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Fundamentals of Ecology

Chapter 1

Introduction to Ecology

1. Introduction

1.1. What is Ecology

As we human beings have societies, nature has it too. We are connected to one another in innumerable types of relationships, each interacting with the rest of the environment, both social and natural. Things such as money that we need pass from one to another, mostly in balance. Nature organizes in almost the same way, only with far more species and the things pass through this mechanism do not include money. In fact, human society is no more than a part of the nature society, a community in biosphere at the global level, which we will be talking about.

So, ecology is just the study of the inclusive nature society dealing with interactions of organisms with other organisms and with the physical environment. Specifically speaking, ecology talks about the processes that determines the distribution and abundance of organisms and the interrelationships among them. In addition, transport and transformation of energy and matter in the biosphere is also an active topic of ecology.

1.2. Classification of Living Things

Before dipping into the various scales of ecology, let's first have a glance at the classification of living things. Modern classification of organisms is based upon the binomial system that gives each species a two-part name. So, honeybee becomes academically known as Apis mellifera.

Scientific taxonomy and classification are built upon several sources of biological data, including homology, genetic data, and the fossil record. Although approximately 30 taxa e.g. superkingdom and subphylum are devised for the classification of 1.4 million known species out of 30 million estimated on earth, 7 taxa are most commonly used. They are kingdom, phylum(or division, for kingdom plantae), class, order, family, genus and species. Kingdoms are the most inclusive level of biological classification. Universally acknowledged kingdoms and their evolutionary relationships are represented below in a very plain manner.

5 Kingdoms and the Evolutionary Relationships

		Monera
		Protista
	Plantae	Animalia	Fungi

For further information, refer to the exterior links section. Following is a table of three representative species described in the modern classification schema.

As you can see from the table above, the species of an organism is indicated by its complete binomial name. Human, for example, is named uniquely Homo sapiens in the binomial naming system, consisting the genus Homo and a specific epithet sapiens.

1.3. Scales of Ecology

Organism		Organ		Tissue		Cell		Organelle		Molecule		Atom
Population		Group of interacting and interbreeding organism of the same species.
Community		Different populations(groups of different species) living together interacting as competitors, predator and prey, or symbiotically.
Ecosystem		Organisms and their physical and chemical environments together in a particular area. "The smallest units that can sustain life in isolation from all but atmospheric surroundings."
Biosphere		Thin film on the surface of the Earth in which all life exists, the union of every ecosystems on earth. This is a highly ordered system, held together by the energy of the sun.
Adapted from http://ocw.mit.edu/OcwWeb/Biology