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39 Cards in this Set

  • Front
  • Back

Biological Species Concept

a group of actually or potentially interbreeding "natural populations that are reproductively isolated from other groups"

Evolutionary Species Concept

"Single lineage of ancestral-descendant populations which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate"

Evolutionary Significant Units

Geographically isolated portion of species population that has a high level of genetic variation from other subpopulations of the same species

Ex. - Buena Vista Prairie Chickens vs Mead Chickens

How many species (approx.) have been identified?

approx. 1.35million species

-majority are arthropods

How many species (approx.) are out there?

3-100 million (best guess is 8.7 million)

Fundamental Theorem of Natural Selection

Rate of evolutionary change is proportional to the amount of genetic variation available

Punctuated Equilbrium vs. Gradualism

Punctuated = quick change

Gradualism= slow change

"Commonness is rare....

and rarity is common"

Alpha Species Diversity

Diversity within a given community

-Simpson Diversity Index, Shannon-Wiener Diversity Index

Beta Species Diversity

Diversity between communities, how similar or different they are.

Measure turnover in community composition

-Sorenson's Coefficient of Community, Percent Similarity

Gamma Species Diversity

Region-wide diversity

How does altitude effect species diversity?

-Species diversity decreases at higher altitudes

-Every 100m increase results in 6 times decrease

What are the 2 most diverse ecosystems on the planets?

Coral Reefs and Tropical Rainforests

Environmental Factors Influencing Species Diversity

-Area (islands vs. mainlands)

-Structural Complexity (richness is correlated to structural complexity)

-Species-energy relationship (positive correlation between productivity and species diversity)


Potential Evapotranspiration

-as PET increases, species richness increases

-best predictor of primary production because there is a greater resource base, easier to survive in warm climates, increased competition in specialized niches


Intermediate Disturbance Hypothesis

-at some level of intermediate disturbance, you get the highest level of species diversity

Biogeographical Influences to Species Diversity

-Panacea, collision of the continents

-Some animals occur on different continents today but have a common ancestor

Genetic Diversity

-Portion of total observed variation that is genetically encoded (morphology, physiology, behavior, etc)

-Measurable at the indiv, population, and species levels

Reproductive Fitness

-fecundity, sperm quality and quality, mate choice, nest defence, survival, etc

Adaptive Potential

-respond to environment change (pathogens, parasites, invasive species, global climate change)

Evolutionary Potential

-speciation/adaptive radiation (e.g. Darwin's Finches)

Net Effective Population

-not censused N, but those genetically unique individuals contributing offspring to future generations

Founder Effect

-propagules starting a new population contain fewer genes than the mother population, hence limited genetic diversity

Genetic Drift

-random changes in gene frequency that can lead to loss of genetic variation

-the amount of heterozygosity loss depends on population size

-a few generations of genetic drift at low populations is very erosive of genetic variation


-dramatic reduction in population size during a short period of time (single generation event)

Impacts of Bottlenecks

-loss of heterozygosity is not severe

-loss of alleles at low frequency is serious

Inbreeding/Outbreeding Depression

-outbreeding depression= reduction in fecundity, offspring size, growth, survivorship, physical deformities due to: dominance hypothesis, overdominance hypothesis

-Measured by Wright's Inbreeding Coefficent

Overdominance Hypothesis

loss of heterozygosity and fitness advantages

Dominance Hypothesis

expression of more deleterious recessive alleles

Symptoms of Ecosystem Risk

1.) rates of decline in ecosystem distribution

2.) restricted distribution with continuing declines or threats

3.) rates of environmental (abiotic) degradation

4.) rates of disruption to biotic processes

5.) quantitative estimates of ecosystem collapse

Coarse Filter

community level conservation strategy; estimated 85-90% species can be protected by protecting natural communities

Fine Filter

Inventory and management of individual species, ESA approach

Flagship Species

Species that can be used to anchor a conservation campaign and public interest and sympathy

Ex. World Wildlife Fund (Giant Panda), Pheasants Unlimited

Umbrella Species

species that needs such large tracts of habitat that saving it will automatically save others

Biodiversity Indicator Species

species that whole presence, flucuations, or productivity are used to reflect attributes too difficult, inconvenient, or expensive to measure

Taxon-based Indicator

presence/absence of species is correlated with changes in biodiversity in a taxon

Ex. Hairy Woodpeckers

Structure-based Indicator

indicates changes in biodiversity through changes in ecological structure (i.e. folliage height density = bird spp. richness)

Function-based Indicator

keystone species concept

active determinants of the ecosystem because of ecological function they perform

Focal Species

management and monitoring for these species insures that a landscape designed and managed to meet their needs will encompass requirements of all other species