Chapter 5 Section 3 Flashcards Preview

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Flashcards in Chapter 5 Section 3 Deck (18):
1

usually only what parts of the organism become fossils

hard parts such as bones or shells

2

most fossils form how

when organisms that die become buried in sediments

3

what are sediments

particles of soil and rock

4

how do petrified fossils form

they form when minerals dissolved in water soak into the buried remains and gradually replace the remains changing them into rock

5

what is a mold

it is a hollow space in sediments in the shape of an organism or part of an organism

6

what is a cast

A cast is a copy of the shape of the organism that made the mold

7

organisms can be preserved in what

ice or other materials like amber or tree sap

8

what two ways can scientist determine a fossil's age

relative dating and radioactive dating

9

scientists use relative dating for what

to determine which of two fossils is older

10

radioactive dating is what

it is a technique used by scientists to determine the actual age of fossils

11

what are radioactive elements

they are unstable elements that decay, or break down, into different elements

12

what is the half life of an element

it is the time it takes for half of the atoms in a sample to decay

13

what is the fossil record

it is what the millions of fossils that scientists have collected is called

14

what does extinct mean

it is a term used to describe a species that has no members of it alive.

15

what is the calendar of the earth referred to as

the geologic time scale

16

what is a mass extinction

it is when many types of organisms become extinct at the same time

17

what is gradualism

it is a theory of evolution where evolution occurs slowly but steadily.

18

what is punctuated equilibria

it is a theory of evolution where species evolve rapidly and quickly in short periods of time.