relung multidimensi

Hierarchy of Complexity

The biosphere is the thin life-bearing outer layer of the Earth.  It extends from the deepest parts of the ocean to miles high into the atmosphere.  It is very large and very complex.  To study the relationships in nature, ecologists (scientists who study ecology) investigate different levels of organization or smaller pieces of the biosphere.  The levels increase in complexity as the numbers and interactions between organisms increase, which is why it is called the hierarchy of complexity.

The levels of organization are:

Individual organism - the lowest level of organization is the organism itself - one organism of one (any) species; an example can be one elk (as in the picture above) or one pine tree or one bacteria.

 Population - the number of organisms of a single species that occupies a certain area at a certain time;  for example, the population of betta fish in our classroom yesterday was 2; the population of humans in our classroom on Tuesday, Dec. 4th during 3rd & 4th period was __(and zero on the same day at 10 pm).

 Biological community - a group of interacting populations that occupy the same area at the same time For example, the populations interacting in our classroom last week during Intermediate Science included 16 humans, one each of 5 different species of plants, a tobacco hornworm pupae, a few box elder bugs we didn't count.  Note that I specified the different populations of each species present in a particular location (our classroom) at a particular time (last week during Intermediate Science).  Note also that I did NOT include any abiotic component.

 Ecosystem - a biological community AND all the abiotic factors that affect it
Abiotic factors include many things, such as temperature, precipitation, availability of water, air, light, and other non-living features such as rocks, soil, mountains etc.
It's important to note that an ecosystem can be as small as the little pond at the end of the drainpipe or the soles of your feet and as big as a forest growing on a mountainside.  Ecosystems have no strictly defined boundary, and they can overlap with other ecosystems (just as a  turtle that is part of a river ecosystem might leave the river to lay her eggs in a grassy riverbank and become part of the grassland ecosystem). 
Using our classroom as an example, we could list all the populations in the biological community AND the abiotic factors such as the temperature (determined by how we set the thermostat), precipitation (none-unless the roof leaks), amount of sunlight or electric light, the walls and floor and furniture in the classroom, the glass of the windows, the water coming through the faucet and every other abiotic thing that is in our classroom.  Another example could be the prairie next to our playground and say the time frame is the last 6 months - the biological community would include different species of bacteria, worms, various species of birds, deer, fox, humans, different species of flowering grasses and plants etc. and the abiotic parts would include the average temperature, the amount of sunlight and precipitation, the air, the slope of the hill and the soil and rocks that make up the hill etc. 

Biome -  large geographic areas on the planet that have two things in common: 1) they share the same climate and 2) have similar, but not necessarily identical types of plant/animal communities; biomes can be in very different locations, even on different continents, but still belong to the same biome

Biosphere - the thin life-bearing outer layer of the Earth that extends from the deepest parts of the ocean to miles high into the atmosphere "bio" is latin for life and "sphere" is geometric shape similar to a ball or the earth.