Botany: An Introduction to Plant Biology - Mauseth, James D. 2017

Ecology

Part Opener Image: We people are the species that has the greatest impact on the ecology of all parts of Earth. This is the Trans-Alaska oil pipeline, and although its construction did disturb the ecology of the region, its operation has been safe, in general. The pipeline runs above ground so that the warm oil will not melt the permafrost. An important aspect of ecological studies at present is to search for ways for us to do less harm to the environment, to preserve natural areas, and to minimize our negative impact on the other creatures that share Earth with us.

The focus of this final part is the plant in its environment—plant biology in the broadest scope. An important aspect of the biology of a plant is to view it as a member of a population; population biology differs from the biology of individual plants. A dense population of grasses will attract the attention of grazers such as deer, and many plants will be eaten; however, if a grass plant is a member of a sparse, widely scattered population, grazers may overlook it, and it might not be harmed. The plants we are considering may be absolutely identical, but their fates will differ because of the nature of the populations of which they are a part.

Every plant is also affected by all other aspects of its immediate environment, which in turn is part of a larger environment—a continent or island or perhaps the water of a lake or ocean. Climate must also be considered. None of these factors is uniform in either time or space; there are differences in soil, rainfall patterns, disturbances, and day length. On a larger scale, periods of global warming alternate with ice ages while the continents drift across the surface of the planet. In addition, each organism is affected by at least some of the other organisms around it, and as they undergo their own evolution, their impacts on each other are altered. Earth’s surface is composed of a rich, changing mosaic of diverse habitats. Within this milieu, evolution by natural selection has produced hundreds of thousands of species of prokaryotes, protists, algae, fungi, animals, and plants. Their various adaptations for particular aspects of the environment have determined where they will survive and where they will be outcompeted by organisms that are better adapted.