ECOLOGY

How we can clarified about ecology

Darwin's finches teach us an important lesson about evolution, which is that understanding how natural selection occurs is really a matter of understanding how species adapt to particular niches. As we saw on the preceding pages, the diversity of finches Darwin found on the Galapagos Islands arose as a consequence of the availability of a variety of niches on the islands, each fostering the evolution of a new finch species. In a very real sense, the nature of the habitats the finches invaded, and the ways in which different populations of finches came to utilize these habitats, determined the course of the evolutionary radiation that followed. Biologists who study the nature of niches, and how the species that occupy them inter-act, are called ecologists. The word ecology was coined in 1866 by the great Ger-man biologist Ernst Haeckel to describe the study of how organisms interact with each other and with their environment. It comes from the Greek words oikos (house, place where one lives) and logos (study of). Our study of ecology, then, is a study of the house in which we live. Do not forget this simple analogy built into the word ecology—most of our environmental problems could be avoided if we treated the world in which we live the same way we treat our own homes. Would you pollute your own house?

Easy Guide To Know Levels of Ecological Organization

 Ecologists consider groups of organisms at five progressively more encompassing levels of organization.

 1. Populations.Individuals of the same species that live together are members of a population. 'they potentially interbreed with one another, share the same habitat, and use the same pool of resources the habitat provides.

2. Communities. Populations of different species that live together in the same place are called communities. Different species typically use different resources within the habitat they share.

3. Ecosystems. A community and the nonliving factors with which it interacts is called an ecosystem. An ecosystem is affected by the flow of energy, ultimately derived from the sun. and the cycling of the essential elements on which the lives of its constituent organisms depend. The Galapagos Islands pictured in figure 2.13 are an ecosystem, where the giant tortoise and other organisms interact with each other and with their biological and physical surroundings.

4. Biomes. Biomes are major terrestrial assemblages of plants, animals, and microorganisms that occur over wide geographical areas that have distinct physical characteristics. Examples include deserts. tropical forests, and grasslands. Similar groupings occur in marine and freshwater habitats.


5. The biosphere. All the world's biomes. along with its marine and freshwater assemblages, together constitute an interactive system we call the biosphere. Changes in one biome can have profound consequences for others.

Some ecologists, called population ecologists, focus on a particular species and how its populations grow. Other ecologists, called community ecologists, study how the dif-ferent species living in a place interact with one another. Still other ecologists, called systems ecologists. are interested in how biological communities interact with their physical environment.