What is a spider and why is it not an insect
Spiders are a large part of the animals that inhabit the planet. They can live in people's houses, in fields and on trees. Like insects, they can benefit or harm humans. But often these two types of arthropods are confused.
Content
Who is a spider: acquaintance
Spider.
Spiders are the eternal neighbors of people. Their role is often underestimated, considering them unpleasant creatures. But their role in nature is very great. There is a whole science, arachnology, which deals with the study of this type of animal.
Spiders are representatives of the phylum Arthropoda, class Arachnida. At the moment, there are more than 42 tons of species and more than 1000 fossils.
There is a recognized disease - arachnophobia. And most of the people can not explain the cause of fear. Experts believe that it is associated with childhood trauma. Symptoms appear: headache, fainting, nausea and a desire to run.
Arachnophobia is one of the most common and intractable diseases.
Order of arthropods
Arthropods are a detachment that includes more than 80% of the living creatures of the planet. Their difference is the external skeleton of chitin and paired jointed limbs.
The ancestors of arthropods are considered to be either worm-like or tracheal. However, there is an opinion that all representatives came from one ancestor - nematodes.
representatives of arthropods.
One of the most famous classifications of origin divides them into three types:
- Tracheal;
- Crustaceans;
- Cheliceric.
Tracheal
This group of arthropods have respiratory organs, which made them adapted to life on land. The respiratory system has been improved, and the skin has been strengthened.
There are several representatives of this species.
Crustaceans
This group includes a large number of animals that live in various types of water bodies. Although there are some species that can live on land or in wet conditions.
They have a chitinous exoskeleton that sheds periodically and their respiratory organs are gills. The group includes:
- crabs;
- lobster;
- shrimp;
- crayfish;
- wing;
- lobsters.
Cheliceral
Cheliceric.
The largest part of this subgroup is represented by arachnids. They also include ticks and racoscorpions. They have a certain role in nature and for humans.
The subclass got its name for the limbs, chelicerae. These are oral appendages that are divided into a pair or three segments. But they are not designed to eat hard food.
Insects and spiders
These two types of arthropods are often confused. But they have much more differences than they have in common. Among insects, there are those who eat meat and those that are vegetarians. Spiders are mostly predators.
Spiders are definitely not insects! More differences in the structure and behavior of insects and spiders in the article at the link.
spider anatomy
What are spiders
Large pink tarantula.
There are over 40 thousand spider species. They can live in grass, near human habitation, and in remote places.
There are very tiny spiders, but there are also large representatives that do not fit on a plate. But all species have the same structure.
Conventionally, the types of spiders can be divided into:
In Russia, according to the latest data, there are about 2400 species. More and more open every year. They are distributed in different regions and climatic conditions.
Detailed acquaintance with the fauna spiders of Russia.
Interesting Facts
Spiders inspire fear in people, but at the same time, interest. Therefore, they are studied and even inraised at home as pets.
Unusual representatives
Conclusion
Uninformed people often confuse insects and spiders. Although they are representatives of arthropods and neighbors of humans, they have more differences than they have in common. Definitely: spiders are not insects.
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