Prokaryotic Taxonomy and Classification

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What is the first step hypothesized by scientists to create the smallest living units of life?

Polymerization of macromolecules

Formation of self-replicating molecules

Synthesis of small organic molecules (correct)

Packaging macromolecules into protocells

Which gas was not a major component of the Earth's early atmosphere?

Oxygen (correct)

Nitrogen

Methane

Carbon dioxide

What was a challenge for life to begin on early Earth due to the impact of rock and ice chunks?

Explosions caused dehydration of organic molecules

Intense heat and vaporization of water (correct)

Creation of favorable conditions for life

Heat generated prevented water vaporization

Why is understanding the composition of the early Earth's atmosphere important for determining how life began?

To understand the formation of organic molecules Signup and view all the answers

When did the oldest fossils of prokaryotic cells appear according to the geological record?

2.5 – 4 billion years ago Signup and view all the answers

Which era marks the appearance of the oldest fossils of eukaryotes, invertebrates, and algae?

Proterozoic Signup and view all the answers

Which event led to the End Ordovician extinction around 440 million years ago?

Ice age with a loss of 86% of species Signup and view all the answers

What caused the End Permian Mass extinction around 251 million years ago which resulted in the loss of 96% of species?

Massive volcanic eruption causing elevation in CO2 and acidification of oceans Signup and view all the answers

Which characteristic of Archaea is unique to them and not found in bacteria or eukaryotes?

Growth at very high temperature possible Signup and view all the answers

What is a distinguishing feature of Thaumarchaeota that sets them apart from other Archaea?

Ammonia-oxidizing chemolithoautotrophic behavior Signup and view all the answers

Which newly proposed candidate phylum of Archaea consists of species that inhabit hot water springs?

Aigarchaeota Signup and view all the answers

What is a characteristic shared by most species in the Crenarchaeota phylum?

(Acido)thermophilic anaerobes Signup and view all the answers

Why was the Kingdom Monera not an accurate taxonomy for prokaryotes?

Genetic analysis revealed that traditional groups like gram-negative bacteria were not monophyletic. Signup and view all the answers

How did Woese & Fox contribute to the understanding of prokaryotic classification?

They proposed the 3-domain theory based on sequencing of ribosomal RNA. Signup and view all the answers

How has molecular techniques influenced the classification of prokaryotes?

Molecular techniques have led to a debate on whether the 3-domain structure is accurate. Signup and view all the answers

What was Lake's hypothesis regarding the domains of life in 1984?

There should only be 2 domains: bacteria and archaea, with eukaryotes included in archaea. Signup and view all the answers

Which process performed by prokaryotes is crucial for unlocking carbon, nitrogen, and other elements from dead organisms?

Decomposition Signup and view all the answers

What is the primary function of cyanobacteria in relation to oxygen?

Oxygen production Signup and view all the answers

Which prokaryotes are responsible for converting atmospheric N2 into nitrogenous molecules for other organisms to use?

Nitrogen fixers Signup and view all the answers

In a symbiotic relationship where one species benefits and the other is unharmed, what type of relationship is this categorized as?

Commensalism Signup and view all the answers