Name: how photosynthesis changed earth
Uploaded: 2026-03-12T13:57:27.000Z
Duration: 1 min 26 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Environmental Science

Earth's Systems

9-12.EVS.3.4

Origin of Photosynthesis

Fotosynteza, proces, w którym organizmy fotosyntetyczne przekształcają energię świetlną w energię chemiczną, prawdopodobnie rozpoczęła się około 3,5 miliarda lat temu.Najwcześniejsza forma fotosyntezy była prawdopodobnie beztlenowa, wykorzystując kilka alternatywnych dawców elektronów, takich jak siarkowodór czy żelazo, oraz uwalniając siarkę lub utlenione żelazo zamiast tlenu.Później sinice wykształciły zdolność do fotosyntezy tlenowej, wykorzystując wodę jako dawcę elektronów i uwalniając tlen jako produkt uboczny.Tlen uwalniany przez cyjanobakterie reagował z rozpuszczonym żelazem w oceanach, tworząc nierozpuszczalne tlenki żelaza, które osiadały na dnie morskim jako formacje żelaza z pasami.Tymczasem cyjanobakterie tworzyły warstwowe maty mikroorganizmów, które ostatecznie skamieniały się w stromatolity.Gdy większość rozpuszczonego żelaza w oceanie ulegała utlenianiu, a główne zbiorniki tlenu w oceanach stawały się coraz bardziej nasycone, wolny tlen ostatecznie mógł się kumulować w atmosferze.Ten wzrost poziomu tlenu w atmosferze wywołał Wielkie Wydarzenie Utleniające około 2,4 miliarda lat temu, umożliwiając metabolizm tlenowy i powstawanie warstwy ozonowej.

pochodzenie fotosyntezy

Fotosynteza stanowi fundamentalny proces biologiczny, który przekształcił atmosferę Ziemi i utorował drogę do złożonego życia. Pojawiając się około 3,4–3,8 miliarda lat temu, najwcześniejsze organizmy fotosyntetyczne wykorzystywały energię świetlną do produkcji związków organicznych. Te beztlenowe fototrofy wykorzystywały donory elektronów, takie jak siarkowodór (H₂S) czy żelazo żelazne (Fe²⁺), zamiast wody, i nie uwalniały tlenu cząsteczkowego (O₂) jako produktu ubocznego. Różne grupy, w tym zielona siarka i bakterie fioletowe, przyczyniły się do tej wczesnej fototroficznej różnorodności.Ważnym kamieniem milowym ewolucyjnym był rozwój fotosyntezy tlenowej przez cyjanobakterie. Te mikroorganizmy wykorzystywały wodę jako dawcę elektronów, produkując tlen cząsteczkowy jako produkt uboczny. Sinice skolonizowały płytkie środowiska morskie, tworząc rozległe maty mikroorganizmów. Z czasem te maty gromadziły się i opadały, skamieniając się w stromatolity — jedne z najstarszych znanych dowodów życia. Wraz ze wzrostem poziomu tlenu lokalnie, reagował z obfitością rozpuszczonego żelaza w wodzie morskiej, wytrącając się w postaci tlenków żelaza. Tlenki te osiadły na dnie morskim, tworząc formacje żelaza prążkowane (BIF), które stanowią kluczowe geologiczne markery wczesnych zmian atmosferycznych.Gdy większość żelaza oceanicznego została utleniona, nadmiar tlenu zaczął dyfundować do atmosfery, wywołując Wielkie Wydarzenie Utleniające (GOE) około 2,4 miliarda lat temu. Ta transformacja diametralnie zmieniła chemię i biologię Ziemi. Wzrost tlenu w atmosferze umożliwił ewolucję oddychania tlenowego, które dostarcza znacznie więcej energii niż metabolizm beztlenowy. Doprowadziło to także do powstania warstwy ozonowej stratosferycznej (O₃), chroniącej planetę przed szkodliwym promieniowaniem ultrafioletowym i torując drogę do ekspansji życia na ląd.Chociaż GOE promowało innowacje ewolucyjne, wprowadziło także stres oksydacyjny i doprowadziło do wyginięcia wielu organizmów beztlenowych. Niemniej jednak pojawienie się fotosyntezy tlenowej pozostaje jednym z najważniejszych ewolucyjnych osiągnięć w historii Ziemi.

Pochodzenie fotosyntezy

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

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Education

JoVE Core

Microbiology

Mikrobiologia

Unit

Jednostka

Microbial Evolution

Ewolucja mikroorganizmów

KEY TERMS AND CONCEPTS

KLUCZOWE TERMINY I POJĘCIA

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 waste product. Green sulfur bacteria and purple bacteria were among the groups that helped shape this early phototrophic diversity.

A major turning point came with cyanobacteria and oxygenic photosynthesis. Cyanobacteria used water as the electron donor and released oxygen. They lived in shallow marine environments and formed large microbial mats. Over time, those mats trapped sediments and precipitates and later became stromatolites, which are some of the oldest evidence of life.

As oxygen built up in local waters, it reacted with dissolved iron in the sea. This formed iron oxides that sank to the seafloor and created banded iron formations, or BIFs. These rocks are important markers of early changes in Earth’s atmosphere and oceans.

After most of the iron in the oceans had been oxidized, oxygen began to enter the atmosphere. This led to the Great Oxidation Event, or GOE, around 2.4 billion years ago. The rise in oxygen changed Earth’s chemistry and biology in major ways.

More oxygen allowed aerobic respiration, which releases much more energy than anaerobic metabolism. It also helped form the stratospheric ozone (O3) layer, which protects life from harmful ultraviolet radiation. That protection helped set the stage for life to spread onto land.

The Great Oxidation Event also had harmful effects. Oxygen created oxidative stress and caused many anaerobic organisms to die out. Even so, the rise of oxygenic photosynthesis remains one of the most important events in Earth’s history.

How Photosynthesis Changed Earth

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key terms and concepts

Explore how early photosynthesis, cyanobacteria, stromatolites, and the Great Oxidation Event transformed Earth’s atmosphere and enabled complex life.

How Photosynthesis Changed Earth | JoVE K12

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9-12.EVS.3.5

How Photosynthesis Changed Earth

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