil fuels such as coal and oil.  

The Nitrogen Cycle

Nitrogen is a gas quite important to you and me, and all the other living things on this Wonderful World.  Nitrogen is used to make Proteins, which are substances used for cell growth and repair.  Since we're mostly protein, that makes Nitrogen pretty important.  The problem is that the Nitrogen in the atmosphere isn't useable by our bodies.  This is where the Nitrogen Cycle comes in.  You might think of the Nitrogen Cycle as the continuous movement of Nitrogen from the atmosphere, to the soil, to living things, and then back to the air or soil.  A similar process also takes place in Earth's oceans as well.  On land, bacteria in the soil, called Nitrogen-fixing Bacteria,  convert the atmospheric Nitrogen into substances called Nitrates.  Plants are able to use these Nitrates to build plant proteins in their bodies.  Animals like you and me, and lemurs, must either eat plants, or eat something that eats plants, to get these same substances into our bodies. When plants or animals die, their bodies are broken down by another bacterial process, called Decay or Decomposition.  Decay returns the Nitrogen to the air or the soil, to become a part of the Nitrogen Cycle once again.

Energy Flows through Ecosystems
Energy from the sun is a precious thing.  Every living thing needs energy, and living
things can be put into one of three categories, based upon how they
get the energy that they need.

Organisms that capture energy and store it in food as chemical energy.
    Producers make energy available to all other living parts of the ecosystem.  
    Plants, algae and certain other microorganisms.
    Producers can make their own food.
    Sunlight usually, but not always, provides the energy to the producers.
Organisms that get their energy by eating, or consuming, other organims.  Consumers are usually classified by what they eat.
            Herbivore-eat only plants
             Carnivore-eat only animals
                                                        Scavenger-a carnivore that feeds on the bodies of dead organisms.
                         Omnivore-eats both plants and animals

Organisms that break down dead plant and animal matter into simpler
    compounds.  They break down waste and dead organisms and return the raw
    materials to the environment.  (Which can be then used by other organisms)

    Bacteria and Fungi are the major groups of decomposers.


Food Chains and Food Webs

Food Chain
  A series of events in which one organism eats another and
        obtains energy.  The first organism in a food chain is always a producer.

        A food chain describes the feeding relationships between a producer and a
            single chain of consumers in an ecosystem.
Food Web
  Consists of many overlapping food chains in an ecosystem.
A model of the feeding relationships between many different
  producers and consumers in an ecosystem.

Both food chains and food webs show how different organisms receive their energy.
They also show how different types of organisms depend on one another.  
If one organism is removed, it may affect other organisms in the ecosystem.

The Energy Pyramid
 Another way to picture the flow of energy in an ecosystem is to use an energy pyramid. 
It’s a model that shows the amount of energy available  at each feeding level of an ecosystem

      Interactions among living things.

is the struggle between individuals or
different populations for a limited resource.

       Competition may occur within the same species.
  Competition within species often occurs during the mating season.
              Competition may also occur between members of different species.

                                    Competition doesn't happen between ALL populations that share the same resources. 
                   Many populations can coexist in a habitat.
                     Different species can live together without causing harm to one another.
                                    Many different species of plants coexist in a forest.  Trees can live side by side and still
                                  have enough water, nutrients and sunlight to meet their needs.

Not all relationships involve competition.  This is an interaction in
     which organisms work in a way that benefits them all.

This is when one organism eats another organism.  Pretty simple.  The one doing the eating is the
               "Predator".  The one getting eaten is the "Prey".    Both predators and prey may
have various adaptations  that allow them to be better at what they do.


This is the relationship between two different species who live together in a close relationship. 
            There are three forms of Symbiosis.

                                   Mutualism-both species benefit
                                                                                     Commensalism-one species benefits, the other isn't affected.
                                                                                              Parasitism-a small partner harms a much larger host.  The parasite
                                                                                                    benefits, the host is harmed.   Parasites are often tiny organisms
                                                        that feed off, and weaken, their  hosts.

In the end, it all boils down to

Stayin' Alive

Natural Selection