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Biogeography: where life lives

Biogeography explores the distribution of plants, animals, and organisms across Earth. New islands form habitats for unique species, like Galápagos finches and Hawaiian honeycreepers. Continental drift explains related species on different continents, with Pangaea's breakup separating organisms. Phylogenetic trees help trace species' movements, revealing Earth's dynamic biodiversity. Created by NOVA.

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  • blobby green style avatar for user Mohammad Najm
    So was there any certain event that caused pangea to separate into different continents?
    (5 votes)
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    • piceratops ultimate style avatar for user Hecretary Bird
      Pangea is just one in a long list of supercontinents going back to when plate tectonics first started somewhere around 3-3.5 billion years ago. It was made of many tectonic plates, and when those began to drift apart due to the convection currents in the mantle, Pangea split.
      (10 votes)
  • starky seed style avatar for user Ricardo
    I don’t understand biogeography very well.
    (3 votes)
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    • blobby green style avatar for user Cat lover
      Biogeography basically means the way that organisms have been able to adapt and evolve to different (and changing) geographical locations. As Pangaea, the first continent on earth, split apart, species diversity grew, as some organisms had to adapt to their new conditions; sometimes evolving to have completely different traits to their counterparts across the globe, such as the Galapagos finches featured in the video. Natural selection also plays a big part, ensuring that only the fittest (most able to survive and reproduce) can live, thus creating a rich biodiversity across the world.
      (2 votes)

Video transcript

Next up—biogeography. Well, biogeography is the study of how animals, plants and other organisms have come to occupy the places on the globe that they do. Imagine a new island being born in the middle of the ocean. At first, it’s a hunk of rock. Lifeless. But gradually, seeds and insects and small animals, originating from nearby landmasses, get blown over on the winds. They come crashing ashore, pushed by the waves. Not all the organisms make it, but those that do, with time, adapt to island living, perhaps even evolving into new species. Just take birds. There are the finches of the Galápagos Islands, the birds of paradise of Papua New Guinea, the honeycreepers of Hawaii, and so on. In each case, a single island species diversified into an array of species found nowhere else on Earth. Biogeography’s also got something to say about why some closely related species flourish on different continents. It seems odd. Until you recall that Earth didn’t always look this way. A few hundred million years ago, all land was part of Pangaea—a hulking supercontinent. There were no vast oceans to interfere with the movements of organisms. But then, starting about 170 million years ago, the continents drifted like vast rafts across the sea. And the species living along the edges—they were split in two. Fast-forward to the present day, and you get a plant in South America whose close relatives grow in the tropical Pacific. We can use phylogenetic trees as sort of maps to help us reconstruct the movements of organisms across the planet.