Causation and laws in biology

2018 ◽  
Author(s):  
Mohan Matthen
Keyword(s):  
Natural Selection ◽  
Evolutionary Theory ◽  
A Priori ◽  
Population Level ◽  
Subject Area ◽  
Structural Determinants ◽  
Individual Level ◽  
Philip Kitcher ◽  
Biological Laws ◽  
Physical Laws

Physicalism appears to undermine the autonomy of ‘special sciences’ such as biology, and to leave little room for proprietary biological laws or causation. Mendel’s ‘Laws’ are so-called because they are fundamental to the subject-area, but since they describe causal processes that are wholly physical in nature, they seem to reduce to physical laws, given certain propositions about the composition of DNA. The same goes for other principles of the biological sciences. This argument has been challenged by Hilary Putnam, on the grounds that good explanations, for instance in mathematical terms, could range more widely than any given physical realization. Putnam argues that mathematics could thus have an autonomous role in science despite physicalism. Putnam’s insight has been applied to classical genetics by Philip Kitcher. A gene is a unit of inheritance that passes unchanged from parent to offspring according to certain rules. It is these rules that are essential to understanding inheritance, not details of interaction in the DNA substrate. Putnam and Kitcher here employ a notion similar to Aristotle’s ‘formal causes’ – functional and structural determinants of biological characteristics that are somewhat independent of material constitution. There are other conceptions of laws to be found in philosophy of science. Some think that they are propositions with the capacity to impart axiomatic structure to what is known about a domain. The principle of natural selection plays this role in biology, though it is a priori. Again, some think that laws are necessary truths: on cladistic systems of classification, the proposition that the common raven is a bird is arguably a law under this understanding. The nature of causal patterns in natural selection has been a matter of some discussion recently. The view that individual-level causes are sufficient to explain selection-outcomes is tempting to the reductionist, but distorts the explanatory aims of evolutionary theory. Clearly, evolutionary theory requires population-level causes. On the other hand, it has been questioned whether natural selection itself should be understood as a ‘force’ acting on a population, somewhat in the same manner as gravitation acts on a body. Statistical views of natural selection seek alternatives to this way of understanding selection. Finally, what are biological entities? Some ontologies admit no priority among collections of atoms – the argument is that an organism, for instance, is nothing more than such a collection. Many biologists, however, treat of composite entities as internally organized complex systems. On this view, cells, organisms, populations, and ecosystems have privileged ontological status.

Epigenetic and cultural evolution are non-Darwinian

2007 ◽  
Vol 30 (4) ◽  
pp. 371-371
Author(s):  
Liane Gabora
Keyword(s):  
Natural Selection ◽  
Cultural Evolution ◽  
Self Assembly ◽  
Population Level ◽  
Early Evolution ◽  
Epigenetic Change ◽  
Assembly Code ◽  
Individual Level ◽  
Evolution Of Life ◽  
Distinct Role

AbstractThe argument that heritable epigenetic change plays a distinct role in evolution would be strengthened through recognition that it is what bootstrapped the origin and early evolution of life, and that, like behavioral and symbolic change, it is non-Darwinian. The mathematics of natural selection, a population-level process, is limited to replication with negligible individual-level change that uses a self-assembly code.

scholarly journals Individual- and population-level drivers of consistent foraging success across environments

2018 ◽  
Author(s):  
Lysanne Snijders ◽  
Ralf H. J. M. Kurvers ◽  
Stefan Krause ◽  
Indar W. Ramnarine ◽  
Jens Krause
Keyword(s):  
Individual Differences ◽  
Natural Selection ◽  
Sex Ratio ◽  
Field Experiment ◽  
Poecilia Reticulata ◽  
A Priori ◽  
Population Level ◽  
Foraging Success ◽  
In The Wild ◽  
The Individual

AbstractIndividual foraging is under strong natural selection. Yet, whether individuals differ consistently in their foraging success across environments, and which individual and population-level traits might drive such differences, is largely unknown. We addressed this question in a field experiment, conducting over 1,100 foraging trials with nine subpopulations of guppies, Poecilia reticulata, translocating them across environments in the wild. A-priori, we determined the individual social phenotypes. We show that individuals consistently differed in reaching food, but not control, patches across environments. Social individuals reached more food patches than less social ones and males reached more food patches than females. Overall, individuals were, however, more likely to join females at patches than males, which explains why individuals in subpopulations with relatively more females reached, on average, more food patches. Our results provide rare evidence for individual differences in foraging success across environments, driven by individual and population level (sex ratio) traits.

Cooperation and Altruism

2001 ◽  
Author(s):  
David Sloan Wilson
Keyword(s):  
Natural Selection ◽  
Evolutionary Theory ◽  
Opposite Direction ◽  
Social Adaptation ◽  
Herbivore Damage ◽  
Individual Level ◽  
Cryptic Coloration ◽  
The Subject ◽  
The Individual ◽  
Shed Light

People have always been fascinated by cooperation and altruism in animals, in part to shed light on our own propensity or reluctance to help others. Darwin’s theory added a certain urgency to the subject because the principle of “nature red in tooth and claw” superficially seems to deny the possibility of altruism and cooperation altogether. Some evolutionary biologists have accepted and even reveled in this vision of nature, giving rise to statements such as “the economy of nature is competitive from beginning to end . . . scratch an ‘altruist’ and watch a hypocrite bleed”. Others have gone so far in the opposite direction as to proclaim the entire earth a unit that cooperatively regulates its own atmosphere (Lovelock 1979). The truth is somewhere between these two extremes; cooperation and altruism can evolve but only if special conditions are met. As might be expected from the polarized views outlined above, achieving this middle ground has been a difficult process. Science is often portrayed as a heroic march to the truth, but in this case, it is more like the Three Stooges trying to move a piano. I don’t mean to underestimate the progress that been made—the piano has been moved—but we need to appreciate the twists, turns, and reversals in addition to the final location. To see why cooperation and altruism pose a problem for evolutionary theory, consider the evolution of a nonsocial adaptation, such as cryptic coloration. Imagine a population of moths that vary in the degree to which they match their background. Every generation, the most conspicuous moths are detected and eaten by predators while the most cryptic moths survive and reproduce. If offspring resemble their parents, then the average moth will become more cryptic with every generation. Anyone who has beheld a moth that looks exactly like a leaf, right down to the veins and simulated herbivore damage, cannot fail to be impressed by the power of natural selection to evolve breathtaking adaptations at the individual level. Now consider the same process for a social adaptation, such as members of a group warning each other about approaching predators.

scholarly journals Shared behavioral mechanisms underlie C. elegans aggregation and swarming

2018 ◽  
Author(s):  
S Serena Ding ◽  
Linus J. Schumacher ◽  
Avelino E. Javer ◽  
Robert G. Endres ◽  
André EX Brown
Keyword(s):  
A Priori ◽  
Population Level ◽  
Agent Based Modeling ◽  
Agent Based ◽  
Individual Level ◽  
C Elegans ◽  
Behavioral Rules ◽  
Level Statistics ◽  
Approximate Bayesian ◽  
Behavioral Mechanisms

AbstractIn complex biological systems, simple individual-level behavioral rules can give rise to emergent group-level behavior. While such collective behavior has been well studied in cells and larger organisms, the mesoscopic scale is less understood, as it is unclear which sensory inputs and physical processes matter a priori. Here, we investigate collective feeding in the roundworm C. elegans at this intermediate scale, using quantitative phenotyping and agent-based modeling to identify behavioral rules underlying both aggregation and swarming—a dynamic phenotype only observed at longer timescales. Using fluorescent multi-worm tracking, we quantify aggregation behavior in terms of individual dynamics and population-level statistics. Based on our quantification, we use agent-based simulations and approximate Bayesian inference to identify three key behavioral rules that give rise to aggregation: cluster-edge reversals, a density-dependent switch between crawling speeds, and taxis towards neighboring worms. Our simulations suggest that swarming is simply driven by local food depletion but otherwise employs the same behavioral mechanisms as the initial aggregation. Hence, mesoscopic C. elegans uses mechanisms familiar from microscopic systems for aggregation, but implemented via more complex behaviors characteristic of macroscopic organisms.

Competitive ability: definitions, contingency and correlated traits

1996 ◽  
Vol 351 (1345) ◽  
pp. 1377-1385 ◽  
Keyword(s):  
Competitive Ability ◽  
Plant Traits ◽  
A Priori ◽  
Population Level ◽  
Model Systems ◽  
Individual Plant ◽  
Competitive Effect ◽  
Competitive Response ◽  
Individual Level ◽  
Competitive Success

Although the relationship between individual plant traits and competitive success in communities is an essential component of comprehensive models of the role of competition in structuring plant communities, three obstacles have stymied efforts to empirically examine such relationships. First, definitions of competitive ability are often inconsistent among bodies of theory and between theoretical predictions and empirical research. Much of the theoretical literature is for populations and often at equilibrium, while experimental work has been largely on individuals and short term. This situation is likely to continue, except for a few model systems, and therefore it is critical that individual-level surrogates for population level phenomena be found. I suggest that competitive response of seedlings to established vegetation may be an effective surrogate for estimating competitive success of populations at equilibrium and that competitive response of individuals with more similar-sized neighbours may be an effective surrogate for competitive success of populations earlier in succession or in non-equilibrium systems. Second, competitive ability may be contingent on many factors, such that it may not be an identifiable characteristic of any particular taxon and thus no broadly applicable relationships between traits and competitive ability may exist. However, a literature survey shows that both competitive response and competitive effect are generally, but not always, consistent regardless of identity of competing species, making the search for relationships with traits reasonable, at least within environments. Among environments, both competitive effect and competitive response are consistent in only about half the studies, making it unreasonable to assume a priori that competitive hierarchies will be similar under different conditions. The third obstacle is logistical; competitive ability is necessarily measured experimentally, and preferably in the field, making it difficult to obtain sufficient sample sizes (numbers of taxa) for rigorous analysis of relationships with traits. I suggest several simplifying assumptions and experimental approaches that could enable much more efficient assaying of competitive abilities of many species.

scholarly journals Shared behavioral mechanisms underlie C. elegans aggregation and swarming

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Siyu Serena Ding ◽  
Linus J Schumacher ◽  
Avelino E Javer ◽  
Robert G Endres ◽  
André EX Brown
Keyword(s):  
A Priori ◽  
Population Level ◽  
Agent Based Modeling ◽  
Agent Based ◽  
Individual Level ◽  
C Elegans ◽  
Behavioral Rules ◽  
Level Statistics ◽  
Approximate Bayesian ◽  
Behavioral Mechanisms

In complex biological systems, simple individual-level behavioral rules can give rise to emergent group-level behavior. While collective behavior has been well studied in cells and larger organisms, the mesoscopic scale is less understood, as it is unclear which sensory inputs and physical processes matter a priori. Here, we investigate collective feeding in the roundworm C. elegans at this intermediate scale, using quantitative phenotyping and agent-based modeling to identify behavioral rules underlying both aggregation and swarming—a dynamic phenotype only observed at longer timescales. Using fluorescence multi-worm tracking, we quantify aggregation in terms of individual dynamics and population-level statistics. Then we use agent-based simulations and approximate Bayesian inference to identify three key behavioral rules for aggregation: cluster-edge reversals, a density-dependent switch between crawling speeds, and taxis towards neighboring worms. Our simulations suggest that swarming is simply driven by local food depletion but otherwise employs the same behavioral mechanisms as the initial aggregation.

Darwinian Evolutionary Theory

2018 ◽  
Author(s):  
Michael Ruse
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Middle Class ◽  
Evolutionary Theory ◽  
Scientific Community ◽  
Homo Sapiens ◽  
Origin Of Species ◽  
Theory Of Evolution ◽  
Descent Of Man

Charles Robert Darwin, the English naturalist, published On the Origin of Species in 1859 and the follow-up work The Descent of Man in 1871. In these works, he argued for his theory of evolution through natural selection, applying it to all organisms, living and dead, including our own species, Homo sapiens. Although controversial from the start, Darwin’s thinking was deeply embedded in the culture of his day, that of a middle-class Englishman. Evolution as such was an immediate success in scientific circles, but although the mechanism of selection had supporters in the scientific community (especially among those working with fast-breeding organisms), its real success was in the popular domain. Natural selection, and particularly the side mechanism of sexual selection, were known to all and popular themes in fiction and elsewhere.

scholarly journals Blood Pressure Trajectories Across the Life Course

2021 ◽  
Vol 34 (3) ◽  
pp. 234-241
Author(s):  
Norrina B Allen ◽  
Sadiya S Khan
Keyword(s):  
Blood Pressure ◽  
Measurement Errors ◽  
Clinical Care ◽  
Population Level ◽  
Cumulative Exposure ◽  
Older Adulthood ◽  
Individual Level ◽  
The Life Course ◽  
Level Group ◽  
Improve Health

Abstract High blood pressure (BP) is a strong modifiable risk factor for cardiovascular disease (CVD). Longitudinal BP patterns themselves may reflect the burden of risk and vascular damage due to prolonged cumulative exposure to high BP levels. Current studies have begun to characterize BP patterns as a trajectory over an individual’s lifetime. These BP trajectories take into account the absolute BP levels as well as the slope of BP changes throughout the lifetime thus incorporating longitudinal BP patterns into a single metric. Methodologic issues that need to be considered when examining BP trajectories include individual-level vs. population-level group-based modeling, use of distinct but complementary BP metrics (systolic, diastolic, mean arterial, mid, and pulse pressure), and potential for measurement errors related to varied settings, devices, and number of readings utilized. There appear to be very specific developmental periods during which divergent BP trajectories may emerge, specifically adolescence, the pregnancy period, and older adulthood. Lifetime BP trajectories are impacted by both individual-level and community-level factors and have been associated with incident hypertension, multimorbidity (CVD, renal disease, cognitive impairment), and overall life expectancy. Key unanswered questions remain around the additive predictive value of BP trajectories, intergenerational contributions to BP patterns (in utero BP exposure), and potential genetic drivers of BP patterns. The next phase in understanding BP trajectories needs to focus on how best to incorporate this knowledge into clinical care to reduce the burden of hypertensive-related outcomes and improve health equity.

‘Short-Spanned Living Creatures’: Evolutionary Perspectives in Rhoda Broughton’s Not Wisely, but Too Well (1867)

2021 ◽  
Author(s):  
James Aaron Green
Keyword(s):  
Natural Selection ◽  
Evolutionary Theory ◽  
Simple Structure ◽  
Charles Darwin ◽  
Origin Of Species ◽  
Charles Lyell ◽  
Crystal Palace ◽  
The Status ◽  
The Individual ◽  
Evolutionary Perspectives

Abstract In Geological Evidences of the Antiquity of Man (1863), Charles Lyell appraised the distinct contribution made by his protégé, Charles Darwin (On the Origin of Species (1859)), to evolutionary theory: ‘Progression … is not a necessary accompaniment of variation and natural selection [… Darwin’s theory accounts] equally well for what is called degradation, or a retrogressive movement towards a simple structure’. In Rhoda Broughton’s first novel, Not Wisely, but Too Well (1867), written contemporaneously with Lyell’s book, the Crystal Palace at Sydenham prompts precisely this sort of Darwinian ambivalence to progress; but whether British civilization ‘advance[s] or retreat[s]’, her narrator adds that this prophesized state ‘will not be in our days’ – its realization exceeds the single lifespan. This article argues that Not Wisely, but Too Well is attentive to the irreconcilability of Darwinism to the Victorian ‘idea of progress’: Broughton’s novel, distinctly from its peers, raises the retrogressive and nihilistic potentials of Darwin’s theory and purposes them to reflect on the status of the individual in mid-century Britain.

scholarly journals Examining the Effects of the Sacramento Dockless E-Bike Share on Bicycling and Driving

2021 ◽  
Vol 13 (1) ◽  
pp. 368
Author(s):  
Dillon T. Fitch ◽  
Hossain Mohiuddin ◽  
Susan L. Handy
Keyword(s):  
Travel Behavior ◽  
Regression Models ◽  
Population Level ◽  
Panel Survey ◽  
Multilevel Regression ◽  
Combine Data ◽  
Cross Sectional ◽  
Individual Level ◽  
Before And After ◽  
Bike Share

One way cities are looking to promote bicycling is by providing publicly or privately operated bike-share services, which enable individuals to rent bicycles for one-way trips. Although many studies have examined the use of bike-share services, little is known about how these services influence individual-level travel behavior more generally. In this study, we examine the behavior of users and non-users of a dockless, electric-assisted bike-share service in the Sacramento region of California. This service, operated by Jump until suspended due to the coronavirus pandemic, was one of the largest of its kind in the U.S., and spanned three California cities: Sacramento, West Sacramento, and Davis. We combine data from a repeat cross-sectional before-and-after survey of residents and a longitudinal panel survey of bike-share users with the goal of examining how the service influenced individual-level bicycling and driving. Results from multilevel regression models suggest that the effect of bike-share on average bicycling and driving at the population level is likely small. However, our results indicate that people who have used-bike share are likely to have increased their bicycling because of bike-share.

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