CH 225

Question 1

fossil record displays. . .

Answer 1

Macroevolution: evolution above the level of species

Question 2

Fossil limits

Answer 2

-relative age only
-not all things fossilize
-rare brief spp.

Question 3

How old is Earth?

Answer 3

~4.6 bya

Question 4

Steps of Origin of Life

Answer 4

small organic molecules -> macromolecules-> “protocells” -> origin of RNA

Question 5

Small organic molecules formed by. . .

Answer 5

-atmosphere (h2o vapor and chemicals, no 02)
-near submerged volcanoes and deep sea vents
-meteorites (carbonaceous chondrites)

Question 6

Abiotic synthesis of macromolecules

Answer 6

small organic molecules polymerized when concentrated in bubbles on ocean’s surface

Question 7

Protocells

Answer 7

-semi membrane bound vesicles of abiotically produced molecules
-simple reproduction and metabolism
-maintain internal chemical envt

Question 8

RNA and early natural selection

Answer 8

-1st gen material was probably RNA as ribozymes (catalyze reactions, self splicing, and replication of self and others)
-early protocells w/RNA (better competitors)

Question 9

Geo record order

Answer 9

-archaean eon
-proterozoic eon
- phanerozoic eon

Question 10

Phanerozoic eras

Answer 10

-Paleozoic
-Mesozoic
-Cenozoic

Question 11

Oldest fossil

Answer 11

Stromatolites (rock-like layer of bacteria and sediment)

Question 12

Where did photosynthesis likely evolve?

Answer 12

Cyanobacteria

Question 13

Effects of oxygen accumulation in atmosphere

Answer 13

-challenge for some life
-opportunity to use light energy
-new niches to occupy

Question 14

How did first eukaryotes come to be?

Answer 14

Evolved via internal membrane folding and serial endosymbiosis (mitochondria, chloroplasts)

Question 15

“Snowball earth” hypothesis

Answer 15

There was extreme glaciation in the time of early eukaryotes and life could only be found at hydrothermal vents

Question 16

Edicarion biota

Answer 16

Diverse soft bodied organisms

Question 17

Colonization of land order (500 million years ago)

Answer 17

-plants and fungi
-inverts
-verts
-mammals evolved

Question 18

Main causes of rise and fall of organisms

Answer 18

-plate tectonics and continental drift
-mass extinction
-adaptive radiation

Question 19

How many supercontinents have there been?

Answer 19

3

Question 20

How many major extinctions have there been?

Answer 20

5

Question 21

Permian extinction (251 mya)

Answer 21

-between Paleozoic and Mesozoic eras
-extinction of ~96% of marine spp.
-volcano driven global warming and drop in ocean O2

Question 22

Cretaceous Extinction(65.5 mya)

Answer 22

-separates Mesozoic from Cenozoic
-extinctions of half of marine spp. and many terrestrial plants and animals, including most dinosaurs

Question 23

Current rate of extinction

Answer 23

100 to 1000x typical rate
-35-150 a day

Question 24

Adaptive radiations

Answer 24

Evolution of diverse spp. from common ancestor as move into newly vacated niches