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

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

The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

/pdf/the-environmental-protection-agency-3gx4opzrjm.pdf

The Environmental Protection Agency

The rise of harmful cyanobacteria blooms: The potential roles of eutrophication and climate change

Phytoplankton can become limited by the availability of nutrients when light and temperature are adequate and loss rates are not excessive. The current paradigms for nutrient limitations in freshwater, estuarine, and marine environments are quite different. A review of the experimental and observational data used to infer P or N limitation of phytoplankton growth indicates that P limitation in freshwater environments can be demonstrated rigorously at several hierarchical levels of system complexity, from algal cultures to whole lakes. A similarly rigorous demonstration of N limitation has not been achieved for marine waters. Therefore, we conclude that the extent and severity of N limitation in the marine environment remain an open question. Culture studies have established that internal cellular concentrations of nutrients determine phytoplankton growth rates, and these studies have shown that it is often difficult to relate growth rates to external concentrations, especially in natural situations. This should lead to a greater reliance on the composition of particulate matter and biomass-based physiological rates to infer nutrient limitation. Such measurements have demonstrated their utility in a wide variety of freshwater and marine environments, and, most importantly, they can be applied to systems that are difficult to manipulate experimentally or budget accurately. Dissolved nutrient concentrations are most useful in determining nutrient loading rates of aquatic ecosystems. The relative proportions of nutrients supplied to phytoplankton can be a strong selective force shaping phytoplankton communities and affecting the biomass yield per unit of limiting nutrient. A current dogma of aquatic science is that marine and estuarine phytoplankton tend to be nitrogen limited, while freshwater phytoplankton tend to be phosphorus limited. Carpenter and Capone (1983) documented the preeminence of N studies in the literature on brackish and marine ecosystems. In 1970 there were equal numbers of references per year to N and P. The decade of the seventies saw a nearly fourfold increase in references to N, while the number of P references per year remained essentially unchanged. No trend was evident for the freshwater literature despite the fact that by the late seventies the evidence for P limitation had become so great that phosphorus control was recommended as the legislated basis for controlling eutrophication in North American and European inland waters (e.g.

/pdf/nutrient-limitation-of-phytoplankton-in-freshwater-and-1gyy8avtuu.pdf

Nutrient limitation of phytoplankton in freshwater and marine environments: A review of recent evidence on the effects of enrichment1

IN marked contrast to their freshwater counterparts, marine planktonic cyanobacteria are restricted to a few nostocalean genera, of which only Trichodesmium is capable of forming extensive water blooms1–3. We report here the widespread occurrence of a small, marine, chroococcalean cyanobacterium belonging to the genus Synechococcus.

Widespread occurrence of a unicellular, marine, planktonic, cyanobacterium

Reduction of marine phytoplankton reproduction rates by copper and cadmium

The reproductive rates of 21 species of marine phytoplankton were measured in media in which free zinc, manganese, and iron ion activities were controlled at different levels using EDTA-trace metal ion buffer systems. In general, the reproductive rates of neritic species were limited by zinc activities below 1O-11.5 M, while those of oceanic species were either not limited or only slightly limited at the lowest zinc activity attained in the experiment, ca. lo-l3 M. The reproductive rates of oceanic coccolithophores were either not limited or only slightly limited by the lowest manganese ion activity attained, ca. 10-l’ M, but those of a neritic coccolithophore and all diatoms, both neritic and oceanic, were limited below a manganese activity of 10-l” M. Neritic species had reduced reproductive rates in media containing clod7 M iron while oceanic species reproduced at maximal or close to maximal rates in the media with the lowest iron concentrations, ca. IO+’ M. The habitat-related patterns in zinc, manganese, and iron requirements of oceanic and neritic species are consistent with the oceanic-neritic distributions of concentrations of these metals. This similarity in requirement and distributional patterns provides evidence that Zn, Mn, and Fe availability have been important selective forces on marine phytoplankton populations and communities. The nutrients most frequently considered to limit the reproductive rates of phytoplankton in the ocean are the macronutrients nitrogen, phosphorus, and silicon. The possibility that trace metal micronutrients can be of significance in the ecology of phytoplankton has been considered occasionally (Harvey 1947; Ryther and Guillard 1959; Ryther and Kramer 1961; Barber and Ryther 1969), but they have not received the attention and quantitative analysis that macronutrients

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1983.28.6.1182

Limitation of marine phytoplankton reproductive rates by zinc, manganese, and iron1

Copper speciation in the upper marine water column is dominated b>, strong ligands thought to be of recent biological origin. Cultures of the marine cyanobacteria Synechococcu.? spp., a ubiquitous and important group of phytoplankton highly sensitive to Cu toxicity, were previously shown to produce chelators comparable in strength to those detected in the water column. Here we shoyw that cultures of Synechococcus exposed to toxic concentrations of Cu produce an extracellular ligand with a binding constant comparable to constants for ligands found in the water column. Coordination of Cu by this compound decreases the concentration of free cupric ion (the toxic form) in the culture media to le-rels that do not inhibit growth. A tight linear correlation between chelator and Cu concentration suggests l.hat production of this substance may be regulated by the concentration of free Cu in the media in a feeldback mechanism. Similarly, the concentrations of Cu and Cu-binding ligands in the water column are o?ten closely related. These results suggest that cyanobacteria modify Cu chemistry in seawater, creating conditions more favorable for growth.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1996.41.3.0388

Production of strong, extracellular Cu chelators by marine cyanobacteria in response to Cu stress

The Fe : PO., ratio at which nutrient limitation of final cell yield shifts from one nutrient to the other was determined for 22 species of marine phytoplankton. Among eucaryotic phytoplankton, coastal species have subsistence optimum Fe: P molar ratios of lo-* to 10-3.1, but most oceanic species have ratios of < 1 O--4, indicating that oceanic species have been able to adapt their biochemical composition to the low availability of Fe in the open ocean. In contrast, both coastal and oceanic species of cyanobacteria have relatively high Fe : P molar ratio requirements, ranging from 1O-1.4 to 1O-2.7. A simple comparison of these requirement ratios with the ratios of the Fe and PO, fluxes to the photic zone from deep water and the atmosphere indicates that new production of cyanobacterial biomass is Fe limited, but new production of eucaryotic algal biomass is not. Because of the large differences among species in their Fe requirements, especially between procaryotes and eucaryotes, changes in the relative inputs of Fe and PO, to the photic zone are expected to lead to changes in the species composition of phytoplankton communities. Indeed, the ratio of atmospheric to deep-water inputs of nutrients and the resulting Fe : P input ratios appear to influence the relative abundance of unicellular cyanobacteria and Trichodesmium and their vertical and biogeographic distributions. Because some phytoplanlcton species have adaptations that reduce their dependence on combined N and Fe but not on P, it is concluded that PO, is the ultimate limiting nutrient of new production of organic C on a geochemical and evolutionary time scale, even though N and Fe are important growth rate-limiling nutrients on an ecological time scale. What controls the rate of new production of organic C in the ocean is of great interest because of its influence on atmospheric 0, and C02, sedimentation and organic burial, and fisheries. One of the first to consider the geochemical control of new production in the ocean, Redfield (195 8) conducted a gedanken experiment in which he compared the ratio of NO3 to PO, in deep water with the ratio of N to P in marine biota and asked which nutrient would be depleted first by the biota if the deep water was upwelled into the photic zone. At that time,, trace metals were not generally considered as important limiting nutrients because of the high concentrations observed in the ocean as a result of inadequate techniques and serious contamination problems. As a result of greatly improved techniques, we now know that many trace metals are present in the ocean

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1991.36.8.1756

Larry E. Brand

Papers

Widespread occurrence of a unicellular, marine, planktonic, cyanobacterium

Reduction of marine phytoplankton reproduction rates by copper and cadmium

Limitation of marine phytoplankton reproductive rates by zinc, manganese, and iron1

Production of strong, extracellular Cu chelators by marine cyanobacteria in response to Cu stress

Minimum iron requirements of marine phytoplankton and the implications for the biogeochemical control of new production