SCN3230-ABED_1: Unit D Introduction

Introduction

Not that long ago, the howling of wolf packs could be heard at night over most of North America. Sharp-toothed and with keen sight and sense of smell, wolves can travel at a long-legged lope for hours in steady pursuit of prey. As major predators of rabbits, mice, deer, elk, and bison, they helped to keep prey populations in check and cleansed the gene pool of the weak and the sick. Today, few wolf packs remain. Ecological communities in which the wolf was an essential player now rely on other predators to fulfill their role with greater or lesser success. Why have wolf populations declined so rapidly? Is human activity the cause, or are other factors at work? Have the characteristics of wolves changed along with population numbers? Is the same decline seen in wildlife preserves? How do we know?

Despite the knowledge biologists have gained about the physiology, environmental influences, and genetics of organisms, we still know very little about how all these factors combine to influence changes in the numbers and characteristics of populations. Scientists continue to collect data to determine how interactions within and among populations contribute to changes in populations and how growth patterns differ among species.

This final unit of Biology 30 considers the processes biologists use to determine how populations change over time.

You will learn

the techniques used to count members of a population
the ways to express this information quantitatively so that it has meaning for wildlife managers who must monitor and attempt to prevent population change.

You will consider

how organisms interact with each other to fulfill their respective roles within ecological communities
how organisms defend themselves in a competitive world in which the goal is to live long enough to reproduce and pass on their genes
population growth models developed by biologists to describe various species, and you will learn how to analyze population data to determine if there is cause for concern

You will analyze

the growth of the human species as an example of a population whose growth is problematic and affecting significantly the growth patterns of other species with whom we share the planet