We know that throughout this planet there are millions of animal species. Each of them has different characteristics depending on their origin and morphology. Many people do not know well what are invertebrate animals and why they are classified in this category.
In this article we will investigate in depth What are invertebrate animals, their characteristics, types and their importance for the ecosystem.
What are invertebrate animals
Invertebrate animals They are all those that do not have a spinal column or an articulated internal skeleton. This group represents more than 95% of all known animal species, with more than 1,7 million species identified to date. Although they do not have bones, many of these animals have external structures that provide them with protection, such as the exoskeleton in insects or the shell in mollusks.
Throughout history, invertebrates have been a difficult group to classify due to their great diversity. This term was coined by the naturalist Jean Baptiste Lamarck, who in his early studies divided them into ten categories: mollusks, annelids, crabs, arachnids, insects, worms, echinoderms, polyps and trichomonads, among others.
Nowadays, the classification of invertebrates has evolved and we have managed to group them into different philos according to more specific characteristics, such as their type of symmetry, presence of protective structures and habitats. Below, we tell you more about these phyla in detail.
Classification of invertebrate animals
Invertebrates are classified mainly according to the structure of your body and other specific biological characteristics. Although they do not possess an internal skeleton, many invertebrates have external structures that allow them to survive in a variety of environments.
Some of the main invertebrate phyla are:
- Phylum Arthropoda: Animals within this group possess an exoskeleton and jointed limbs. This phylum includes insects, arachnids (such as spiders and scorpions), crustaceans (crabs, shrimps), and myriapods (centipedes and millipedes).
- Phylum Mollusca: Soft body, usually covered by a shell. Mollusks include snails, octopuses, mussels and clams.
- Phylum Porifera: Sponges belong to this group. They are simple animals with porous bodies that allow water to pass through. They usually have radial symmetry.
- Phylum Cnidaria: Animals such as jellyfish, corals and anemones. They are characterized by having stinging tentacles, used to capture prey.
- Phylum Echinodermata: Mainly marine inhabitants, with bodies covered with spines or calcareous plates, such as starfish and sea urchins.
- Phylum Platyhelminthes: Flatworms, which are usually parasites, such as tapeworms.
- Phylum Nematoda: Cylindrical worms, some parasites of the intestines of animals and humans.
- Phylum Annelids:This group includes earthworms and leeches, with bodies segmented into rings.
Due to the great diversity Existing within the group of invertebrate animals, we can find species in virtually all environments on Earth, including terrestrial, aquatic and aerial ecosystems.
Importance of invertebrate animals
Invertebrates are of crucial importance in ecosystems. Although they often go unnoticed due to their size, they perform essential functions for maintaining life on the planet.
Some of its key features are:
- Plant pollination: Insects such as bees and butterflies play a fundamental role in the reproduction of plants by helping them in the pollination process.
- Decomposition of organic matter: Organisms such as worms and sponges contribute to the decomposition of organic material, helping to maintain the soil fertility and promoting the nutrient cycle.
- Pest control: Many arthropods, such as spiders and praying mantises, help control pest populations in natural ecosystems and agricultural settings.
- Base of the food chainInvertebrates are the main food for many vertebrate species, such as birds, fish and mammals.
Examples of invertebrate animals and their classification
There are thousands of examples of invertebrate animals. Here are some key examples from different invertebrate phyla:
- Insects (Arthropods): Cockroaches, butterflies, flies, ants.
- Arachnids (Arthropods): Spiders, scorpions, ticks.
- Seafood (Arthropods): Crabs, shrimps, lobsters.
- Molluscs: Octopus, mussels, squid.
- Platelmintos: Tapeworms, broad fish worms.
- Cnidarians: Jellyfish, corals, sea anemones.
- Echinoderms: Starfish, sea urchins, sea lilies.
- Nematodes: Intestinal worm, cylindrical worm.
Main characteristics of invertebrate animals
Although invertebrates form the largest group of animals on Earth, they present a great variety of characteristics:
- They do not have an articulated internal skeleton or a spinal column.
- Some species, such as arthropods, have a exoskeleton that provides them with protection and support.
- Their methods of reproduction vary greatly, although many invertebrates are oviparous (they reproduce by means of eggs).
- Most invertebrates have bilateral symmetry, although some have radial symmetry, such as echinoderms.
An important aspect of some invertebrates is that undergo metamorphosis, a process that involves drastic changes in their form and function as they grow. Insects such as butterflies and beetles are good examples of animals that go through this process.
Relationship with vertebrates
Although vertebrate and invertebrate animals are clearly differentiated by the presence or absence of a vertebral column, there is an evolutionary connection between them. Vertebrates evolved from invertebrates..
Both groups perform similar functions in ecosystems and, in many cases, depend on each other to survive. For example, invertebrates serve as food for many vertebrates, including birds, mammals and fish. In addition, without insect pollination, many flowering plants would not survive.
On the other hand, locomotion is a general characteristic in almost all invertebrates, some of which are capable of moving even in their juvenile phase, as is the case of marine sponges.
Therefore, invertebrates not only share an evolutionary origin with vertebrates, but are also vital to the preservation of global biodiversity.
Invertebrates are responsible for much of the balance in the world's ecosystems. Although they often go unnoticed or are seen only as small organisms, each of them performs essential functions for life on Earth. From pollination to the decomposition of organic matter, invertebrates play a crucial role in the conservation of biodiversity and the maintenance of ecosystems.