What is Conservation Biology? Ch. 1: An overview

What is Conservation Biology?
Ch. 1: An overview
American ConBio History
• John Muir
• Founder Sierra Club
• Preservationist ethic:
set aside areas from
human development
• Wilderness: spiritual
and artistic uses.
American ConBio History
• Gifford Pinchot
• First head US Forest Service
(early 1900s)
• Resource conservation ethic:
use resources wisely for all
society.
American ConBio History
• Quote: “greatest good of the greatest number
for the longest time”
• Legacy: “multiple use” philosophy (manage
for several functions)
American ConBio History
• Aldo Leopold
• Land ethic: humans a part of
ecosystems rather than apart
from them
– Management can:
– 1) maintain ecological
processes & ecosystem health
– 2) enhance diversity beyond
natural communities.
American ConBio History
• Recent expansion:
“reconciliation ecology”
(Rosenzweig 2001)
• Modify human habitats to
share with other species
• Also: Dr. Doug Tallamy
(Guest Lecture Oct. 19)
American ConBio History
• Rachel Carson: writer
• Book “Silent Spring” (1962)
• Motivated DDT legislation
Chapter 2:
What is Biological Diversity?
NatureServe
Explorer
Alabama
Natural Heritage
Program
Biological Abstracts
• The Delhi Sands Flower-Loving Fly: First fly on the
Federal Endangered Species List!
What is Biological Diversity?
• 1) Species diversity
– Provides resources
• 2) Genetic diversity
– Allows species to survive and
adapt (evolve!)
• 3) Community diversity
– Supports ecosystem function
– Provides human benefits:
ecological services (filter
water/air, flood/erosion control,
etc.).
Species diversity: what is a species?
• Morphological def’n: Group
morphologically, physiologically,
biochemically different from others
• Biological def’n: Interbreed to
produce fertile offspring
• Phylogenetic def’n: Share recent
common ancestor
Species diversity: what is a species?
• Practical def’n: Whatever a competent
taxonomist says it is!*
*Supreme Court Justice Potter Stewart (1964),
Jacobellis vs. Ohio, on defining obscenity: “I
know it when I see it”
Species diversity: what is a species?
• Rare Species Webpage connection:
– Species description
– Taxonomic history
• Both belong in “General Description” section!
General description of the species: Provide an overview of the species.
Don't assume that because it's a duck we all know the general features of ducks.
Be sure to explain unusual technical words so that a generalist can get an idea
what you are talking about. Provide specific differences between this species and
others similar to it (including other subspecies if present). Also include how to tell
this species from similar-appearing members of other genera, families, etc. This is
very helpful information, as it can show how someone can tell if they have seen a
rare species (or have a particular species on their land).
Also include the reference for where the description of the species was first
published and information regarding classification changes. The latter information
can be very helpful for people interested in learning about a species' taxonomic
history. The former can give helpful information on the species' key
characteristics, range, etc.
Species diversity: what is a species?
• Rare Species Webpage connection: Species
description!
Importance of species def’n
• Described as species
(1851)
Gray
Wolf &
Range
Map
Canis lupus
Red Wolf
Canis rufus
Importance of species def’n
•
•
•
•
Predator control programs!
Endangered 1967
Captive breeding 1973
Extinct in wild 1980
– Captive breeding program
– $millions…..
Shrek
Importance of species def’ns
• Problem? 1994 genetic study: red wolf hybrid
between gray wolf and coyote
– Likely detected hybridization of red wolf + coyote
• Currently: courts rule it distinct species
Who am I??
Species and hybridization
• Hybrids: fertile offspring 2 taxonomic species
• Introgression: transfer genes between species
via hybrids
– Can erode species identity
Hybridization examples:
Ethiopian Wolf
• Critically endangered
• Mates with feral dogs
• “Genetic assimilation”:
Canis
simensis
swamping rare species’
identity thru introgression
Canis familiaris
Locutus
Hybridization examples: Lantana
depressa
• Found only in Dade County FL
Hybridization examples: Lantana
depressa
• Hybridizes Lantana camara
(introduced shrub)
• Hybrids & Lantana camara genes
spreading
Lantana camara
Can hybridization help?
• Ex: Florida panther
– About 110 (pumas or
cougars)
– One of 30 subspecies
– Low genetic diversity
(inbreeding depression)
Current range
Can hybridization help rare organisms?
• Texas pumas introduced (1995): add new
genes
• Question:
– Change conservation status Florida panther?
– Now 18-22% Texas genes!
Are species the target “unit”?
• Recall taxonomic levels
Are species the target “unit”?
• Degree uniqueness: conservation criterion
• So: emphasize species, genera, families?
• Tuatara: Last example of Rhynchocephalians
(beaked reptiles)
How new species arise?
• BIOL review!
How new species arise?
• Phyletic speciation: One species changes
thru time
• Divergent evolution: Breeding barriers
allow populations to evolve independently
Divergent evolution
• Allopatric: populations
separated in space
(geographic isolation)
• Peripatric: population enters
isolated new niche, evolves
• Parapatric: population
enters new adjacent niche,
evolves
• Sympatric: speciation
occurs within original
population
Sympatric speciation
• Polyploidy (often plants): multiple sets
chromosomes due to non-disjunction (meiosis)
How do new species arise?
• Adaptive radiation: Rapid speciation when
new habitats colonized (common: islands)
Problem!
• Speciation vs. extinction determine # species
• Evolution slow, extinction fast!
– Estimates: current extinction rate >35 times
(maybe >1000 times!) speciation rate
– And slowing!
Rate evolution slow
• And slowing!
– 1) Fewer populations
– Local extinctions decrease evolutionary
potential
Federally endangered
American Burying Beetle
Rate evolution slow
• And slowing!
– 2) Protected areas too small to evolve in (prevents
geographic isolation)
Area in which 1
species
has split to form
two
Areas of
large National
Parks
Fig. 2.4
Rate evolution slow
• And slowing!
– 3) Some species last of distinct lineages - these arise
more slowly than species
– Ex: who am I?
Measuring species diversity
• Species richness: number species present
• Also called alpha diversity
• Species diversity: combination richness and
evenness
– Evenness: how numbers individuals
divided among species
Measuring species diversity
• Diversity indices: math approaches
• Example: Shannon Wiener Index:
s
H´ = - pi logepi
i=l
–
–
–
–
H´ = Value of index.
Pi = Proportion inds. in the ith species.
loge = Natural logarithm.
S = Number of species in community.
2. Genetic diversity….What is
genetic diversity?
What you should know…….
• Gene: basic unit heredity (expressed as phenotype)
• Allele: alternate form of gene
• Locus (plural: loci): position or place on
chromosome
• Heterozygote: individual possessing two different
alleles for given locus (e.g., Aa)
• Homozygote: individual possessing identical
alleles at given locus (e.g., AA or aa)
What is genetic diversity?
• Heterozygosity (H): fraction individuals
heterozygous per locus
• Measure genetic variation within population
• High H generally good (Why?)
BGYNH:
Be Glad
You’re
Not
Haploid!
Why is genetic diversity
important?
• High H generally good
– 1) Masks harmful alleles (ex, lethal
recessives)
– 2) “Raw material” for evolution:
adaptation to change
BGYNH:
Be Glad
You’re
Not
Haploid!
Measuring genetic diversity
• Allozymes: protein phenotypes
(e.g. enyzmes) reflect genotypic
differences
• RFLP: differences in DNA
sequence using restriction
enzymes
• Molecular markers: molecular
“alleles” (e.g. microsatellites:
“junk”)
• Mitochondrial DNA (mtDNA):
compare sequences between and
among populations
scott
Measuring genetic diversity
• Guest lecture #6 (11/18): Dr. Scott Santos
Halocaridina
shrimp
Calculating H
• Score individuals as homozygous or
heterozygous
• Calculate proportion heterozygous loci in
each individual
• Average across individuals = H
H in vertebrates
• Allozyme data (n=648 species)
• Notice all values <0.25!
From Avise (1994)
Examples of H
• Who am I?
– 30 individuals in
1900
Man, am I
lonely or
what??
Examples of H
• Northern Elephant Seal
– 30 individuals in
1900
– Now 130,000+
– Conservation success
story
That’s
better!!
Examples of H
• Northern Elephant Seal
– Little genetic
diversity
– Due to genetic
bottleneck (type of
genetic drift)
– 55 allozyme loci:
H=0
Examples of H
• Who am I? (Fastest!!)
• Allozyme study: 155
proteins
• H=0.013
Examples of H
• Cheetah
• Allozyme study: 155
proteins
• H=0.013
• Genetic similarity great:
skin grafts between cats
accepted as “own” skin!
• Lesson???