The interaction of questions in evolutionary ecology

Throughout the book several issues have been raised in more than one chapter, implying that understanding one topic in evolutionary ecology can enhance understanding of another. This occurs for two reasons. First, the topics are biologically interdependent. Second, the techniques we can use to aid understanding are often general. These connections have also led many notable evolutionary ecologists to move from one subject to the next. Let us now recap the connections illustrated by the book...

Extinction when rare

A variety of processes may eventually cause population extinction once the population has reached a small size or range. The importance of these processes can vary with the size of the population and the characteristics of the species. Many of these processes are stochastic, meaning they are not exactly predictable but occur with a probability that can be known. Others are more predictable or 'deterministic'. The processes can be environmental, demographic, or genetic in nature (Lande 1988). We...

Evolution of the biosphere a brief history

The origin of the biosphere and of earth's ecology occurred between 3.8 and 3.5 billion years ago. Both autotrophic and heterotrophic origins have been proposed. Previously the heterotrophic use of organic molecules synthesized in the pre-biotic broth was a popular idea (see Lazcano and Miller 1999). More recently, autotrophic theories have re-emerged, for two reasons first, early cell membranes would probably have lacked sufficient permeability to transport large molecules. Second, it is now...

Cichlids and evolutionary ecology

The cichlid story illustrates many of the broader features of evolutionary ecology, the science that involves both ecological and evolutionary knowledge. Evolutionary biology is the field concerned with understanding how biological lineages change through time (anagenesis), split (cladogenesis), and ultimately go extinct. Ecology is concerned with the interaction of organisms with their environment. The organisms can be considered at various levels of a hierarchy, comprising the individual, the...

The origins and maintenance of mutualism

Figures 10.3, 10.4) are those interactions in which both partners accrue increased fitness relative to individuals that do not engage in it. How might selection favour the expression of traits that help other individuals of a different species, given a prior relationship that was more nearly neutral or even antagonistic Frank (1997) has suggested that two processes act to help the spread of such traits first, an initially high level of expression on first meeting in both...

The evolution of animal flight understanding a major transition in ecology

There is now little doubt among most biologists that birds derive from a group of theropod dinosaurs. The theropods were a bipedal carnivorous group that share many anatomical features with birds. A series of recent fossils, most notably from Liaoning province of China and described by Xu Xing and colleagues, include therapods with epidermal feather-like structures that we might collectively refer to as 'fuzz'. They were pre-adapted for flight through a fast cursorial predatory lifestyle. This...