Central Dogma and Definitions of Life

Study of life outside of Earth, involving the search for extraterrestrial life.

A set of basic characteristics that define what makes something 'alive'. It's not about a specific organism, but the shared features of all living systems.

The study of the origin, evolution, and diversity of life on Earth.

The idea that life can arise from non-living matter.

The last universal common ancestor is the hypothetical single-celled organism from which all living organisms on Earth descended.

A science based approach to understanding the scientific meaning of being alive. It investigates the essential characteristics that define life.

The central dogma describes the flow of genetic information from DNA to RNA to protein. DNA replication produces an identical copy of the DNA. Transcription copies the DNA sequence into RNA. Translation converts the RNA sequence into a protein.

Proteins are the workhorses of cells. Their 3D structure is determined by the order of amino acids, and this structure dictates their function.

Viruses can have genomes made of DNA or RNA, and they use different strategies to replicate. Some viruses can even rewrite the rules of the central dogma!

A chemical system that can reproduce itself and evolve is the proposed definition of life by NASA. This encompasses the idea of self-sustainability and Darwinian selection.

The search for a unified theory of biology is key to understanding the nature of life. Just as water is defined by H2O, a theoretical framework for life is needed.

The belief that life was created by a divine force and then evolved through natural processes.

The belief that life was created by a divine force and has remained unchanged since.

The idea that life arises from non-living matter.

The belief that species are unchanging and were directly created in their current form.

The method of measuring the incorporation of radioactive carbon (specifically 14CO2) into organic molecules within a sample.

The method of measuring the release of radioactive carbon dioxide (14CO2) from metabolizing organic compounds in a sample.

The process of heating a sample to release any newly formed organic molecules, which are then detected for radioactive carbon.

A type of experiment designed to investigate the presence and activity of heterotrophic microorganisms within an environment.

A method used to detect the presence of photosynthetic organisms by measuring the incorporation of radioactive carbon dioxide (14CO2) into organic molecules.

The experiment designed to measure the gases produced or consumed by microbes under simulated wet conditions, providing information about their metabolic activity.

The technique used in the GEx Experiment to separate and identify different gases in a sample.

Organisms that obtain energy by breaking down organic matter.

Francesco Redi's experiment in 1668 that challenged spontaneous generation. He used jars with meat, some covered and some exposed, to show that maggots only appeared in the uncovered jars where flies had access to lay eggs.

Louis Pasteur's experiment in 1859 that further disproved spontaneous generation. He used a swan-neck flask to show that sterilized broth remained sterile unless exposed to dust from the air, confirming that life arises from existing life, not inanimate matter.

Jean-Baptiste Lamarck's theory that evolution proceeded in a linear fashion from simpler to more complex life forms. This theory is now considered outdated but was influential in its time.

An outdated theory that proposed that maggots were created spontaneously from decaying matter. This theory was disproven by Francesco Redi.

A theory of evolution that suggests that organisms change over time in order to adapt to their environment. This is the accepted theory of evolution today.

Hydrothermal vents are openings in the ocean floor where heated water and dissolved minerals are released from the Earth's interior.

Black smokers are tall chimney-like structures formed by the precipitation of dissolved minerals from hydrothermal vents, giving them a dark color.

White smokers are chimneys formed from deposits of barium, calcium, and silicon, resulting in a white color.

The water that erupts from hydrothermal vents is highly acidic (pH 2-3) and rich in dissolved sulfide minerals like iron (Fe) and manganese (Mn).

Hydrothermal vents support a diverse ecosystem of chemotrophic bacteria, tube worms, arthropods, fish, and other benthic lifeforms adapted to these harsh environments.

Chemotrophic bacteria use sulfur compounds as a source of energy, forming the base of the food chain in hydrothermal vent ecosystems.

Hydrothermal vents occur in areas where tectonic plates are moving apart, allowing magma to rise and heat seawater.

Hydrothermal vents play a critical role in the global biogeochemical cycles, influencing the distribution of elements like carbon, sulfur, and metals.