The important relationship between ecology and genetic inheritance predates modern molecular analysis techniques. Molecular-ecological research has become more feasible with the development of rapid and accessible genetic technologies such as polymerase chain reaction (PCR). The rise of molecular technologies and the influx of research questions in this new ecological field led to the publication of Molecular Ecology in 1992. [153] Molecular ecology uses various analytical techniques to study genes in an evolutionary and ecological context. In 1994, John Avise also played a leading role in this field of science with the publication of his book Molecular Markers, Natural History and Evolution. [154] New technologies have opened up a wave of genetic analyses of organisms that are difficult to study from an ecological or evolutionary point of view, such as bacteria, fungi and nematodes. Molecular ecology has given rise to a new research paradigm for studying ecological questions considered otherwise intractable. Molecular studies have revealed previously obscured details in nature`s tiny subtleties and have improved the resolution of questions about behavior and biogeography. [154] For example, molecular ecology has shown promiscuous sexual behavior and multiple male mates in tree swallows previously considered socially monogamous. [155] In a biogeographic context, the combination of genetics, ecology and evolution has led to a new sub-discipline called phylogeography. [156] The second law of ecology, Everything Must Go Somewhere, formulates a fundamental law of thermodynamics: in nature, there is no final waste, matter and energy are preserved, and waste generated in one ecological process is recycled in another. For example, a tree or trunk fallen into an old-growth forest is a source of life for many species and an essential part of the ecosystem. Similarly, animals excrete carbon dioxide into the air and organic compounds into the soil, which helps maintain the plants the animals feed on.

In order to structure the study of ecology in a conceptually manageable framework, the biological world is organized in an interlocking hierarchy ranging from genes to cells, tissues, organs, organisms, species, populations, communities, ecosystems, biomes at the level of the biosphere. [9] This framework forms a panarchy[10] and exhibits non-linear behaviors; This means that “the effect and cause are disproportionate, so small changes to critical variables, such as the number of nitrogen fixators, can lead to disproportionate, perhaps irreversible, changes in system properties.” [11]:14 Nature knows best, the third informal law of ecology, writes Commoner, “states that any major change made by man in a natural system is likely to be detrimental to that system.” Over the course of 5 billion years of evolution, living things have developed a series of substances and reactions that together form the living biosphere. However, the modern petrochemical industry suddenly created thousands of new substances that did not exist in nature. Based on the same basic carbon chemical patterns as natural compounds, these new substances easily penetrate existing biochemical processes. But they do so in a way that is often destructive to life, leading to mutations, cancer, and many different forms of death and disease. “The absence of a particular substance of nature,” Commoner writes, “is often a sign that it is incompatible with the chemistry of life.” Elaborate sexual representations and poses are found in the behavioral ecology of animals. Birds of paradise, for example, sing and display elaborate ornaments during courtship. These displays have a dual purpose of signaling healthy or well-adapted individuals and desirable genes.

The displays are motivated by sexual selection as an advertisement for the quality of the characteristics among the suitors. [128] Predator-prey interactions are an introductory concept in food web and behavioural ecology research. [124] Prey species can exhibit various types of behavioural adaptations to predators, such as avoiding, fleeing or defending themselves. Many prey animals face several predators, which differ in the degree of danger. In order to adapt to their environment and counter predatory threats, organisms must balance their energy balance when investing in various aspects of their life cycle, such as growing, feeding, mating, socializing or modifying their habitat. The hypotheses advanced in behavioral ecology are generally based on adaptive principles of conservation, optimization or efficiency. [34] [110] [125] For example: “The assumption of avoiding threatening predators predicts that prey should assess the degree of threat of different predators and adapt their behaviour to the current level of risk”[126] or “[t]he optimal flight initiation distance occurs when the expected physical condition is maximized after the encounter, which depends on the initial physical condition of the prey, The benefits that can be achieved by not running away, the costs of energy evacuation and the expected loss of fitness due to the risk of predator. [127] Soil is the living top layer of mineral and organic dirt that covers the surface of the planet. It is the main organizational center of most ecosystem functions and is crucial for agricultural science and ecology. The decomposition of dead organic matter (e.g.

leaves on the forest floor) leads to soils that contain minerals and nutrients that flow into crop production. The set of soil ecosystems on the planet is called the pedosphere, in which a large biomass of the Earth`s biodiversity is organized in trophic levels. Invertebrates that feed and crush large leaves, for example, create smaller parts for small organisms in the food chain. Together, these organisms are the detritivores that regulate soil formation. [208] [209] Tree roots, fungi, bacteria, worms, ants, beetles, centipedes, spiders, mammals, birds, reptiles, amphibians and other lesser-known creatures all work to create the food web of life in soil ecosystems. Soils form composite phenotypes in which inorganic matter is wrapped in the physiology of an entire community. When organisms feed and migrate through soils, they physically move materials, an ecological process called bioturbation.