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GED > Lecture 3- Origin of species > Flashcards

Lecture 3- Origin of species Flashcards

1
Q

How many years ago did Earth arise?

A

4 billion years ago

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2
Q

how many years did deep sea arise?

A

3.8/ 4.2 billion years ago

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3
Q

where did energy to fuel the first few replicating molecules come from?

A

proton gradients around alkaline hydrothermal vents- ‘Lost City’ in mid- Atlantic (where weird bacteria has been identified)

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4
Q

Darwin’s hypothesis of the beginning of Earth

A

Earth was a warm muddy pond

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5
Q

what brought water forming oceans in the beginning of earth

A

bombardments by comets and asteroids

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6
Q

what was the basis for reproduction before DNA

A

RNA

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7
Q

why is there no pure RNA organisms

A

RNA has a short life cycle of only a matter of weeks so there would be be little time for mutations

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8
Q

time line of the RNA world

A
  1. complex organic molecules produced by random chemistry
  2. RNA world
  3. RNP world
  4. LUCA (last universal common ancestor)
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9
Q

LUCA

A

last universal common ancestor ( a population of single-celled DNA organisms that lived approx 3.8 billion years ago)

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10
Q

what did earliest life use as enzymes

A

RNA so they could copy themselves

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11
Q

when were amino acids used

A

after the RNA world (formed spontaneously)

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12
Q

which is more fragile: DNA or RNA

A

RNA

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13
Q

how can you have a cell without DNA?

A

-tiny pores in rocks around vents
-lipid protobionts can reproduce and metabolise
-RNA can spontaneously reproduce within them

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14
Q

how old is the universe?

A

14 billion years old

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15
Q

how old is life?

A

3.8 billion years old

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16
Q

what does life need to survive?

A

cool temperatures, gravity, water, protection from radiation

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17
Q

how long did it take for multicellular organisms to appaear?

A

over 2 billion years

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18
Q

origin of oxygen

A

unknown

19
Q

when did the great oxidation event occur

A

around 2.5 billion years ago

20
Q

great oxidation event

A

high levels of oxidised rocks in the Earth’s surface

21
Q

first prokaryotes

A

methane-producing bacteria

22
Q

which algae produced oxygen

A

cyanobacteria (blue-green algae)

23
Q

which bacteria consumed most of the oxygen

A

methanogenic bacteria

24
Q

why do most methanogens eventually die out

A

due to changes in trace metals in sea

25
Q

are most eukaryotes unicellular or multicellular

A

unicellular but some are multicellular

26
Q

individual cells of eukaryotes are …. times the volume of a prokaryote

A

1,000,000

27
Q

what is the common hypothesis for the evolution of eukaryotes

A

an archaebacterium engulfed a heterotrophic eubacterium, which eventually became mitochondria
-the energy provided by mitochondria allows for complex life

28
Q

what is the hypothesis for the evolution of eukaryotic plants

A

autotrophic eubacterium engulfed by eukaryotic plant ancestor

29
Q

why is the creation of eukaryotes a chance event

A

combination of different types of bacteria

30
Q

did natural selection create eukaryotes?

A

no

31
Q

what did natural selection act on (in the creation of eukaryotes)

A

individuals/ populations that were created by chance events

32
Q

when was Ediacaran biota (early eukaryote)

A

570 My

33
Q

Ediacaran life

A

Spriggina
- annelid worm?
- arthropod?
- 3cm long

34
Q

Dickinsonia: early eukaryotes

A

Can reach up to 1m in length
Molecules from rock were recently shown to be animal in origin (produced cholesterol)

35
Q

Rangeomorphs (early eukaryotes)

A

fractally branched, vaguely fern-like but lived in the dark depths. Ecology and growth patterns suggest they were animals

36
Q

Erniettomorphs (early eukaryotes)

A

-modular or quilted

37
Q

why are rangeomorphs and erniettomorphs, not plants?

A

-live deep in the sea
-not plants as they lived too deep therefore aren’t possible to photosynthesise

38
Q

Cambrian explosion

A

20-30 million years ago when most of the types of animals we now see first appeared
-e.g arthropods, chordates, worms
- appearance of soft body organisms ( preservation in Burgess Shale, China, Greenland, Russia)
-not all species fir into modern taxonomies

39
Q

examples of species that don’t fit in modern taxonomies

A

opabinia
-first reconstruction in 1972
-7cm long

40
Q

physiological theories of the Cambrian explosion

A

dissolved oxygen levels to allow active lifestyle

41
Q

geographical theories of the Cambrian explosion

A

new seas and new niches

42
Q

geochemical theories of the Cambrian explosion

A

sea level changes leads to abundance of trace metals to make exoskeletons

43
Q

biological theories of the Cambrian explosion

A

increase in zooplankton allows new predators to arise, increasing selection pressure

GED (14 decks)

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