Luckily insects are smaller in size at present. Various studies showed that hundreds and millions of years ago, insects were large in size. Due to certain reasons, evolution changed them to a smaller size. Learn more to know about the frequently asked question why are insects smaller now?
In the animal kingdom, the insects fit into the group called phylum Arthropoda. Insects come under the category of Insecta under the group Arthropoda.
Features of Arthropods
- Hard external skeleton
- Segmented body
- Minimum of three pairs of joint legs
Features of Insects (Insecta)
- The insect body is divided into three main categories as head, thorax, and abdomen.
- The internal skeleton is absent, they are covered with the external shell that covers the soft tissue which is present inside.
- Most insects have one pair of antennae on their head.
- Most of them have one or two pairs of wings. For some insects like lice, fleas, bristletails, and silverfish the wings are completely absent.
Insects are proven to be successful groups because they involve in many activities. The first and foremost thing is they help in the pollination of flowers, disperse seeds, control the population of other organisms, and maintain soil fertility.
Name the paleobiologist in LiveScience who had commented on the article.
- A. Matthew Clapham
- B. Ken Campbell
- C. Jack Horner
- D. Matthew McCurry
Prehistoric giant insects
Large insects were very common on earth in the pre-historic period. About 300 million years ago, the Meganeura, a genus of extinct insects, was related to modern-day dragonflies. The researchers in Kansas in 1937 found that M. permiana, a species of genus Meganeura, was one of the largest known insects that have a wingspan of over two feet (0.6 meters).
Why did they disappear?
The most important reason is the atmosphere change. During the Carboniferous and Permian periods, the composition of oxygen content is high. The planet itself contains moisture and is surrounded by more oxygen around 35%. The air content today is 21%.
Why do insects get bigger with oxygen? Oxygen is essential for insects for their survival. They do not have lungs, they depend only on the spiracles (respiratory system). Due to the gradual decrease in the airflow, their size also gets decreased slowly.
How dinosaurs involved?
Due to the evolution of ancient dinosaurs that had the ability to fly, both became the competition for predators and gradually the birds grew faster than giant insects.
Matthew Clapham, paleobiologist in LiveScience, commented in an article, “The change in insect size is gradual. This gradual change fits quite nicely with the gradual evolution in birds at the time.”
Hope the answer to the question Why are insects smaller now is clear.