Across
- 4. the end of an organism or of a group of organisms
- 8. a vertebrate animal of a class that includes snakes, lizards, crocodiles, turtles, and tortoises.
- 10. Any preserved evidence of life from a past geological age
- 11. age: The geologic age of a fossil organism, rock, or geologic feature or event defined relative to other organisms, rocks, or features or events rather than in terms of years.
- 15. an animal lacking a backbone, such as an arthropod, mollusk, annelid, coelenterate
- 17. a scientist who studies fossils.
- 19. of superposition: a basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom,
- 20. decay: any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product
- 22. the action or process of forcing a body of igneous rock between or through existing formations, without reaching the surface.
- 24. Words:
- 27. A fossil formed when an animal, plant, or other organism dies and is covered by sediment
- 29. The time required for half the quantity of a drug or other substance deposited in a living organism to be metabolized or eliminated by normal biological processes.
Down
- 1. the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
- 2. a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun
- 3. age: the true age of a rock or fossil
- 4. the movement of magma onto the surface of the earth through volcanic craters and cracks in the earth's crust, forming igneous rock.
- 5. fossil: a fossil that is useful for dating and correlating the strata in which it is found.
- 6. film: fossil found in any rock when organic material is compressed, leaving only a carbon residue or film
- 7. a major division of time that is a subdivision of an eon and is itself subdivided into periods.
- 9. an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
- 12. belonging to or characteristic of a past historical time, especially in style or design.
- 13. a surface of contact between two groups of unconformable strata.
- 14. extinction: a large number of species within a relatively short period of geological time
- 16. a warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, the secretion of milk by females for the nourishment of the young, and (typically) the birth of live young.
- 18. fossil: a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
- 21. A fossil formed when an animal, plant, or other organism dies, its flesh decays and bones deteriorate due to chemical reactions
- 23. a crack in a rock along which slippage has occurred.
- 25. a cold-blooded vertebrate animal of a class that comprises the frogs, toads, newts, and salamanders.
- 26. time scale: a system of chronological dating that relates noah macuha
- 28. fossil: a fossil through the replacement of the original material and the filling of the original pore spaces with minerals.