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  • If insects suddenly morphed into large beings,

  • and decided to wage war on us,

  • there's no doubt that humans would lose.

  • We'd simply be crushed by their sheer numbers.

  • There are an estimated 10 quintillion individual insects on Earth.

  • That's a one followed by 19 zeroes.

  • So, compared with our population of about 7 billion,

  • these invertebrates outnumber us by more than a billion to one.

  • Their astounding numbers exist at the species level, as well.

  • There are more than 60,000 vertebrate species on the planet.

  • But the class of insects contains a million known species,

  • and many others that haven't been classified.

  • In fact, these critters make up approximately 75% of all animals on Earth.

  • So, what's their secret to success?

  • Insect abundance comes down to many things

  • that together make them some of the most adaptable and resilient creatures,

  • beginning with their impressive ability to breed.

  • Many species can produce hundreds of offspring within their lifetimes.

  • Most offspring will die,

  • but more than enough will survive into adulthood to reproduce.

  • Offspring also mature very rapidly,

  • so the cycle of reproduction resumes quickly,

  • and can occur over and over again in a short time.

  • These numbers mean that as a class,

  • insects harbor a tremendous amount of genetic diversity.

  • The different species contain a wealth of genetic data

  • that give them the necessary adaptations they need to thrive

  • in a range of environments across the planet.

  • Even some of the most extreme environments are in bounds;

  • Flat bark beetles can live at -40 degrees Fahrenheit,

  • Sahara Desert ants can venture out

  • when surface temperatures exceed 155 degrees,

  • and some bumblebees can survive 18,000 feet above sea level.

  • Insect exoskeletons also work like body armor,

  • protecting insects against the outside world

  • and helping them cope with habitats that other creatures can't.

  • Even their small size,

  • which we might see as a disadvantage,

  • is something they use to their benefit.

  • Because most species are so tiny,

  • millions of insects can inhabit a small space

  • and make use of all the available resources within it.

  • This means they can occupy hundreds of different niches across ecosystems.

  • Some insects survive by eating the roots,

  • stems,

  • leaves,

  • seeds,

  • pollen,

  • and nectar of specific plants.

  • Others, like wasps,

  • make use of live insects by paralyzing the victims

  • and laying their eggs inside

  • so that when the hatchlings emerge,

  • they can eat their way out and get nourishment.

  • Mosquitos and biting flies feed on blood,

  • taking advantage of this unusual resource to ensure their survival.

  • And a whole bunch of other insects have built a niche around feces.

  • Flies lay their eggs there,

  • and some beetles even build large balls out of animal dung,

  • which they eat and use as accommodation for their eggs.

  • And then there's the insects' mighty power of metamorphosis.

  • This trait not only transforms insects,

  • but also helps them maximize the available resources in an ecosystem.

  • Take butterflies.

  • In their larval caterpillar form,

  • they chomp hungrily through leaves at a rapid rate

  • to help them grow and spin cocoons.

  • But when they emerge as butterflies,

  • these insects feed only on flower nectar.

  • Metamorphosis means the larvae and adults of one species

  • will never compete for the same resource,

  • so they successfully share an ecological niche

  • without limiting their own success.

  • This process is so efficient

  • that an incredible 86% of insect species undergo complete metamorphosis.

  • We're big and they're small,

  • so it's easy to forget that these critters are moving in their millions

  • all around us,

  • all the time.

  • But examine almost any patch of ground,

  • and you're sure to find them there.

  • Their numbers are immense, and their success is unmatched.

  • We may have to accept that it's insects,

  • not us,

  • that are the true conquerors of the planet.

If insects suddenly morphed into large beings,

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【TED-Ed】Why are there so many insects? - Murry Gans

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