Lesson 1 Flashcards
What is LUCA?
Last Universal Common Ancestor
LUCA is estimated to have existed around 4.2 billion years ago and is believed to have shared genes across various branches of life.
Where is it suggested that LUCA lived?
Hydrothermal vents
LUCA’s metabolism is shared with modern archaea methanogens that inhabit hydrothermal vents.
What was the composition of the early Earth’s atmosphere according to Oparin and Haldane’s theory?
H2O vapor, N2, CO2, H2, H2S, methane, ammonia
This atmosphere was reducing and favored the synthesis of organic compounds.
What did Miller and Urey’s experiment simulate?
The early atmosphere
They produced amino acids but did not include sulfur, hence no sulfur-containing amino acids were formed.
What is abiogenesis?
The formation of life from non-life
It represents a transition from geochemistry to biochemistry.
What does the RNA World Hypothesis propose?
RNA can self-replicate, store information, and catalyze reactions
This hypothesis suggests a key role for RNA in the origin of life.
What is the Goldilocks zone?
The temperature range where H2O is liquid on the surface
This zone varies based on the brightness of the star.
What significant event occurred around 2.7-2.4 billion years ago?
The Great Oxidation Event
This event marked a significant increase in atmospheric oxygen due to oxygenic photosynthesis.
What is the Endosymbiotic Theory?
Eukaryotes formed from an archaeal host and bacteria
The bacteria became mitochondria through a symbiotic relationship.
What are the oldest known fossils of eukaryotes?
Date back to ~1.8 billion years
These fossils are evidence of early eukaryotic life.
What was the Boring Billion?
A period from 1.8 billion to 800 million years ago
This time is thought to have low evolutionary pressure but saw the rise of major eukaryotic groups.
What is adaptive radiation?
Rapid evolution of diversely adapted species from a common ancestor
This often follows mass extinctions or environmental changes.
What does a phylogenetic tree represent?
The evolutionary history of a species or group of related species
It is often used to illustrate relationships and descent among organisms.
What is a monophyletic group?
All descendants of a common ancestor
This group includes the common ancestor and all its descendants.
What is a paraphyletic group?
Some, but not all descendants of a single common ancestor
This group excludes certain descendants.
What is the significance of horizontal gene transfer?
It complicates the understanding of evolutionary relationships
Genes can move between organisms, even if they are distantly related.
What are the three domains of life?
Bacteria, Archaea, Eukarya
These are the most general groups in the taxonomy hierarchy.
Fill in the blank: The first true microfossils are _____.
Stromatolites
These date back to approximately 3.5 billion years.
True or False: The molecular clock allows us to estimate speciation events.
True
It calculates the amount of mutations and their accumulation rate.
What event is referred to as the Cambrian Explosion?
The sudden appearance of most modern animal phyla
This occurred during the Cambrian period (541-485 million years ago).
What is the significance of the colonization of land by plants and fungi?
It marks a transition of life forms from aquatic to terrestrial environments
Early plants likely depended on fungi for nutrient acquisition.
