Transcript Introduction - Department of Ecology, Evolution, and Organismal

Introduction to Biodiversity
Biology/Env S 204
Spring 2009
The variety of life
is biological diversity.
Use of the term
“biological diversity”
in its current sense began
in 1980.
Biodiversity = biological diversity
Coined in 1985 for a conference, the
proceedings of which were published
as the book “Biodiversity”edited
by E. O. Wilson.
What does it mean?
The variability among living organisms from
all sources including terrestrial and aquatic
systems and the ecological complexes of
which they are a part; diversity within
species, among species, and of ecosystems;
interactions at all levels among organisms.
From Frankel et al., 1995, The conservation of plant biodiversity.
Fundamental levels of
organization
• Genetic
• Organismal
• Ecological
Ecological Diversity
• Communities of species, their
interactions
• Communities + resources (energy,
nutrients, etc.) = ecosystem
• Measured primarily in terms of
vegetation but relative abundance of
species also important
• No unique definition and classification
at the global level
Organismal Diversity
• Individuals, species
• Mostly measured by numbers of
species
• Estimated 1.7 million species
described to date
• Estimated total number ranges from 2
to 50 million (up to 100 million)
species
• Mostly microorganisms and insects
Genetic diversity
• Heritable variation within and between
populations of organisms
• Encoded in the sequence of 4 base-pairs
that make up DNA
• Arises by mutations in genes
and chromosomes
• Very small fraction of genetic
diversity is outwardly expressed
Why care about what we can’t
see?
• Genetic variation enables evolutionary
change and artificial selection
• Estimated 109 different genes across
the Earth’s biota
• Represents a largely untapped genetic
library