Name: how early cells got their start
Uploaded: 2026-03-12T13:57:39.000Z
Duration: 1 min 24 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Environmental Science

Earth's Systems

9-12.EVS.3.4

Origin of Cellular Life

Eine der mehreren Hypothesen besagt, dass die frühesten Lebensformen wahrscheinlich an hydrothermalen Quellen auf dem Meeresboden entstanden sind.Hydrothermale Quellen lieferten Wärme, chemische Gradienten und anorganische Verbindungen wie Wasserstoff und Schwefelwasserstoff. Dieses Umfeld könnte die abiotische Synthese organischer Moleküle erleichtert haben, darunter Aminosäuren, Lipide und Nukleotiden.Mineralporen in hydrothermalen Quellstrukturen könnten als erste biologische Kompartimente dienen, indem sie diese Moleküle konzentrierten und für chemische Reaktionen zusammenbrachten.Einige Modelle deuten darauf hin, dass Protozellen entstanden, als sich Lipidmembranen bildeten, und schließlich mineralbasierte Kompartimente ersetzten.Diese Zellen enthielten wahrscheinlich selbstreplizierende RNA, die genetische Informationen speichern und die Proteinsynthese katalysieren konnte.Als Proteine entstanden, trieben ihre Wechselwirkungen mit RNA wahrscheinlich den Übergang zu DNA voran, einem stabileren genetischen Material.Metabolisch waren die frühen Zellen wahrscheinlich Chemolithotrophe, die Wasserstoff als Elektronenspender und Schwefel oder Kohlendioxid als Elektronenakzeptor zur Synthese organischer Verbindungen verwendeten.

ursprung des zellulären lebens

Der Ursprung des Lebens auf der Erde ist ein komplexes und rätselhaftes Ereignis, das in antiken biochemischen Prozessen und geologischen Bedingungen verwurzelt ist. Experimentelle Belege stützen die Hypothese, dass das Leben mit der spontanen Bildung organischer Moleküle wie RNA-Nukleotiden, Aminosäuren und Lipiden unter frühen Erdbedingungen begann. Faktoren wie vulkanische Aktivität, intensive UV-Strahlung und eine reduzierende Atmosphäre ohne freien Sauerstoff haben diese Reaktionen wahrscheinlich ermöglicht. Hydrothermale Quellen auf dem Meeresboden gelten als wahrscheinlicher Standort für die ersten Lebensformen, da sie reduzierte Gase wie Wasserstoff (H₂) und Schwefelwasserstoff (H₂S) liefern könnten, was präbiotische Chemie erleichtert. Mineralporen bieten begrenzte Räume, die Reaktanten konzentrieren, im Gegensatz zum offenen Ozean, wo Moleküle stark verdünnt wären. Außerdem können mineralische Oberflächen – oft reich an Eisen und Schwefel – als primitive Katalysatoren wirken. Diese Oberflächen könnten dazu beigetragen haben, chemische Reaktionen zu beschleunigen, indem sie Moleküle in engen Kontakt brachten und die für Reaktionen benötigte Energie senkten.Man nimmt an, dass RNA im frühen Leben eine zentrale Rolle spielte, da sie genetische Informationen speichern und biochemische Reaktionen katalysieren kann. Ribozyme zeigen, dass RNA enzymähnliche Funktionen erfüllen kann, was eine plausible Zwischenstufe vor der Entwicklung proteinbasierter Enzyme darstellt. Das spätere Entstehen von DNA, RNA und Proteinen legte die Grundlage für die tripartite molekulare Architektur, die alle modernen Organismen teilen. Der letzte universelle gemeinsame Vorfahre (LUCA) wird auf etwa 3,8 bis 3,7 Milliarden Jahre geschätzt, was die Trennung von Bakterien und Archaeen markiert, obwohl der genaue Zeitpunkt ungewiss bleibt.Das frühe zelluläre Leben diversifizierte sich metabolisch in der anoxischen Umgebung der Erde. Primitive Autotrophe nutzten CO₂ als Kohlenstoffquelle und stützten sich oft auf H₂ als Energiespender. Die Entwicklung der Stickstofffixierung erweiterte die Stoffwechselmöglichkeiten, während schwefelbasierte Energiewege wahrscheinlich zusätzliche exergonische Reaktionen ermöglichten. Wasserstoffgetriebene Chemolithotrophie ermöglichte die Synthese organischer Moleküle aus CO₂ und unterstützte zunehmend komplexe Ökosysteme. Im Laufe der Zeit veränderten mikrobielle Innovationen – darunter die Einführung der sauerstoffhaltigen Photosynthese – die Erdatmosphäre und ermöglichten letztlich den Aufstieg aerobens Lebens.

Ursprung des zellulären Lebens

The origin of life on Earth is a complex and enigmatic event rooted in ancient biochemical processes and geological conditions. Experimental evidence ...

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Education

Lehre

JoVE Core

Microbiology

Mikrobiologie

Unit

Einheit

Microbial Evolution

Mikrobielle Evolution

KEY TERMS AND CONCEPTS

SCHLÜSSELBEGRIFFE UND KONZEPTE

how early cells got their start

Early cellular life began under the harsh conditions of early Earth, where simple chemicals could form more complex organic molecules. Experimental evidence supports the idea that RNA nucleotides, amino acids, and lipids could arise spontaneously in this environment. Volcanic activity, strong UV radiation, and an atmosphere with little or no free oxygen likely helped drive these reactions.

Hydrothermal vents on the ocean floor are considered one likely setting for the first life forms. These vents could supply reduced gases such as hydrogen and hydrogen sulfide, which support prebiotic chemistry, or chemistry that happens before life exists. Mineral pores would have trapped molecules in small spaces, so reactants were less diluted than they would be in the open ocean.

Mineral surfaces may also have helped early reactions. Many of these surfaces are rich in iron and sulfur, and they can act as primitive catalysts. A catalyst speeds up a reaction by lowering the energy needed and by bringing molecules close together.

RNA likely played a major role in early life because it can store genetic information and also help carry out chemical reactions. RNA molecules that act like enzymes are called ribozymes, and they show how RNA could have worked before protein enzymes evolved. Over time, DNA, RNA, and proteins formed the basic molecular system shared by modern organisms.

Scientists estimate that the last universal common ancestor, or LUCA, lived about 3.8 to 3.7 billion years ago. This was the point at which Bacteria and Archaea began to diverge, although the exact timing is still uncertain. Early cells then diversified in Earth’s oxygen-free environment.

Primitive autotrophs used carbon dioxide as a carbon source and often depended on hydrogen as an energy donor. Later, nitrogen fixation expanded the kinds of metabolism that were possible. Sulfur-based energy pathways also likely provided useful energy, and hydrogen-driven chemolithotrophy helped cells make organic molecules from carbon dioxide. Over time, microbial innovations, including oxygenic photosynthesis, changed Earth’s atmosphere and made aerobic life possible.

How Early Cells Got Their Start

origin of cellular life

Early cellular life began under the harsh conditions of early Earth, where simple chemicals could form more complex organic molecules. Experimental evidence supports the idea that RNA nucleotides, amino acids, and lipids could arise spontaneously in this environment. Volcanic activity, strong UV radiation, and an atmosphere with little or no free oxygen likely helped drive these reactions. Hydrothermal vents on the ocean floor are considered one likely setting for the first life forms. These...

origin of photosynthesis

How Photosynthesis Changed Earth

Photosynthesis changed Earth’s atmosphere and made complex life possible. It began about 3.4 to 3.8 billion years ago, when the first photosynthetic organisms used light energy to build organic compounds. These early organisms were anoxygenic phototrophs, which means they made food from light but did not release oxygen. Early photosynthesis used hydrogen sulfide (H2S) or ferrous iron (Fe2+) as electron donors instead of water. Because of that, it did not produce molecular oxygen (O2) as a...

evolutionary processes in microbes

How Microbes Gain New Traits

Microbes gain new traits through fast genetic change. Their short generation times help evolution happen quickly. Mutation, horizontal gene transfer, recombination, and genetic drift all contribute to this process. Together, these mechanisms help microbial populations adjust to changing environments. Horizontal gene transfer, or HGT, moves genes between different species. It happens in three main ways: conjugation, transformation, and transduction. Conjugation requires direct cell-to-cell...

evolution of new traits in microbes

Microbial Adaptation in Changing Environments

Microbial adaptation in changing environments can happen very quickly. Microorganisms often evolve fast because they have large population sizes and short generation times. In the lab, these changes can sometimes be measured within days. Natural selection acts on standing genetic variation, which is the genetic diversity already present in a population. When conditions change, helpful traits can be kept and increased because they improve fitness. This lets microbes respond to new pressures...

evolution of microbial genome

Microbial Core and Pan-Genome Changes

Microbial genomes change through gene gain and gene loss. These changes help microbes adapt to new environments and to other organisms they live with. In many species, genome evolution is fast and ongoing. A key idea is the difference between the core genome and the pan-genome. The core genome is the set of genes shared by all sampled strains of a species. These genes support basic cell functions. For example, Salmonella enterica has about 2,800 core genes, although the exact number can change...

microbial phylogeny

Reading Microbial Family Trees

Reading microbial family trees helps scientists study how microorganisms are related. These trees are important in microbial ecology and taxonomy. They use molecular sequences such as DNA, RNA, or proteins to compare bacteria and archaea and trace genetic changes over time. A phylogenetic tree has tips, branches, and nodes. The tips are the species that are sampled or still alive. The branches show evolutionary paths, and branch length reflects the number of genetic changes between nodes.

phylogenetic species concept in microbiology

phylogenetic-species-concept-in-microbiology

How DNA Defines Microbial Species

The phylogenetic species concept helps define microbial species by looking at DNA and evolutionary relatedness. It focuses on shared ancestry and genetic traits that can be diagnosed in different organisms. This approach is especially useful in microbiology, where other species concepts often do not work well. Traditional morphological and biological species concepts rely on body form or reproduction. Those methods can fall short for microbes because many reproduce asexually, show little...

key terms and concepts

Explore how early cells may have formed on Earth, from RNA and hydrothermal vents to LUCA, early metabolism, and the rise of oxygenic photosynthesis.

How Early Cells Got Their Start | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Origin of Photosynthesis

Photosynthesis represents a fundamental biological process that transformed Earth's atmosphere and paved the way for complex life. Emerging roughly ...

Soil Microbial Ecology

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Microbial Corrosion

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Microbial Bioremediation of Hydrocarbons

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Analysis of Earthworm Populations in Soil

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Using mustard, Lumbricus terrestris earthworm populations can be sampled ...

What is an Ecosystem?

Overview

An ecosystem is the interaction between all abiotic and biotic factors in an environment and can be classified as terrestrial or aquatic. ...

4. Engage in an evidence-based argument to explain how Earth's systems affect the biosphere and the biosphere affects Earth's systems over various amounts of time. Examples: Use data to make a claim that microbial life increases the formation of soil or that corals create reefs and argue that these processes can alter patterns of erosion and deposition along coastlines. Clarification: This discussion should consider Earth's geological history.

Ecological Disturbance

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Biodeterioration

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Igneous Volcanic Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
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Applications of GIS: Disaster Management and Emergency Response

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5. Obtain, evaluate, and communicate information regarding how short-term and long-term natural cyclic fluctuations cause ecosystem change. Examples: Explain how the eruption of volcanoes alters global temperatures or how the El Niño-Southern Oscillation shifts weather patterns. Share information regarding how forest fires can cause deforestation which increases water runoff and soil erosion. Describe how hurricanes destroy dunes and increase coastal flooding.

9-12.EVS.3.5

How Early Cells Got Their Start

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