Lecture 2

Biology 5865 –

Conservation Biology

What is Biological Diversity? • Chapter 2 – spend additional time on this chapter if

you have not had “ecology”

• Generally – know the meaning and use of terms in

bold – also throughout the book

“Biodiversity contains the accumulated wisdom of nature and the key to its future. If you ever wanted to destroy a society, you would burn its libraries and kill its intellectuals. You would destroy its knowledge. Nature’s knowledge is contained in the DNA within living cells. The variety of genetic information is the driving engine of evolution, the immune system of life, the source of adaptability.”

(From Meadows 1990 - Biodiversity: the key to saving life on earth. Land Stewardship Letter 4-5)

from an Indian newspaper - Hyderabad

January 7, 2009

Box 2.1 Naming and Classifying Species

Figure 2.14 Keystone species determine the ability of large numbers of other

species to persist within a biological community

What is biological diversity?

(from Groom et al. (2006)

• “The sum total of all living things – the immense richness and variation of the living world.”

• “Few people are aware of the full spectrum of biodiversity, because our own experience focuses on interactions with people and those species that interact directly with people”

• Ignorance is bliss (my comment)

What is Biological Diversity or Biodiversity?

“The variety and variability among living organisms and the ecological complexes in which they occur.” (US Office of Technology Assessment, 1987)

Primack (2010) subdivides into three levels:

1. Species diversity – All the species on Earth, from single-celled bacteria and protists to the multicellular kingdoms (plants, fungi, and animals),

2. Genetic diversity - The genetic variation within species, both among geographically separate populations and among individuals within single populations, and

3. Ecosystem diversity - The different biological communities and their associations with the chemical and physical environment (“the ecosystem”).

What is Biological Diversity continued..

• Most „modern‟ definitions, however, would include basic biological and ecological processes that have led to the previous 3 – “the ecological processes that link with one another and with soil, air, and water” (Hunter 1996)

• Another viewpoint (Noss 1990)

– Structural diversity - genetic structure, physiognomy, landscape patterns

– Functional diversity – ecological and evolutionary processes (e.g., photosynthesis, biogeochemical cycling, predation, parasitism, life history, etc.)

– Compositional diversity – genes, species, ecosystems

David Montgomery – Professor of Earth and Space

Sciences, University of Washington

What is biological diversity – continued?

Noss (in Groom et al. 2006) –

• “Biodiversity and how to save it is the subject

matter of conservation biology”

• “It (biodiversity) is complex and it is always

changing”

• “How on earth can a conservation biologist or

land manager deal with this mess?”

The Species Game

• Estimated 26,000

species vanishing each

year

• About 18,000 species

described each year

• In 2007

– 75 % were invertebrates

– 11 % were vascular plants

– 7 % vertebrates Science 330: 745, 5 Nov „10

Biodiversity – the Heart of Conservation

Biology

• What is species diversity?

• What is genetic diversity?

• What is ecosystem diversity?

• Where is this diversity?

• Why is this diversity there?

• Is high or low diversity good or bad?

What is a species?

• Species are groups of actually or

potentially interbreeding natural

populations, which are reproductively

isolated from other such groups (Mayr

1942 from Hunter 1996, p. 32)

What is a species - 2

Species are generally defined in one of two ways (Primack 2002, 2006, 2010):

1. A group of individuals that are morphologically, physiologically, or biochemically distinct from other groups in some important characteristic is the morphological definition of species – (most commonly used by taxonomists) – genetic methods are increasingly being used to distinguish species,

2. A group of individuals that can potentially breed among themselves in the wild and that do not breed with individuals of other groups is the biological definition of species.

What is a species? - 3

• The ambiguity of the “species category” –

stems from the fact that the biological

world is a continuum of organization, from

atoms and molecules, through cells, organ

systems, and individuals, to populations

and species, to communities, ecosystems,

and landscapes. Cut-off points that

separate categories within this continuum

are often fuzzy (Meffe and Carroll 1994).

Complications of the species

concept – it is not necessarily clear

• A single species may have many varieties – – Dogs – all derived from the gray wolf,

– Cabbage, cauliflower, brussels sprouts, and broccoli all derived from Brassica oleracea

• Is the Mallard duck a separate species from the Black Duck or from the Mexican duck?

• What is a subspecies in light of geographic variation?

• It is estimated that 70 % of angiosperms owe their origins to hybridization (Grant 1981, Whitham et al. 1991 from Hunter 1996, pg. 33).

Two major ways of viewing species

(adapted from Meffe and Carroll (1994)

• Typological - views species as categorical entities, distinct and somewhat clearly differentiated. Originated from the Greek philosopher, Plato, who maintained that all physical objects in our world represent an eternal and changeless ideal or “perfect type” - variations about that ideal are merely unfortunate imperfections of the material world.

• Populational or evolutionary - focuses directly on the variation within species. This view recognizes that a category such as the species is a group of individuals that collectively express genetic, morphological, physiological, and behavioral variation. This variation is not unimportant and annoying, but is in fact the basis for evolutionary change and adaptation.

“For the typologist, the type is

real and the variation an illusion,

while for the populationist the

type (average) is an abstraction

and only the variation is real. No

two ways of looking at nature

could be more different” (from

Mayr 1959).

Current View of Species

• Virtually all contemporary biologists accept the population view of species, but genetic analysis is the “best” way to define a species

• Population view of species emphasizes the need to preserve the genetic variation of species, but how much can be preserved? This is a hot topic and a difficult one to deal with in conservation biology (e.g., protection of subspecies, protection of species populations throughout their range, etc.)

• It is obvious by now that the nature and definition of species is an area fraught with difficulty, and one which has the potential to bog us down and obstruct our progress toward more pressing questions in conservation (Meffe and Carroll 1992)

• Conservation biologists need to be aware of the debate over species definitions, but they cannot allow themselves to be paralyzed by it (Rojas 1992 in Hunter 1996, p. 34)

Summary of species concept

• Biologists need to understand the Biological Species Concept and its shortcomings

• Yet, the public will best understand “species” protection, especially charismatic megafauna like mammals and birds – e.g., mountain lion, gray wolf, spotted owl, elephants

and other flagship species

• Preservation of genetic diversity, ecosystems, habitats, etc. must be done on large “ecosystem” and “landscape” scales along with corridors of interconnecting areas to allow appropriate gene flow among populations

Beetles not Beatles

• When asked by a group

of theologians what he

learned about God from

having spent a lifetime

studying His creations,

J.B.S. Haldane (a 19th

century biologist) replied

(in Hunter 1996, p. 34) -

• “ He seems to have

inordinate fondness for

beetles.”