Heterochrony and the Problem of Missing Links in Evolutionary Sequences

1984 ◽  
Vol 1 ◽  
pp. 84-96 ◽  
Author(s):  
Thomas W. Broadhead ◽  
Johnny A. Waters
Keyword(s):  
Natural Selection ◽  
Feature Recognition ◽  
Biological Meaning ◽  
Juvenile Stages ◽  
Transitional Forms ◽  
Living Organisms ◽  
Taxonomic Groups ◽  
Organic Change

Critics of the concept of organic change through time have demanded proof not only of “transitional forms” but of specific transitions among higher taxonomic groups. Transitional forms among species and between a species of one genus and a species of another genus have been criticized because most demonstrated ancestor-descendant transitions are considered to occur within one “kind” of organism; the “kind” concept is bereft of biological meaning.Natural selection acts upon organisms at all stages of ontogeny, and especially at larval-juvenile stages. Large shifts in the morphology of one or more features are common in groups of organisms that evolve by heterochrony. Because heterochrony involves a change in timing of the appearance or development of a particular feature, recognition of heterochrony requires a confident knowledge of ontogeny. The resulting increase in complexity (e.g. recapitulation) or decrease in complexity (e.g. paedomorphosis), well documented among living organisms, commonly excludes morphologic intermediates. Paedomorphosis is especially important in the evolution of progressively simplifying lineages and has been well documented from living plants and animals and fossil representatives of echinoderms (blastoids, crinoids), conodonts, arthropods, mollusks and vertebrates. Heterochrony characterizes the evolution of most metazoan organisms, occurs at all taxonomic levels and was probably responsible for major innovations by which higher taxonomic groups are recognized.

scholarly journals Constructor theory of life

2015 ◽  
Vol 12 (104) ◽  
pp. 20141226 ◽  
Author(s):  
Chiara Marletto
Keyword(s):  
Natural Selection ◽  
Evolutionary Theory ◽  
Digital Information ◽  
Evolution Theory ◽  
Physical Processes ◽  
Darwinian Theory ◽  
Gene Replication ◽  
Theory Of Information ◽  
Living Organisms

Neo-Darwinian evolutionary theory explains how the appearance of purposive design in the adaptations of living organisms can have come about without their intentionally being designed. The explanation relies crucially on the possibility of certain physical processes : mainly, gene replication and natural selection . In this paper, I show that for those processes to be possible without the design of biological adaptations being encoded in the laws of physics, those laws must have certain other properties. The theory of what these properties are is not part of evolution theory proper, yet without it the neo-Darwinian theory does not fully achieve its purpose of explaining the appearance of design. To this end, I apply constructor theory's new mode of explanation to express exactly within physics the appearance of design, no-design laws, and the logic of self-reproduction and natural selection. I conclude that self-reproduction, replication and natural selection are possible under no-design laws, the only non-trivial condition being that they allow digital information to be physically instantiated. This has an exact characterization in the constructor theory of information. I also show that under no-design laws an accurate replicator requires the existence of a ‘vehicle’ constituting, together with the replicator, a self-reproducer.

scholarly journals Predators as Agents of Selection and Diversification

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 415
Author(s):  
Jerald B. Johnson ◽  
Mark C. Belk
Keyword(s):  
Natural Selection ◽  
Empirical Evidence ◽  
Mortality Rates ◽  
Predator Species ◽  
Natural Systems ◽  
Evolutionary Diversification ◽  
Multiple Predator Species ◽  
In The Wild ◽  
Taxonomic Groups ◽  
Future Work

Predation is ubiquitous in nature and can be an important component of both ecological and evolutionary interactions. One of the most striking features of predators is how often they cause evolutionary diversification in natural systems. Here, we review several ways that this can occur, exploring empirical evidence and suggesting promising areas for future work. We also introduce several papers recently accepted in Diversity that demonstrate just how important and varied predation can be as an agent of natural selection. We conclude that there is still much to be done in this field, especially in areas where multiple predator species prey upon common prey, in certain taxonomic groups where we still know very little, and in an overall effort to actually quantify mortality rates and the strength of natural selection in the wild.

scholarly journals La etología como herramienta para la conservación de fauna silvestre

2016 ◽  
Vol 8 ◽  
pp. 391
Author(s):  
ALCIDES SAMPEDRO MARÍN
Keyword(s):  
Natural Selection ◽  
Environmental Education ◽  
Behavioral Ecology ◽  
Biological Diversity ◽  
Anthropogenic Impacts ◽  
Adaptive Strategies ◽  
The State ◽  
Effective Size ◽  
Darwinian Theory ◽  
Living Organisms

The origins of ethology as a discipline are explained and is a proof of the Darwinian theory of the action of natural selection leading to the adaptive strategies that allow survival of living organisms. The emergence of behavioral ecology stands out as an important tool for the conservation of biological diversity. Its premises are explained, as well as several examples of behavior that affect the effective size of populations and anthropogenic impacts on various behaviors.Finally, the use of behavioral ecology as an indicator of the state of ecosystems and species and to develop environmental education is exemplified.

scholarly journals Foundations of Biology

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1701
Author(s):  
Jean-Louis Sikorav ◽  
Alan Braslau ◽  
Arach Goldar
Keyword(s):  
Natural Selection ◽  
Deductive Reasoning ◽  
Laws Of Nature ◽  
Logical Structure ◽  
Principle Of Sufficient Reason ◽  
Physico Chemical ◽  
Logical Content ◽  
The Origin Of Life ◽  
Living Organisms ◽  
Biological Entities

It is often stated that there are no laws in biology, where everything is contingent and could have been otherwise, being solely the result of historical accidents. Furthermore, the customary introduction of fundamental biological entities such as individual organisms, cells, genes, catalysts, and motors remains largely descriptive; constructive approaches involving deductive reasoning appear, in comparison, almost absent. As a consequence, both the logical content and principles of biology need to be reconsidered. The present article describes an inquiry into the foundations of biology. The foundations of biology are built in terms of elements, logic, and principles, using both the language and the general methods employed in other disciplines. This approach assumes the existence of a certain unity of human knowledge that transcends discipline boundaries. Leibniz’s principle of sufficient reason is revised through a study of the complementary concepts of symmetry and asymmetry and of necessity and contingency. This is used to explain how these concepts are involved in the elaboration of theories or laws of nature. Four fundamental theories of biology are then identified: cell theory, Darwin’s theory of natural selection, an informational theory of life (which includes Mendel’s theory of inheritance) and a physico-chemical theory of life. Atomism and deductive reasoning are shown to enter into the elaboration of the concepts of natural selection, individual living organisms, cells, and their reproduction, genes, as well as catalysts and motors. This work contributes to clarify the philosophical and logical structure of biology and its major theories. This should ultimately lead to a better understanding of the origin of life, of system and synthetic biology, and of artificial life.

scholarly journals Integrating natural and sexual selection across the biphasic life cycle

2021 ◽  
Author(s):  
Craig Purchase ◽  
Jonathan Evans ◽  
Julissa Roncal
Keyword(s):  
Sexual Selection ◽  
Life Cycle ◽  
Natural Selection ◽  
Conceptual Framework ◽  
Life Cycles ◽  
Parental Effect ◽  
Biphasic Life Cycle ◽  
Evolutionary Trajectories ◽  
Taxonomic Groups ◽  
Natural And Sexual Selection

An alternation between diploid and haploid phases is universal among sexual eukaryotes. Across this biphasic cycle, natural selection and sexual selection occur in both phases. Together, these four stages of selection act on the phenotypes of individuals and influence the evolutionary trajectories of populations, but are rarely studied holistically. Here, we provide a conceptual framework that transcends taxonomic groups, and unifies the entire selection landscape within and across the diploid and haploid phases. Our synthesis produces six direct links among four selection stages, and from this we define four types of parental effect. We argue that knowledge of the complex and intertwined opportunities for selection within biphasic life cycles will offer clearer insights into key ecological and evolutionary processes, with benefits to applied science.

The content of mercury and lead in the feed base of valuable fish species of the Caspian Sea

Fisheries ◽  
2021 ◽  
Vol 2021 (4) ◽  
pp. 10-14
Author(s):  
Tatiana Ershova ◽  
Vladimir Chaplygin ◽  
Vyacheslav Zaitsev ◽  
Alisher Khursanov ◽  
Natalia Shaboyants
Keyword(s):  
Caspian Sea ◽  
Chemical Elements ◽  
Essential Elements ◽  
The Body ◽  
The Caspian Sea ◽  
Rhithropanopeus Harrisii ◽  
The North ◽  
Living Organisms ◽  
Taxonomic Groups ◽  
High Level

Mercury and lead are not essential elements and have a high degree of toxicity to all groups of living organisms, including hydrobionts. In turn, the accumulation of dangerous chemical elements in the primary trophic units of marine ecosystems is also reflected in the high level of accumulation and toxication of fish-valuable objects of fishing. As part of the study of the ecological state of the biota of the Volga-Caspian basin, there is a need to study the concentrations of heavy metals such as mercury and lead. The aim of the work is to study the content of mercury and lead in some invertebrate species of the Caspian Sea. The main source of mercury and lead in the body of the studied species is the water of the north-western part of the Caspian Sea. Among the studied taxonomic groups of organisms, mercury accumulators were all species of mollusks, as well as Balanus improvises and Rhithropanopeus harrisii. The lead concentrating organisms were Cerastoderma lamarcki and Mytilaster lineatus, Rhithropanopeus harrisii, and Balanus improvises.

Evolution and cancer

2019 ◽  
pp. 33-40
Author(s):  
Tom Donnem ◽  
Kingsley Micklem ◽  
Francesco Pezzella
Keyword(s):  
Natural Selection ◽  
Genetic Disease ◽  
Evolutionary Biology ◽  
Tumour Growth ◽  
Cellular Level ◽  
The Body ◽  
Evolutionary Medicine ◽  
Evolutionary Approach ◽  
Living Organisms ◽  
Evolution By Natural Selection

Evolution is the process by which living organisms change through time, and natural selection is the process which leads some organisms to thrive and others to die out. Evolutionary medicine tries to explain why traits leading to susceptibility to disease get maintained or even positively selected. Cancer, being a genetic disease, can be analysed as an example of evolution by natural selection. The observation that humans in developed societies have much higher rates of cancer can be analysed and explained by an evolutionary approach. At a cellular level, tumours are made up by a population of cells continuously growing and mutating while interacting with the microenvironment of the body. Thus, the mechanism of changes in individual tumours is the process of natural selection. Evolutionary biology is now increasingly used to better understand tumour growth and therefore to improve treatments.

Modification of specular reflexion and light transmission by biological surface structures

1968 ◽  
Vol 1 (1) ◽  
pp. 89-105 ◽  
Author(s):  
C. G. Bernhard ◽  
G. Gemne ◽  
A. R. Møller
Keyword(s):  
Natural Selection ◽  
Special Interest ◽  
Light Transmission ◽  
Surface Structures ◽  
Proper Understanding ◽  
Biological Surface ◽  
Basic Characteristics ◽  
Living Organisms ◽  
Apply Physical ◽  
The Many

Biophysicists, who, by definition, apply physical and mathematical principles to their analysis of biological problems for the understanding of the functions of living organisms, are to a great extent concerned with basic characteristics more or less common to all organisms. As pointed out by Griffin (1958) in his book on acoustic orientation, it may well be that ‘this fruitful preoccupation with the universals of protoplasm tends to foster an unduly restricted view of its many intricate potentialities’. The knowledge of the many ways in which animals and plants are adapted for a ‘successful life’ has had a great impact upon the concepts of evolution and natural selection. As a contribution to the proper understanding of these concepts the study of the biophysical principles, by which various geometrically oriented tissues serve different functions, becomes of special interest.

scholarly journals BIOMIMETICS: NOTIONS, PROBLEMS AND TECHNOLOGIES

2019 ◽  
Vol 1 (92) ◽  
pp. 31-35
Author(s):  
Shafagat Mahmudova
Keyword(s):  
Economic Development ◽  
Natural Selection ◽  
Imitation Model ◽  
The Future ◽  
Living Organisms ◽  
Further Development

Biomimetics is an imitation model of systems and elements in the nature to solve complex human problems. Living organisms have well-adapted structures and materials for natural selection and have evolved over many years. The study of biomimetics technologies and their application in different areas can play an important role in the perfect economic development. This article touches upon various aspects of biomimetics and analyzes its technologies. The further development of these technologies in the future is intended.

scholarly journals Triggering Factors for Organism' Evolution

2021 ◽  
Vol 2 (5) ◽  
pp. 1-9
Author(s):  
Do Sepachai ◽  
Yuuyen Pathompul
Keyword(s):  
Natural Selection ◽  
Triggering Factors ◽  
Living Organisms

The purpose of the article is to know the trigerring factor for arganism’ Evolution. Evolution is defined as the change in the heritable features of a population of organisms from one generation to the next, or from one generation to the next. Evolution, according to the contemporary conception, is characterized by changes in the attributes of living organisms through time, with these changes being guided by the process of natural selection

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