Chapter 17

Question 1

node

Answer 1

points on a tree where branch points occur

Question 2

phylogeny

Answer 2

the actual evolutionary history of the organisms

Question 3

biogeography

Answer 3

the study of the natural geographic distribution of species

seeks to explain why particular organisms are found in some areas and not in others

Question 4

radiometric dating

Answer 4

the use of radioactive isotopes as a measure for determining the age of a rock or fossil

Question 5

radioactive isotopes

Answer 5

unstable form of an element that decays into another element by radiation, that is, by emitting energentic particles

Question 6

mass extinction

Answer 6

an extinction of between 50% and 90% of all species that occurs relatively rapidly

Question 7

half-life

Answer 7

the time it takes for one-half of a sample of radioactive isotope to decay

Question 8

extinction

Answer 8

the elimination of all individuals in a species

may occur over time or in a mass die off

Question 9

convergent evolution

Answer 9

the process by which organisms that are not closely related evolve similar adaptations as a result of independent episodes of natural selection

Question 10

mammals

Answer 10

members of the class mammalia
all members of this class have mammary glands and a body covered with hair/fur

Question 11

taxonomy

Answer 11

process of identifying, naming, and classifying organism on the basis of shared traits

Question 12

plate tectonics

Answer 12

movement of Earth’s upper mantle and crust, which influences the geographical distribution of landmasses and organisms

Question 13

punctuated equilibrium

Answer 13

periodic bursts of species change as a result of sudden environmental change

Question 14

adaptive radiation

Answer 14

spreading and diversification of organisms that occur when they colonize a new habitat

Question 15

sedimentary rock

Answer 15

where most fossils are found

Question 16

unicellular photosynthetic organisms

Answer 16

added oxygen to the atmosphere

Question 17

endosymbiosis

Answer 17

theory for when first eukaryotic cells appeared

Question 18

invertebrate animals

Answer 18

animals without a backbone

Question 19

multicellular eukaryotes

Answer 19

first was green algae (1.2 bya)

Question 20

volvox

Answer 20

modern colonial algae

may have resembled first multicellular eukaryotes

Question 21

Cambrian Explosiion

Answer 21

many diverse invertebrate animals appeared in the oceans

plants were the first to colonize land

Question 22

protists

Answer 22

species diversity may be immeasurable (along with bacteria and archaea)

Question 23

pangeae

Answer 23

all the continents were together at the beginning and called

Question 24

cretaceous extinction

Answer 24

led to the extinction of dinos after this mammals underwent adaptative radiation

Question 25

permian extinction

Answer 25

95% of all living species went extinct during this

then surviving organisms spread and diversified (adaptive radiation)

Question 26

eukaryote cells

Answer 26

first appeared about 2 billion years ago

endosymbiotic theory

Question 27

prokaryotes

Answer 27

first forms of life with fossils

dated at 3.5 billion years

Question 28

igneous rock

Answer 28

made from hardened lava