The Origins of Life

Flashcards on the origins of life, focusing on geological evidence, fossil records, and the conditions on early Earth.

Earth is estimated to be __ years old.

4.6 billion

The fossils in the lower layers of geological strata are __ than those in higher layers.

older

The geological field developed in the __ century.

19th

Fossils usually preserve the details of hard structures, such as __, bones and shells.

teeth

The term __ refers to the theory that life originated spontaneously from non-living matter.

abiogenesis

Soft-bodied organisms do not fossilize __.

frequently

The fossil record provides an __ picture of life in the past.

incomplete

Fossils form when organisms are buried by __ or are preserved in oxygen-poor environments.

sediments

A possible origin of life theory is __, which suggests life could come from extraterrestrial sources.

Panspermia

A system using the genetic code to produce proteins and other biological is a characteristic of all present-day cells.

molecules

The first atmosphere of Earth was formed from gases released during __ activities.

volcanic

Conditions on primordial Earth may have led to the formation of __ molecules.

organic

Fossilization is a race against time due to __ and decomposers.

scavengers

The earliest precursors of cells are believed to be __.

protocells