Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Statistics for Spatial Data.

Nitrogen is a key element controlling the species composition, diversity, dynamics, and functioning of many terrestrial, freshwater, and marine ecosystems. Many of the original plant species living in these ecosystems are adapted to, and function optimally in, soils and solutions with low levels of available nitrogen. The growth and dynamics of herbivore populations, and ultimately those of their predators, also are affected by N. Agriculture, combustion of fossil fuels, and other human activities have altered the global cycle of N substantially, generally increasing both the availability and the mobility of N over large regions of Earth. The mobility of N means that while most deliberate applications of N occur locally, their influence spreads regionally and even globally. Moreover, many of the mobile forms of N themselves have environmental consequences. Although most nitrogen inputs serve human needs such as agricultural production, their environmental conse- quences are serious and long term. Based on our review of available scientific evidence, we are certain that human alterations of the nitrogen cycle have: 1) approximately doubled the rate of nitrogen input into the terrestrial nitrogen cycle, with these rates still increasing; 2) increased concentrations of the potent greenhouse gas N 2O globally, and increased concentrations of other oxides of nitrogen that drive the formation of photochemical smog over large regions of Earth; 3) caused losses of soil nutrients, such as calcium and potassium, that are essential for the long-term maintenance of soil fertility; 4) contributed substantially to the acidification of soils, streams, and lakes in several regions; and 5) greatly increased the transfer of nitrogen through rivers to estuaries and coastal oceans. In addition, based on our review of available scientific evidence we are confident that human alterations of the nitrogen cycle have: 6) increased the quantity of organic carbon stored within terrestrial ecosystems; 7) accelerated losses of biological diversity, especially losses of plants adapted to efficient use of nitrogen, and losses of the animals and microorganisms that depend on them; and 8) caused changes in the composition and functioning of estuarine and nearshore ecosystems, and contributed to long-term declines in coastal marine fisheries.

/pdf/human-alteration-of-the-global-nitrogen-cycle-sources-and-1xgqgm60gm.pdf

Human alteration of the global nitrogen cycle: sources and consequences

Nine polymorphic microsatellite loci were isolated from Neotypus melanocephalus (Gmelin), a parasitoid of the parasitic large blue butterfly Maculinea nausithous. Allelic diversity and heterozygosity were quantified in samples from the Upper Rhine valley in Southwest Germany.

Nine polymorphic microsatellite loci for the parasitic wasp Neotypus melanocephalus (Hymenoptera: Ichneumonidae)

In agricultural habitats, selection may favour plants that show a pronounced ability to tolerate stress induced by specific management methods. However, genetic erosion associated with habitat fragmentation may diminish this ability. To assess the role of mowing as a selection pressure and the impact of fragmentation processes on the ability to tolerate foliage loss, we grew 215 plants of the perennial herb Sanguisorba officinalis L. originating from 16 differently sized pop- ulations, located in mown meadows and successional fallows, in a common environment, and measured their performance and response to defoliation. Plants from meadows and fallows neither differed in performance characters nor in their abil- ity to compensate for foliage loss. However, independently from the habitat of origin, populations slightly differed in per- formance. This variation was not due to differences in population size, plant density, or level of genetic variation, indicating its independence from genetic erosion, which may go along with habitat fragmentation. Rather, these differences between populations appear to be the outcome of unknown selection pressures or random genetic drift. Plants from succes- sional fallows retain their potential to cope with mowing, presumably due to the low generation turnover of the perennial species. Selection by mowing may act over time scales larger than those reflected by the developmental stage of the cur- rent habitats.

Performance and response to defoliation of Sanguisorba officinalis (Rosaceae) seedlings from mown and successional habitats

Open cast lignite mines, sand pits and military training areas represent human-made, secondary habitats for specialized xerothermophilous and psammophilous species. Rare species, including the earwig Labidura riparia, are found in high population densities in such sites. However, it is unknown from which sources colonisation took place and how genetic variation compares to that of ancient populations on natural sites. Using nine microsatellite markers, we analysed genetic variation and population structure of L. riparia in 21 populations in NE Germany both from secondary habitats such as lignite-mining sites, military training areas and a potassium mining heap, and rare primary habitats, such as coastal and inland dunes. Genetic variation was higher in populations from post-mining sites and former military training areas than in populations from coastal or inland dune sites. Overall population differentiation was substantial (FST = 0.08; FʹST = 0.253), with stronger differentiation among primary (FST = 0.196; FʹST = 0.473) than among secondary habitats (FST = 0.043; FʹST = 0.147). Differentiation followed a pattern of isolation by distance. Bayesian structure analysis revealed three gene pools representing primary habitats on a coastal dune and two different inland dunes. All populations from secondary habitats were mixtures of the two inland dune gene pools, suggesting multiple colonization of post-mining areas from different source populations and hybridisation among source populations. Populations of L. riparia from primary habitats deserve special conservation, because they harbour differentiated gene pools. The majority of the L. riparia populations, however, thrive in secondary habitats, highlighting their role for conservation. A dual strategy should be followed of conserving both remaining natural habitat harbouring particular intraspecific gene pools and secondary habitat inhabited by large admixed and genetically highly variable populations.

/pdf/colonisation-of-secondary-habitats-in-mining-sites-by-4pl6w863xy.pdf

Colonisation of secondary habitats in mining sites by Labidura riparia (Dermaptera: Labiduridae) from multiple natural source populations

In Mediterranean ecosystems, climate change is projected to increase fire danger and summer drought, thus reducing post-fire recruitment of obligate seeder species, and possibly affecting the population genetic structure. We performed a genome-wide genetic marker study, using AFLP markers, on individuals from one Central Spain population of the obligate post-fire seeder Cistus ladanifer L. that established after experimental fire and survived during four subsequent years under simulated drought implemented with a rainout shelter system. We explored the effects of the treatments on marker diversity, spatial genetic structure and presence of outlier loci suggestive of selection. We found no effect of fire or drought on any of the genetic diversity metrics. Analysis of Molecular Variance showed very low genetic differentiation among treatments. Neither fire nor drought altered the small-scale spatial genetic structure of the population. Only one locus was significantly associated with the fire treatment, but inconsistently across outlier detection methods. Neither fire nor drought are likely to affect the genetic makeup of emerging C. ladanifer, despite reduced recruitment caused by drought. The lack of genetic change suggests that reduced recruitment is a random, non-selective process with no genome-wide consequences on this keystone, drought- and fire tolerant Mediterranean species.

/pdf/no-genetic-adaptation-of-the-mediterranean-keystone-shrub-8x2gdcitnm.pdf

Walter Durka

Papers

Nine polymorphic microsatellite loci for the parasitic wasp Neotypus melanocephalus (Hymenoptera: Ichneumonidae)

Performance and response to defoliation of Sanguisorba officinalis (Rosaceae) seedlings from mown and successional habitats

Colonisation of secondary habitats in mining sites by Labidura riparia (Dermaptera: Labiduridae) from multiple natural source populations

No genetic adaptation of the Mediterranean keystone shrub Cistus ladanifer in response to experimental fire and extreme drought.

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