Q:

When did dinosaurs roam the earth?

A:

Dinosaurs first walked the earth 230 million years ago and dominated the land for 160 million years. They became extinct 65 million years ago during the Cretaceous period.

The three ages of the dinosaurs include the Triassic, Jurassic and Cretaceous. These periods fall under the Mesozoic Era, which lasted from 250 to 65 million years ago. Dinosaurs evolved from lizards known as archosaurs, having developed quadrupedal or bipedal posturing. It's believed that reptiles began exhibiting dinosaur and archosaur traits during the middle of the Triassic. Early dinosaurs can be categorized as therapods, bird-hipped dinosaurs and herbivores, among other categories. Therapods evolved into tyrannosaurs, Allosaurus, dino-birds and raptors. Herbivore dinosaurs existed in greater numbers than therapods. Bird-hipped dinosaurs included ornithopods and ankylosaurs.


Is this answer helpful?

Similar Questions

  • Q:

    How long did dinosaurs live?

    A:

    It is almost impossible to tell exactly how long dinosaurs lived, but educated guesses can be made by studying the lifespans of their descendants. This group includes modern alligators, tortoises, fish and birds. Scientists are studying the rings of dinosaur bones much like trees are studied for their rings.

    Full Answer >
    Filed Under:
  • Q:

    When did the first animals appear on Earth?

    A:

    The first occurrence of simple animals was approximately 600 million years ago. These were characterized as multi-cellular organisms with basic structures, but no true tissues. An example would be a jellyfish or marine sponge.

    Full Answer >
    Filed Under:
  • Q:

    When did the first land animals appear on Earth?

    A:

    According to Earth System Science Education, the first land animals appeared toward the middle of the Paleozoic Era, in the late Silurian period. The earliest animals to adapt to the land were small arthropods similar to mites, spiders and scorpions.

    Full Answer >
    Filed Under:
  • Q:

    When did plant life begin to appear on Earth?

    A:

    Plant life first appeared on land during the Ordovician period, between 495 and 443 million years BCE. One 2001 study from Penn State University claims that plants and fungi first appeared on land 700 million years BCE, but this has not yet become accepted by the larger scientific community.

    Full Answer >
    Filed Under:

Explore