How to predict whether a species will become extinct?

Conservation biologists use population viability analysis (PVA), a relatively new method, to predict the viability of a species in a particular habitat. Computer modeling generates PYAs using life history data, genetic variability, and a population's response to environmental conditions-especially disturbances-to predict viability of a species.

How does comparative biochemistry provide evidence for evolution?

The evolutionary relationship between many organisms can be traced back to a common ancestor. A common ancestor is an individual from which two or more related species could have evolved. With the passage of time, organisms change and diverge from their common ancestor to form new species. The following evidence for evolution demonstrates the concept of the common ancestor. DNA, RNA, the genetic code and protein synthesis are similar in all organisms. The greater the genetic and molecular similarity between species, the closer their common ancestor. Humans and chimpanzees have 98% of their genes in common. The remaining 2% is what distinguishes these two species from each other. Humans did not descend from chimpanzees but from primitive humans. However, at some point in evolutionary history, primitive humans and primitive chimpanzees probably diverged from a common ancestor. Diabetics can use insulin from cows and pigs because insulin from these animals is almost identical to human insulin. In addition, hemoglobin in humans, which has almost 600 amino acids, is almost identical to hemoglobin in all other vertebrates. This similarity in chemical structure demonstrates that all vertebrates can be traced back to a common ancestor.

What are the strengths and weaknesses of an ecological perspective in understanding life?

The great strength of ecology is that it deals with living things in terms of their natural surroundings rather than in artificial isolation. Other branches of biology focus upon particular aspects of organisms and may thereby lose the reality of connections and interrelationships that are vital to understanding life in its entirety. Ecology, by its very nature of focusing on the context within which organisms develop and function, brings together a variety of disciplines. Evolution, which provides a central structure in the study of biology, can be fully appreciated only from
the ecological vantage point of populations interacting with their environment.Anatomy, systematics, biochemistry, and even molecular biology becomemore fully focused when utilized in analyses of ecosystems.Onamore practical level, the study of existing ecosystems has vitalized the conservation movement and enhanced the active effort to
maintain ecosystems or even individual species of plants or animals threatened with extinction. Apossible weakness of ecology stems from the broad spectrum of its concerns—it tends to be diffuse. Individual ecologists do focus on particular aspects of communities or the physical environment but the novice might find the field daunting by its very breadth. In its descriptive phase, that breadth was more easily handled.The recentemphasis on experimentation tends to encourage a specialization within the field but experimentation introduces another problem. With experimentation, controlled conditions may not be readily obtained in a field situation. Ecosystems can be studied froma passive approach, in which the experimenter merely observes such phenomena as energy flow, diversity of species, etc., but more ambitious attempts to establish an ecological science require interventions that may be difficult to isolate and control. Some success has been achieved, particularly where clear boundaries to a habitat exist, such as on islands