Chapter 57: Conservation Biology
57.1 What is Conservation Biology?
• Devoted to preserving the diversity of life on Earth
• Draws heavily on concepts and knowledge from population genetics,
evolution, ecology, biogeography, wildlife management, economics and
Conservation biology is a normative scientific discipline
• Conservation biology is a normative discipline embraces certain values
and applies scientific methods to the goal of achieving these values;
motivated by the belief that preservation of biodiversity is good and that loss
• Is guided by three principles:
o Evolution is a process that unites all of biology.
o The ecological world is dynamic.
o Humans are a part of ecosystems.
Conservation biology aims to prevent species extinctions
• Organisms have always altered Earth’s ecosystems.
• Very first organisms probably reduced the supply of energetically and
structurally useful compounds (replacing them with waste products).
• Early photosynthetic prokaryotes and eukaryotes generated oxygen
(unsuitable for anaerobic organisms).
• Plants colonized the land, accelerating the weathering of rocks thus, gaining
access to rock-bound nutrients.
• Weathering of phosphorus increased global productivity = rise of oxygen
• Rise of vascular plants increased oxygen concentration; lower carbon dioxide
• Human beings cause extinctions of other species
o When first arrived in N. America (20 000 years ago), encountered a
rich fauna of large mammals.
o Most species were exterminated (overhunting) within a few thousand
• The productivity and richness of Earth’s biota has increased during the long
course of life’s evolution, but current situation is unique: all environmental
changes are being caused by a single species.
• That’s why now more and more people value biodiversity for many reasons:
o Humans depend on other species for food, fiber, and medicine
o Species are necessary for the functioning of ecosystems and its many
benefits and services.
o Humans derive enormous aesthetic pleasure from interacting with
o Extinctions deprive us of opportunities to study and understand
ecological relationships among organisms.
o Living in ways that cause the extinction of other species raises serious
57.2 How Do Biologists Predict Changes in Biodiversity? • To preserve Earth’s biodiversity, we need to both maintain the processes that
generate new species and provide conditions that will keep extinction rates
at a typical level
• There are four reasons why scientists cannot accurately predict the number
of future extinctions:
o Do not know how many species live on Earth.
o Do not know where species live (i.e. animal ranges are poorly known).
o Difficult to determine when a species actually becomes extinct.
o Do not know what will happen in the future.
• Regardless, there are some methods for estimating probabl