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Closer to the humans
Domestication consists of a substantial transformation of a wild animal or plant species to become under human control. Nowadays, it concerns more than 350 plant species and about 50 animal species. Actually, to be domesticated, a species requires both behavioral changes – also called taming – and the transmission of these characters from generation to generation. For example, we estimate that we can tame a large mammal in thirty generations. In the history, the wolf was the first species to have been domesticated 20,000 years ago, probably in several locations simultaneously. His distribution area was common with the human’s one where both of them hunted the same preys. Gradually, the wolf was transformed as a dog that, 8,000 years later, lived in close association with humans. Since the end of the last glacial period, the European landscapes changed to large pastures. Humans followed these changes and began to domesticate the first cereals, such as wheat and barley, around −9,000 years. Then, boar, aurochs, and other wild goats were captured as a long-term food through breeding. In −3,000 years, humans realized that domesticated animals might be used not only for food: thanks to their strength, cattle helped in the field. We have to wait −3,500 years for the domestication of the horse in Ukraine. For the cat, clues indicate multiple independent domestications: in −7,000 years to protect crops against commensal rodents, and in 1,000 years by the Egyptians. Domestication also facilitated commercial and cultural exchanges between regions, as observed with camels in the Arabian Peninsula 1,000 years ago. In the 19th century, strong morphological, behavioral, and physiological modifications were observed in relation to our new demand: animals lose their natural cycles for a better yield. A domestic hen lays hundreds of eggs per year, which increases at least by two the yield of a wild hen. The concept of pedigree emerged in the 1930’s with a new objective: acquiring of aesthetic animals. A domestic species is entirely dependent on humans and unable to survive alone, with a few exceptions of individuals returning to the wild, also called feralization.
The monarch migration
The monarch butterfly (Danaus plexippus) is known for its famous migration over several generations reaching similar distances as some migratory birds. In summer, it lives in North America – US and Canada – where it is in close relationship with the plant of the genus Asclepias (Apocynaceae family). Monarch females lay eggs on this plant species due to the nutritional role for the future caterpillars. There are two distinct populations of monarchs living on the east and west of the continent, roughly separated by the Rocky Mountains. In winter, the lack of Asclepias and low temperatures make the environment inhospitable. The latest generation enters diapause, i.e., a reduced metabolic activity, in order to accumulate enough resources before moving to warmer southern regions. After a journey of 3,000 km, the butterflies spend the winter in the same reserves as their predecessors. The western population flies to the California coast whereas the eastern population flutter their way to Mexico and the Gulf of Mexico’s islands. For example, the Oyamel forests (Abies religiosa) in the central states of Mexico is a recognized biosphere reserve by Unesco (United Nations educational, scientific and cultural organization). In spring, the monarchs become active and prepare the northward journey that occur over two to five generations. The cost of the migration in terms of predation risk, energy and time is worth the increase in survival chance avoiding the risk of freezing. The mechanisms involved for orientation are still discussed among scientists. Nevertheless, it appears that, besides the influence of light, the monarchs have a magnetic compass located in the antennas. The butterflies are guided by the tilt of the Earth's magnetic field, allowing them to maintain direction even under cloudy weather.
Walking on water
Although the human capacity to walk on water is only documented in spiritual books, some animals have developed this faculty. Several species of insects in Gerridae, Hydrometridae, Hebridae, Veliidae, and Macroveliidae families, and spiders of Dolomedes genus colonized these new environments. The water striders (Gerris) is likely the most famous example. This ubiquitous Hemiptera is able to walk on water due to a specific physical property of the liquid: the surface tension which repels the hydrophobic substances located on the legs of the insect. Its legs are developed along the width to increase the surface of contact in order to distribute its mass, and so, to stand on water. But a large surface area on their legs alone is not sufficient for these insects to conquer the water. Their weight, although almost imperceptible, actually plays a role in distorting the surface creating curvature forces which allows them to be stabilized over water. If curvature forces are too low or absent, voluntary movements would be infeasible. Although they possess the power of walking over water, they are not invincible. Water pollution such as surfactants disperse prevents the Gerris from walking over water. Their mishap is a biondication of water quality.
Alice in resistance land
Children’s stories may illustrate complex concepts used in science. For example, a key idea of evolutionary biology is developed in Lewis Carroll’s novel Alice's adventures in wonderland: the Red Queen theory. Alice is surprised by the stationary background while she is running faster and faster. Leigh Van Valen took over this concept in 1970’s to evolution of living species as an arms race: a species evolves under the stress caused by other species and the environment. It is the case of prey–predator coevolution: the antelope is adapted to leopard chase, while the feline develops new predation subterfuges. We also find examples in the media with antimicrobial resistance. When these mechanisms threaten human health, we need to use cunning to overcome such resistances. Thus, our society developed more and more powerful biocides to eliminate various species considered as pests. Nature is not static and new resistant species appear in reply to our chemicals, as observed for mosquito that are the vector of several diseases such as malaria, dengue fever, and chikungunya. The gene transmission through generations is necessary to have a real evolution, which depend on the generation time: 30 minutes for bacteria vs 25 years for human being. Understanding nature allows to better adapt our evolutionary responses, keeping in mind that we are not uniquely responsible of controlling the world. The evolution provides the key way to keep in the same place.
Bamboo wood
Wood is a natural resource necessary to human society with various uses, as fuelwood, roundwood, or pulpwood. Wood exploitation results in massive deforestation, especially in tropical latitudes. Annual wood consumption reaches four billion tons, 16% of which is for paper production. Among all exploited plant species, the bamboo is particularly interesting. But, is there wood in bamboo? To answer this question, we need to define wood by studying the internal structure of stems. In the central area, we find the pith and two transport tissues: xylem and phloem. On one hand, the xylem sap, which constitutes a diluted solution, flows up from roots to aerial part. On the other hand, the phloem sap, which contains nutrients, flows down from photosynthesis organs. Secondary structures are gradually developed in gymnosperms and angiosperms dicots: vascular and cork cambia, responsible to the lateral growth. The vascular cambium produces secondary xylem inwards and secondary phloem outwards. The secondary phloem and tissues produced by cork cambium constitute bark. In contrast, the secondary xylem constitutes wood. Bamboo, as well as herbs and reeds, is an angiosperm monocot, which develops without lateral growth. This means that such plants do not produce wood. The bamboo plant is therefore not a wood.
When the spider builds its web
Spiders are often misunderstood creatures with a bad reputation among humans. Often mistaken as insects, these critters actually belong to the arachnid family which has two more legs than insects. Currently, 40,000 species have been identified worldwide. Spiders are found in every environment, and some of them particularly appreciate our homes. A meadow harbors about 200 spiders within one square meter, capturing more than 40,000 insects per year. Spider webs are also exciting with their various functions such as trapping their unsuspecting prey or protecting their eggs. The silk threads are part of a complex geometry that the dew reveals thanks to the droplets of glue. Thirty times finer than a strand of hair, this silk threads are part, this thread is both strong (stronger than steel of the same diameter) and elastic. The silk is composed of a liquid protein mixture solidifying in the glands of the spider. The stock of this precious liquid is enough to build three complete webs. The silk ejection by chelicerae is very fast (3 m per second, in 30 ms bursts). The web rigidity is provided by crystal proteins, whereas the elasticity is given by amorphous matrix. The composition of this mixture varies according to the use of the web: solid threads for the basic framework, elastic threads for catching prey. The circular geometry is the better way to evenly distribute the forces acting on the web. However, we find various geometries depending on the species (funnel-web for Tegenaria, disorganized web for Pholcus), and sometimes, very complex structures (like Zygiella with a signal thread). When wind, rain, or dew damages the web, the spider consumes the silk threads for recycling. On average, spiders build and recycle all their web once or twice a day.
Selfishness: plague of animal sociality
Sociality in the animal world – including human beings – are found in different biological scales (cell, organ, organism...), and in various degrees of complexity. At first glance, living in a group has some drawbacks: competition between individuals of this group for food search, for reproduction, transmission of diseases, etc. However, the abundance of this relationship in various animal families (e.g., amoeba Dictyostelium discoideum, Atlantic puffin Fratercula arctica, or Southern elephant seal Mirounga leonina) demonstrates the existence of individual benefits of such organization. At each hierarchical level, altruistic cooperation promotes the upper level; individual benefits are indirect. For example, gregariousness reduces the threat of predators through collective vigilance, whereas the individual vigilance decrease (reduction of individual surveillance period). The cost for each individual is then reduced by the support of the group. The defense is not the only area where the group is an advantage: it is also found in the care of the young individuals, or in food search. Nevertheless, the benefit for the altruistic individual is always lower than for the selfish individual. Such marginal individuals may therefore appear in a group. A question arises: how to explain, in an evolutionary context, the paradoxical coexistence of two antagonist behaviors in a group? Such organization necessarily result in the sociality decline without any regulation system. Each group uses mechanisms to limit these behaviors. For example, tadpoles recognize their genetic family to avoid intrusion of foreign individuals benefiting from the safety of the group. All these mechanisms must be transmitted from generation to another to be viable, a non-functional system over time is doomed to disappear. However, many scientific questions remain unanswered.
The roadside plane trees
The London plane (Platanus ×acerifolia, Platanaceae family) is a less fertile species originated from a cross between American plane (Platanus occidentalis) and Oriental plane (Platanus orientalis). During the 17th century, the London plane appeared in Europe. The lifespan of this tree with a smooth and scaly bark reaches 1,000 years. It is often planted in urban areas like an ornamental and alignment tree; it is commonly found along roadsides and canals of Europe. But, two major pest species impacts its development: the sycamore lace bug (Corythucha ciliata) – small bug feeding on the leaves – and an ascomycete fungus (Ceratocystis platani) responsible for the canker stain. Originally from the United States and accidentally introduced into the Mediterranean region at the end of the Second World War, the canker stain currently occurs in Italy, southern Switzerland and the south of France. This fungus grows in the tree tissue and clogs the sap-conducting vessels. The tree dries and dies in 4–6 years. Tens of thousands of cases have been reported in France. After the Southeast, the Southwest of France is affected, especially along the Canal du Midi. Under Napoleon, the many willows, ash and poplars planted during the completion of its construction initiated by Pierre-Paul Riquet in 1666, are gradually replaced by plane trees. But, its recent history (less than four centuries) and horticultural selection lead to a poor genetic diversity, preventing the emergence of canker-resistant individuals. In 2013, after long research, the French institute for agronomic research (Inra) got a hybrid variety resistant to this parasite (Platanor® Vallis clausa). However, the entire living world has a complex evolution; the question about the efficiency duration of this resistance then arises. 
Assisted reproduction of fig
The common fig (Ficus carica, Moraceae family) has a very particular productive cycle. It depends on a little wasp of the Agaonidae family: Blastophaga. Although the common fig is considered to be dioecious (existence of female and male trees within the same species), each individual has an inflorescence (the fig) composed of female and male flowers. The Blastophaga females lay their eggs in female flowers of caprifigs (male figs). These flowers have an appropriate morphology to the egg establishment. In response to the eggs, the fig produces a nourishing and protective gall allowing the proper development of the larvae. After hatching and reproduction of the next generation of wasps, the females will be able to colonize new figs. On leaving the caprifigue, they will take the pollen from the male flowers located near the fig opening (ostiole). During their conquest by air, the Blastophaga females may find either a new caprifig, or a “female” fig. The inflorescences of female figs are constituted of sterile male flowers and fertile female flowers with unsuitable morphology for egg establishment. The insect must come back and go on to a new fig. This inconclusive attempt allows the pollination of female flowers by pollen deposited by the Blastophaga female. This fecundation results in mature figs. This relationship with mutual benefits is called mutualism.