Chapter 25 Flashcards Preview

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Flashcards in Chapter 25 Deck (13):
1

what are some examples of macroevolutionary changes over large time scales (not proven)

-emergence of terrestrial vertebrates
-impact of mass extinctions
-origin of flight in birds

2

fossil record reveals ....

changes in the history of life on Earth

3

sedimentary rocks are deposited into layers called ____

strata
---and are the richest source of fossils

4

few individuals have fossilized
-fossil record is biased in favor of species that...

1. existed for a long time
2. were abundant and widespread
3. had hard parts

5

sedimentary strata reveal...

the relative ages of fossils

6

radiometric dating

The absolute ages of fossils can be determined by this
-A “parent” isotope decays to a “daughter” isotope
at a constant rate

7

half life

Each isotope has a known half-life, the time required for half the parent isotope to deca

8

radiocarbon dating can be used to date fossils up to ....

75,000 years old

9

cambrian explosion

refers to the sudden appearance of fossils resembling modern animal phyla in the Cambrian period (535 to 525 million years ago)

10

continental drift has many effects on living organisms

– A continent’s climate can change as it moves
north or south
– Separation of land masses can lead to allopatric speciation

11

Extinction can be caused by

changes to a species’
environment

12

mass extinction can _____ and _____

Mass extinction can alter ecological communities and the niches available to organisms

13

adaptive radiation
*what three things might it follow?

-organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.
• Adaptive radiations may follow
– Mass extinctions – The evolution of novel characteristics – The colonization of new regions