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Biology 108 > Theme 2 Origin of Life, Prokaryotes and Protists > Flashcards

Theme 2 Origin of Life, Prokaryotes and Protists Flashcards

1
Q

How is the Geologic Record Divided?

A

Into the:
Archaean, Proterozoic and Phanerozoic Eons

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2
Q

What are the pros and cons of the Fossil Record?

A
  1. Biased and Incomplete
  2. Sedimentary Strata can be warped, or even flipped
  3. Very Few Organisms are fossilized
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3
Q

What are the types of fossils?

A

Cast
Replacement
Trace
Preserved

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4
Q

How does Plate Tectonics Theory Help understand history of Earth?

A

Fossil distributions

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5
Q

When did the first life emerge?

A

~ 3.9bya

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6
Q

Define the Permian Extinction

A

Occurred between Paleozoic and Mesozoic era
- worst mass extinction
-likely caused by volcanic activity

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7
Q

Define the Cretaceous Extinction

A

Between the Mesozoic and Cenozoic
-extinction of non avian dinosaurs
-likely caused by meteorite (Chicxulub)

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8
Q

What is a possible consequence of mass extinction?

A

Availability of new niches results in Adaptive Radiation

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9
Q

When may adaptive radiation occur?

A
  1. After mass extinction events
  2. After colonization of new region
  3. Evolution of novel characteristics (e.g powered flight enabled many new niches)
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10
Q

Describe how life began on Earth

A
  1. Through abiotic synthesis of organic molecules (likely near volcanoes, with strong chemical reduction conditions)
  2. Abiotic synthesis of organic polymers
  3. Formation of proto-cells (encapsulation of RNA, proteins, amino acids) by vesicles
  4. Evidence that RNA is self-replicating
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11
Q

What are the consequences of Continental Drift?

A
  1. Formation of Pangaea (reduced biodiversity)
  2. Strongly influenced biodiversity
  3. Distribution of fossils reflects movement of continents
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12
Q

When did the first prokaryotes emerge?

A

~ 3.5-3.7 bya

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13
Q

What were the consequences of the Oxygen Revolution

A

Extinction of obligate anaerobic prokaryotes

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14
Q

What were the first organisms on Earth?

A

Prokaryotes (don’t say proto cells)

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15
Q

What advantages contributed to prokaryote success?

A
  1. Simple DNA/structure
  2. Binary Fission
  3. Motility
  4. Endosporulation
  5. Cell-Surface Structures (ie polysacchride layers, cell walls
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16
Q

What are the 3 factors that contribute to prokaryote’s substantial diversity?

A
  • rapid reproduction
  • mutations
  • genetic recombination (horizontal gene transfer)
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17
Q

Define Genetic Recombination

A

Combining DNA from two sources
in Prokaryotes:
1. Transformation (uptake of foreign DNA, ie dead cells)
2. Transduction (transfer DNA through bacteriophages)
3. Conjugation

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18
Q

True or False:
Prokaryotes are metabolically diverse

A

True

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19
Q

List the 5 major groups of Bacteria

A
  1. Proteobacteria
  2. Spirochetes
  3. Chlamydias
  4. Cyanobacteria
  5. Gram Positive
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20
Q

Characterize Proteobacteria

A

alpha: often associated with Euk host
gamma and epsilon: includes pathogens, and also E. Coli

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21
Q

Characterize Chlamydias

A

a) parasites within animal cells
b) lack peptidoglycan (because they don’t need if in other cells)

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22
Q

Characterize Cyanobacteria

A

a) only prokaryotes that produce oxygen through photoautotrophy
b) likely ancestor of eukaryote chloroplast

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23
Q

Characterize Gram-Positive Bacteria

A

Only bacterial group that are gram positive, also include gram negative
a) includes many decomposers, also pathogens

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24
Q

What are the 3 main categories of Archaea?

A

Methanogens: (anoxic environments, produce methane, found in swamps, intestinal tracts)

Extreme halophiles

Thermophiles

25
What caused the oxygen revolution?
Cyanobacteria
26
What caused the oxygen revolution?
Cyanobacteria
27
In what ways to Eukaryotes differ from prokaryotes?
1. Usually larger 2. Have membrane bound-organelles 3. Linear chromosomes (prokaryotes have circular) 4. Have dynamic membranes (e.g amoeba) 5. Sexual Reproduction promotes genetic diversity
28
Difference between primary and secondary endosymbiosis?
Primary: Uptake of prokaryote by prokaryote or eukaryote Secondary: Uptake of Eukaryote by another eukaryote
29
Give the approximate timeline of eukaryote characteristics
1. Infoldings became internal (nucleus, etc) 2. Endosymbiosis of alpha-proteobacteria forms mitochondria 3. Uptake of cyanobacteria (chloroplasts
30
What are the evolutionary advantages of Multicellularity?
1. cell specialization 2. increased organism size and complexiity 3. longer life span 4. avoid predation note: multicellularity evolved indepdently in several lineages
31
Define Horizontal Gene Transfer
Movement of genes between genomes of different species
32
True or False: Protist is a monophyletic group (clade)?
False, its more of an umbrella term for any eukaryote besides animal, fungi or plants
33
List all of the taxa within SAR Protists
1.Diatoms 2.Brown Algae 3.Oomcycetes 4.Dinoflagellates 5.Apicomplexans 6.Cilliates 7.Forams 8.Cercozoans 9.Radiolarians Mnemonic: Do brown oranges disgust all Canadians for Canadians Rememember
34
Characterize Protist Clade **Excavata**
-are unicellularly - some share cytoskeleton morphology - modified mitochondria and/or flagella
35
List the three clades of Protist Clade **Excavata**
1. **Diplomonads** and **parabasalids**: - unicellular, heterotrophic no plastids, most are anaerobes 2. **Euglenozoans**: - a diverse clade - characterized by spiral/chrystalline rod in flagella - group consists of **kinetoplastids** (single mitochondria) and **euglenids** (ome or two flagella from end of cell) -
36
Summarize the SAR Clade | Stramenophiles, alveolates and Rhizarians
-likely emerged by secondary endosymbiosis of red algae - dominate eukaryote diversity in oceans Made of: 1. **Stramenophiles**: - **strameophiles** include **diatoms** (phytoplankton), **brown** **algae** (seaweeds, lifecycle involves alternation of generations) and **oomycetes** - many are **unicellular** flagellates 2.**Alveolates** - characterized by membrane bound sacs (alveoli) - consists of **dinoflagellates** (diverse group, abundant marine and freshwater phytoplankton) - **apicomplexans** are **parasites** of animals (spread as infection **sporozites** cells), - **alveolates** are also made of **cilliates** (use cillia to move) 3. **Rhizarians** - little to no morphological similarity, defined by **DNA** **similiarity** - most rhizarians are amoebas
37
Characterize Archaeplastida
Photosynthetic group consisting of red and green algae and land plants - evolved when eukaryote acquired plastids from cyanobacteria - archeaplastida have cell walls of cellulose 1. **Red** **Algae** - reddish due to pigment, mostly seaweeds, 2. **Green** **algae** -have chlorophyll, are a paraphyletic group - two groups of **green** **algae** include **chlorophytes** and **charophytes** (close ancestor of land plants) - most live in freshwater
38
Summarize supergroup Unikonta
Heterotrophic protists closely related to fungi and animals -most have a single flagella or are amoebas 1. Amoebozoans -tube like pseuodpodia - include slime moulds, etc
39
What are Amoebozoans?
1. Protist, belonging to supergroup Unikonta 2. Have thread-like pseudopodia
40
What are the 3 main types of Amoebozoans?
1. Slime molds 2. Tubulinids 3.entamoebas
41
What **clade** do **Diatoms** belong to?
SAR Clade, Stramenophiles
42
What Clade do **brown** algae, **red** and **green** algae belong to?
Brown Algae: Stramenophiles SAR Red and Green: Archaeplastidia
43
True or False: Algae are **monophyletic**?
**False** Algae refer to any **photoautotrophs** that are not members of **Plantae** **Kingdom**, are actually **polyphyletic**
44
What is the defining feature of Archaeplastidia?
Cell walls made from cellulose
45
**Oomycetes** belong to what clade?
Stramenophiles, SAR
46
**Euglenozoans** belong to which clade?
Clade **Excavata**
47
Characterize Euglenozoans
1.Kinetoplastids (single large mitochondria with a mass of DNA called **kinetoplast)** 2.Euglenids - spiral structure of unknown function in flagella
48
True or False: **Excavata** are **unicellular**
True
49
Diplomonads and Parabasalids belong to which protist clade?
Excavata
50
What group are land plants in?
Archaeplastidia
51
What are the closest ancestors to land plants?
In supergroup Archeaplastidia, **charophytes**, a type of green algae
52
Which Supergroup is shared by fungi, animals, and Amoebozoans?
Unikonta
53
What is responsible for the diversity of protists?
Endosymbiosis
54
What are mixotrophs?
Gain energy and carbon from different sources ie at time chemotrophic and sometimes phototrophic
55
True or false: Diatoms are photosynthetic
True
56
True or False: Brown Algae undergo alternation of generations
True
57
What do apicomplexans require to reproduce?
At least two host species to complete life cycle
58
True or False Rhizarians are characterized by morphological similarity
False mostly defined by DNA similiarities and are heretrophic, use pseudopodia
59
How were achaeplastida formed?
Primary endosymbiosis of cyanobacteria (includes red and green algae and plants)

Biology 108 (5 decks)

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