Chapter 7

Question 1

aerobic organisms

Answer 1

need oxygen

Question 2

anaerobic

Answer 2

do not need oxygen

Question 3

first cells

Answer 3

anaerobic prokaryotes: cyanobacteria

Question 4

endosymbiosis theory

Answer 4

one cell engulfed a smaller cell and they developed a symbiotic relationship; ex: mitochondria in animal cells

Question 5

Precambian Era

Answer 5

unicellular organisms, sponges, jellyfish

Question 6

Paleozoic Era

Answer 6

oceans full of life, seed plants, amphibians then reptiles

Question 7

Mesozoic Era

Answer 7

dinosaurs, small mammals, birds

Question 8

Cenozoic Era

Answer 8

mammals flourish, primates and hominids appear

Question 9

252 mya

Answer 9

Permian extinction takes out 90% of all species

Question 10

3.5 bya

Answer 10

first prokaryotic cells appear

Question 11

2.5bya

Answer 11

cyanobacteria create enough oxygen to create Earth’s atmosphere

Question 12

1.5 bya

Answer 12

first eukaryotic cells appear

Question 13

.5 mya

Answer 13

first homo sapiens appear

Question 14

the more precise method of dating

Answer 14

absolute dating

Question 15

relative dating

Answer 15

does not provide exact age; depends on how deep the fossils were found in the ground to get an estimate

Question 16

absolute dating

Answer 16

measures the decay of radioactive materials to provide an age in years