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???