history of life

Question 1

life may have happened in 4 stages on earth

Answer 1

1. creation of small organic molecules
2. joining of organic molecules into polymers
3. packing polymers into protocells
4. origin of self replicating molecules

Question 2

hypothesis of 1. creation of small organic molecules

Answer 2

early atmosphere are mostly N and CO2, which forms energy when combined with amino acids (amino acids form around sea volcanoes or in space)

Question 3

hypothesis of 2. joining of organic molecules into polymers

Answer 3

hot rocks or clay could have provided energy to form polymers
-RNA polymers
-amino acid polymers

Question 4

hypothesis of 3. packing polymers into protocells

Answer 4

hydrophobic/hydrophillic lipids mixed in water ca form vesicles (and clay can improve vesicle formation rate). the vesicles can grow if lipids are added and reproduce if they are cut in half. RNA attached to clay can enter vesicle

Question 5

hypothesis of 4. origin of self replicating molecules

Answer 5

ribozyme (RNA enzyme) can code for proteins and RNA molecules may encourage self replication

Question 6

panspermia hypothesis

Answer 6

life arrived from elsewhere in the universe

Question 7

fossilized stromatolites
-how long ago?
-what is it?

Answer 7

-3.5 billion Y.A
-layers of prokaryotes and sediment

Question 8

after fossilized stromatolites, no other fossil evidence for ___ years

Answer 8

1.5 billion

Question 9

oxygen revolution:
- ___ adds oxygen to atmosphere
- first oxygen absorbed by ___ and ___ minerals
- oxygen then entered atmosphere when ___ and ____ were ______
- oxygen killed many _____
-oxygen enabled new ______ (cellular respiration)

Answer 9

-photosynthesis
-water and iron
-water and iron were saturated
-prokaryotes
-lifestyles

Question 10

earliest eukaryotes were ____ years ago

Answer 10

1.8 billion

Question 11

endosymbiosis

Answer 11

eukaryotic organelles formed when small prokaryotes lived inside large prokaryotes

Question 12

endosymbiosis started as a ___ relationship between species.

Answer 12

symbiotic

Question 13

serial endosymbiosis: ___ first, ___ later

Answer 13

mitochondria first, chloroplasts later

Question 14

evidence of endosymbiosis:

Answer 14

-membrane of enzymes are similar to bacteria
- has circular DNA like prokaryotes
-contains ribosomes that are Dif from eukaryotic ribosomes
-double membrane

Question 15

first multicellular eukaryotes

Answer 15

-first red algae (1.2 billion Y.A)
-ediacaran biota (600 million Y.A)

Question 16

what is an ediacaran?

Answer 16

multicellular eukaryote
soft bodied
some over 1m long

Question 17

Cambrian explosion

Answer 17

explosion of animal groups 530 million years ago

Question 18

some examples of animals from the Cambrian explosion

Answer 18

sponges, mollusks, cnidarians, arthopods

Question 19

Cambrian explosion:many groups probably evolved earlier, BUT…

Answer 19

this was the first time they were turned into fossils (likely due to some disaster)

Question 20

evidence that many animals had already adapted before Cambrian explosion?

Answer 20

many fossils had developed defenses/methods of hunting

Question 21

when did multicellular life colonize land?

Answer 21

about 500 million years ago

Question 22

to colonize land, they had to learn how to

Answer 22

trap water inside

Question 23

order of organisms that colonized land

Answer 23

1.plants and fungi
2. arthropods
3. amphibians

Question 24

when looking at mass extinctions, what do we compare and why?

Answer 24

we compare marine genera lost since 2 of the mass extinctions occurred before anything colonized land

Question 25

how many mass extinctions?

Answer 25

5

Question 26

permian mass extinction loss

Answer 26

-more than half of marine genera were lost
-96% of known species were lost

Question 27

what caused permian mass extinction?

Answer 27

massive volcano (Siberian traps) released 160 trillion tons of CO2, leading to huge atmospheric warming
-oceans were 100F
-ocean were super acidic

Question 28

cretaceous mass extinction loss

Answer 28

killed the dinosaurs (except birds)

Question 29

what caused the cretaceous mass extinction ?

Answer 29

impact of large meteorite in Mexico, huge wave covered a lot of North America, dust and ash blocked sun, triggered volcanoes in India (Deccan traps)

Question 30

after an extinction, what usually happens?

Answer 30

adaptive radiation: species adapt to new conditions

Question 31

how long does recovery take after mass extinction?

Answer 31

5 million years