Historical Ecology as a Research Program

Modern evolutionary biology is the descendant of two theories proposed by Darwin. First, all organisms are connected by common genealogy, and second, the form and function of organisms is closely tied to the environments in which they live. Of these two theories, the role of the first (phylogeny) in evolutionary explanations has been diminishing in some fields, most notably in ecology and ethology. However, the last ten years have witnessed the beginning of a reversal in this trend. With increasing frequency, ecologists (Wanntorp et aI., 1990; Maurer and Brooks, submitted), ethologists (Dobson, 1985; Huey and Bennett, 1987; Mclennan et aI., 1988), functional morphologists (Lauder, 1982), and other evolutionary biologists (Ridley, 1983; Clutton-Brock and Harvey, 1984; Endler and McLellan, 1988) are accepting the proposition that some innovations that arose in the past have been integrated into the phenotype and function today as constraints on the evolution of other characters

Historical Ecology as a Research Program

Modern evolutionary biology is the descendant of two theories proposed by Darwin. First, all organisms are connected by common genealogy, and second, the form and function of organisms is closely tied to the environments in which they live. Of these two theories, the role of the first (phylogeny) in evolutionary explanations has been diminishing in some fields, most notably in ecology and ethology. However, the last ten years have witnessed the beginning of a reversal in this trend. With increasing frequency, ecologists (Wanntorp et aI., 1990; Maurer and Brooks, submitted), ethologists (Dobson, 1985; Huey and Bennett, 1987; Mclennan et aI., 1988), functional morphologists (Lauder, 1982), and other evolutionary biologists (Ridley, 1983; Clutton-Brock and Harvey, 1984; Endler and McLellan, 1988) are accepting the proposition that some innovations that arose in the past have been integrated into the phenotype and function today as constraints on the evolution of other characters

Coronary CT Angiography and 5-Year Risk of Myocardial Infarction.

BACKGROUND: Although coronary computed tomographic angiography (CTA) improves diagnostic certainty in the assessment of patients with stable chest pain, its effect on 5-year clinical outcomes is unknown. METHODS: In an open-label, multicenter, parallel-group trial, we randomly assigned 4146 patients with stable chest pain who had been referred to a cardiology clinic for evaluation to standard care plus CTA (2073 patients) or to standard care alone (2073 patients). Investigations, treatments, and clinical outcomes were assessed over 3 to 7 years of follow-up. The primary end point was death from coronary heart disease or nonfatal myocardial infarction at 5 years. RESULTS: The median duration of follow-up was 4.8 years, which yielded 20,254 patient-years of follow-up. The 5-year rate of the primary end point was lower in the CTA group than in the standard-care group (2.3% [48 patients] vs. 3.9% [81 patients]; hazard ratio, 0.59; 95% confidence interval [CI], 0.41 to 0.84; P=0.004). Although the rates of invasive coronary angiography and coronary revascularization were higher in the CTA group than in the standard-care group in the first few months of follow-up, overall rates were similar at 5 years: invasive coronary angiography was performed in 491 patients in the CTA group and in 502 patients in the standard-care group (hazard ratio, 1.00; 95% CI, 0.88 to 1.13), and coronary revascularization was performed in 279 patients in the CTA group and in 267 in the standard-care group (hazard ratio, 1.07; 95% CI, 0.91 to 1.27). However, more preventive therapies were initiated in patients in the CTA group (odds ratio, 1.40; 95% CI, 1.19 to 1.65), as were more antianginal therapies (odds ratio, 1.27; 95% CI, 1.05 to 1.54). There were no significant between-group differences in the rates of cardiovascular or noncardiovascular deaths or deaths from any cause. CONCLUSIONS: In this trial, the use of CTA in addition to standard care in patients with stable chest pain resulted in a significantly lower rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years than standard care alone, without resulting in a significantly higher rate of coronary angiography or coronary revascularization. (Funded by the Scottish Government Chief Scientist Office and others; SCOT-HEART ClinicalTrials.gov number, NCT01149590 .)

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

The Phylogenetic Component of Cooperative Breeding in Perching Birds: A Commentary

The study of behavioral and ecological evolution within a phylogenetic context (historical ecology; Brooks and McLennan 1991) is an important component of comparative studies in evolutionary biology. Although the number of historical ecological studies is growing rapidly, this research field is still in its infancy--an infancy whose maturation is hampered by the absence of rigorous phylogenetic hypotheses for many of the groups that have traditionally fascinated behavioral ecologists. In the absence of such critical information, behavioral ecologists are faced with the options either of forming cooperative groups with phylogenetic systematists or of investigating their ecological data based on trees reconstructed from old classification schemes or phenograms, neither of which produces a robust phylogenetic hypothesis of genealogy. Most researchers have opted for the second approach, prefacing their investigations with the caveat that the analysis and conclusions are only preliminary because of the unsatisfactory nature of the phylogenetic hypotheses available to them. The importance of a preliminary analysis cannot be underestimated for researchers who, recognizing the importance of incorporating phylogenetic information into evolutionary explanations, are frustrated by their inability to apply such an approach to their burgeoning data sets. It is, however, equally important to realize that a preliminary analysis can, at best, produce only tentative results (see, e.g., Sillen-Tullberg 1988). If the data themselves are both incomplete and ambiguous, this will compound the problems arising from an absence of a rigorous phylogenetic framework, which will produce a confusing picture of behavioral or ecological evolution

The Evolutionary Origin of \u3ci\u3ePlasmodium falciparum\u3c/i\u3e

Among species of Plasmodium, P. falciparum is an enigma. It is unusually pathogenic and is not characterized by the relapsing episodes characteristic of other species. Its primary vector is a species of mosquito that is highly anthropophilic (Anopheles gambiae), and which shows evidence of rapid genetic change apparently coincident with the rise of human agriculture. Plasmodium falciparum has no alternative vertebrate reservoir hosts, and if the number of human infections drops below a threshold level, the species is unable to maintain itself. All of these observations suggested a novel hypothesis to Boyd (1949, cited in Waters et al. [ 1991]), who proposed that P. falciparum is a relatively new species that originated when the advent of agriculture brought humans and certain types of mosquitoes into contact on a regular basis

Parasites and Sexual Selection: A Macroevolutionary Perspective

The Hamilton-Zuk hypothesis postulates a causal link between parasitism and the evolution of epigamic traits by intersexual selection. Oversimplified assumptions about basic parasite biology, ambiguous formulation of the hypothesis, and poor communication between ethologists and parasitologists have hampered its testing. The hypothesis is supported at the microevolutionary level if females show significant preference for lightly or uninfected males, if intensity of infection reflects host resistance to parasites that depress host fitness by causing disease, and if intensity of infectionis related to the degree of epigamic development. It must be shown that particular parasites cause disease, that the host population is polymorphic for resistance to infection by those species, and that female hosts are capable of distinguishing male hosts with low parasite loads due to heritable aspects of host resistance from males that are uninfected due to chance. The macroevolutionary prediction of the hypothesis, that species displaying strongly developed epigamic characters should host more parasites than species with weakly developed epigamic traits, contradicts the microevolutionary dynamic of the hypothesis, and is too ambiguous. We propose a macroevolutionary prediction based on understanding the evolutionary origin of epigamic traits and the evolutionary origin of each host-parasite association. Associations originating in the ancestor in which the epigamic trait appeared corroborate the hypothesis most strongly; those originating prior to the evolution of the epigamic trait corroborate it weakly; those beginning after the origin of the epigamic trait could not have been involved in the origin and spread of the epigamic trait

Comparative Study of Adaptive Radiations with an Example Using Parasitic Flatworms (Platyhelminthes: Cercomeria)

Studies of adaptive radiations require robust phylogenies, estimates of species numbers for monophyletic groups within clades, assessments of the adaptive value of putative key innovations, and estimates of the frequency of speciation modes. Four criteria are necessary to identify an adaptive radiation within the parasitic platyhelminths: (I) a group contains significantly more species than its sister group, (2) species richness is apornorphic , (3) apomorphic traits enhance the potential for adaptively driven modes of speciation (sympatric speciation and speciation by peripheral isolation via host switching), and (4) the frequency of adaptively driven speciation modes is high within the group when compared with data from free-living groups. Only the species-rich Monogenea fulfill all four criteria. The Digenea and Eucestoda also are more species rich than their sister groups, their species richness is derived, and they possess unique characters that increase the potential for host switching to occur. However, because there is not enough information to determine whether the frequency of adaptive modes of speciation is high for those groups, we cannot yet assert that their radiations have been adaptive

The Concept of Co-option: Why Evolution Often Looks Miraculous

Abstract Darwin believed that evolution generally occurred through a series of small, gradual changes. This proposal was counter-intuitive to many people because it seemed likely that “transitional” forms would not survive. Darwin, and later Cuènot, recognized that this problem was easily solved if characters that had evolved for one reason changed their function at a later time with little to no concurrent structural modification, at least initially. In other words, traits that had evolved under one set of conditions were co-opted to serve a different function under a second set of conditions. This meant that organisms carried with them in the structures of their genes, proteins, morphological, physiological, and behavioral characters the potential for rapid evolutionary change, so rapid, indeed, that the process looked miraculous and Lamarckian. In this paper, I discuss some of the paradigm examples of co-option, from genes to behavior