chapter 19

Question 0

explain the process by which fossils are formed

Answer 0

sediment is transferred by water and the hard parts are replaced with minerals (layer=strata)

Question 1

compare the 5 different types of fossils

Answer 1

permineralized- minerals are carried by water and decompose around structure (bone to rock)

natural casts- flowing water removes original tissue

trace fossils- record of activity of organisms

preserved remains- found in ice or peat bog

amberpreserved- preserved in tree resin

Question 2

what types of info can paleontologists determine from fossils

Answer 2

structure
diet
predators
environment

Question 3

distinguish between relative and radioactive dating

Answer 3

relative- age is determined by placement of fossils, lower layers contain older examples, and index fossils are used to compare ages

radioactive- uses radioactive isotopes to age fossils, they decay into nonradioactive elements at a steady rate

Question 4

what is the half life of C14

Answer 4

5730 years

Question 5

what other isotopes can be used to date older fossils

Answer 5

potassium 40
uranium 238
rubidium 87

Question 6

describe the nebula hypothesis

Answer 6

gas and dust were swirling. some collided to build up and melt together. elements then arranged according to density

Question 7

what allowed the oceans and skies to become blue

Answer 7

oceans- oxygen reacted with the iron in the oceans and it rusted. it sunk to the bottom

sky- the ozone formed ad oxygen levels increased, methane and hydrogen sulfide decreased causing sky to become blue

Question 8

what was oparins hypothesis

Answer 8

gases went under chemical reactions, lighting then struck primitive oceans creating life (primordial soup model)

Question 9

what was sydney fox’s contribution to the history of life

Answer 9

suggested that protenoid microspheres could have given rise to first cells

Question 10

why do scientists think RNA evolved first

Answer 10

simpler
can help DNA replicate
can replicate itself (ribosome)
its a catalyst

Question 11

what were the first organisms formed on earth

Answer 11

prokaryotic heterotrophs

Question 12

what led to the first mass extinction

Answer 12

oxygen levels increased, methane and hydrogen sulfide decreased forming ozone. many died due to the presence of oxygen

Question 13

describe lynn margulis’ theory

Answer 13

a large prokaryote consumed a smaller. host didnt digest and smaller didnt infect. evidence comes from mitochondria & chloroplast
(both have own dna and ribosomes similar to bacteria and can replicate independent of cell)

Question 14

why is sexual reproduction important to evolution

Answer 14

it allowed it to occur at a faster rate which led to greater genetic diversity

Question 15

what about the process of fossil formation makes the fossil record so incomplete

Answer 15

its a unique process, so some species may not have been fossilized. soft body organisms couldnt become fossils

Question 16

list the geological time scale from largest to smallest

Answer 16

eon, era, period

Question 17

what allowed primitive earth to cool

Answer 17

growing atmosphere

raining for millions of years

Question 18

why is the precambrian time so incomplete

Answer 18

there are few soft fossils because they were all soft bodied organisms

Question 19

what major event took place during the cambrian period

Answer 19

cambrian “explosion”

organisms developed hard parts and there were inverts (jellyfish, worms, brachiopods, trilobites, sponges)

Question 20

when did the first land plants evolve

Answer 20

ordovician and sulurian periods

Question 21

which period is known as the age of fishes

Answer 21

devonian period

Question 22

when did animals move to land

Answer 22

devonian period

Question 23

when did reptiles and winged-insects evolve

Answer 23

carboniferous and permian periods

Question 24

which period is known as the age of reptiles

Answer 24

triassic period (mesozoic era)

Question 25

when did the first birds evolve

Answer 25

jurassic period (close to dinosaurs)

Question 26

when did flowering plants evolve

Answer 26

cretaceous period (another mass extinction, 1/2 disappeared)

Question 27

when did dinosaurs go extinct

Answer 27

cretaceous period (mesozoic era)

Question 28

when did whales and dolphins evolve

Answer 28

tertiary period (cenozoic era)

Question 29

when did the ice ages occur

Answer 29

quarternary period (cenozoic era)

Question 30

what are the characteristics of primates

Answer 30

long fingers and toes
nails not claws
arms can rotate around shoulder joints
strong clavicle(stabilize shoulder)
binocular vision
well-developed cerebrum

Question 31

what are the 2 major groups of primates

Answer 31

prosimians (lemurs, lorises, tarsiers)

anthropoids (human-like primates)

Question 32

distinguish between new and old world monkeys

Answer 32

new world- central and south america, live almost entirely in trees, have prehensile tails (spider monkey)

old world- africa and asia, sometimes in trees, lack prehensile tails (langurs, macagues)

Question 33

what makes humans different from other hominoids

Answer 33

changes in skeleton allowed for bipedalism

opposable thumbs

larger brains

Question 34

list the ancestors of humans and characteristics of each

Answer 34

Homo habilis- used tools
Homo ergaster- larger brain, downward facing nostrils
Homo erectus- migrated out of africa
Homo neaderthalensis- cave man
Homo sapien- skeletons identical to ours

Question 35

how did members of the genus Homo change over time

Answer 35

used tools
developed larger brain
smaller jaw
migrated

Question 36

describe how miller and urey tested oparins hypothesis

Answer 36

they boiled a flask of water

added methane, ammonia, and hydrogen to water vapor

passed gases through electrodes to simulate lightning

passed through condensation chamber cooling and forming drops

produced 21 amino acids