Origin and Characteristics of Life: Biomolecules to Taxonomy

Item 8 — The Appearance of Life

Being alive

Being alive: A set of atoms and molecules form a highly organized and complex structure of materials that are involved in molecular communication systems. These systems are related to the environment through an orderly exchange of matter and energy and perform the basic functions of life.

Characteristics of a living being

• a) Ability to transform matter into usable energy.
• b) Capacity for self-replication.
• c) Is complex and organized.
• d) Is self-supporting.
• e) Is not at equilibrium.
• f) Contains information on the processes that take place.

Biomolecules

Biomolecules: The molecules that make up living matter; they are composed of carbon and other elements.

Theory of spontaneous generation

Theory of spontaneous generation: The old biological theory held that animal and plant life could arise (complex life) spontaneously from inert matter. Louis Pasteur proved this theory wrong and demonstrated that all living beings come from other living beings.

Origin of life

Origin of life: Among the scientific community, a well-established theory proposes that life evolved from inert matter sometime between 3,900 and 3,500 million years ago.

Aleksandr Oparin

Aleksandr Oparin: A Soviet biochemist who proposed that the conditions on primitive Earth could have produced the first biomolecules—amino acids and nucleic acids. His ideas initially had limited impact at the international level.

J. B. S. Haldane

J. B. S. Haldane: A British biologist and geneticist who reached conclusions similar to Oparin's and introduced the concept of the prebiotic soup to describe early organic compounds dissolved in water.

Stanley L. Miller

Stanley L. Miller: An American scientist who performed experiments simulating an atmosphere described by Oparin and subjected it to electric sparks; biomolecules were produced in these experiments.

Coacervates

Coacervates: Biomolecular aggregates surrounded by a membrane with selective properties and containing enzymes that transform matter into energy. They are not considered true cells because they lack DNA and RNA.

Panspermia

Panspermia: The theory that the emergence of life on Earth is of extraterrestrial origin. If true, this theory shifts the problem of the origin of life elsewhere but does not explain how life originally arose.

Carolus Linnaeus

Carolus Linnaeus: A Swedish scientist who laid the foundations of modern taxonomy. He is considered one of the fathers of ecology and developed the system of binomial nomenclature.

Binomial nomenclature

Binomial nomenclature: A standardized convention for naming species. The scientific name of a species is formed by combining two words: the genus name (starts with a capital) and the species epithet (starts with a lowercase letter). Note that both terms are written in italics or underlined when writing by hand.