Evolutionary Father Charles Darwin spoke of the need to adapt to changing living conditions. What is the reason for this paradox?

In 1859, Charles Darwin (1809-1882) published a book on the origin of species, in which he presented his evolutionary theory based on natural selection. He argued that only those animals that would best adapt to the environment where they live will survive.

While some animals face challenges in the face of climate change, or human activity, others do not change at all. Why? These species existed until they were able to perfectly adapt to the environment, which is also permanent. So now they have no reason to change.

Animals that do not evolve

Crocodile

Size: 1.5-6 meters. Age: live up to 80 years. Food: large species catch zebra, or young hippopotamus, smaller ones feed on fish.

Crocodiles are not warm-blooded, their body temperature depends on the ambient temperature. That's why they like to warm up, it helps them during digestion. They also swallow stones that remain in their stomachs and serve to grind food, and as a load when immersed.

A strong flattened tail allows them to move in the water. Of all the reptiles, they have the most perfect brain. Their vision (well seen in the dark), hearing and sense of smell are well developed. Jaws are very dangerous for prey. Crocodile blood contains special proteins that destroy a wide range of bacteria and viruses - therefore they have excellent immunity.

Why don't crocodiles evolve?

The species of crocodiles from which the modern ones originate appeared 195 million years ago. Crocodiles originally lived on land, but here they had to confront the dinosaurs in order to survive, so they went into the waters, where they had no enemies. And only water allowed them to survive.

Climate change, which began about 65 million years ago, least affected the aquatic environment and allowed aquatic species to continue to exist. In addition, crocodiles live up to 4 months without food and water.

Sharks

Size: 1-12 meters. Age: live up to 30 years. Food: fish, seafood, birds, seals, walruses, gulls.

These predators inhabit most of the marine and oceanic territories. They have sharp, triangular teeth of cutaneous origin that grow in several rows. The number of rows is not final; they are constantly growing. The lower teeth are used to hold the prey, the upper teeth are used for cutting. In the body of sharks, there is a special substance: squalene, which serves to soften and better movement in water. In search of prey, they are helped by the so-called Lorenzini ampoule, which captures a change in the electromagnetic field.

Why don't sharks evolve?

Modern sharks began to appear about 100 million years ago. Throughout their lives, they have adapted perfectly to life in water and do not need further changes. In the past, however, the jaw went through a change. For example, in sharks, the upper jaw was tightly attached to the skull, so they could catch only small prey.

However, over time, the muzzle moved, and the upper jaw began to move. Thanks to this, today's sharks can also catch a giant catch. The most primitive and oldest sharks are the so-called Hexanchiformes, which have from 6 to 7 crevice gaps (in other species only 5) and do not have a whistle (empty third eyelid).

Platypus

Size: 30-40 cm, plus tail about 8-15 cm. Age: live up to 16 years (in captivity 6 years). Food: worms, insect larvae, crayfish.

This Australian animal looks like a duck (beak and membranes), beaver (tail) and otter (body covered with brown fur) in one. This is an amphibian and a nocturnal animal, seeking prey with the help of electric exposure (like a shark).Young cubs hatch from eggs, but suck milk from the so-called milk boxes on the mother’s body. Males have poisonous spurs on their legs. Their poison will not kill a person, but it will cause him great pain and swelling.

Why don't platypuses evolve?

The evolution of pathogens began about 110 million years ago, the oldest fossils found are 31 million years old and come from South America, where the bird no longer lives. Recently, a tooth was discovered by another relative, the modern pudophyta obdurodona, who lived 5-15 million years ago and had sizes up to one meter.

Researchers believe that survival in an isolated region of Australia, its homeland, can also help its low body temperature of around 32 ° C, which is not typical for mammals. He has no reason for further evolution.

Horseshoe crab

Size: up to 60 cm. Age: live up to several decades. Food: small invertebrate animals.

A distinctive feature of the horseshoe crab is the menacing looking carapace and spine. They have no blood, but a blue blood mass that contains copper. They eat fish on the seabed, but they can swim. They have five pairs of legs. They lay 200 to 300 eggs. The horseshoe crab lives mainly in the Gulf of Mexico and the North Atlantic coast of North America.

Why doesn't the horseshoe crab evolve?

Horseshoe crabs are aquatic arthropods. They are perfectly adapted to life on the seabed, so they have not changed over the past 200 million years. Today's horseshoe crabs are very similar to those who inhabited the planet 570 million years ago. Therefore, they are called living fossils, they belong to the closest relatives of trilobites. Of the initial 42 genera, only 4 have survived to this day. Nevertheless, the results show that the priority Atlantic crabs were much smaller than today’s, some of them measured only 1 inch.

Coelacanth

Size: 1.5-2 meters. Age: live about 24 years. Food: small marine animals, cephalopods.

Coelacanth has a bluish color, its cognate coelacantha celebeska is brown, with golden spots. They live at a depth of about 200 meters, swim next to the rocky bottom. They see the same use of electroreceptors for orientation, like a shark. For hunting or escape, these fish are able to move at speeds up to 26 m./s., Their tail fin and textured scales on the surface of the body help them.

Why does coelacanth not evolve?

Latimeria is the only representative of fish in the form of lobster that lived on our planet 300 million years ago, and for a long time it was believed that it died out 70 million years ago. Until 1938, when live latim was caught off the coast of Africa. In 1998, a second living species was discovered. Coelacanths are called living fossils and the precursors of the development of amphibians. On the seabed, their living conditions have not changed, but it is estimated that their population is about 500 units.

Animals that change

Gray owl, or common owl

Size: 36-43 cm (wingspan from 81 to 96 cm). Age: live up to 18 years. Food: forest rodents (mice), insects, moles, birds (jays) and amphibians (frogs) and fish.

Owl lives in all of Eurasia, mainly in forests. This is a rather unobtrusive owl with a large head. She has a round head with a veil and brown eyes. Active at night, then you can hear her loud sounds. Nests are built on trees, bring 2-5 eggs, which the female in every way protects. At such a moment, she is able to attack even a large beast, or a person, and deprive them of their sight.

Why does an owl evolve?

Eye color varies from gray to different shades of brown with a dark overflow. In more northern areas, due to cold white winters, gray colors prevailed, which were better protected from predators in the snow. Mitigating over the last 50 years of winter, gray owls began to decline, while brown owls dominate, because their color merges with the bark of trees, so they are well protected from attack in the forest.

Reason for change: climate.

Mice

Size: 7-11 cm (without tail). Age: live 1.5-3 years. Food: seeds, cereals, human food.

The domestic mouse is a widespread rodent living near settlements. Its color ranges from yellow-brown to gray-black. It has excellent hearing and smell, but vision is not very developed. She mostly goes out for food at night, trying to eat everything in the house, including soap and candles. She loves grain, looking for granaries, sheds and feeders. They can carry various diseases (salmonellosis) and parasites (tapeworms) to people.

Why do mice evolve?

Man considers mice to be pests and has always tried to get rid of them. In particular, warfarin, a blood coagulation inhibitor, was used. In humans, it is used as a medicine; in mice, it causes internal bleeding. Nevertheless, mice received immunity against this poison in two ways - thanks to a mutation. In mice of the Mediterranean (Mus spretus), which had a deficiency of vitamin K. In addition, with the transfer between species, that is, with the intersection of domestic and Mediterranean mice, in Spain or North Africa, where both species live.

Reason for change: human activity.

Elephant

Size: height up to 4 meters, length up to 9 meters. Age: live up to 90 years. Food: grass, leaves, roots, fruits, seeds, flowers.

Elephants are the largest land mammals. Their typical feature is the trunk, which is actually the nose with the upper lip. All three living representatives of elephants use it not only for breathing, but also for capturing small objects. They don’t drink with the trunk, they only collect water into it, which they spray into their mouths. Elephants are smart, have a good memory, are able to cooperate with each other and communicate, and have strong social feelings.

Why do elephants evolve?

A common feature of elephants has always been tusks (actually expanded upper incisors), formed from ivory, which grow throughout life. But this is in the past. It was the tusks that caused poachers to target elephants until they almost destroyed them in some areas.

Elephants coped with this in their own way, fangs stopped growing. First, it happened in the Indian elephant, then the African. Although they avoid the attacks of poachers, elephants without fangs, for example, will have problems tipping over trees to get to food and water. In addition, without fangs, elephants lose their (primarily male) attraction.

Reason for change: human activity.

North American Red-necked Anolis

Size: up to 20 cm, of which the body is 7.5 cm. Age: live about 7 years. Food: insects - cockroaches, moths, ants, grasshoppers, crickets, spiders.

Anolis is a small and medium sized lizard, it belongs to the iguana, lives in Florida. Her legs have suction cups that make her climbing easier. Males are usually 15% larger than females and their laryngeal sac is red, and three times as large. These lizards are green, but can partially change color to brown.

What is evolving and why?

In the 1970s, a gray anolis (Anolis sadrei), a highly invasive species, was introduced to Florida. The green anolis moved to the top of the trees. Over the course of just 15 years and 20 generations, their foot pads have increased and their suction cups have become more sticky.

Reason for change: arrival of competitor food.

Wolf spiders

Size: 10-35 mm. Age: live up to 2 years. Food: insects - ants, grasshoppers, crickets, other spiders.

These spiders are called wolf spiders because of their hunting abilities. They also use eyes that are arranged in three rows one above the other. The female carries an egg cocoon and looks after the larvae. They are epighean animals, that is, they run and hunt exclusively on the surface of the soil.

Why do wolf spiders evolve?

In Siberia, honey spiders of the genus Hogna live. In this unhealthy environment there are predators, and there are many.It was here that an experiment simulating global warming was conducted. Scientists believed that a larger number of microorganisms will multiply and eat faster, when heated with the release of more methane. But the result was amazing, despite this, the number of spiders began to increase significantly and the microorganisms lacked a food source, so they rushed to the decaying moss, which otherwise could release methane. In fact, climate change has slowed their behavior. Reason for change: climate.