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Articles 61 - 88 of 88

Full-Text Articles in Evolution

Recently Described Vulture One Of Several New Avian Species From The Ashfall Fossil Beds, Rick E. Otto Feb 2013

Recently Described Vulture One Of Several New Avian Species From The Ashfall Fossil Beds, Rick E. Otto

University of Nebraska State Museum: Programs Information

Several species of fossil bird are known from the Ashfall Fossil Beds. As of publication date, all represent previously undescribed species. In 2012, ornithologists Zhang, Feduccia and James described a vulture from isolated remains recovered from the Ashfall site in 1979. Similar in morphology to the Palm-nut Vulture (Gypohierax) of Africa, the relationship to the Ashfall vulture is unclear, and may represent an example of convergent evolution. The fossil vulture was designated Anchigyps voorhiesiin honor of paleontologist Michael Voorhies.


The Lives Of Others: Social Rationality In Animals, Jeffrey R. Stevens, Andrew J. King Jan 2013

The Lives Of Others: Social Rationality In Animals, Jeffrey R. Stevens, Andrew J. King

Jeffrey Stevens Publications

Darwin (1871) boldly claimed that humans and other animals differ very little in their cognition; a statement that has raised the ire of many scientists (Bolhuis & Wynne, 2009; Penn, Holyoak, & Povinelli, 2008). Rather than stating this continuity as a fact, we will explore the similarities and differences between humans and animals in the social rationality of their decision making. We find this a fruitful exercise because it can profit researchers of both humans and animals. Our purpose here is to provide an evolutionary background of social rationality: Why do animals attend to the lives of others? To this …


Gene Duplication And The Evolution Of Hemoglobin Isoform Differentiation In Birds, Michael T. Grispo Dec 2012

Gene Duplication And The Evolution Of Hemoglobin Isoform Differentiation In Birds, Michael T. Grispo

School of Biological Sciences: Dissertations, Theses, and Student Research

The majority of bird species co-express two functionally distinct hemoglobin (Hb) isoforms in definitive erythrocytes: HbA (the major adult Hb isoform, with α-chain subunits encoded by the αA-globin gene) and HbD (the minor adult Hb isoform, with α-chain subunits encoded by the αD-globin gene). The αD-globin gene originated via tandem duplication of an embryonic α-like globin gene in the stem lineage of tetrapod vertebrates, which suggests the possibility that functional differentiation between the HbA and HbD isoforms may be attributable to a retained ancestral character state in HbD that harkens back to a primordial, …


Life History Tradeoffs And Phenotypic Plasticity: The Tale Of A Flight Polyphenic Field Cricket, Chandreyee Mitra Dec 2011

Life History Tradeoffs And Phenotypic Plasticity: The Tale Of A Flight Polyphenic Field Cricket, Chandreyee Mitra

School of Biological Sciences: Dissertations, Theses, and Student Research

Most organisms are resource limited. Such limitations can result in tradeoffs between life history traits -- any traits that affect survival or reproduction. Flight polyphenic field crickets are thought to be a classic example of such a life history tradeoff, in which individuals tradeoff investment in flight capability and investment in reproduction. This polyphenism results from the interaction of two morphological traits: wing morphology (short or long) and flight muscle morphology (functional pink or non-functional white), and is affected by both genes and the environment. I examined life history traits of a flight polyphenic field cricket, Gryllus lineaticeps. First, …


Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo Jul 2011

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …


Biology, Systematics, Phylogenetic Analysis And Dna Character-Based Species Diagnosis Of The False Root-Knot Nematode Nacobbus Aberrans (Thorne, 1935) Thorne & Allen 1944 (Nemata: Pratylenchidae), Angel Ramirez-Suarez Jun 2011

Biology, Systematics, Phylogenetic Analysis And Dna Character-Based Species Diagnosis Of The False Root-Knot Nematode Nacobbus Aberrans (Thorne, 1935) Thorne & Allen 1944 (Nemata: Pratylenchidae), Angel Ramirez-Suarez

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The False Root-Knot nematode Nacobbus aberrans is a plant parasitic nematode that causes yield losses in several crops and plant protection agencies have established regulations to prevent infestations from spreading to new agricultural areas. The taxonomic status of the nematode has been the subject of controversy due to wide degree of variation exhibited by the species. This variability has led to the suggestion that N. aberrans is actually a species complex rather than a single species. In order to test this hypothesis, we compared twelve N. aberrans populations, which include isolates from western Nebraska, two distinct regions of Mexico and …


Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis Apr 2011

Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis

School of Biological Sciences: Dissertations, Theses, and Student Research

Accurate knowledge of species boundaries and species phylogeny are fundamental to testing hypotheses of recent evolutionary processes, but the estimation of these partitions is challenging due both to inherent confusion about what is being estimated as well as the data available to estimate them. Using multilocus data from mtDNA, microsatellites, and nuclear locus sequences of over 1100 individuals, we delimited eight separately evolving species of Cichla rather than the 15 described. Among species we found evidence of rare but widespread introgressive hybridization, while within these species we observed evidence of long-term gene exchange and constrained evolutionary trajectories. In most cases …


Mechanisms For Decisions About The Future, Jeffrey R. Stevens Jan 2011

Mechanisms For Decisions About The Future, Jeffrey R. Stevens

Jeffrey Stevens Publications

Evolutionary and psychological perspectives on decision making remain largely separate endeavors. The bounded rationality approach integrates these two perspectives by focusing on simple, plausible mechanisms of decision making and the cognitive capacities needed to implement these mechanisms. Decisions about the future provide a class of decisions that lend themselves to a bounded rationality approach. Though many different mechanisms may exist for making decisions about the future, only a subset of these mechanisms actually require a representation of the future. The bounded rationality approach helps focus on the cognitive capacities and decision mechanisms that are necessary for a full understanding of …


Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert Dec 2010

Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.


Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville Nov 2010

Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville

School of Biological Sciences: Dissertations, Theses, and Student Research

Two ecological risks associated with the use of transgenic crops include the effects of transgene products on non-target organisms and the effects of a transgene after it moves from crops into a wild plant population. In work presented here, we specifically investigate the ecological risks of virus-resistant transgenic squash. We observed pollinator behavior to determine if pollinators are affected by nontarget effects of the virus-resistant transgene. We found that pollinator behavior did differ between conventional and virus-resistant transgenic squash due to pleiotropic effects of the transgene. This difference in pollinator behavior can affect plant mating patterns, thereby affecting crop-wild hybridization …


Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford May 2010

Ecology And Relationships Of Rhabdias Spp. (Nematoda: Rhabdiasidae) From North American Amphibians And Reptiles, Gabriel J. Langford

School of Biological Sciences: Dissertations, Theses, and Student Research

Lungworms of the cosmopolitan genus Rhabdias (Nematoda: Rhabdiasidae) are among the most common parasites of amphibians and squamate reptiles. The life cycles, life histories, host specificities, and evolutionary relationships of Rhabdias spp. were studied through examination of their free-living and parasitic stages in amphibians and reptiles. This study found free-living development of anuran lungworms was primarily limited to heterogonic reproduction, whereas snake lungworms primarily reproduced homogonically. Infective anuran lungworms penetrated the skin of frogs and toads; in contrast, snake lungworms penetrated snake esophageal tissue during per os infections. Our molecular phylogeny strongly supported separate clades for anuran and snake lungworms, …


Longevity-Fertility Trade-Offs In The Tephritid Fruit Fly, Anastrepha Ludens, Across Dietary-Restriction Gradients, James R. Carey, Lawrence G. Harshman, Pablo Liedo, Hans-Georg Müller, Jane-Ling Wang, Zhen Zhang Aug 2008

Longevity-Fertility Trade-Offs In The Tephritid Fruit Fly, Anastrepha Ludens, Across Dietary-Restriction Gradients, James R. Carey, Lawrence G. Harshman, Pablo Liedo, Hans-Georg Müller, Jane-Ling Wang, Zhen Zhang

Lawrence G. Harshman Publications

Although it is widely known that dietary restriction (DR) not only extends the longevity of a wide range of species but also reduces their reproductive output, the interrelationship of DR, longevity-extension and reproduction is not well understood in any organism. Here we address the question: “Under what nutritional conditions do the longevity-enhancing effects resulting from food restriction either counteract, complement or reinforce the mortality costs of reproduction? To answer this question we designed a fine-grained DR study involving 4,800 individuals of the tephritid fruit fly Anastrepha ludens in which we measured sex-specific survival and daily reproduction in females in each …


Simpler Mode Of Inheritance Of Transcriptional Variation In Male Drosophila Melanogaster, Marta Wayne, Marina Telonis-Scott, Lisa Bono, Lawrence G. Harshman, Artyom Kopp, Sergey V. Nuzhdin, Lauren Mcintyre Nov 2007

Simpler Mode Of Inheritance Of Transcriptional Variation In Male Drosophila Melanogaster, Marta Wayne, Marina Telonis-Scott, Lisa Bono, Lawrence G. Harshman, Artyom Kopp, Sergey V. Nuzhdin, Lauren Mcintyre

Lawrence G. Harshman Publications

Sexual selection drives faster evolution in males. The X chromosome is potentially an important target for sexual selection, because hemizygosity in males permits accumulation of alleles, causing tradeoffs in fitness between sexes. Hemizygosity of the X could cause fundamentally different modes of inheritance between the sexes, with more additive variation in males and more nonadditive variation in females. Indeed, we find that genetic variation for the transcriptome is primarily additive in males but nonadditive in females. As expected, these differences are more pronounced on the X chromosome than the autosomes, but autosomal loci are also affected, possibly because of X-linked …


The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens Jan 2004

The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens

Jeffrey Stevens Publications

Animals may share food to gain immediate or delayed fitness benefits. Previous studies of sharing have concentrated on delayed benefits such as reciprocity, trade and punishment. This study tests an alternative model (the harassment or sharing–under–pressure hypothesis) in which a food owner immediately benefits because sharing avoids costly harassment from a beggar. I present an experiment that varies the potential ability of the beggar to harass, and of the owner to defend the food, to examine the effects of harassment on food sharing in two primate species: chimpanzees (Pan troglodytes) and squirrel monkeys (Saimiri boliviensis). For …


A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby Jan 2004

A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby

Jeffrey Stevens Publications

Many animal species, from arthropods to apes, share food. This paper presents a new framework that categorizes nonkin food sharing according to two axes: (1) the interval between sharing and receiving the benefits of sharing, and (2) the currency units in which benefits accrue to the sharer (especially food versus nonfood). Sharers can obtain immediate benefits from increased foraging efficiency, predation avoidance, mate provisioning, or manipulative mutualism. Reciprocity, trade, status enhancement and group augmentation can delay benefits. When benefits are delayed or when food is exchanged for nonfood benefits, maintaining sharing can become more difficult because animals face discounting and …


Body Mass Of Late Quaternary Mammals (Data Set), Felisa A. Smith, S. Kathleen Lyons, S.K. Morgan Ernest, Kate E. Jones, Kansas State University, Tamar Dayan, Pablo A. Marquet, James H. Brown, John P. Haskell Dec 2003

Body Mass Of Late Quaternary Mammals (Data Set), Felisa A. Smith, S. Kathleen Lyons, S.K. Morgan Ernest, Kate E. Jones, Kansas State University, Tamar Dayan, Pablo A. Marquet, James H. Brown, John P. Haskell

School of Biological Sciences: Faculty Publications

The purpose of this data set was to compile body mass information for all mammals on Earth so that we could investigate the patterns of body mass seen across geographic and taxonomic space and evolutionary time. We were interested in the heritability of body size across taxonomic groups (How conserved is body mass within a genus, family, and order?), in the overall pattern of body mass across continents (Do the moments and other descriptive statistics remain the same across geographic space?), and over evolutionary time (How quickly did body mass patterns iterate on the patterns seen today? Were the Pleistocene …


Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens Jan 2002

Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens

Jeffrey Stevens Publications

The Iterated Prisoner’s Dilemma (IPD) is a central paradigm in the study of animal cooperation. According to the IPD framework, repeated play (repetition) and reciprocity combine to maintain a cooperative equilibrium. However, experimental studies with animals suggest that cooperative behavior in IPDs is unstable, and some have suggested that strong preferences for immediate benefits (that is, temporal discounting) might explain the fragility of cooperative equilibria. We studied the effects of discounting and strategic reciprocity on cooperation in captive blue jays. Our results demonstrate an interaction between discounting and reciprocity. Blue jays show high stable levels of cooperation in treatments with …


Out Of Africa: Origins Of The Taenia Tapeworms In Humans, Eric P. Hoberg, Nancy L. Alkire, Alan De Queiroz, Arlene Jones Jan 2001

Out Of Africa: Origins Of The Taenia Tapeworms In Humans, Eric P. Hoberg, Nancy L. Alkire, Alan De Queiroz, Arlene Jones

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Phylogenetic and divergence date analyses indicate that the occurrence of Taenia tapeworms in humans pre-dates the development of agriculture, animal husbandry and domestication of cattle (Bos spp.) or swine (Sus scrofa) Taeniid tapeworms in Africa twice independently colonized hominids and the genus Homo prior to the origin of modern humans. Dietary and behavioural shifts, from herbivory to scavenging and carnivory, as early Homo entered the carnivore guild in the Pliocene/Pleistocene, were drivers for host switching by tapeworms to hominids from carnivores including hyaenids and felids. Parasitological data provide a unique means of elucidating the historical ecology, foraging behavior …


Systematics Of The Eucestoda: Advances Toward A New Phylogenetic Paradigm And Observations On The Early Diversification Of Tapeworms And Vertebrates, Eric P. Hoberg, Scott Lyell Gardner, Ronald A. Campbell Aug 1999

Systematics Of The Eucestoda: Advances Toward A New Phylogenetic Paradigm And Observations On The Early Diversification Of Tapeworms And Vertebrates, Eric P. Hoberg, Scott Lyell Gardner, Ronald A. Campbell

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Evolutionary relationships of the Eucestoda have received intense but sporadic attention over the past century. Since 1996, the landscape has dramatically changed with respect to our knowledge of the phylogenetic relationships among the tapeworms. The 2nd International Workshop for Tapeworm Systematics (IWTS) held in Lincoln, Nebraska in October of that year provided the catalyst for development of novel hypotheses for inter-and intra-ordinal phylogeny. The working-group structure of the 2nd IWTS and results of phylogenetic studies are briefly introduced in the present manuscript. Higher-level phylogenies derived from parsimony analysis of independent data bases representing comparative morphology or molecular sequences were largely …


Evolutionary Relationships Among The Protostrongylidae (Nematoda: Metastrongyloidea) As Inferred From Morphological Characters, With Consideration Of Parasite-Host Coevolution, Ramon A. Carreno, Eric P. Hoberg Jan 1999

Evolutionary Relationships Among The Protostrongylidae (Nematoda: Metastrongyloidea) As Inferred From Morphological Characters, With Consideration Of Parasite-Host Coevolution, Ramon A. Carreno, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The phylogeny of nematodes in the family Protostrongylidae (Nematoda: Metastrongyloidea) was reconstructed by cladistic analysis of 28 binary and multistate characters derived from comparative morphology. Analyses were hierarchical, and examined (1) relationships among genera, including 13 ingroup taxa and Metastrongylidae as an outgroup (single tree, 78 steps, consistency index [CI]=0.705); and (2) relationships among genera and species groups including 21 ingroup taxa and Metastrongylus apri as an outgroup (single tree, 76 steps, CI=0.582). In the species-level tree, Protostrongylidae was divided into 2 major clades, one containing the subfamilies Muelleriinae (including the recently described Umingmakstrongylus pallikuukensis) Elaphostrongylinae, and the Varestrongylinae …


Amphicyonidae, Robert Hunt Jan 1998

Amphicyonidae, Robert Hunt

University of Nebraska State Museum: Mammalogy Papers

The Amphicyonidae occur in North America from late Eocene (~40 Ma) to early late Miocene (~9 Ma), a span of 31 million years. In the North American land mammal biochronology, this diverse family extends from the Duchesnean to the end of the Clarendonian and is especially well represented in the Miocene (~5-24 Ma). In the Old World, amphicyonids survive no longer than in North America: The last European records are Vallesian (Dinotheriensande, Mainz Basin, Germany, Kuss, 1965, Tobien, 1980; Vallés-Penédes Basin, Spain, Crusafont-Pairó and Kurten, 1976), and the last representative may occur at about 9 Ma at Kohfidisch, Austria (latest …


Faunal Diversity Among Avian Parasite Assemblages: The Interaction Of History, Ecology, And Biogeography In Marine Systems, Eric P. Hoberg Jan 1996

Faunal Diversity Among Avian Parasite Assemblages: The Interaction Of History, Ecology, And Biogeography In Marine Systems, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Systematics and parasite biodiversity provide power and predictability in broad studies of history, ecology and biogeography in marine systems. Parasitic helminths are elegant markers of contemporary and historical ecological relationships, geographic distribution and host-phylogeny. Complex life cycles of helminths are strongly correlated with intricate food-webs. Dependence on a series of intermediate, paratenic, and definitive hosts indicates that each parasite species represents an array of organisms within a community and tracks broadly and predictably across many trophic levels. Host and geographic ranges of parasites are historically constrained by genealogical and ecological associations, and these determinents interact resulting in characteristic parasite community …


Historical Biogeography And Modes Of Speciation Across High-Latitude Seas Of The Holarctic: Concepts For Host-Parasite Coevolution Among The Phocini (Phocidae) And Tetrabothriidae (Eucestoda), Eric P. Hoberg Jan 1995

Historical Biogeography And Modes Of Speciation Across High-Latitude Seas Of The Holarctic: Concepts For Host-Parasite Coevolution Among The Phocini (Phocidae) And Tetrabothriidae (Eucestoda), Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Species of Anophryocephalus are host-specific parasites of pinnipeds in the Holarctic. Phylogenetic analysis of 7 species postulates A. anophrys as the basal taxon and A. inuitorum as basal to A. skrjabini; A. arcticensis is basal to A. nunivakensis and A. eumetopii + A. ochotensis (single tree; consistency index = 74.4%; homoplasy slope ratio = 36.45%). Evaluation of host and geographic distributions postulates ringed seals of the Atlantic-Arctic as ancestral hosts, and the Arctic basin as a paraphyletic area with respect to the North Pacific. Cospeciation within this assemblage was dependent on intense isolation of small effective populations of definitive hosts …


Phylogenetic Systematic Analysis Of The Trichostrongylidae (Nematoda), With An Initial Assessment Of Coevolution And Biogeography, Eric P. Hoberg, J. Ralph Lichtenfels Dec 1994

Phylogenetic Systematic Analysis Of The Trichostrongylidae (Nematoda), With An Initial Assessment Of Coevolution And Biogeography, Eric P. Hoberg, J. Ralph Lichtenfels

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Phylogenetic analysis of the subfamilies of the Trichostrongylidae based on 22 morphological transformation series produced a single cladogram with a consistency index (CI) = 74.2%. Monophyly for the family was supported by the structure of the female tail and copulatory bursa. Two major clades are recognized: the Cooperiinae clade with the basal Cooperiinae and Libyostrongylinae + Trichostrongylinae, and the Graphidiinae clade with the basal Graphidiinae and Ostertagiinae + Haemonchinae. Dendrograms presented by Durette- Desset (1985) (CI = 56.1%) and Lichtenfels (1987), based on the key to the Trichostrongylidae by Gibbons and Khalil (1982) (CI = 59.0%), were found to be …


Book Review Of Parascript: Parasites And The Language Of Evolution By D. R. Brooks And D. A. Mclennan, Smithsonian Institution Press, Washington, D.C., 1993., Eric P. Hoberg Jan 1993

Book Review Of Parascript: Parasites And The Language Of Evolution By D. R. Brooks And D. A. Mclennan, Smithsonian Institution Press, Washington, D.C., 1993., Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Review of Parascript: Parasites and the Language of Evolution by Daniel R. Brooks and Deborah A. McLennan, with bibliographical references.


Eulimdana Rauschorum N. Sp., A Filarioid Nematode (Lemdaninae) From Larus Dominicanus In Antarctica, With Comments On Evolution And Biogeography, Eric P. Hoberg Oct 1986

Eulimdana Rauschorum N. Sp., A Filarioid Nematode (Lemdaninae) From Larus Dominicanus In Antarctica, With Comments On Evolution And Biogeography, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Eulimdana rauschorum n. sp. is described from southern black-backed gulls, Larus dominicanus Lichtenstein in Antarctica. The species is most similar to Eulimdana lari (Yamaguti, 1935) from Charadriiformes in the Holarctic. Males have spicules equal in length that are asymmetric in structure distally. There are 4-5 and 3-5 caudal papillae in rows to the right and left of the anus, and two small genital papillae at the posterolateral margin of the anus. Females have a variable number of prominent caudal papillae and large microfilariae (365 μm in length). The morphological similarities and host distribution of E. rauschorum and E. lari suggest …


Evolution And Historical Biogeography Of A Parasite-Host Assemblage: Alcataenia Spp. (Cyclophyllidea: Dilepididae) In Alcidae (Charadriiformes), Eric P. Hoberg Jan 1986

Evolution And Historical Biogeography Of A Parasite-Host Assemblage: Alcataenia Spp. (Cyclophyllidea: Dilepididae) In Alcidae (Charadriiformes), Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The methodology of phylogenetic systematics was used to develop hypotheses for the evolution of eight species of Alcataenia, a group of host-specific cestodes of the Alcidae and, to a lesser extent, the Laridae (Charadriiformes). Concurrently, aspects of the early biogeography of alcids were reevaluated making it possible to study the historical and distributional relationships of parasites and hosts. The most parsimonious hypothesis for the phylogeny of Alcataenia suggested that sequential colonization or host switching with limited coevolution (coaccommodation) by parasites best explained the distributional patterns exhibited by Alcataenia spp. Morphological evolution of specific species of Alcataenia accompanied host switching, …


Evolution And Classification, Charles E. Bessey Sep 1893

Evolution And Classification, Charles E. Bessey

Papers in Systematics and Biological Diversity

As we have gathered up the scattered masses of botanical knowledge, laboriously wrought out by many isolated workers, and attempted to fit them together into a consistent whole, which should outline the structure of the temple of botany, we have found that the workmen have not always followed the same architectural plan, and have often used different units of measurement. With the increasing specialization so noticeable year by year there is a corresponding lack of coordination of work. To this lack of coordination, this want of unity of measurement, this misunderstanding of plan, we can no longer close our eyes, …