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Biology 2 - Midterm > Lecture 4: History of life on Earth > Flashcards

Lecture 4: History of life on Earth Flashcards

(80 cards)

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1
Q

What are the 3 first eon?

A

1-Hadean
2-Archaean
3-Proterozoic (early life)

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2
Q

What are the 3 ears of Phanerozoic eon?

A

-Paleozoic (ancient life)
-Mesozoic (age of reptiles)
-Cenozoic (recent life)

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3
Q

What represents the major boundaries between different eras?

A

Major extinctions events

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4
Q

During the Hadean eon what made the origin of life possible?

A

-Water vapour was in the atmosphere and form the ocean

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5
Q

What were the key event during the Archean Eon that made origin of life possible?

A

-Formation of Earth’s crust began
-All life was in the ocean – no oxygen in the atmosphere
-PHOTOSYNTHESIS
starts production of oxygen
dissolved and interact with iron in oceans

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6
Q

During the Proterozoic eon what made the origin of life possible?

A

-oxygen starts to accumulate in the atmosphere
Great oxygenation atmosphere
-land constantly bombarded by UV radiation
-ozone forms
-Multicellulary and Sexual Reproduction

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7
Q

What caused the great oxygenation event?

A

*extinctions of prokaryotes poisened by oxygen
*evolution of Eukaryotes

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8
Q

What is the advantage of the ozone layer?

A

gave protection to the organisms

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9
Q

During the Phanerozoic Eon what is the main thing that allowed life on Earth?

A

the dense ozone layer

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10
Q

What main event occurred during Paleozoic era?

A

*Cambrian explosion
-emmerge of more complex animals
-colonization of land by plants

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11
Q

What defines the Mesozoic era?

A

-dinosaurs
-flowering plants
-small mammals

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12
Q

What is the main principle that allowed origin of life?

A

chemical evolution

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13
Q

What is the chemical evolution?

A

simple chemical compounds combined – form more complex carbon containing substance – accumulated in the ocean

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14
Q

What are the four main stages of the Evolution of the cell?

A

1-Early organic molecules
2-Abiotic synthesis of macromolecules
3-Protocells
4-Self-replicating RNA

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15
Q

What were the conditions on early Earth?

A

-carbon dioxide
-water vapour
-hydrogen gaz
**Atmosphere is REDUCING the availability of Hydrogen atoms – form bonds

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16
Q

What was the goal of the Miller and Urey experiment?

A

to recreate the early atmosphere

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17
Q

What were the 3 thins Miller and Urey put in place to reproduce the early atmosphere?

A

-placed atmosphere over liquid level
-maintain this mixture below 100 degree celcius
-simulated lightning by bombarding it with energy spark

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18
Q

What was the condition Miller and Urey tried to reproduce?

A

atmosphere HIGH in hydrogen and LOW in oxygen

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19
Q

What was the conclusion of the Miller/Urey experience?

A

that key molecules have formed on early earth by the synthesis of organic compounds

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20
Q

What was the result of the experience?

A

adenine was produce – 15% of the gas methane was converted to simple carbon compounds

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21
Q

What are the 3 main points of abiotic synthesis of macromolecules?

A

-amino acids found in meteorites
-RNA monomers have been produced from simple molecules
-Small organic molecules polymerize – concentred on hotsand clay or rocks

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22
Q

What key element of protocells happens when you put lipids and other organic molecules in water?

A

spontaneously form vesicles with a lipid bilayer

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23
Q

What key role vesicle have?

A

exhibit simple reproduction and metabolism and maintain an internal chemical environment

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24
Q

What are two key properties of life and that may have appeared together?

A

-Replication
-Metabolism

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25
What is the result of adding clay to form vesicle?
increase the rate of self-vesicle formation
26
What was the first genetic material?
RNA
27
Why RNA is considered "better" than DNA?
-More stable genetic material -Replicate DNA more quickly
28
Enumerate the 6 events of History of life on Earth?
1-First single celled organisms (prokaryotes) 2-Photosynthesis and the oxygen evolution 3-First Eukaryotes 4-Early multicellular eukaryotes 5-Cambrian Explosion 6-Colonisation of land
29
What are the roles of ribozymes? (RNA enzymes)
*make copies of RNA and catalyze different reactions
30
What provided the template for DNA?
RNA
31
What are the 3 monophyletic clades (Domains)? *Descendants of LUCA
-Bacteria -Archea -Eukarya
32
What arose in the Archean eon?
progenitor of life on earth
33
What is LUCA?
scientist hypothesis the existence of last universal common ancestor
34
What were the first organisms?
single celled prokaryotes that lived in the ocean
35
What are stromatolites?
oldest fossils: layered rock that form when certain prokaryotes bind thin film of sediment together
36
How O2 was produced in the oxygen revolution?
by oxygenic photosynthesis in organisms similar to cyanobacteria
37
What was caused by the "Oxygen revolution"?
extinction of prokaryotic group
38
What was the key role of cellular respiration?
to harvest energy -- so some groups can survive
39
What was caused by the later increase in atmospheric O2?
evolution of eukaryotic cells containing chloroplast
40
Where were the first appearance of eukaryotes?
in microfossils
41
What are the main characteristics of the eukaryotic cell?
-mitochondria -nuclear envelope -endoplasmic reticulum -cytoskeleton
42
What is the key event that lead to complex eukaryotic cells?
loss of rigid cell wall that allowed membrane to fold inward -- increasing the surface area
43
What is the main advantage of the membrane flexibility?
made it possible for one cell to engulf another
44
What is the origin of the nucleus and the ER?
arisen from inflating of plasma membrane in prokaryotic cells
45
How was the formation of the nucleus?
surrounding of the prokaryotic DNA by the cell's membrane
46
How did the endoplasmic reticulum formed?
infolding of the plasma membrane
47
What is the endosymbiotic theory?
evolution of modern eukaryotic cells and symbiotic bacteria
48
How did the mitochondria evolved via endosymbiosis?
aerobic bacteria engulfed by larger bacteria
49
How did the chloroplast evolved via endosymbiosis?
-primary endosymbiosis (larger bacteria engulfed smaller bacteria) -Secondary endosymbiosis (engulfed a organisms that already has a chloroplast)
50
In mitochondria, what did the host supply?
protection and carbon compounds
51
What process did the mitochondria used to produce more ATP?
cellular respiration
52
What is the origin of the chloroplast?
protist engulfed a cyanobacterium
53
What is the principle of secondary endosymbiosis?
organisms engulfs a photosynthetic eukaryotic cell -- retains its chloroplast as intracellular symbionts
54
How many membranes does the chloroplast of the secondary endosymbiosis has?
4 membranes
55
What are the 4 key evidences supporting endosymbiosis idea of mitochondria and chloroplast
*Inner membranes are similar to plasma membranes of prokaryotes *Division + DNA structure are similar in these organelles and prokaryotes *These organelles transcribe and translate their own DNA *Ribosomes are more similar to prokaryotic than eukaryotic
56
When did the second wave of diversification happen?
when multi cellularly evolved and give raise to plants, fungi, algae and animals
57
What are the two things that are increased by sexual reproduction?
-genetic diversity by meiosis + crossing over -pace of evolution
58
What did the evolution of multicellular allowed?
organisms to deal with their environments in ways through differention of cell types into tissues and organs
59
What happened during the Cambrian explosion?
a sudden appearance of fossils ressembling modern animals phyla
60
What are 3 characteristics of the bilaterians organisms?
-complete digestive tract -one way digestive system -bilaterally symetric form *All confined in the ocean
61
What are the approximative date of the Cambrian explosion?
535 to 525 MYA
62
What provided evidence of the Cambrian explosion?
predator-prey interactions
63
What is the Burgess Shale?
fossils from both hard-body shells and soft tissues in the same place
64
What happened during the colonisation of land (500 MYA)?
fungi, plants and animals began to colonize land moving from an aquatic environment
65
How did the gas exchange adapt during the colonisation of land?
gills to lungs
66
What is the order of appearance of the colonisation of land by plants?
alga -- nonvascular plants -- vascular seedless plants -- vascular seed plants
67
What are the Carboniferous forests?
*first swampy forest -- increased growth and photosynthesis removing CO2 from the atmosphere
68
How did plankton formed?
oil deposit formed plankton falling at the bottom of the ocean
69
Compare the rate of productivity compared to the rate of decomposition
rate of productivity > rate of decomposition
70
The rise and fall of groups of organisms are the reflection of what?
differences in speciation and extinction rate within one group
71
Define mass extinction
its a result of disruptive global environmental changes
72
What are the main causes of mass extinction? (4)
-ocean/atmosphere chemistry -climate change -volcanic activity -meteor/ asteroids impacts
73
What causes extinction?
changes to a specie's environment
74
What showed that most species have ever lived are not extinct?
fossil records
75
How many mass extinctions occurred through the history of earth?
5
76
What is the main evidence that we are now experiencing a 6th mass extinction? (2)
-global temperatures increase -human-caused
77
What are the 5 mains consequences of mass extinction?
*alter ecological communities + niches available to organisms *5 to 100 millions years for diversity to recover *change types of organisms found in communities *lineages with novel + advantageous features can be lost *Adaptive radiation
78
What is the principle of adaptive radiation?
rapid evolution of diversely adapted species from a common ancestor
79
Describe the role of the break up of Pangaea by Continental drift?
separated marsupials from eutherian mammals since marsupials were isolated from the rest of the world, it contributed to shape different evolutionary paths
80
What was special about the eutherian mammals?
that they give birth to young that nourished by the placenta during gestation

Biology 2 - Midterm (5 decks)

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