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David J. Bottjer

Bio: David J. Bottjer is an academic researcher from University of Southern California. The author has contributed to research in topics: Extinction event & Early Triassic. The author has an hindex of 64, co-authored 265 publications receiving 15119 citations. Previous affiliations of David J. Bottjer include Indiana University & University of Rhode Island.


Papers
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Journal ArticleDOI
10 Nov 2006-Science
TL;DR: The sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus is reported, a model for developmental and systems biology and yields insights into the evolution of deuterostomes.
Abstract: We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.

1,059 citations

Journal ArticleDOI
04 Jul 2008-Science
TL;DR: In this paper, a new data set of fossil occurrences representing 3.5 million specimens was presented, and it was shown that global and local diversity was less than twice as high in the Neogene as in the mid-Paleozoic.
Abstract: It has previously been thought that there was a steep Cretaceous and Cenozoic radiation of marine invertebrates. This pattern can be replicated with a new data set of fossil occurrences representing 3.5 million specimens, but only when older analytical protocols are used. Moreover, analyses that employ sampling standardization and more robust counting methods show a modest rise in diversity with no clear trend after the mid-Cretaceous. Globally, locally, and at both high and low latitudes, diversity was less than twice as high in the Neogene as in the mid-Paleozoic. The ratio of global to local richness has changed little, and a latitudinal diversity gradient was present in the early Paleozoic.

650 citations

Journal ArticleDOI
01 Jan 1986-Geology
TL;DR: In this paper, a trace-fossil tiering model was proposed to estimate changes in the degree of paleooxygenation of bottom waters recorded in fine-grained pelagic strata.
Abstract: Recognition of fluctuations in the degree of paleo-oxygenation of bottom waters recorded in fine-grained pelagic strata is important for interpretation of paleoceanographic and paleoclimatologic conditions. General sedimentary fabric, composition of trace-fossil assemblages, and burrow size and crosscutting relationships have been incorporated into a trace-fossil tiering model that permits detailed reconstruction of changes in paleo-oxygenation of bottom waters. Applications of this model to the Miocene Monterey Formation (California) and the Cretaceous Niobrara Formation (Colorado) indicate that the ichnologic approach is more sensitive to both magnitude and rates of change in oxygenation levels compared to macrobenthic body-fossil information.

352 citations

01 Sep 2000
TL;DR: In this paper, the evolutionary and ecological effects of these substrate changes on benthic metazoans, referred to as the Cambrian substrate revolution, are presented for two major animal species, Phyla, Echinodermata and Mollusca.
Abstract: The broad marine ecological settings prevalent during the late Neoproterozoic– early Phanerozoic (600–500 Ma) interval of early metazoan body plan origination strongly impacted the subsequent evolution and development of benthic metazoans. Recent work demonstrates that late Neoproterozoic seafloor sediment had well-developed microbial mats and poorly developed, vertically oriented bioturbation, thus producing fairly stable, relatively low water content substrates and a sharp water-sediment interface. Later in the Cambrian, seafloors with microbial mats became increasingly scarce in shallow-marine environments, largely due to the evolution of burrowing organisms with an increasing vertically oriented component to their bioturbation. The evolutionary and ecological effects of these substrate changes on benthic metazoans, referred to as the Cambrian substrate revolution, are presented here for two major animal phyla, the Echinodermata and the Mollusca.

321 citations


Cited by
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: 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

14,171 citations

Journal ArticleDOI
03 Mar 2011-Nature
TL;DR: Differences between fossil and modern data and the addition of recently available palaeontological information influence understanding of the current extinction crisis, and results confirm that current extinction rates are higher than would be expected from the fossil record.
Abstract: Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

3,051 citations

Journal ArticleDOI
TL;DR: The general relationships between abundance and distribution developed here eventually should contribute to the understanding of the biogeography, population genetics, and evolution of species as well as the ecological attributes of populations and communities.
Abstract: There appears to be a general relationship between abundance and distribution that has two parts. First, within species, population density tends to be greatest in the center of the range and to decline gradually toward the boundaries. This pattern holds over a range of spatial scales from steep environmental gradients within local regions to the entire geographic range. Exceptions include: (1) abrupt changes in abundance that usually correspond to sharp, discontinuous changes in single environmental variables; and (2) multimodal patterns of abundance that are caused by environmental patchiness. The second general relationship is that among closely related, ecologically similar species spatial distribution is positively correlated with average abundance. Again this pattern holds over a variety of spatial scales from local regions to entire geographic ranges. These empirical patterns have already been reported in the literature, but their generality is demonstrated by analysis of additional data for divers...

2,630 citations

Journal ArticleDOI
TL;DR: The function of the fifth adaptor, SARM, has been revealed, which negatively regulates TRIF, and it is shown that it acts as a bridging adaptor in the initiation of TLR signalling.
Abstract: Signalling by Toll-like receptors (TLRs) involves five adaptor proteins known as MyD88, MAL, TRIF, TRAM and SARM. Recent insights have revealed additional functions for MyD88 apart from NF-kappaB activation, including activation of the transcription factors IRF1, IRF5 and IRF7, and also a role outside the TLRs in interferon-gamma signalling. Biochemical information on MAL and TRAM has shown that both act as bridging adaptors, with MAL recruiting MyD88 to TLR2 and TLR4, and TRAM recruiting TRIF to TLR4 to allow for IRF3 activation. Finally, the function of the fifth adaptor, SARM, has been revealed, which negatively regulates TRIF. These new insights allow for a detailed description of the function of the five TIR-domain-containing adaptors in the initiation of TLR signalling.

2,474 citations