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How many years ago did single-celled eukaryotes arise?
2 billion years ago
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How many years ago did multicellular eukaryotes arise?
1.5 billion years ago
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In what era did animals colonize land?
Paleozoic Era
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In what era did prokaryotes arise?
Archaean Era
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Protists were defined as the kingdom of_______
Primitive forms
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First eukaryotes were probably _____
protists
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What was Ernest Haeckel known for?
Introduced terms protist phylogeny
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What did Ernest Haeckel classify organisms based on?
Their morphological characteristics
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Who came up with the first tree of life?
Darwin, “I think”
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Definition of a protist
A eukaryote that is neither a fungus, plant or animal
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4 properties of protists
- 1. mostly unicellular
- 2. mostly microscopic
- 3. aquatic
- 4. nutritionally diverse
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Chemoheterotrophs
ingest their food
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Photoautotrophs
perform photosynthesis to make their food
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Mixotrophs
combination of performing making their own food and ingesting it
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Properties of protist example: stentor (ciliate)
- 1. unicellular
- 2. microscopic
- 3. freshwater
- 4. chemoheterotroph
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Properties of protist example: red alga
- 1. multicellular
- 2. macroscopic
- 3. marine
- 4. photoautotroph
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What type of protists are algae? How do they get their food?
Plant-like protists, photosynthetic
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What type of protists are protozoa? How do they get their food?
Animal-like protists, ingestive
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What are the four supergroups of eukaryotes?
- 1. Unikonta
- 2. Archaeplastid
- 3. SAR-clade
- 4. Excavata
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Protists are no longer viewed as a ________
kingdom
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What is an endosymbiont?
a cell that lives within a host cell
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Symbiosis=?
Living Together
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Mitochondria and plastids were formerly _________
small prokaryotes living within larger host cells
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Mutualism
both organisms benefit
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Commensalism
one organism benefits, the other is unaffected
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Parasitism
one organism benefits at the expense of the host
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How to tell which is host and which is symbiont?
- host= larger organism
- symbiont= smaller organism
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Who suffers in parasitism?
the host cell
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How did modern day eukaryotes acquire mitochondrion?
Larger eukaryotic cell engulfed aerobic heterotrophic prokaryote and evolved to have mitochondrion in almost every eukaryotic organism
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Second type of endosymbiosis led to___________
chloroplasts and plastids
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Acquisition of mitochondrion happened in ________, whereas acquisition of plastids/chloroplasts happened in _________
every eukaryotic; only in a limited number of eukaryotes
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What is a photosynthetic prokaryote?
a cyanobacterium
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Plastids refer to?
chloroplasts and related organelles
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Primary endosymbiosis?
evolution of red and green algae
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Pigments are _______
substances that absorb light
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Chlorophyll a
main photosynthetic pigment
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Pigment in green algae
chlorophyll b
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Pigment in red algae/cyanobacteria
chlorophyll d
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Pigment in red algae
phycoerythrin
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Pigment in cyanobacteria
phycocyanin
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What do accessory pigments do?
broaden the spectrum used for photosynthesis
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Red algae are usually found where?
deep within the ocean, which is why they developed ability to absorb blue light
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What is the porphyrin ring?
structure in chlorophyll that absorbs light
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What does the hydrocarbon tail in chlorophyll do?
zanchors the molecule into membrane of thylakoid
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CH(?) in chlorophyll a vs. CH(?) in chlorophyll b
CH3 vs. CHO
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Differences in chlorophyll a/b/c/d are made by
one or two substitutions in porphyrin ring
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What happens when a chlorophyll molecule is excited?
electron goes into excited state, while it falls back down heat and fluorescence is released
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