EVOLUTIONARY ECOLOGY A HISTORICAL PERSPECTIVE

Evolutionary ecology is probably best described as an approach to the study of ecology 1. Recognized by the way in which ecological problems are conceived and analyzed using ecological, genetic and evolutionary principles 2. Branch that considers how organisms have evolved to become adapted to their environment

Take Home Message for Today Ecology developed considerable autonomy in the first half of this century, thus the fusion of ecology and evolutionary biology was a real event. Three elements led to the emergence of Evolutionary Ecology 1. Proximate-ultimate perspective (or Functional- Evolutionary/Historical perspective) 2. Commonness of microevolution 3. Strength with which natural selection was expected to act at various levels of biological organization NOW, THE REST OF STORY!

Uniting concepts from ecology and evolutionary biology Why would one ask, what is “nonevolutionary” ecology?

For much of the early history of ecology and evolution, the distinction between the fields was blurred or nonexistant Nonetheless, ecology developed considerable autonomy throughout the first half of this century

Reasons include the following 1. Perceived need for ecology to gain respect as an independent science 2. Adaptive radiation into specialized niches 3. The core concept of Darwin’s theory, natural selection, fell into disrepute for much of the early 20th century

Because ecology did develop considerable autonomy throughout the first half of this century, its conjunction with evolutionary biology in the 1960’s was a real event Orians, G.H Natural selection and ecological theory. American Naturalist 96:

There were 3 elements that led to the emergence of evolutionary ecology 1. Functional-evolutionary or proximate- ultimate perspective 2. Commoness of microevolution in natural communities 3. Strength with which natural selection was expected to act at various levels of biological organization

Functional biologists focus on “how” biological processes operate Evolutionary biologists pursue causation by asking “why” a particular trait has evolved

Neither alone provides a complete explanation Mayr, E Cause and effect in biology. Science 134:

Four factors need to be considered 1. An ecological cause 2. A genetic cause 3. An intrinsic physiological cause 4. An extrinsic physiological cause

The immediate causes of migration are the physiological condition of the bird and the sudden decrease in temperature These are the proximate causes of the migration

Mayr contrasts them with lack of food during the winter and the genotype of the bird, both of which are ultimate causes of migration Ultimate causes are distinguished primarily by their historical component

Commoness of Microevolution “increasing evidence has been accumulated to show that evolutionary, population genetic, biogeographic, and demographic events are not on entirely incommensurate time scales”

This condensation of scales was probably an important factor in the union of ecological, genetic and evolutionary theory during and since the 1960’s

As evolutionary ecology developed two different approaches were taken 1. One approach combined population genetics and ecology 2. The adaptationist approach

Level of Selection V.C. Wynne-Edwards and Group Selection vs. G.C. Williams and Individual Selection