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Evolution and Ecology

4.1 Forerunners

       4.1.1 Ancient Greek thoughts on evolution

 

The notion of scala naturae dates back to thinkers such as Aristotle, who placed plants below animals and ranked the latter along a graded scale of complexity from ‘lower’ to ‘higher’ animals, such as humans. Aristotle was a great classifier and codifier. In his effort to develop a strong taxonomic scheme, he noticed important similarities and differences between various zoological forms. He arranged these upon a basis of increasing perfection, extending from lower to higher animals. In its way, this was a theory of evolution. In the last decades, evolutionary biologists have tended to move from one extreme (i.e. the idea of scala naturae or the existence of a general evolutionary trend in complexity from ‘lower’ to “higher” taxa, with Homo sapiens as the end stage) to the other, opposite, extreme (i.e. to avoid using terms such as ‘phylogenetically basal’ and ‘anatomically plesiomorphic’ taxa, which are seen as the undesired vestige of old teleological theories). The latter view tries to avoid any possible connotations with the original anthropocentric idea of a scala naturae. (Diogo, Ziermann, & Linde-Medina, 2014)

Aristotle's theories of essentialism and classification of his logic and metaphysics demand that substantial kinds be completely distinct or discrete kinds. In his biology Aristotle adopts as a classificatory scheme the scala naturae, which, according to some of his expounders, is incompatible with the theories of essentialism and classification of the logic and metaphysics. According to their interpretation, kinds in the scala naturae n form a continuous series in which they overlap one another, and thus it is impossible for them to be completely distinct from one another or to be discrete kinds. Arthur 0. Lovejoy argues for this interpretation of the scala naturae in ‘The Great Chain of Being,' and several other more recent scholars adopt or argue for much the same interpretation. (Granger, 1985)

        4.1.2 The scientific revolution

Copernicus, Galileo, and Kepler contributed to elucidating the nature of the relationship of the earth to other planets in the solar systems. Isaac Newton (Riebeek, 2009) went beyond attempts of Renaissance astronomers to explain the puzzling path of planets across the night sky led to modern science’s understanding of gravity and motion in his “Mathematical Principles of Natural Philosophy” published in 1687.

The scientific revolution had its origin in the works of natural philosophers such as Francis Bacon. The "interpretation of nature" (interpretatio naturae) is the leading idea in Francis Bacon's natural philosophy. He also had outstanding ideas about method, induction, and experiment. (Serjeantson R. 2014)

The existence of microscopic organisms was discovered during the period 1665–83 by two Fellows of The Royal Society, Robert Hooke and Antoni van Leeuwenhoek. In Micrographia (1665), Hooke presented the first published depiction of a microrganism, the microfungus Mucor. Later, Leeuwenhoek observed and described microscopic protozoa and bacteria. These important revelations were made possible by the ingenuity of Hooke and Leeuwenhoek in fabricating and using simple microscopes that magnified objects from about 25–fold to 250–fold. (Gest, 2004)   A prominent scientist who contributed to the study of paleontology was Cuvier whose ideas led him to oppose the theories of his contemporaries, such as Buffon who suggested that animal morphology might be much more changeable and be affected by environmental conditions. They pointed to vestigial, functionless structures and to embryonic development to show that dissimilar organisms with different functions might nonetheless share a common structural plan. Cuvier and Geoffroy engaged in a famous public debate over their different philosophies in 1830, at the Académie Royale des Sciences in Paris. While Cuvier is generally said to have won the debate, the views of Geoffroy St Hilaire continued to be perpetuated in scientific circles, and the repercussions of this debate on form versus function can still be felt in modern biology. Cuvier's most crucial and longest-lasting contribution to biology was establishing extinction as a fact. (Waggoner, 1996) The Swedish botanist, physician and zoologist Carl Linnaeus (1707–1778) used to describe his contribution to science as: God created, but Linnaeus organized. Although there have been several modern alterations to Linnaeus' original system, the basis of Linnaean taxonomy has allowed biologists to group related species into genealogical trees, which represent the evolutionary lineage of modern organisms from common ancestors. (Paterlini, 2007)

        4.1.3 Jean Baptiste De Lamarck

French biologist Jean-Baptiste Lamarck (1744 -1829) advanced the ideas that (1) nature produced successively all the different forms of life on earth, and (2) environmentally induced behavioral changes lead the way in species change. (Burkhardt, 2013) Lamarck’s name is commonly associated with the theory of the inheritance of acquired characteristics. Evolution is today a scientific fact of the modern world. It is all the more remarkable, therefore, that Lamarck believed in organic evolution at a time when there was little or no empirical evidence to support his belief and nor was there any theoretical framework to even explain the idea of evolution. It was, in fact, seen as heretical at the time. (Honeywill, n.d.)

4.2 Charles Lyell and Robert Malthus

       4.2.1 The age of the earth

Charles Lyell (1797 – 1875) is one of the eminent geologists who initiated the scientific thinking in geology, in which his famous volumes of the Principles of Geology were taken as the authority. These reference volumes are based on multiple observations and field works collected during numerous fieldtrips in western Europe (principally Spain, France, and Italy) and North America. To his name are attached, among others: ( i ) the concept of uniformitarianism (or actualism), which was opposed to the famous catastrophism, in vogue at that time, and which may be summarized by the expression “The present is the key to the past”; ( ii ) the division of the Tertiary in three series denominated Eocene, Miocene, and Pliocene, due to the study of the age of strata by fossil faunas; ( iii ) the theory according to which the orogenesis of a mountain chain, as the Pyrenees, results from different pulsations on very long time scales and was not induced by a unique pulsation during a short and intense period. The uniformity of the laws of Nature is undeniably a principle Charles Lyell was the first to state clearly and to apply to the study of the whole Earth's crust, which opened a new era in geology. (Virgili, 2007)

The generally accepted age for the Earth and the rest of the solar system is about 4.55 billion years (plus or minus about 1%). This value is derived from several different lines of evidence.

Unfortunately, the age cannot be computed directly from material that is solely from the Earth. There is evidence that energy from the Earth's accumulation caused the surface to be molten. Further, the processes of erosion and crustal recycling have apparently destroyed all of the earliest surface.

The oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.

While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age. (Stassen, n.d.)

        4.2.3 principles of populations

In 1798 Malthus (1766 -1834) published An Essay on the Principle of Population, in which he argued that the supply of food could not follow for a long period of time the natural tendency of human populations to grow exponentially. If the population remained relatively constant, this was because a great part of mankind was suffering from food shortage. Malthus saw the “principle of population” as an argument against the writings of Godwin and Condorcet, which emphasized progress in human societies. Malthus’ essay influenced the theory of evolution of Darwin and Wallace and was criticized by Marx but was put into practice with the Chinese one-child policy. (Bacaër, 2011)

4.3 Charles Darwin

        4.3.1 The Origin of Species

On the Origin of Species, published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection. It presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had gathered on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation. (Darwin)

        4.3.2 The Descent of Man

The Descent of Man, and Selection in Relation to Sex is a book by English naturalist Charles Darwin, first published in 1871, which applies evolutionary theory to human evolution, and details his theory of sexual selection, a form of biological adaptation distinct from, yet interconnected with, natural selection. The book discusses many related issues, including evolutionary psychology, evolutionary ethics, differences between human races, differences between sexes, the dominant role of women in mate choice, and the relevance of the evolutionary thesis.

4.4 Heredity

        4.4.1 The basis of particulate inheritance

Our modern understanding of how traits may be inherited through generations comes from the principles proposed by Gregor Mendel in 1865. However, Mendel didn't discover these foundational principles of inheritance by studying human beings, but rather by studying Pisum sativum, or the common pea plant. Indeed, after eight years of tedious experiments with these plants, and—by his own admission—"some courage" to persist with them, Mendel proposed three foundational principles of inheritance. Today, whether you are talking about pea plants or human beings, genetic traits that follow the rules of inheritance that Mendel proposed are called Mendelian.

Before Mendel's experiments, most people believed that traits in offspring resulted from a blending of the traits of each parent. However, when Mendel cross-pollinated one variety of purebred plant with another, these crosses would yield offspring that looked like either one of the parent plants, not a blend of the two. For example, when Mendel cross-fertilized plants with wrinkled seeds to those with smooth seeds, he did not get progeny with semi-wrinkly seeds. Instead, the progeny from this cross had only smooth seeds. In general, if the progeny of crosses between purebred plants looked like only one of the parents with regard to a specific trait, Mendel called the expressed parental trait the dominant trait. From this simple observation, Mendel proposed his first principle, the principle of uniformity; this principle states that all the progeny of a cross like this (where the parents differ by only one trait) will appear identical. Exceptions to the principle of uniformity include the phases of penetrance, expressivity and sex linkage which were discovered after Mendel's time. (Miko)

        4.4.2 The science of heredity

Perhaps the most fundamental property of all living things is the ability to reproduce. All organisms inherit the genetic information specifying their structure and function from their parents. Likewise, all cells arise from preexisting cells, so the genetic material must be replicated and passed from parent to progeny cell at each cell division. How genetic information is replicated and transmitted from cell to cell and organism to organism thus represents a question that is central to all of biology. Consequently, elucidation of the mechanisms of genetic transmission and identification of the genetic material as DNA were discoveries that formed the foundation of our current understanding of biology at the molecular level. (Cooper, Heredity, Genes, and DNA, 2000)

4.5 The Synthetic Theory

        4.5.1 Inheritance and Evolution

Darwin's lack of a model of the mechanism of inheritance left him unable to interpret his own data that showed Mendelian ratios, even though he shared with Mendel a more mathematical and probabilistic outlook than most biologists of his time. Darwin's own “pangenesis” model provided a mechanism for generating ample variability on which selection could act. It involved, however, the inheritance of characters acquired during an organism's life, which Darwin himself knew could not explain some evolutionary situations. Once the particulate basis of genetics was understood, it was seen to allow variation to be passed intact to new generations, and evolution could then be understood as a process of changes in the frequencies of stable variants. Evolutionary genetics subsequently developed as a central part of biology. Darwinian principles now play a greater role in biology than ever before, which we illustrate with some examples of studies of natural selection that use DNA sequence data and with some recent advances in answering questions first asked by Darwin (Charlesworth & Charlesworth, 2009)

Current ideas on evolution are usually referred to as the Modern Synthesis which is described by Futuyma;

"The major tenets of the evolutionary synthesis, then, were that populations contain genetic variation that arises by random (i.e. not adaptively directed) mutation and recombination; that populations evolve by changes in gene frequency brought about by random genetic drift, gene flow, and especially natural selection; that most adaptive genetic variants have individually slight phenotypic effects so that phenotypic changes are gradual (although some alleles with discrete effects may be advantageous, as in certain color polymorphisms); that diversification comes about by speciation, which normally entails the gradual evolution of reproductive isolation among populations; and that these processes, continued for sufficiently long, give rise to changes of such great magnitude as to warrant the designation of higher taxonomic levels (genera, families, and so forth)." (Moran, n.d.)

 

        4.5.2 The progress of evolutionary theory

Evolutionary psychology emerged from within the sociobiological paradigm. Human sociobiology sought to draw upon the study of other social animals to create accounts of human social conduct. It regarded current social science as hopelessly ill-informed about biology and in some of his less guarded pronouncements, E.O. Wilson in particular has appeared to entertain imperialistic ambitions towards social science. Contemporary evolutionary psychology shares that hostility and some of those ambitions. For instance, it seeks to found social science on an account of evolved psychology that has little space for social facts as they have been traditionally conceived. At the same time, it has distanced itself from sociobiology in several crucial respects. For instance, sociobiology was confronted by some fairly devastating political and ideological criticisms, and these played a large role in the enterprise’s decline. Evolutionary psychologists, for the most part, have been keen to distance themselves from any stance which appears to endorse racism, sexism or social inequality. Evolutionary psychology has recently experienced a rapid and often controversial growth in popularity and influence that has been evident in both the academic and the popular press. A resurgence of interest in the importance of evolutionary theory for understanding human psychological processes is noted from around the early 1970s onward. (Hamilton, 2008)

The goal of research in evolutionary psychology is to discover and understand the design of the human mind. Evolutionary psychology is an approach to psychology, in which knowledge and principles from evolutionary biology are put to use in research on the structure of the human mind. It is not an area of study, like vision, reasoning, or social behavior. It is a way of thinking about psychology that can be applied to any topic within it.

The origin of altruistic behavior, i.e. the behavior that is useful for a population or a species but goes at the expense of an altruistic individual, has long been a challenge for students of evolutionary biology. The populations with altruistic individuals thrive better than those without altruists; however, the altruists within a population thrive worse than the non-altruists and their prevalence in the population decreases due to individual selection. Under certain conditions, the strength of group selection, i.e. the competition between populations, can surpass the strength of individual selection; however, such conditions are rarely achieved in practice. It was suggested recently that chances for altruistic behavior to spread highly increase when it is controlled not by a single gene but by multiple independent genes substitutable in their effects on the phenotype of the individual.

The idea of Group Selection has a superficial appeal because humans are indisputably adapted to group living and because some groups are indisputably larger, longer-lived, and more influential than others. This makes it easy to conclude that properties of human groups, or properties of the human mind, have been shaped by a process that is akin to natural selection acting on genes. Despite this allure, I have argued that the concept of Group Selection has no useful role to play in psychology or social science. It refers to too many things, most of which are not alternatives to the theory of gene-level selection but loose allusions to the importance of groups in human evolution. And when the concept is made more precise, it is torn by a dilemma. If it is meant to explain the cultural traits of successful groups, it adds nothing to conventional history and makes no precise use of the actual mechanism of natural selection. But if it is meant to explain the psychology of individuals, particularly an inclination for unconditional

self-sacrifice to benefit a group of nonrelatives, it is dubious both in theory (since it is hard to see how it could evolve given the built-in advantage of protecting the self and one's kin) and in practice (since there is no evidence that humans have such a trait).

None of this prevents us from seeking to understand the evolution of social and moral intuitions, nor the dynamics of populations and networks which turn individual psychology into large-scale societal and historical phenomena. It's just that the notion of "group selection" is far more likely to confuse than to enlighten—especially as we try to understand the ideas and institutions that human cognition has devised to make up for the shortcomings of our evolved adaptations to group living. (Wilson, 2012)

A widespread claim in evolutionary theory is that every group selection model can be recast in terms of inclusive fitness. Although there are interesting classes of group selection models for which this is possible, we show that it is not true in general. With a simple set of group selection models, we show two distinct limitations that prevent recasting in terms of inclusive fitness. The first is a limitation across models. We show that if inclusive fitness is to always give the correct prediction, the definition of relatedness needs to change, continuously, along with changes in the parameters of the model. This results in infinitely many different definitions of relatedness – one for every parameter value – which strips relatedness of its meaning. The second limitation is across time. We show that one can find the trajectory for the group selection model by solving a partial differential equation, and that it is mathematically impossible to do this using inclusive fitness. (Veelen, Veelen, Luo, & Simon, 2014)

The last 45 years of research provide clear evidence of the relative use of the kin and group selection approaches. Kin selection methodologies are more tractable, allowing the construction of models that can be applied more easily to specific biological examples, including those chosen by Wilson to illustrate the utility of the group selection approach. In contrast, the group selection approach is not only less useful, but also appears to frequently have negative consequences by fostering confusion that leads to wasted effort. More generally, kin selection theory allows the construction of a unified conceptual overview that can be applied across all taxa, whereas there is no formal theory of group selection. (West, Griffin, & Gardner, 2008)

4.6 Ecology

        4.6.1 The science of the environment

The late Howard T. Odum (1924-2002), the renowned American ecologist and systems analyst, viewed thermodynamic constraints as limiting the development of self-organizing biological organisms. In work with his then colleague Richard C. Pinkerton in the mid-1950s he devised the so-called 'maximum power and optimum efficiency' axiom for ecology. This led to a means for analyzing the energetics of systems more generally with the notion of EMERGY, or 'energy memory', at its core. This rightly allowed for differences in the quality of energy sources, although the practical application of the property has had its critics over time. Later in his life, Odum was concerned with the need for human society to embrace a new ethics and set of policies for the 'descent' away from a growth path in order to ensure 'a prosperous way down' for this complex world modelled on the pulsing paradigm in nature. Here, Odum's ideas are critically assessed from outside his own circle in terms of insights gleaned from the use of engineering thermodynamics (energy and exergy analysis) and environmental appraisal methods, as well as those provided by the modern paradigm of ‘sustainability'. This contribution forms part of a sequence of papers in which the author and his collaborators have re-evaluated the use of thermodynamic ideas outside their traditional domain of energy systems. These have encompassed the use of Second Law concepts for resource and/or emissions accounting and, more recently, in ecological economics. It was argued that in these earlier cases the use of such ideas outside the realm of energy systems implies a weak analogy or metaphor, rather than representing thermodynamic limits in a physical sense. The present work also employs the results of environmental, or 'ecological', foot printing at a global and national scale to judge where humanity stands on the pathway towards sustainability. (Hammond, 2007)

        4.6.2 Ecological succession

Successions are a central issue of ecological theory. They are governed by changes in community assembly processes that can be tracked by species’ traits. While single-trait-based approaches have been mostly promoted to address community assembly, ecological strategies actually encompass tradeoffs between multiple traits that are relevant to succession theory. We analyzed plant ecological strategies along a 140-year-long succession primary succession of 52 vertical outcrop communities after roadwork. We performed an RLQ analysis to relate six functional traits, associated with resource acquisition, competition, colonization ability and phenology, to the age of the outcrops. We found the prominence of two main axes of specialization, one related to resource acquisition and the other to reproduction and regeneration. We further examined the community-level variation in ecological strategies to assess the abiotic and biotic drivers of community assembly. Using trait-based statistics of functional richness, regularity and divergence, we found that different processes drove the variation in ecological strategies along the axes of specialization. In late succession, functional convergence was detected for the traits related to resource acquisition as a signature of habitat filtering, while the coexistence of contrasted strategies was found for the traits related to reproduction and regeneration as a result of spatial micro-heterogeneity. We observed a lack of niche differentiation along the succession, revealing a weak importance of biotic interactions for the regulation of community assembly in the outcrops. Overall, we highlight a prominent role of habitat filtering and spatial micro-heterogeneity in driving the primary succession governed by water and nutrient limitation. (Raevel, Violle, & Munoz, 2012)

        4.6.3 Ecological biomes

Biomes are areas of vegetation that are characterized by the same life-form. Traditional definitions of biomes have also included either geographical or climatic descriptors. This approach describes a wide range of biomes that can be correlated with characteristic climatic conditions, or climatic envelopes. The application of remote sensing technology to the frequent observation of biomes has led to a move away from the often-subjective definition of biomes to one that is objective. Carefully characterized observations of life-form, by satellite, have been used to reconsider biome classification and their climatic envelopes. Five major tree biomes can be recognized by satellites based on leaf longevity and morphology: needleleaf evergreen, broadleaf evergreen, needleleaf deciduous, broadleaf cold deciduous and broadleaf drought deciduous. Observations indicate that broadleaf drought deciduous vegetation grades substantially into broadleaf evergreen vegetation. The needleleaf deciduous biome occurs in the world's coldest climates, where summer drought and therefore a drought deciduous biome are absent. Traditional biome definitions are quite static, implying no change in their life-form composition with time, within their particular climatic envelopes. However, this is not the case where there has been global ingress of grasslands and croplands into forested vegetation. The global spread of grasses, a new super-biome, was probably initiated 30-45 Myr ago by an increase in global aridity and was driven by the natural spread of the disturbances of fire and animal grazing. These disturbances have been further extended over the Holocene era by human activities that have increased the land areas available for domestic animal grazing and for growing crops. The current situation is that grasses now occur in most, if not all biomes, and in many areas, they dominate and define the biome. Croplands are also increasing, defining a new and relatively recent component to the grassland super-biome. In the case of both grassland and croplands, various forms of disturbance, particularly frequent disturbance, lead to continued range extensions of the biomes. (Woodward, Lomas, & Kelly, 2004)

 

4.7 Human Evolutionary Ecology

       4.7.1 The human econiche

The niche construction model postulates that human bio-social evolution is composed of three inheritance domains, genetic, cultural and ecological, linked by feedback selection. Many kinds of archaeological data can serve as proxies for human niche construction processes and presents a method for investigating specific niche construction hypotheses. To illustrate this method, the repeated emergence of specialized reindeer (Rangifer tarandus) hunting/herding economies during the Late Paleolithic (ca 14.7–11.5 Kyr BP) in southern Scandinavia is analyzed from a niche construction/triple-inheritance perspective. This economic relationship resulted in the eventual domestication of Rangifer. The hypothesis of whether domestication was achieved as early as the Late Paleolithic, and whether this required the use of domesticated dogs (Canis familiaris) as hunting, herding or transport aids, is tested via a comparative analysis using material culture-based phylogenies and ecological datasets in relation to demographic/genetic proxies. Only weak evidence for sustained niche construction behaviors by prehistoric hunter–gatherer in southern Scandinavia is found, but this study nonetheless provides interesting insights into the likely processes of dog and reindeer domestication, and into processes of adaptation in Late Glacial foragers. (Riede, 2011)

       4.7.2 Conservation

Conservation biology and environmental anthropology are disciplines that are both concerned with the identification and preservation of diversity, in one case biological and in the other cultural. Both conservation biology and the study of traditional ecological knowledge function at the nexus of the social and natural worlds, yet historically there have been major impediments to integrating the two. Linguistic, cultural, and epistemological barriers between the two disciplines may be identified.The two disciplines are uniquely positioned to inform each other and to provide critical insights and new perspectives on the way these sciences are practiced. There are common themes found in conservation success stories, and several suggestions on integration. These include cross- disciplinary publication, expanding memberships in professional societies and conducting multidisciplinary research based on similar interests in ecological process, taxonomy, or geography. Extinction threats be they biological or cultural/linguistic are imminent, and that by bringing these disciplines together we may be able to forge synergistic conservation programs capable of protecting the vivid splendor of life on Earth. (Drew & Henne, 2006)