Have you ever come face to face with a dragonfly the size of a hawk?
If you had walked on the surface of the Earth in the Carboniferous period, it could have happened. When people talk about gigantism, they tend to think of the famous dinosaurs that roamed the Earth during the Jurassic, 150 million years ago. However, dragonflies, millipedes, spiders and even scorpions once reached exceptional sizes. This amazing evolution is due to the constraints imposed by the living environment.
But how did insects so small reach such large dimensions? And why did they become extinct?




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Earth in the time of giant insects:
Insects are everywhere. They are one of evolution's greatest hits. Threequarters of all animals are insects. Their numbers are exceptional. All around us, billions upon billions of insects fly, swim and walk without us seeing them. Their mass is 300 times greater than that of mankind. Their small size means that we often ignore them. There was a time on Earth when insects did not go unnoticed. It is a very ancient history that is the result of an accumulation of adaptations, each one more surprising than the last. From flying insects with a wingspan of 70 centimeters to giant millipedes up to 3 meters long, these are creatures that actually walked the surface of the Earth more than 350 million years ago. When did insects begin to conquer the land? And how did they reach such exceptional sizes?

All insects are arthropods, with a rigid cuticle or carapace called an exoskeleton and a body divided into segments. Each has a pair of jointed appendages. Arthropods include insects, crustaceans, spiders and centipedes. The body of these creatures is divided into three parts: the head, thorax and abdomen. The head consists of antennae, eyes and mouth. The thorax has three pairs of legs and two pairs of wings. The abdomen is divided into several segments, has no appendages and the genital openings open at the end. Crustaceans were the first animals to leave the water. Hexapods needed multiple adaptations to differentiate themselves from these crustaceans. The largest and most important adaptation was the appearance of wings.


425 million years ago, a few million years after the first plants began to invade the land, the first animals also ventured out of the water.
These first curious creatures are segmented beings, the ancestors of our millipedes. At first they stayed close to the water. Then they venture into the mosses, which contain moisture and food through plant debris and spores. As these myriapods are initially adapted to aquatic life, they must evolve. They develop an external skeleton and a different way of breathing. Myriapods are equipped with a system of respiratory tubes, called tracheae. Each tube leads to the side of the carapace and divides into an increasingly fine network that leads to organs and tissues, even penetrating into each cell to bring oxygen to them.






In today's program:
00:00 Introduction
01:40 Who are insects?
04:07 The emergence of insects and their evolution.
11:36 The wings of insects
14:47 Fauna, flora and giant insects in the Carboniferous period.
19:55 The Carboniferous Flora
25:37 The richness of the Carboniferous flora implicated in the phenomenon of gigantism
27:15 What are giant insects?
27:28 Arthropleura
28:45 Meganeura monyi
31:58 Pulmonoscorpius
32:55 Megarachne
33:40 Giant insects are not alone...
34:31 Marine life
40:40 Terrestrial Fauna
43:40 A great novelty in animal life: the appearance of the amniote
48:37 The causes of the disappearance of giant insects
49:52 Oxygen levels in the atmosphere decline
52:22 The Permian Mass Extinction
54:25 The emergence of new winged predators
57:19 Appearance of the first birds and bats
01:02:15 The emergence of flowering plants
01:05:10 Do giant insects still exist?


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