Askjagden's Guide to Biology: the Biosphere
Because this will be my first guide on ecology, I shall tell you what it is. In 1866, Ernest Haeckel coined the term "ecology" to describe the interactions among organisms and between organisms and the environment. (Environment here means "surroundings", so don't get any other ideas.) Ecology is a significant portion of biology, and a significant part of ecology is the level of organisms. An organism is a living being. Populations are groups of species -- the same species, let me emphasize. Communities are made up of different populations. Both populations and communities are made up of biotic things, which means living. An ecosystem, on the other hand, is many communites and the environment. The environment is, therefore, made up of biotic and abiotic factors (abiotic means nonliving). Biomes are made up of different ecosystems. And then, of course, the biosphere is planet Earth.
Another significant portion of ecology is the flow of energy. Energy usually starts at the sun. In fact, the sun is the main source of energy for life on Earth. There are a few organisms that rely on inorganic minerals, but every other ones rely on the sun. Here's how it works: Autotrophs, also called producers, are organisms that make their own food. This is made possible through the sun: photosynthesis is the process of using the sun's energy to make food. Autotrophs use photosynthesis to produce energy. Plants are not the only organisms on Earth that use photosynthesis. Alga and cyanobacteria also use photosynthesis. Chemosynthesis is the process of using chemical energy to produce energy. Some autotrophs use chemosynthesis instead of photosynthesis.
Energy then moves to heterotrophs, also called consumers. Heterotrophs are organisms that must obtain energy from other organisms. Note that I said energy moves. There are many different types of heterotrophs: herbivores eat plants; carnivores eat meat; detritivores eat dead things; decomposers break down organic stuff.
Energy flow can be demonstrated through food chains. Food chains display the direction of the flow of energy. Hence you do not draw an arrow from a grasshopper to grass; you draw one from the grass to the grasshopper. Food webs are made up of food chains. Each step is called a trophic level. Trophic levels can also be represented through pyramids. There are three main types of ecological pyramids (which are biological pyramids): the energy pyramid, the biomass pyramid, the pyramid of population. Energy pyramids show the flow of energy. 10 percent of energy is lost as moves from one trophic level to the next. Biomass pyramids show potential biomass. Biomass, by the way, is the amount of living tissue within each trophic level. A pyramid of population shows the amount of organisms within each trophic level. Remember this: the trophic level on top is the smallest because that level needs more energy than any other.
There are many cycles in the biosphere. A cycle is a repating process. These cycles are called biogeochemical cycles, which are biological, geological, and chemical aspects of the biosphere combined.
In the water cycle, water is evaporated. Water condenses to form clouds. Water is released back to the Earth's surface in solid or liquid form. Water also evaporates from solid to gas or liquid to gas. Change from liquid to gas is called evaporation. Change from solid to gas is called sublimation. The water cycle repeats itself.
Have fun with ecology and biology!
