Why the island rule only applies to animals. island biota. biogeography. The largest animals in the world

Oceanic islands have never been connected to land, they rose from the bottom of the ocean. "These include coral volcanic islands and islands of folded arcs. Continental islands are parts of continents that separated from them in one or another geological epoch. Naturally, the conditions for the development of biota on these or other islands are sharply different.

The mainland islands separated from the continent along with the totality of living organisms that were characteristic of these parts of the continent. Later, part of the original population died out, and species that crossed the ocean came to replace them.

Ch. Darwin tried to find out how the settlement of oceanic islands took place, who experimentally established that the fruits and seeds of many plant species remain viable after a long stay in sea water, and during this time they can be delivered by currents to many islands. In addition, the seeds of some species can "travel" in the intestinal tract of birds without losing their germination. Finally, they can be delivered along with soil particles on bird feet and floating tree trunks. If we consider the issue more broadly, we can say that the ways plants and animals get to the islands are diverse: sea and air currents, storms and hurricanes, a fin, a person and his vehicles, active movement by water or air.

J. Gressit and S. Yoshimoto (1963) characterize the dispersal abilities of animals belonging to different systematic groups. They point out that among reptiles, for example, skinks and geckos are very widespread, while other groups of lizards, like snakes, as well as freshwater fish, are absent on many oceanic islands. Apparently, representatives of these two groups of lizards are well adapted to travel on floating tree trunks or on their clusters - "rafts". From other systematic groups, amphibians are very poorly tolerated by salt water. Therefore, the possibilities of their movement across the ocean are extremely limited.

Among the invertebrates living on oceanic islands, insects dominate, the second largest place is occupied by terrestrial molluscs. Insects are spread by all of these methods. Species distributed by humans differ markedly from others, since on the islands they are usually synanthropic, i.e. they use human food reserves, his clothes (kozheedy, moths, etc.) and dwellings, are associated with domestic animals and agricultural plants. Many of them have cosmopolitan areas. The transfer of insects by birds is rare. Salt water has an extremely unfavorable effect on them, so the species that swim across the ocean are also few.

Mature plants rarely remain alive when transported across the ocean. So epiphytes can move with tree trunks. Usually, plants spread with the help of diaspores. Light seeds and spores are carried by the wind. Undoubtedly, an important role in the spread of the plant is played by a person who spreads weeds all over the world, including on the islands.

If two islands of different sizes have recently separated from the same continent, then on the larger island, the mainland biota is able to be preserved almost completely, and on the smaller one, the possibility of the existence of entire taxonomic groups, for example, representatives of the entire class of mammals, can be completely or almost completely excluded. . The limiting influence of the size of the island increases as its territory decreases.

F. Darlington (1957) for the Antilles established the following ratio between the size of the island and the number of species of amphibians and reptiles: with a decrease in the size of the island by 10 times, the number of species of these groups is halved.

The closer the island is to the source of migration, the higher the degree of saturation with migrants. Biota of continental and oceanic islands obey this regularity. Although the distribution of each individual is random, however, with a long development of migration processes, they obey the law of large numbers, i.e. statistical probability. F. Darlington pointed out that if one individual out of 1000 successfully crossed a space 100 miles wide, then when overcoming the next 100 miles, one individual out of 1000 who passed the first 100 miles will successfully complete this task again. In other words, only one individual in a million will reach an island located 200 miles from the source of migration, and only one individual in a billion will reach an island located 300 miles from the continent.

The position of the island in relation to the direction of the winds also has a great influence. that cross it, the so-called "_________________" For insects and seeds of plants: if the island, elongated in length, is located perpendicular to the flow of migrants, then there will be more chances that any species will reach it; if the island is located along the main direction of movement, then the chances that organisms carried by wind or sea currents will fall on it will be much less.

The gradual extinction of species on the islands is evidenced by the fact that small islands of continental origin have an almost purely oceanic fauna, in contrast to large islands. Thus, among the Pearl Islands, about a third of the continental species are concentrated on the large island of Rey, and only 1 out of 10 is concentrated on the small island of Contadora. there was not the number of species that could exist on it if this island were part of the mainland. Fifty years after the first observations on these islands, the number of species averaged almost half of what was possible.

Distribution, dispersion, - only ______________________ of the species on the island. It must go through a full cycle of development (ecesis) from appearing in a given place to bringing viable offspring. More tolerant and valence (i.e., with wide ecological capabilities) species pass through the stage of ecesis more easily than less tolerant and stenobiont ones.

Ecesis is carried out in the presence of favorable conditions for the life of the organism: light, heat, moisture, and especially write. It remains incomplete most often as a result of the unavailability of the necessary resources. Thus, many insects cannot settle on the islands due to the lack of food plants for their larvae or adults, or in cases where there are no open fresh water bodies necessary for passing through the first stages of development. Many birds are unable to breed due to the lack of suitable nesting sites on the island.

Among plants, the inhabitants of the coasts have the greatest opportunities for successful development and reproduction, the seeds of which, when they get to the island, meet there an environment close to the original one. On the contrary, the inhabitants of the highlands have little opportunity to transfer their seeds across the ocean (mountains are often located far from the coast) and very little chance for plants to undergo ecesis in their new homeland, where there may not be high mountains.

The rate of settlement of the islands is low. True, specific data on the rate of this process differ greatly. Based on the number of species of flowering and vascular spore plants in the flora of the Hawaiian Islands and the geological age of this archipelago, F. Fosberg came to the conclusion that the successful development of the territory by plants was carried out here on average once every 20-30 thousand years, i.e. not more often than 30-35 settlements in 1 million years. However, this speed cannot be accepted for all islands. So, low-lying atolls are most often 4000-6000 years old. If we accept the population rate calculated by F. Fosberg for the Hawaiian Islands, the age of low-lying atolls is less than the period of their settlement by one species. In fact, in the flora of each of these atolls, there are up to several dozen species, of which not all have been introduced by humans. The uplifted atoll of Nauru, estimated by geologists to be about 100,000 years old, could be invaded by only 4-5 plant species at the rate calculated by F. Fosberg, while the atoll's flora includes almost 100 species. In addition, it should be borne in mind that the data on the flora are undoubtedly underestimated, since some plants that entered the island may subsequently die out. Thus, for many islands, the rate of their colonization is much higher than that calculated by F. Fosberg: for low-lying atolls it is one settlement in 200-300 years, for the elevated Nauru atoll - approximately one in 1000 years.

Most biogeographers believe that the penetration of species from the continent to certain islands could be facilitated by the existence of "stonework", i.e. intermediate islands and islets, which, over the course of geological history, either appeared from the waters of the ocean, or again hid in them. Most often, such temporary shelters were islands of volcanic origin.

island biota

The smaller the island, the more monotonous living conditions are, as a rule, on it. Both of these reasons explain the direct relationship that is observed between the size of the island and the number of species that make up its biota. This can be illustrated by the example of nesting birds.

The number of species living on the island also depends on other reasons, primarily on the age of the island and the degree of its isolation - remoteness from the mainland.

A necessary condition for speciation on islands is isolation. If everything is continuously carried out new and new

the introduction of individuals of the same species to the island, then as a result of crossing of individuals that previously lived here with individuals that have recently appeared, some stabilization of the characteristics of the species is observed, and the process of speciation slows down sharply. The process of speciation is also associated with the natural features of the islands. On high islands, where a significant variety of ecological conditions is observed in a small space, the possibilities for the emergence of new subspecies and species are higher than on low islands, with the uniformity of their natural features.

The absence of a number of life forms and systematic groups on the islands as part of their biota has led to the fact that some species, when they get to such islands, undergo the so-called adaptive radiation; the descendants of one species that has entered an island or archipelago change greatly. Thus, the ancestor of the flower birds Drepani-didae, the American finch, having penetrated the Hawaiian Islands, did not meet competitors here and gave rise to chaffinch-like, honey-like, feather-like, woodpecker-like and oak-like forms. Several genera and many species of flower girls arose, which occupied various ecological niches, which made it impossible to repeat such adaptive radiation in later times. Similar examples of adaptive radiation are palm trees on the island of Cuba, some insects and molluscs in the Hawaiian Islands.

An example of the same adaptive radiation, but not as far advanced, is the psosutukava tree (Metrosideros kermadecensis) on Raul Island (Kermadec Archipelago). Depending on the conditions of the habitat, it forms forms that have not yet reached the level of species differences. So, it is a squat, pressed to the ground shrub in the lower parts of the slopes, exposed to the action of the ocean surf; low erect shrub on volcanic pumice at the bottom of the volcano caldera; a straight-stemmed tree in dense stands, a giant tree with outstretched horizontal branches in sparse stands, and finally an epiphyte and strangler tree when settling on tree trunks.

In other cases, as a result of speciation, monotypic genera and even families arise on islands. Such are the tree of degeneration from the fam. degeneriaceae Degeneriaceae on the island of Fiji, the kagu bird on New Caledonia.

A striking feature of island biotas is a large number of endemics, often of a high taxonomic rank. The number of endemics and the level of endemism depend on the size of the islands, their distance from the continent, the variety of ecological conditions, and the duration of isolation.

On the islands, deviations from the usual appearance of representatives of certain groups are often observed; gigantism or, conversely, ___________________. The reasons for this are unclear. Flightless birds and insects are often characteristic of the islands. For birds, the main role in the emergence of flightless species is played by the absence of mammals on the islands that could exterminate them. For insects, the drift of flying species into the ocean by wind and hurricanes. In order to survive, insects must either have a fast flight, or, conversely, lose the ability to fly, or hide in the wind in secluded corners. On many, even small islands, there are many species characterized by a fluttering, slow flight - lacewings, mosquitoes, bedbugs, small diurnal butterflies, moths. Their abundance is facilitated by the peculiarities of the lifestyle associated with the ability to hide from gusts of wind. Thus, natural selection should have contributed to the survival of non-flying individuals and eventually led to the formation of forms that have lost even the organs of flight.

Finally, the islands contribute to the preservation of primitive archaic forms. Examples are the New Zealand tuatara, an extremely primitive genus of insectivores - the flint tooth from the Antilles, the Madagascar ferret cat, or fossa. This is explained by the fact that in small isolated ecosystems, the existing structure of communities is protected by external geographical barriers from the intrusion of new, most active groups that have won the struggle for existence, which, successfully settling on the continents, invade previously formed ecosystems. It is noted that isolation on the islands contributes to the divergence of forms, i.e. geographical speciation, but at the same time, the evolutionary process here is slower than on the mainland.

A characteristic feature of island biotas in general, apart from endemism, is their poverty. This is explained by the extinction and the difficulty of migrants penetrating the islands. The number of species is subject to more or less significant fluctuations over the years. But over large areas, these ups and downs in numbers can occur only in some part of the species range. While in one place the number of a species is falling, in another it is rising. Thus, even if all individuals of a known species in one part of the range die out, then it will be relatively quickly populated from adjacent parts. On the islands, the species can easily disappear completely. It is clear that the smaller the territory of the island, the greater the chance for the species to become extinct.

The isolation of the biotas of individual islands is the reason for their slight disturbance when natural conditions are changed by humans. Deforestation and their replacement with plantations of both woody and herbaceous plants are often irreversible on the islands, especially the replacement of forests with fields. Therefore, giving examples of the extinction of species under human influence, we first of all recall the inhabitants of the islands: the Steller (sea) cow that lived off the coast of the Commander Islands, the wingless guillemot (Newfoundland Island), the moa (New Zealand), the dodo, etc.

However, the most catastrophic for the fauna and flora of many islands is the introduction by humans (conscious or unconscious) of new species to these islands. For example, goats on many islands have exterminated many plant species. The flora of St. Helena has lost, to goats, a considerable number of species of trees formerly characteristic of it; the same was noted on the islands of Kermadec and others. At present, detachments of hunters are sent to many islands, the purpose of which is to sharply reduce the number of these animals.

Herbivorous marsupial possum, brought from Australia to New Zealand, destroyed forests in many parts of this country. Significant harm to the fauna of the islands is caused by rats that have got there. They destroy the eggs and chicks of birds nesting on the ground. So, on Raoul Island (Kermadec archipelago), they completely exterminated the Kermadec petrel, now preserved only on several small islands, where rats did not penetrate. To combat rats, which caused significant damage to agriculture, in particular the cultivation of sugar cane and rice, the mongoose was introduced to Cuba and Fiji. However, not limited to eating rats, this animal has drastically reduced the number of birds nesting on the ground, in Cuba it almost destroyed the endemic species of the sand tooth, and in Fiji it minimized the number of the Fijian iguana.

Huge devastation in the composition of the animal population of the islands is produced by pigs. In New Zealand, they exterminated a representative of a monotypic endemic detachment - a tuatara, preserved only on small islands off the coast of New Zealand; almost exterminated flightless birds - kiwi and owl parrot, etc.

The introduction of European red deer to New Zealand led to the destruction of forests over a large area. It turned out that it is very difficult to exterminate this animal, introduced by man. The bonuses assigned for each animal killed did not help either. At present, New Zealand has moved to the creation of reindeer farms with a fierce struggle against the deer living freely on the island.

From the foregoing, it follows that any introduction to the island of species that did not previously exist here must be carefully considered. It is necessary to always remember the vulnerability of the nature of the islands and the difficulties, if not complete impossibility, of eliminating the consequences of such actions.

E evolution of island communities

The word "island" in this section does not necessarily mean a piece of land surrounded by water. Lakes are "islands" of water in the midst of land; mountain peaks - "islands" with high mountain conditions in the "ocean" of lower areas; the windows in the forest canopy, which arose when the trees fell, are "islands" in the sea of ​​forest stand. We can talk about "islands" with a special geological structure, a certain type of soil or vegetation, surrounded by other rocks, soils or phytocenoses (Fig. 59). For all these types of "islands" one can also trace a regular relationship between species richness and area.

It has been established that the number of species on the island is the smaller, the smaller its area. Examples of such dependence for different groups of organisms are shown in Fig.61. Usually, in its graphical representation, a logarithmic scale is taken for both parameters, although, if we correlate the number of species with the logarithm of the area, the resulting line is sometimes closer to a straight line. However, in simple coordinates, the dependence always looks like a curve, and with an increase in the area, the growth in the number of species slows down. Three approaches are used to study the processes of formation of island biotas: a) assess the diversity of habitats suitable for settlement on the island; b) pay attention to the ratio of the speed of two processes: the colonization of the island by species new to it and the extinction of those that have already settled (equilibrium theory); c) reveal the relationship between the settlement of the island from the outside and the evolution of species on it.

In reality, all these processes go on simultaneously, and the specific result - the uniqueness of the island biota - is the result, the balance of their interaction.

One of the major achievements of biogeography of our time is the creation by MacArthur and Wilson (1967) of the “equilibrium theory of island biogeography”, based on a mathematical apparatus for describing the dynamic process of species migration to islands and their extinction, as well as the nature of the established species equilibrium. Its essence - the number of species inhabiting the island, is determined by the balance between immigration and extinction. How this happens is shown in Fig. 62. Consider first immigration. Imagine an uninhabited island. The intensity of species immigration for it will be high, because any individual that has settled here represents settled species; the rate of introduction of new (not yet represented) species is reduced. It will vanish when all species of the "original population" (i.e., the neighboring mainland or nearby islands) have settled on the island.

The specific immigration curve depends on how far the island is from the source of its potential settlers. Zero will always be marked at the same point (all types of the “initial population” are represented on the island), but the function as a whole will have the higher values, the closer the source of immigration, i.e. the more likely migrants are to reach the island. The rate of introduction to large islands, as a rule, is higher than to small ones, since the former are more accessible.

The extinction rate is zero when there are no species on the island, and generally low when there are few. However, as the number of settled species grows, it, according to the theory, increases.

To consider the combined effect of immigration and extinction, let's superimpose both graphs on top of each other. The number of species corresponding to the point of intersection of the curves (S*) reflects the state of dynamic equilibrium, i.e. potential species richness of the island. Below this point, species richness increases (the rate of immigration exceeds the rate of extinction), and above this point it decreases (extinction is more intense than immigration). This theory allows us to make a number of assumptions about the formation of island communities.

1. The number of species on the island should eventually roughly stabilize.

2. This stabilization is not the result of the constancy of the species composition, but of the continuous change of species, when some forms die out, while others are introduced.

3. There are more species on large islands than on small ones.

4. Species richness will decrease as the island moves away from the sources of settlement.

The main question of island biogeography is whether there is an "island effect" as such, or are islands poorer in species simply because of their small territory and small number of habitats? A number of studies have attempted to separate the species-to-area ratio for islands from components that are fully explained by habitat heterogeneity from those that are due to area. For example, the diversity of fish species in the lakes of northern Wisconsin is significantly correlated with both the area of ​​the lake and the diversity of its vegetation. A clear relationship has also been found between the species richness of birds and the area of ​​islands off the coast of Western Australia (Abbott, 1978).

A study of the relationship between species number, island area and bird habitat diversity in the Aegean islands (Watson 1964) showed that habitat diversity is a more important factor than area.

The equilibrium theory is also applicable to phytophagous insects (Janzen, 1968): relatively widespread plants can be considered as relatively "large islands" surrounded by a "sea" of different flora. In addition, a certain type of plant can be considered "remote" from others if it is specific in its morphological, biochemical or other biological features. Thus, it follows from the equilibrium theory that insect species richness will be higher on plants with large ranges and lower on geographically isolated or rare species, as well as on morphologically or biochemically "isolated" plants.

The equilibrium theory is in good agreement with the data on the islands, which in the past were part of the isthmus connected to the mainland, which then submerged under water. If the equilibrium number of species is to some extent determined by the ratio between the rate of extinction and the area of ​​the island, it must be assumed that such recently detached landmasses will lose species until a new equilibrium is established corresponding to their size. This process is called "relaxation". Thus, the relationship between the time of separation of the islands of the Gulf of California from the mainland and the number of lizard species found on them has been described (Wilcox, 1978).

The equilibrium theory assumes for an “island” not only the presence of a characteristic species richness, but also a constant “circulation” of species, i.e. the continuous settlement of new forms and the extinction of those already present. This means that the specific composition of the island biota at each moment of time must be largely random.

It has long been noted that one of the main features of island biotas is the "disharmony" of the taxonomic and trophic structure of the community (Hooker, 1866). This implies a different than on the mainland, the relative participation of various taxa in the composition of the biota, in the construction of food webs of island ecosystems. Considering the relationship between the number of species and area, we have already seen that organisms that are able to disperse well (such as ferns and birds) are more likely to inhabit individual islands than species in which this ability is not so developed (most mammals, practically all conifers). The potential possibilities of dispersal of individual species, of course, are not the same within such groups. On fig. 63 shows the eastern boundaries of the distribution of various terrestrial and freshwater birds across the Pacific Islands, found in New Guinea, whose fauna is halved over a distance of 2600 km from the settlement area. At the same time, it turned out that most species of land snails of the Pacific region, being very small in size, are easily transferred from island to island, and most of the beetles of Saint Helena are xylophages or subcrustal forms, brought here, most likely, through the sea along with floating tree trunks.

However, different dispersal abilities are not the only reason for disharmony. Species with a low density per unit area under natural conditions will always be represented on the islands by extremely small populations, for which the probability of complete extinction as a result of random fluctuations is very high. On many islands, the absence of predators is striking, the populations of which, as a rule, are relatively small. For example, in the Tristan da Cunha archipelago in the South Atlantic, there is not a single bird-eating predator, not counting those brought here by man.

Predators may also be absent from the islands because their immigration can only lead to settlement on the island if their prey has already settled there (whereas such dependence on predators does not exist for prey species). This is also true of parasites, mutualists, and the like. In other words, disharmony in the settlement of the islands arises from the fact that some categories of organisms are more “dependent” than others.

Isolation is one of the most important mechanisms of evolution. When a group of living beings is separated from the main breeding population, the isolated group evolves independently of the parent group, because there is no longer any possibility of free interbreeding. The new group interacts with its environment, mutating into new forms and evolving in directions that would be completely excluded from it if it existed among the original enemies and competitors. This phenomenon is especially pronounced when the animals are isolated in a sparsely populated or previously completely uninhabited area, and is currently best seen on oceanic islands.
In this context, there are two main varieties of isolation, each of which creates its own set of forms of environmental pressure and gives rise to its own forms of evolution.
The first occurs when one part of a continent breaks off from another. What then happens to their fauna depends on the subsequent movement of the two continents. One land mass may move north or south in relation to another, bringing its fauna into new climate and environmental conditions that affect their evolution and eventually lead to the formation of new genera and species. This is exactly what happened in the Age of Reptiles, when the South American continent, which shared a dinosaur fauna with Africa, broke off, leading to the evolution of completely different animals in each of these territories.
When drifting continents collide with each other, there is very often a significant mutual exchange of mammalian fauna between the two landmasses. It may happen that the fauna of one continent completely replaces the fauna of another. This happened when the small continent that is now the Indian subcontinent collided with the massif of Asia.*
The second form of biological isolation occurs when an entirely new group of volcanic islands forms. In plate tectonics, the greatest activity between adjacent plates of the earth's crust is observed in the open ocean. New plates emerge along mid-ocean ridges and collapse as they slide one under the other into deep ocean trenches. Such violent activity generates earthquakes and volcanic eruptions, creating new islands from the ocean floor.
Volcanic islands, initially bare, are soon populated by living organisms. Plants germinating from windblown seeds are usually the first to arrive on the island, but insects soon overtake them. The first vertebrate inhabitants are usually flying creatures like birds and bats. Only later do other inhabitants arrive here, usually reptiles and small mammals, sometimes on floating branches or tree trunks - the result of some rivers flooding the area for hundreds of kilometers. All these creatures then evolve independently of their ancestral population from the continent to fill all the ecological niches of the island. A classic example of this sequence of events is the settlement of the Galapagos Islands, off the west coast of South America, during the first half of the Age of Mammals. These islands were originally inhabited by a small number of species, which eventually gave rise to a large number of new animals, including four-eyed fish**, sea lizards and giant tortoises. Island fauna, especially the differences between related species from different islands, have been carefully studied and stimulated the development of evolutionary doctrine.

* In fact, the fauna of Hindustan still shows similarities with the fauna of the southern continents - for example, a number of amphibian species show a clear relationship with the species of the island of Madagascar, which previously gave rise to the hypothesis of the existence of the "sunken mainland of Lemuria". – V.P.

** This refers to the Galápagos Dialoma blenny, not the Anableps from Central America. – V.P.

SOUTH AMERICAN FORESTS

Impact of continental drift on animal communities

Throughout its history, the movement of the lithospheric plate that carries the South American continent has occurred predominantly in a westerly direction, and as a result, the land mass has tended to remain at the same latitudes. This is the reason for the stability of climatic regions and the conservatism of its fauna.
During the early history of the mainland, the grassy plains, or pampas, provided for their own fauna of running ungulates, similar to that found in other parts of the world, but completely isolated from them. These animals existed until the mainland was connected by a land bridge with North America, when they and the native population of marsupials were completely destroyed as a result of the influx of animals from the north. It is rather strange that northern ungulates did not take a stable position in the pampas, and some rodents, maras Dolichotis and capybaras Hydrochoerus that existed in human times were more successful. In this respect, the South American continent anticipated the emergence of running rodents and lagomorphs in the rest of the world.
Since the continent broke away from the northern supercontinent, the rodent fauna has developed along its own lines. The running rodents of the pampas are dominated by strange bipedal herbivores descended from jumping rodents that evolved in the wind shadow deserts along the western mountains. Although long hind legs have independently evolved among desert rodents on other continents, only species from South America have switched from jumping to running during their evolutionary history. Along with this change in gait, there was an increase in size and changes in the dental system, which resulted in the transformation from jumping and gnawing rodents into running lowland herbivores.
The most common type of running rodent is the streak. Cursomys longipes, which looks very similar to herbivorous marsupials - kangaroos that once existed in Australia. They graze among the tall grasses in closely knit groups that are large enough to ensure that at all times at least two or three animals keep their heads up, looking out for danger while the rest's senses are occupied by the grass.
The most specialized creature in this family of animals, and perhaps the most highly specialized running animal in the world, is the wakka. Anabracchium struthioforme. Due to his bipedal position, his forelimbs have become less important and are now completely atrophied. On its globular body and long hind legs, the neck and tail of equal length balance each other out, maintaining the animal's center of gravity above its hips. These signs give the animal a good overview of the surrounding area. Even when grazing in tall grass, the wakka's eyes are set high enough on its elongated head to see the approach of a predator.
flower-billed potto Gryseonycta rostriflora- this is the strangest of the birds living in the savannah. The inner lining of its beak is colored and textured like the petals of a flower, so when it holds its mouth open it looks exactly like an open flower. This sophisticated mimicry is designed to deceive insects and provides the Potto with food whenever it opens its mouth. Since tropical savannah flowers only appear when there is sufficient moisture, the potto makes seasonal migrations along with the rains.

ISLAND OF LEMURIAS

Bastion of ungulates

ISLANDS OF BATAVIA

Island world of bats

Although mountains and islands of volcanic origin usually form where two lithospheric plates meet and crash into one another, they also form over "hot spots" in the earth's crust - areas that lie above an area of ​​greater activity deep in the earth's mantle. A volcano forms directly above the "hot spot". When the crust shifts from the center of activity, the volcano fades, and a new one forms next to it, forming over time a chain of successively aging volcanic islands in the center of the ocean. In the Age of Man, a "hot spot" was responsible for the formation of the Hawaiian Island chain, and at present, in the Pacific, a "hot spot" is involved in the formation of the Batavia* islands.
Birds are usually the first vertebrates to reach and colonize new islands, but in the case of Batavia, the first vertebrates to reach them were their mammalian equivalents, bats. By the time the birds reached the islands, the bats were so well established there that there were few evolutionary niches left unoccupied, and the birds never populated the islands to such an extent. The availability of suitable food on the ground and the absence of terrestrial predators has allowed many bats to master the terrestrial lifestyle and fill a large number of ecological niches.
flower-snout Florifacies mirabila remained insectivorous, but now leads a predominantly sedentary lifestyle. Its brightly colored ears and nasal lobes mimic the kind of flowers found on the islands. It sits among them with its muzzle turned upwards, grasping any insect that makes an attempt to land on it. The mode of feeding of the flower-snout is remarkably similar to that of the flower-billed potto. Griseonycta rostrifiora from South America, although it arose independently, and therefore is an interesting example of convergent evolution.
Flightless Bat Sloth Arboverspertilio apteryx is an omnivorous tree-dwelling bat that spends its entire life hanging upside down like the sloth of old. It feeds on leaves and occasional insects and small vertebrates taken with a quick stroke of a single claw.
Beaches are home to flocks of surfers Remala madipella, which fish in shallow waters around coral reefs. Their hind legs, wings and tail membranes were transformed into swimming and turning organs, and their bodies became smooth and streamlined. Their evolution from a flying animal through a terrestrial form to an aquatic creature is very similar to the evolutionary development of a penguin.
When other vertebrates established themselves on the islands, a family of terrestrial predatory bats arose. These creatures walk on their forelimbs - what, in the case of flying bats, would be wings, the attachment point for most of their muscles responsible for movement. Their hind legs and feet are still used for grasping, but now point forward, dangling near their chin. Because bats locate their prey using echolocation, their ears and nasal protrusions have grown to replace their eyes, which are now atrophied.
The largest and most intimidating of these creatures is the nocturnal tramp. Manambulus perhorridus. Reaching a height of one and a half meters, he wanders in flocks at night through the forests of Batavia, uttering squeals and cries. They prey on all mammals and reptiles indiscriminately, attacking them with their fearsome teeth and claws.

* Here is an untranslatable pun: Dixon's choice for this chapter of the islands' name "Batavia" (in the original "Batavian Islands") is related to the English word "bat" (bat). Therefore, I consider it necessary to leave behind the islands their original name. – V.P.

A few thousand kilometers east of the Australian subcontinent lies the Pacaus Island chain. They formed over the past 40 million years due to contact between the northward-moving Australian lithospheric plate and the westward-shifting Pacific Plate. Volcanic islands formed at the boundary between the two plates, to which coral deposits were gradually added around the coast.
After the ash and lava slopes were covered with vegetation and an insect population formed, birds began to inhabit the islands. The first birds to fly there were golden whistlers. Pachycephala pectoralis, which was brought by the wind across the ocean from Australia. Initially quite unspecialized birds, in the Age of Man they began to show some differentiation, forming different beak shapes on islands along the Australian coast. However, only on the Pacaus archipelago, where all ecological niches were open to them, whistlers developed truly impressively, forming both insectivorous and herbivorous, and predatory forms.
The descendants of a separate group of golden whistlers that inhabited these islands are now recognized as belonging to the same genus. Insulornis. All species within the genus are now highly specialized and markedly different from one another, with the exception of I.harti, which is similar in shape to the original ancestral bird species.
At I. piciforma developed a strong chisel-shaped beak, with which he hollows the bark in search of gnawing insects. Its paws have been modified to allow it to climb vertical tree trunks, and the bird is very similar to the extinct woodpeckers of the Northern Continent, whose lifestyle it follows in almost every way.
Nuts and durable seeds eats I. macrorhyncha, a parrot-like species that has evolved a massive beak and strong musculature to control it. This bird has retained legs to perch on branches inherited from its ancestor, and has grown a long tail to balance its large head.
All Pacaus whistlers are attacked by their hawk-like I. aviphaga, which exhibits the same adaptations known to be found in carnivorous birds around the world, regardless of their origin - a hooked beak, binocular vision through forward-positioning eyes, and a high degree of agility when chasing prey.
Other than the hawk-whisker, the only natural enemies encountered by the Pacaus whistlers are snakes that entered the Pacaus archipelago from Australia or other islands in this part of the Pacific, either at the same time or at another time. Pakaus whistlers' fear of snakes uses the scary tail

Grass Eaters: Plains Giants: Meat Eaters

Forest Canopy: Tree Dwellers: Undergrowth: Water Life

Australian Forests: Australian Forest Undergrowth

ISLANDS AND ISLAND CONTINENTS 100

South American Forests: South American Pampas: Lemuria Island

Batavia Islands: Pacaus Islands

Vocabulary: Tree of Life: Index: Acknowledgments

POSITION

about the regional team ecological tournament

"Time Machine"

1. 1. Goal and tasks

The goal is to involve students in research activities in the field of ecology.

- fostering a careful and humane attitude towards nature;

- the formation of students' ability to think logically, analyze and solve environmental problems;

– formation of environmental literacy.

1. 2. Tournament Participants

Teams of students from educational organizations of municipal districts and city districts of the Nizhny Novgorod region take part in the Tournament. The number of team members is 6 people. Age of participants is from 14 to 18 years.

1. 3. Tournament content

Teams present solutions to environmental tasks in the form of three presentations. The title page of each presentation should contain: last names, first names, patronymics and dates of birth of all authors, last name, first name and patronymic of the team leader, full name and address of the educational organization, contact phone number, e-mail.

Technical requirements for the presentation: number of slides 10-15, file format - .ppt or .pptx; the presence of media files (audio, video) and hyperlinks. The executable file must run under the Windows XP operating system.

Tasks for the Tournament:

1. 1. "The ark". In 2526, a star system was discovered in the M13 galaxy, in which one of the planets turned out to be very similar to Earth in most parameters, but it completely lacked any signs of life. It was decided to colonize this planet. People can equip only one ship for this mission, the number of places on which is very limited. You need to draw up a minimum list of species of living beings that will be transported to the planet. What considerations will you be guided by? Will these species be enough to create a biosphere on a planet being developed?
2. 2. "Kingdom of Hades". For animals - roglobionts, caves are a permanent habitat. What ecological and physiological adaptations are necessary for a vertebrate to become a permanent inhabitant of caves? Guess which order of vertebrates that do not currently live in caves would be most likely to become troglobionts and indicate the signs that will allow them to switch to this way of life.

3. "Alice on the island". In animal species isolated on the islands, in the course of evolution, changes in body size often occur, both upwards (the giant Maltese swan) and downwards (the pygmy Maltese elephant). What factors predict whether an organism will grow or shrink in the course of such evolution? What other terrestrial and aquatic biotopes show a similar evolutionary effect? Why does this effect most often extend to animals and not to other living organisms?

1. 4. Procedure and terms of the Tournament

4.1. The tournament is held in two stages:

Qualifying;

4.2. Tournament dates:

Istage(qualifying): February 2018. Takes place in GBUDO CRTD NO.

To participate in the Tournament, the organizing committee, created by the body responsible for managing the education of the municipal district and city district, sends an email to This email address is being protected from spambots before March 1, 2018. You must have JavaScript enabled to view. (GBUDO TsRTDiYU NO, department of environmental education and upbringing) application (Appendix 1), consent to the processing of personal data of a minor (Appendix 2), consent to the non-commercial use of competitive works (Appendix 3) and presentations of teams.

Based on the results of an expert assessment of the content of the presentations, the composition of the participants of the II stage of 9 teams is formed. Until March 28, 2018, an invitation to participate in the II stage of the Tournament is sent to the educational organizations whose teams have passed the qualifying stage.

4.3. The final of the Tournament is held in three rounds:

The first team presents the solution of one environmental task in the form of a short illustrated report (the time of the report is 5-7 minutes);

The second team plays the role of an opponent (subjects to a critical assessment of the completeness, correctness and validity of the presented decision of the opposing team);

The third team acts as a reviewer (observes the progress of the discussion and makes a conclusion about how well the other two teams coped with their roles).

In the next rounds, the teams change roles and play the following tasks.

The captain leads the team.

All actions of the team members are evaluated by the jury.

1. 5. Summing up and awarding

Based on the results of the Tournament, the following are awarded:

In the final with diplomas, the team is the winner (1st place), the teams are prize-winners (2nd and 3rd places).

All teams have a certificate of participation.

___________________________

ANNEX 1

to the regulation on the regional

team ecological tournament

"Time Machine"

Application

for participation in the regional team ecological tournament "Time Machine"

(body exercising management in the field of education of a municipal district, city district)

The person responsible for organizing and holding the regional team ecological tournament "Time Machine" in the municipal district / city district (full name, position, contact phone number), ________________________________________________________________________________________________________________________

APPENDIX 2

to the regulation on the regional command environmental

Tournament "Time Machine"

Consent to the processing of personal data of a minor

I,________________________________________________________________,

(last name, first name, patronymic - mother, father, guardian, etc.)

residing at ______________________________________________

place of registration _________________________________________________

name of the identity document: _____________, series ________ number ______________ issued by _______________________________

date of issue _____________, I express my consent to the processing of personal data _____________________________________________,

(last name, first name, patronymic, date of birth of a minor), whose legal representative I am, as well as my following personal data: last name, first name, patronymic, year, month, date, place of birth, registration address, passport data (hereinafter referred to as personal data ) GBU DO "Center for the Development of Creativity for Children and Youth of the Nizhny Novgorod Region"(hereinafter referred to as the Center), for the execution of all necessary documents required in the process of holding the regional team environmental tournament "Time Machine" (hereinafter referred to as the Tournament), as well as subsequent events associated with the Tournament, taking into account the current legislation.

In case of misuse of my provided and personal data of the person, whose official representative I am, I reserve the right to withdraw my consent by submitting a written application to the Center.

Research question. In animal species that are isolated on the islands, in the course of evolution
often there are changes in body size, and both in the direction of increase
(giant Maltese swan), and downward (pygmy
maltese elephant). What factors predict whether an organism will grow
in the course of such evolution or will it decrease? What other terrestrial and aquatic biotopes
show a similar evolutionary effect? Why is this effect more common
only applies to animals and not to other living organisms?

Research objectives.

Giant swan and pygmy elephant

Insular gigantism and insular dwarfism.

Biotopes in which changes in the size of organisms are observed.

Seas and oceans.

Forests.

Forests.

10. Steppes.

11. Savannahs.

12. Savannas.

13. Deserts and icy deserts.

14. Why is this effect more common in animals?

15.

16. Research results.

17. Conclusion.

18. List of references.

Islands are like cages - animals or plants cannot just jump and jump to another habitat. Therefore, sometimes they remain isolated from the outside world. Whether it's a whim of evolution or human intervention, there are still islands on Earth inhabited by a single or dominant animal species.

The small island of Okunoshima, located in the Inland Sea of ​​Japan, is very popular among tourists, as its only inhabitants are wild rabbits, which are not at all afraid of people. In the 20th century, Okunoshima was home to a chemical weapons plant and its location was so secret that the island was removed from maps.

According to one version, during the time the rabbits on this island were used to test chemical weapons, and after the termination of the program, they were released into the wild. According to another version, a group of schoolchildren released several rabbits onto the island, which then bred and occupied the entire territory of Okunoshima. Tourists visiting the island bring food for the rabbits and even leave water for them, as the water on Okunoshima is polluted by the factory.

In the 1970s, scientists from the New York Blood Research Center opened a laboratory in Liberia to study viruses. A medical research center called the Blood Center of New York was looking for a vaccine for several diseases, so wild chimpanzees were used as test subjects, since human DNA is 99% identical to that of primates.

In 2005, the research facility was closed and the remaining chimpanzees were released into the wild. Since the New York Blood Center was located on an island in a meandering river, and because chimpanzees cannot swim, the primates remained cut off from the outside world. When the project was closed, its director promised to continue to support animals infected with viruses, but this did not happen. The abandoned chimpanzees are now supported by local residents and charitable organizations.

Better known as Pig Beach, this is an uninhabited sandy beach in the Exuma region of the Bahamas. Wild pigs live here, which are not at all afraid of people. They can swim up to the tourist boat without fear to beg for some treats. There is no consensus on how the pigs got to this place. Some believe that the animals ended up on the beach after a long-standing shipwreck. Today, the pigs have no reason to worry - they have become a landmark of this place, and no one encroaches on their lives.

The name "Rat Island", which is part of the Aleutian Islands in Alaska, is due to the sailors of a Japanese ship who were shipwrecked in the late 1700s. The uninhabited island was immediately colonized by ship rats - the animals quickly set about destroying the local ecosystem, eating the eggs of the birds that lived on the island. In 2007, the services sounded the alarm, after which, in 2008, rat poison began to be dumped on the island within a week. The following year, the island was declared rodent-free, allowing some bird species to return to their breeding grounds.

Strictly speaking, there are several islands in Japan where there are more cats than people. One of these is the famous Tashiro Island, popularly known as the "Isle of Cats".

A long time ago, silk production was established in this place, but at one point the production began to be threatened by mice, as they destroyed silkworms, which play an important role in the production of silk. Without thinking twice, the locals began to keep cats, which in turn did not allow the rodent population to grow. Over time, the younger generation began to leave Tashiro, and now about 100 local residents live on the island. The numerous population of cats has not gone away, but, on the contrary, continues to thrive.

Christmas Island is a small inhabited island in the Indian Ocean, where the most famous inhabitant of the island is the red ground crab (Gecarcoidea natalis). This type of crustacean lives only on Christmas Island and its population is several million times larger than the local population. Every year, during the mating season of earth crabs, which runs from about mid-October to January, more than 100 million individuals of this species go on a multi-day trip from the rainforests to the shores of the Indian Ocean. Many red earth crabs move towards the coast to spawn. This event attracts many tourists, ecologists and researchers.

To protect the crabs, special fences are being built along the roads, as well as special ones. At the peak of migration, certain roads are blocked and signs are erected to announce the migration.

The island of Queimada Grande, also known as the "Isle of Snakes", is located in the Atlantic Ocean, 35 kilometers from the coast of Brazil. Queimada Grande is the habitat of one of the most dangerous in the world - island botrops.

The venom of this snake almost instantly causes tissue death, blood destruction, acute kidney failure and internal bleeding. For this reason, the country's authorities prohibit visiting the island, which is included in the list of the most dangerous places on Earth. And yet, despite the ban, Queimada Grande is popular with tourists: of course, you can’t get to the island itself, but guides bring tourists by boat to a safe, as close as possible distance from the rocky shore. From this distance, those who wish can see tangles of snakes hanging from trees and covering coastal rocks.