Most of us think of animals as medium sized four-legged creatures having a pair of eyes and ears, for example, our beloved canine companions cats and dogs and other wild creatures such as lions and hippos.
But you’ll be surprised to learn that the animal kingdom is actually far bigger and much more diverse than what you’re thinking. Urchins, fishes and jelly fishes are actually animals too, and likewise, sponges that have bodies full of pores and basically look like plants are nothing but ocean dwelling animals!
But what about insects? Where do they stand?
Are insects animals?
Yes, insects are animals. They are regarded as animals because they fulfill the necessary criteria that qualify any living organism to be classified as an animal.
Some of these conditions include; the inability to produce their own food, the ability to move around in at least one life cycle stage of theirs, having specialized tissues in their bodies such as nerve, muscle, connective and epithelial tissues and also having cells that do not have cell walls, among many other things.
Why are insects regarded as animals?
Insects are regarded as animals because, generally, they fulfill (most, if not all) of the conditions required to classify any organism as an animal.
By the way, organisms classified as animals belong to the kingdom Animalia. Other kingdoms (or worlds of living things different from animals) include; Kingdom: Plantae, Protista, Fungi, Eubacteria (true bacteria) and Archaebacteria (ancient bacteria).
Want to learn how organism classification works? Below is a quick two minutes guide to help you with that — you can skip and continue with the traits that distinguish animals from other organisms and also makes insects members of the animal kingdom.
How organism classification works:
Taxonomy is basically the way living things are classified.
It starts off by classifying all living things on the surface of the earth (those that we currently know of), into three basic groups based on some general and loose traits that they each share, and then continues to taper down (in terms of organism number) but broadens up in terms of the criteria needed for classification, until the most narrow and specific group is achieved. This group is the one that contains organisms that are most closely related to one another.
Each progressive group has members that are more closely related to one another than with members of the preceding broader group and with those of other different groups.
Here is how the classification works:
All living things that exists on the surface of the earth today (the ones that we currently know of) are classified as either: Eukarya, Archaea or Bacteria.
These groups are known as domains and they represent the largest possible distinction between all living organisms. Before them, there’s really no distinction, all life forms are simply organisms!
The next rank of classification (branching off from the domains) is the Kingdom. It includes: Animalia, Plantae, Protista, Fungi, Eubacteria (true bacteria) and Archaebacteria (ancient bacteria). The first four kingdoms belong to the Eukarya domain, the Eubacteria belongs to the Bacteria domain and the Archaebacteria belongs to the Archaea domain.
The next rank after the kingdom classification is the Phylum, and then there’s Class, Order, Family, Genus and finally species. The specie group contains all living organism that are very closely to one another that they can actually interbreed with one another. For example all subspecies or species of lions, of sloths, of hippos, of moose, or, of any other reptile species. Felids is the broader group of big cats such as lions and tigers, but we know from common sense and taxonomy that lions are no tigers!
Also, within each of these seven groups are smaller intermediary groups which further classify organisms based on similar traits. In the next section, you’ll see the basic or summarized phylogenetic tree of insects.
Taxonomic classification of living things from highest rank (domain) to lowest rank (species:
Now back to the original question.
Insects are regarded as animals because they share the general traits and features that help distinguish animals from organisms of other kingdoms.
These traits on their own do not and cannot serve as a fully distinguishing feature of animals from all other organisms such i.e plants and the rest, but when collected in numbers in any species, they give scientist the ability to be able to draw the fine line that helps pinpoint an animal from plants, protist and other kingdom of living things.
Some of the traits that separate animals from the other kingdoms include:
1] Animals are unable to produce their own food, and must eat other organism to derive sustenance. This helps distinguish animals from most plants, as they can product their own food, but not from fungi and bacteria, as they too can produce their own food. Insects of course, are unable to produce their own food.
2] All animals have multiple cells, human beings for examples have cells in the excess of trillions. This trait helps distinguish animals from Archaebacteria and Eubacteria but not from the other kingdoms. The bodies of insects of course, is made up of multiple cells.
3] All animals have eukaryotic cell, a type of cell in which there’s a true nucleus encasing the DNA of the organisms alongside some highly specialized structures called organelles distributed within the plasma membrane which are necessary for optimum performance of the cell. This trait helps distinguish animal from Archaebacteria and Eubacteria as they all have prokaryotic cells with no true nucleus, but not from plants, protists and fungi as they too have eukaryotic cell structure.
3] Animals have highly specialized cells, their multiple cells clog together to form tissues, and from there evolve into organs that are highly developed. The result of this multi cell structure is a complex living organism. Insects of course, are complex creatures because they too are made up of multiple cells.
4] Animals have well developed nervous systems, and perhaps this is the only their distinguishing feature from all other living kingdoms.
All insects have these characteristics, (even if some are in the rudimentary forms), and this is what justifies their placement into the Kingdom Animalia.
Insects are invertebrates classified under the phylum Arthropods (animals with jointed legs, partitioned bodies and exoskeleton) and then under the class Insecta — animals with three body sections, the head, thorax and abdomen, possessing antennas and may or may not have wings to fly.
The class Insecta is one of the six classes of animals recognized today; the others include Mammalia: the group we belong, Aves (birds), Reptilia (reptiles), Pisces (fish), Amphibia.
Insects are the most diverse and abundant animal species on the universe, accounting for up to 75 percent of all animal species currently known. This figure is staggering, but even more so when one realizes that about 10 million members of the arthropod family exist that are still undescribed by science yet.
Insect taxonomic classification
Sub-class (Main groups)
— Wingless insects (Apterygota)
— Winged insects (Pterygota)
Different groups of insects exists and are shared between these two broad groups, about 29 of them, but it’ll be too boring and arduous of a task to begin mentioning each one of them here. For a little insight, here are some of them:
— Dragonflies and Damselflies.
— Butterflies and Moths.
— Bees, Wasps, and Ants.
Examples of insects include: bees, flies, mosquitoes, bugs, beetles, grasshoppers etc.
How are insects different from mammals?
When you look back at the taxonomical tree that we outlined in the earlier section, it becomes pretty evident the line that separates insects from mammals: the animal class that they are each subscribed into. But what makes insects truly different from mammals? What are the characteristics?
Below, we’ll describe some of the traits that set apart insects from mammals like you and me.
All animals grouped as insects are invertebrates; having no back bones. Mammals on the other hand are vertebrates; having back bones.
Insects have a three-part body: head, thorax and abdomen, three pairs of jointed legs, compound eyes, a pair of antenna and chitinous exoskeleton i.e their skeletal structure is situated outside their bodies. Insects may or may not have wings and are all cold blooded. Mammals on the other hand, have endoskeletons i.e their skeletons are located inside their bodies, have breasts that produce milk which insects don’t have, give birth to their young ones alive, are mostly endothermic (warm blooded) and possess body hairs in at-least one life-cycle stage of theirs.
Mammals also, do not possess the body configuration as described for insects above and all with the exception of bats, do not have the ability to fly unlike most insects.
Many other difference exist that can be used to distinguish between insects and mammals, but the ones mentioned above are the main ones.
More interesting articles:
Cite this Article ” (APA Format)
Bunu. M. (2020, May 22). Are insects animals?. Retrieved from http://emborawild.com/are-insects-animals/