The History of Life Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

4.6 BYA

A

Sun and Planets Form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

4.6 - 3.9 BYA

A

Meteoritic bombardment and volcanic activity create reducing atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

by 3.9 BYA

A

reducing atmosphere(high in hydrogen content, no free oxygen, thick with water vapor)

  • H2O, CO2, CO, CH4, NH3, H, etc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3.9 BYA onwards

A

first cells appear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Steps from Inorganic to Cells

A
  1. Abiotic synthesis of small organic molecules.
  2. Single molecules(monomers) join with other molecules to produce polymers.
  3. Self replication.
  4. Polymers and monomers packed into a cell-like structure.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  1. Abiotic synthesis of simple organic molecules(monomers)
A

PROBLEM: Early scientists assumed that organic molecules are formed only by organic life.

SOLUTION: inorganic chemistry found to create organic compounds.

  1. Miller/Urey Experiments
    • recreated early earth atmosphere in lab
    • formed Amino Acids withing a few weeks.
  2. Hydrothermal Vents
    • localized reducing environments still possible today
      - made possible life on earth without sunlight
      o chemosynthesis uses Methane and Sulfur to create glucose
  3. Extraterrestrial origins
    - A nebula is an accumulation of gas and dust in space
    o 10-15% is organic molecules so it actually is potential
    - Meteorites actually contain amino acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. Monomers to Polymers
A

PROBLEM: Complex polymers are generally created via organic enzymatic processes

SOLUTION: Clay minerals facilitate polymer formation

  • Lattice structure
  • Can behave like an enzyme under specific conditions
  • Protects against UV(breaks down organic molecules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. Self-replicating hereditary material
A

PROBLEM: DNA needs enzymes to replicate

SOLUTION: RNA- the original unit of heredity

  1. Self replicates
    - Acts as own enzyme during replication
    - Genetic material AND an enzyme
  2. Self splices
  3. Catalyzes
  4. Possess a phenotype and genotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. Protobiont
A

aggregate of abiotically produced organic
molecules suorrounded by membrane-like structure
- Can abiotically create a membrane with organic molecules in it

PROBLEM: Cell membranes associated w/ organic molecules derived from other organic cells

SOLUTTION: Several “cell-like” structures form abiotically that can self-replicate and metabolizes.

  1. Coacervates
    - Can self replicate and metabolize
    - Not technically alive but are organic
  2. Liposomes
    - Lipid bi-layer vesicles formed abiotically.
    - Clay is vital in these processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Protobiosphere

A
  1. Multiple protobiont lineages may have independently evolved
  2. Competition among lineages
  3. Lineages evolve
    - Xna->rna->dna
  4. Only one lineage remains today.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

First cells appear

A

3.9 - 3.5 BYA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

First cells were chemoautotrophs

A

chemoautotrophs rely on chemosynthesis to produce glucose from chemicals, such as

 a. Sulfur (found at hydrothermal vents)
 b. Methane (found at cold seeps)
  • Still exists today
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The first photoautotrophs

A

Stromatolites (3.5 BYA) - rock like structures comprised of layering photosynthetic bacteria and sediment over time
a. oldest known fossils that formed ~3.5 billion years ago

Very rare now
o Some still off the coast of Australia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The Oxygen Revolution

A

Stromatolites create an oxygen rich atmosphere(byproduct of photosynthesis)

  1. Oxygen toxic to most existing prokaryotes
    - Fundamental change to the chemistry of life on earth
    - The “oxygen revolution”
  2. Aerobic metabolism spreads
    a. aerobic metabolism produces ~19 times > ATP than anaerobic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

From Prokaryote(without organelles) to Eukaryote(membrane bound organelles)

A

Creates a new ecological niche of heterotrophs

The Endosymbiotic model (Lynn Margulis)

 - Prokaryotic cell engulfs another prokaryotic cell but they live symbiotically with each other creating Eukaryotes
 - Mitochondria is an example of this
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The three domains of life

A

established by 2.1 BYA

  1. Bacteria(prokaryote)
  2. Archaea(prokaryote)
  3. Eucarya(Eukaryote)
  • Have a common ancestor but branched since then
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

From single cell to multicellular Eukaryote

A
  1. Evolves multiple times
    • Independently in plants, fungi, and animals
  2. Oldest multicellular lineage ~ 1.5 BY old
  3. Allows for the evolution of cellular specialization (i.e. tissues)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Geologic Time

A

3 main eons

  1. Archaean 4.5 BYA – 2.5BYA
  2. Proterozoic 2.5 BYA – 540 MYA
  3. Phanerozoic 540 MYA - present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Archaean Eon

A

4.5 BYA - 2.5 BYA

  • 4.5 - 3.9 BYA – First cells
  • 3.9-3.5 BYA – First prokaryotes
  • 3.5 BYA – First fossil evidence of phototrophic autotrophs
  • 2.7 BYA – Oxygen Revolution
20
Q

Proterozoic Eon

A

2.5 BYA - 540 BYA

  • 2 BYA – Eukaryotes
  • 1.5 BYA – Multicellularity first evolves
  • ~700 MYA – first animals
21
Q

Phanerozoic Eon

A

540 MYA - Present

Paleozoic Era(Explosion of Animal Diversity) 550 MYA - 251 MYA
- Cambrian Explosion
Periods:
Cambrian(oldest)->Ordovician->Silurian->Devonian->Carboniferous->Permian(youngest)

Mesozoic Era (age of dinosaurs) 250 MYA - 65.5 MYA
Periods:
Triassic(oldest)->Jurassic->Cretaceous(youngest)

Cenozoic Era (age of mammals) 65.6 MYA - Present
– last major extinction 65MYA
Periods:
Paleogene(oldest)->Neogene->Quaternary(youngest)

22
Q

Plate Tectonics - dynamic earth

A

Pangea (Paleozoic) 251 MYA

Gondwana (Mesozoic) 135MYA

Laurasia (Mesozoic) 135MYA

Cenozoic(present earth) 65.6 MYA

Plates associated with geological activity

23
Q

Mass Extinctions

A

Five major mass extinctions at beginning of Paleozoic, Mesozoic and Cenozoic eras (other minor mass extinctions occurred)

Probable cause of Cenozoic extinction – meteorite impacting Yucatan Peninsula

  • 65 MYA
  • Changed atmospheric conditions and brought mammals to the forefront

5 major mass extinctions

most recent 65 MYA

24
Q

Coacervates

A
  • Can self replicate and metabolize

- Not technically alive but are organic

25
Q

Liposomes

A
  • Lipid bi-layer vesicles formed abiotically.

- Clay is vital in these processes

26
Q

Miller/Urey Experiments

A
  • recreated early earth atmosphere in lab

- formed Amino Acids withing a few weeks.

27
Q

Hydrothermal Vents

A
  • localized reducing environments still possible today
  • made possible life on earth without sunlight
    o chemosynthesis uses Methane and Sulfur to create glucose
28
Q

Extraterrestrial origins

A
  • A nebula is an accumulation of gas and dust in space
    o 10-15% is organic molecules so it actually is potential
  • Meteorites actually contain amino acids
29
Q

Evidence for the endosymbiotic model:

A
  1. Organelle Biochemistry homologous to prokaryotes
    - has everything for a prokaryote
  2. Organelles replicate via binary fission (like prokaryotes)
    - Like prokaryotes
  3. Organelles possess their own DNA
    - most important
30
Q

Paleozoic Era(Phanerozoic Eon)

A

542 MYA - 251 MYA

Periods:
Cambrian(oldest)->Ordovician->Silurian->Devonian->Carboniferous->Permian(youngest)

31
Q

Mesozoic Era(Phanerozoic Eon)

A

251MYA - 65.5MYA

Periods:
Triassic(oldest)->Jurassic->Cretaceous(youngest)

32
Q

Cenozoic Era(Phanerozoic Eon)

A

65.5 MYA - Present

Periods:
Paleogene(oldest)->Neogene->Quaternary(youngest)

33
Q

(Phanerozoic Eon, Paleozoic Era) Cambrian Period(1st period)

Explosion of animal diversity

A

1st period

Explosion of animal diversity

- complex life
- oxygen revolution = more ATP = more complexity able
- diversifying selection (new predator X prey)
- Hox genes – tells the body what genes to turn off/on and what
34
Q

(Phanerozoic Eon, Paleozoic Era) Ordovician Period(2nd period)

Explosion of animal diversity

A

colonization of land by small plants and arthropods

- plants got to land first followed by arthropods
- plants = mosses(very tiny not trees or forest)
35
Q

(Phanerozoic Eon, Paleozoic Era) Silurian Period(3rd period)

Explosion of animal diversity

A

Evolution of vascular plants (e.g. forests)

36
Q

(Phanerozoic Eon, Paleozoic Era) Devonian Period(4th period)

Explosion of animal diversity

A

colonization of land by tetrapods (i.e. vertebrates) & insects Appear
- first vertebrates evolve into something(check it)

37
Q

(Phanerozoic Eon, Paleozoic Era) Carboniferous Period(5th Period)

Explosion of animal diversity

A

reptiles & seed plants appear. Vascular plants form vast forests

- mass extinction happens
- converts almost everything into fossil fuels
	- trees to coal
	- animals to oils
38
Q

(Phanerozoic Eon, Paleozoic Era) Permian Period(6th Period)

Explosion of animal diversity

A

diversification of reptiles and insects

39
Q

(Phanerozoic Eon, Mesozoic Era) Triassic Period(1st period)

age of dinosaurs

A

gymnosperms, dinosaurs & mammal-like reptiles

40
Q

(Phanerozoic Eon, Mesozoic Era) Jurassic Period(2nd period)

age of dinosaurs

A

Dinosaurs diversify

41
Q

(Phanerozoic Eon, Mesozoic Era) Cretaceous Period(3rd period)

age of dinosaurs

A

Flowing plants appear & dinosaurs go extinct

- last major mass extinction no more dinosaurs(65MYA)

42
Q

(Phanerozoic Eon, Cenozoic Era) Paleogene Period(1st period)

age of mammals

A

last major extinction 65MYA

mammals birds and pollinating insects diversify

43
Q

(Phanerozoic Eon, Cenozoic Era) Neogene Period (2nd period)

age of mammals

A

meh

44
Q

(Phanerozoic Eon, Cenozoic Era) Quaternary Period (3rd period)

age of mammals

A

Genus Homo appears; last ice age

- period in which we evolve
- we are about 200,000 years old
45
Q

Oparin-Haldane hypothesis

A

Reducing atmosphere facilitates organic molecule formation

Miller/Urey experiments confirmed Amino Acids could be formed