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What is the significance of phylogenetic research? Driving forces of macroevolution. Parallelisms and their evolutionary significance

Question 1. What is the difference between macro and microevolution?

By microevolution we mean the formation of new species.

The concept of macroevolution denotes the origin of supraspecific taxa.

Nevertheless, there are no fundamental differences between the processes of formation of new species and the processes of formation of higher taxonomic groups. The term “microevolution” in the modern sense was introduced by N.V. Timofeev-Resovsky in 1938.

Question 2. What processes are the driving forces of macroevolution? Give examples of macroevolutionary changes.

In macroevolution, the same processes operate as during speciation: the formation of phenotypic changes, the struggle for existence, natural selection, extinction of the least adapted forms.

The result of macroevolutionary processes is significant changes in the external structure and physiology of organisms - such as, for example, the formation of a closed circulatory system in animals or the appearance of stomata and epithelial cells in plants. Fundamental evolutionary acquisitions of this kind include the formation of inflorescences or the transformation of the forelimbs of reptiles into wings and a number of others.

Question 3. What facts underlie the study and evidence of macroevolution?

The most convincing evidence of macroevolutionary processes comes from paleontological data. Paleontology studies the fossil remains of extinct organisms and determines their similarities and differences with modern organisms. From the remains, paleontologists reconstruct the appearance of extinct organisms and learn about the flora and fauna of the past. Unfortunately, the study of fossil forms gives us an incomplete picture of the evolution of flora and fauna. Most remains consist of hard parts of organisms: bones, shells, and external supporting tissues of plants.

Of great interest are fossils that preserve traces of burrows and passages of ancient animals, imprints of limbs or entire organisms left on once soft sediments.

Question 4. What is the significance of the study of phylogenetic series?

The study of phylogenetic series constructed on the basis of data from paleontology, comparative anatomy and embryology is important for further development general theory evolution, construction natural system organisms, recreating the picture of the evolution of a specific systematic group of organisms.

Currently, to construct phylogenetic series, scientists are increasingly using data from such sciences as genetics, biochemistry, molecular biology, biogeography, ethology, etc.

Parallelisms and their evolutionary significance

This branch of the evolution of lower vertebrates arose at the end of the Cambrian period and has not been known in the fossil state since the end of the Devonian period. The fact is that in fossil agnathans, the gill cavities, the cavity of the brain, the walls of many large blood vessels and other internal organs. In this case, only comparative anatomy works and, to a very necessary extent, embryology. The widespread use of computer technology has facilitated such analysis, and cladograms (from the Greek "klados" - branch) began to appear in most phylogenetic publications.

The study of the structure of nucleic acids and other macromolecules has now become one of the most important additions to the triple parallelism method. This could be taken as a mistake, if in 1983 M.F. Ivakhnenko did not prove on paleontological material that turtles originated from amphibians independently of all other reptiles.

The refinement is expressed in the fact that the reconstructions become more and more detailed. If there is something unknown in the world around us, then the task of science is to study and explain this unknown, regardless of the theoretical and practical significance of the subject of study. In addition, phylogenetic reconstructions are the basis on which the patterns of evolution are clarified.

There are many other patterns of evolution that have been discovered through phylogenetic studies. Evolutionary processes are observed both in natural and laboratory conditions. The fact of evolution at the intraspecific level has been proven experimentally, and the processes of speciation have been directly observed in nature.

Evidence of evolution

Somewhere between generations 31,000 and 32,000, however, cardinal changes occurred in one of the populations that were not observed in the others. At 36 years old (an extremely short period for evolution), the size and shape of the head changed, the bite force increased and new structures in the digestive tract developed.

In addition, the intestines of the new population contain nematodes that were not present in the original population. In particular, to combat the codling moth Cydia pomonella (the larvae of which are the very “worms” in wormy apples), Cydia pomonella granurovirus is actively used.

Observations of modern species indicate that speciation occurs continuously in existing populations. There are many examples of how different types can interbreed under exceptional conditions. Depending on the habitat around the mountains, salamanders form various forms, gradually changing their morphological and ecological characteristics.

Judging by the fossil record and measurements of the rate of mutations, complete incompatibility of genomes, making interbreeding impossible, is achieved in nature in an average of 3 million years. This means that observing the formation of a new species under natural conditions is in principle possible, but this is a rare event. At the same time, in laboratory conditions the rate of evolutionary change can be increased, so there is reason to hope to see speciation in laboratory animals.

The apple moth Rhagoletis pomonella is an example of observed sympatric speciation (i.e., speciation as a result of division into ecological niches). Practice shows that biological classifications built on the basis of different characteristics tend to tend to the same tree-like hierarchical scheme - natural classification.

This is precisely the result that can be expected with the evolutionary origin of animals from a common ancestor. The branching of the phylogenetic tree corresponds to the division of populations during the process of speciation. As a rule, objects that did not arise during evolution do not have this property. You can combine these objects into different hierarchies if you wish, but there is no single objective hierarchy that is fundamentally better than all the others.

The term was proposed by the German evolutionist E. Haeckel in 1866. Later, the term “phylogeny” received a broader interpretation - it was assigned the meaning of the history of the evolutionary process. We can talk about the phylogeny of individual characters: organs, tissues, biochemical processes, the structure of biological molecules, and the phylogeny of taxa of any rank - from species to superkingdoms. The goal of phylogenetic research is to reconstruct the origin and successive evolutionary transformations of the structures and taxa being studied.

Paleontological data, as already mentioned, introduce a time scale into these reconstructions and supplement it with extinct forms, that is, they make the series more detailed and thereby more reliable.

One of the best known and best studied is the phylogenetic series of modern single-toed ungulates. Multiple paleontological finds and identified transitional forms create a scientific evidence base for this series. The phylogenetic series of the horse, described by the Russian biologist Vladimir Onufrievich Kovalevsky back in 1873, remains an “icon” of evolutionary paleontology today.

Evolution through the centuries

In evolution, phylogenetic series are successively successive transitional forms that led to the formation of modern species. Based on the number of links, the series can be complete or partial, but the presence of successive transitional forms is a prerequisite for their description.

The phylogenetic series of the horse is considered evidence of evolution precisely due to the presence of such sequential forms that replace each other. The multiplicity of paleontological finds gives it a high degree of reliability.

Examples of phylogenetic series

The row of horses is not the only one among the examples described. The phylogenetic series of whales and birds has been well studied and has a high degree of reliability. And controversial in scientific circles and most used in various populist insinuations is the phylogenetic series of modern chimpanzees and humans. Disputes about the missing intermediate links here continue in the scientific community. But no matter how many points of view there are, the importance of phylogenetic series as evidence of the evolutionary adaptability of organisms to changing conditions remains indisputable environment.

The connection between the evolution of horses and the environment

Multiple studies by paleontologists have confirmed the theory of O. V. Kovalevsky about the close relationship of changes in the skeleton of the ancestors of horses with changes in the environment. The changing climate led to a decrease in forest areas, and the ancestors of modern single-toed ungulates adapted to living conditions in the steppes. The need for rapid movement provoked modifications in the structure and number of fingers on the limbs, changes in the skeleton and teeth.

The first link in the chain

In the early Eocene, more than 65 million years ago, lived the first ancestor of the modern horse. This is a “low horse” or Eohippus, which was the size of a dog (up to 30 cm), rested on the entire foot of the limb, which had four (front) and three (back) fingers with small hooves. Eohippus fed on shoots and leaves and had tuberculate teeth. Brown coloring and sparse hair on a mobile tail - this is the distant ancestor of horses and zebras on Earth.

Intermediates

About 25 million years ago, the climate on the planet changed, and steppe expanses began to replace forests. In the Miocene (20 million years ago), mesohippus and parahippus appeared, more similar to modern horses. And the first herbivorous ancestor in the phylogenetic series of the horse is considered to be Merikhippus and Pliohippus, which entered the arena of life 2 million years ago. Hipparion - the last three-fingered link

This ancestor lived in the Miocene and Pliocene on the plains of North America, Asia and Africa. This three-toed horse, resembling a gazelle, did not yet have hooves, but could run fast, ate grass, and it was she who occupied vast territories.

One-toed horse - pliohyppus

These one-toed representatives appear 5 million years ago in the same territories as hipparions. Environmental conditions are changing - they are becoming even drier, and the steppes are expanding significantly. This is where single-fingeredness turned out to be a more important sign for survival. These horses were up to 1.2 meters high at the withers, had 19 pairs of ribs and strong leg muscles. Their teeth acquire long crowns and folds of enamel with a developed cement layer.

Horse we know

The modern horse, as the final stage of the phylogenetic series, appeared at the end of the Neogene, and at the end of the last ice age (about 10 thousand years ago), millions of wild horses were already grazing in Europe and Asia. Although the efforts of primitive hunters and the reduction of pastures made the wild horse a rarity already 4 thousand years ago. But two of its subspecies - the tarpan in Russia and the Przewalski's horse in Mongolia - managed to last much longer than all the others.

Wild horses

Today there are practically no real wild horses left. The Russian tarpan is considered an extinct species, and the Przewalski's horse does not occur in natural conditions. Herds of horses that graze freely are wild domesticated forms. Although such horses quickly return to wild life, they still differ from truly wild horses.

They have long manes and tails and are of different colors. Exclusively dun Przewalski's horses and mousey tarpans have trimmed bangs, manes and tails.

In Central and North America, wild horses were completely exterminated by the Indians and appeared there only after the arrival of Europeans in the 15th century. The feral descendants of the conquistadors' horses gave rise to numerous herds of mustangs, the numbers of which today are controlled by shooting.

In addition to mustangs, there are two species of wild island ponies in North America - on Assateague and Sable Islands. Semi-wild herds of Camargue horses are found in the south of France. Some wild ponies can also be found in the mountains and moors of Britain.

Our favorite horses

Man tamed the horse and bred more than 300 of its breeds. From heavyweights to miniature ponies and handsome racing horses. About 50 breeds of horses are bred in Russia. The most famous of them is the Oryol trotter. Exclusively white coat, excellent trot and agility - these qualities were so valued by Count Orlov, who is considered the founder of this breed.

Question 1. What is the difference between macro- and microevolution?
Microevolution- evolution within a species; occurs on the basis of mutational variability under the control of natural selection. Thus, microevolution is the very beginning stage of the evolutionary process, it can occur in relatively short periods of time, and can be observed and studied directly. As a result of hereditary (mutational) variability, random changes in the genotype occur. Mutations are most often recessive and, moreover, are rarely beneficial for the species. However, if as a result of a mutation changes that are beneficial for any individual occur, then it receives some advantages over other individuals of the population: it receives more food or becomes more resistant to the influence of pathogenic bacteria and viruses, etc. For example, the appearance of a long neck allowed the ancestors of the giraffe to feed on leaves with tall trees, which provided them with more food than individuals of the population with a short neck.
Macroevolution- evolution at the supraspecific level; leads to the formation of large taxa (from genera to phyla and kingdoms of nature). Macroevolution organic world- this is the process of forming large systematic units: from species - new genera, from genera - new families, etc. The processes of macroevolution require enormous periods of time, so it is impossible to study it directly. However, macroevolution is driven by the same driving forces as microevolution: genetic variation, natural selection, and reproductive disjunction. Just like microevolution, macroevolution has a divergent character.

Question 2. What processes are the driving forces of macroevolution? Give examples of macroevolutionary changes.
Macroevolution is based on the same driving forces as microevolution: hereditary variation, natural selection, and reproductive disjunction. Just like microevolution, macroevolution has a divergent character.
The result of macroevolutionary processes is significant changes in the external structure and physiology of organisms - such as, for example, the formation of a closed circulatory system in animals or the appearance of stomata and epithelial cells in plants. Fundamental evolutionary acquisitions of this kind include the formation of inflorescences or the transformation of the forelimbs of reptiles into wings and a number of others.
Question 3. What facts underlie the study and evidence of macroevolution?
The most convincing evidence of macroevolutionary processes comes from paleontological data. Such evidence includes the found remains of extinct transitional forms, which make it possible to trace the path from one group of living beings to another. For example, the discovery of three-toed and five-toed ancestors of the modern horse, which have one toe, proves that the horse's ancestors had five toes on each limb. The discovery of fossil remains of Archeopteryx allowed us to conclude that there were transitional forms between reptiles and birds. Finding the remains of extinct flowering ferns makes it possible to solve the question of the evolution of modern angiosperms, etc. Unfortunately, the study of fossil forms gives us an incomplete picture of the evolution of flora and fauna. Most remains consist of hard parts of organisms: bones, shells, and external supporting tissues of plants. Of great interest are fossils that preserve traces of burrows and passages of ancient animals, imprints of limbs or entire organisms left on once soft sediments.

Question 4. What is the significance of the study of phylogenetic series?
On the basis of paleoanthological finds, phylogenetic series were built, that is, series of species that successively replace each other in the process of evolution. The study of phylogenetic series based on data from paleontology, comparative anatomy, and embryology is important for the further development of the general theory of evolution, the construction of a natural system of organisms, and the reconstruction of the picture of the evolution of a particular systematic group of organisms.
Currently, to construct phylogenetic series, scientists are increasingly using data from such sciences as genetics, biochemistry, molecular biology, biogeography, ethology, etc.

Question 1. What is the difference between macro- and microevolution?

By microevolution we mean the formation of new species.

The concept of macroevolution denotes the origin of supraspecific taxa (genus, order, clan, type).

Nevertheless, there are no fundamental differences between the processes of formation of new species and the processes of formation of higher taxonomic groups. The term "microevolution" in the modern sense was introduced by N. V. Timofeev-Resovsky in 1938.

Question 2. What processes are the driving forces of macroevolution? Give examples of macroevolutionary changes.

In macroevolution, the same processes operate as in speciation: the formation of phenotypic changes, the struggle for existence, natural selection, the extinction of the least adapted forms.

Question 3. What facts underlie the study and evidence of macroevolution?

The most convincing evidence of macroevolutionary processes comes from paleontological data. Paleontology studies the fossil remains of extinct organisms and establishes their similarities and differences with modern organisms. From the remains, paleontologists reconstruct the appearance of extinct organisms and learn about the flora and fauna of the past. Unfortunately, the study of fossil forms gives us an incomplete picture of the evolution of flora and fauna. Most remains consist of solid parts of organisms: bones, shells, and external supporting tissues of plants. Of great interest are fossils that preserve traces of burrows and passages of ancient animals, imprints of limbs or entire organisms left on once soft sediments.

Question 4. What is the significance of the study of phylogenetic series?Material from the site

The study of phylogenetic series built on the basis of data from paleontology, comparative anatomy and embryology is important for the further development of the general theory of evolution, the construction of a natural system of organisms, and the reconstruction of a picture of the evolution of a specific systematic group of organisms.

Currently, to build phylogenetic series, scientists are increasingly using data from such sciences as genetics, biochemistry, molecular biology, biogeography, ethology, etc.