Origins and Evolution

These flashcards cover essential vocabulary and concepts related to the origins and evolution of life as discussed in the lecture.

Prebiotic soup theory

Proposes that the fundamental biomolecules of life arose spontaneously through condensation of reduced inorganic molecules.

Stromatolites

Earliest forms of life for which clear fossil evidence exists, consisting of bacterial communities.

Biosignature

Evidence for life in the geological record, which may include chemical indicators of biological activity.

Hadean eon

The first period of Earth's existence, ranging from 4.6 to 4.0 billion years ago, characterized by extreme conditions.

Archaean eon

Period in Earth's history from 4.0 to 2.5 billion years ago, noted for the less frequent meteor bombardment and the emergence of microbial life.

Isotope ratios

Quantitative evidence that provides biosignatures if altered by biological activity.

Horizontal gene transfer

The acquisition of a piece of DNA from another cell, as opposed to vertical gene transfer, which is from parent to offspring.

Natural selection

The mechanism that enables certain variants to survive and reproduce based on their fitness in a given environment.

Molecular clocks

Temporal information contained in a macromolecular sequence, used to estimate evolutionary time based on mutations.

Pangenome

The complete set of genes within a species, encompassing the core genome and accessory genes.

Endosymbiosis

The intimate association of two unrelated species, where one partner grows within the body of another.

Experimental evolution

The laboratory study of evolutionary processes by observing the changes in populations under controlled conditions.

Mutualism

A type of symbiosis where both partners benefit.

Reduction evolution

The evolutionary process where an organism loses or mutates DNA encoding unselected traits.

Cyanobacteria

Bacteria that can perform photosynthesis, significant for the production of oxygen in Earth's early atmosphere.

Ribozyme

A catalytic RNA molecule that exhibits enzymatic properties and may have fulfilled key functions in the early RNA world.

Prokaryotic species definition

Aproposed definition of a prokaryotic species based on genetic relatedness and phenotypic traits.