Dinosaur Glossary H - M

H

Habitat
A habitat is a space (which includes food, water and shelter) suitable for the survival and reproduction of an organism.

Hadrosaurids
A group of dinosaurs from the late Cretaceous period that were ornithischian, herbivorous and had a wide, flat beak that earned them the nickname of "duck-billed dinosaurs". They could walk on either two or four legs. The maiasaur is part of the hadrosaurid family.

Herbivores
Herbivores are animals that eat plants. Most dinosaurs were herbivorous (plant-eating).

I

Ice Age
An ice age is a time lasting thousands of years during which the Earth is very cold and largely covered by ice and glaciers.

Ichnology
The study of fossilized footprints.

Ichthyosaurs
Sea-dwelling, prehistoric reptiles. Ichthyosaur means "fish-lizard".

Igneous Rock
When molten rock (lava) cools, igneous rock is formed.

J

Jurassic Period
A geological period of the Mesozoic Era, between about 200 and 135 million years ago. Dinosaurs flourished during this time.

K

Kingdom
The highest group of like-organisms in scientific classification. Dinosaurs are part of the Animal Kingdom.

K-T Extinction
The mass extinction that marked the end of the Cretaceous period, about 65 million years ago.

L

Lava
Molten rock which reaches the Earth's surface through erupting volcanoes.

Living Fossil
A living fossil is an organism that lived during ancient times and still live today, relatively unchanged, like the horseshoe crab.

M

Magnetic Field
The Earth's magnetic field is aligned with the north and south poles, and has reversed many times during geologic history. A fossil's magnetic orientation can give clues to its date.

Mass extinction
Mass extinction is the process in which huge numbers of species die out suddenly. The dinosaurs (and many other species) became extinct, probably because of an asteroid that hit the Earth.

Mesozoic Era
The Mesozoic Era ("The Age of Reptiles"), occurred from 248-65 million years ago. It is divided into the Triassic, Jurassic, and Cretaceous Periods. Dinosaurs, mammals and flowering plants evolved during the Mesozoic Era.

Meteor
A interplanetary rock or dust particles create a streak of light in the night sky sometimes called a shooting star. Most burn up before hitting the Earth.

< Back | Next >

Dinosaur Digs