C'était quoi qui a changé plus pendant le Dévonien, les poissons ou les plantes qui sont sorties de l'eau ? Je comprends pas trop pourquoi on dit que c'était l'âge des poissons mais en même temps y'avait plein de nouvelles plantes aussi.
The Devonian is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.2 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.9 Ma. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free-sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants (pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Revolution. The earliest land animals, predominantly arthropods such as myriapods, arachnids and hexapods, also became well-established early in this period, after beginning their colonization of land at least from the Ordovician period. Fishes, especially jawed fish, reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The armored placoderms began dominating almost every known aquatic environment. In the oceans, cartilaginous fishes such as primitive sharks became more numerous than in the Silurian and Late Ordovician. Tetrapodomorphs, which include the ancestors of all four-limbed vertebrates, began diverging from freshwater lobe-finned fish as their more robust and muscled pectoral and pelvic fins gradually evolved into forelimbs and hindlimbs, though they were not fully established for life on land until the Late Carboniferous. The first ammonites, a subclass of cephalopod molluscs, appeared. Trilobites, brachiopods and the great coral reefs were still common during the Devonian. The Late Devonian extinction, which started about 375 Ma, severely affected marine life, killing off most of the reef systems, most of the jawless fish, half of all placoderms, and nearly all trilobites save for a few species of the order Proetida. The subsequent end-Devonian extinction, which occurred at around 359 Ma, further impacted the ecosystems and completed the extinction of all calcite sponge reefs and placoderms. Devonian palaeogeography was dominated by the supercontinent Gondwana to the south, the small continent of Siberia to the north, and the medium-sized continent of Laurussia to the east. Major tectonic events include the closure of the Rheic Ocean, the separation of South China from Gondwana, and the resulting expansion of the Paleo-Tethys Ocean. The Devonian experienced several major mountain-building events as Laurussia and Gondwana approached; these include the Acadian Orogeny in North America and the beginning of the Variscan Orogeny in Europe. These early collisions preceded the formation of the single supercontinent Pangaea in the Late Paleozoic.
Période dévonienne

La période dévonienne s'étend de 419 à 359 millions d'années. Également connue sous le nom de « Âge du poisson », le Dévonien a été marqué par une immense diversification des poissons, notamment des poissons blindés comme *Dunkleosteus* et des poissons à nageoires lobées qui ont finalement évolué en premiers tétrapodes. Sur terre, les groupes de plantes se sont diversifiés rapidement lors d'un événement connu sous le nom d'explosion dévonienne, lorsque les plantes ont produit de la lignine, entraînant une croissance plus importante et des tissus vasculaires ; les premiers arbres et les premières graines ont évolué. Ces nouveaux habitats ont conduit à une plus grande diversification des arthropodes. Les premiers amphibiens sont apparus et les poissons occupaient le sommet de la chaîne alimentaire. Le deuxième événement d'extinction massive du Phanérozoïque de la Terre (un ensemble de plusieurs événements d'extinction plus petits), l'extinction du Dévonien supérieur, a entraîné la disparition de 70 % des espèces existantes.
### Query ###
C'était quoi qui a changé plus pendant le Dévonien, les poissons ou les plantes qui sont sorties de l'eau ? Je comprends pas trop pourquoi on dit que c'était l'âge des poissons mais en même temps y'avait plein de nouvelles plantes aussi.

### Main Text ###
The Devonian is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.2 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.9 Ma. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free-sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants (pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Revolution. The earliest land animals, predominantly arthropods such as myriapods, arachnids and hexapods, also became well-established early in this period, after beginning their colonization of land at least from the Ordovician period. Fishes, especially jawed fish, reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The armored placoderms began dominating almost every known aquatic environment. In the oceans, cartilaginous fishes such as primitive sharks became more numerous than in the Silurian and Late Ordovician. Tetrapodomorphs, which include the ancestors of all four-limbed vertebrates, began diverging from freshwater lobe-finned fish as their more robust and muscled pectoral and pelvic fins gradually evolved into forelimbs and hindlimbs, though they were not fully established for life on land until the Late Carboniferous. The first ammonites, a subclass of cephalopod molluscs, appeared. Trilobites, brachiopods and the great coral reefs were still common during the Devonian. The Late Devonian extinction, which started about 375 Ma, severely affected marine life, killing off most of the reef systems, most of the jawless fish, half of all placoderms, and nearly all trilobites save for a few species of the order Proetida. The subsequent end-Devonian extinction, which occurred at around 359 Ma, further impacted the ecosystems and completed the extinction of all calcite sponge reefs and placoderms. Devonian palaeogeography was dominated by the supercontinent Gondwana to the south, the small continent of Siberia to the north, and the medium-sized continent of Laurussia to the east. Major tectonic events include the closure of the Rheic Ocean, the separation of South China from Gondwana, and the resulting expansion of the Paleo-Tethys Ocean. The Devonian experienced several major mountain-building events as Laurussia and Gondwana approached; these include the Acadian Orogeny in North America and the beginning of the Variscan Orogeny in Europe. These early collisions preceded the formation of the single supercontinent Pangaea in the Late Paleozoic.

### Supplementary Text ###
Période dévonienne

La période dévonienne s'étend de 419 à 359 millions d'années. Également connue sous le nom de « Âge du poisson », le Dévonien a été marqué par une immense diversification des poissons, notamment des poissons blindés comme *Dunkleosteus* et des poissons à nageoires lobées qui ont finalement évolué en premiers tétrapodes. Sur terre, les groupes de plantes se sont diversifiés rapidement lors d'un événement connu sous le nom d'explosion dévonienne, lorsque les plantes ont produit de la lignine, entraînant une croissance plus importante et des tissus vasculaires ; les premiers arbres et les premières graines ont évolué. Ces nouveaux habitats ont conduit à une plus grande diversification des arthropodes. Les premiers amphibiens sont apparus et les poissons occupaient le sommet de la chaîne alimentaire. Le deuxième événement d'extinction massive du Phanérozoïque de la Terre (un ensemble de plusieurs événements d'extinction plus petits), l'extinction du Dévonien supérieur, a entraîné la disparition de 70 % des espèces existantes.

### Draft ###

Query breakdown: "C'était quoi qui a changé plus pendant le Dévonien" → comparative evolutionary impact assessment.

Key semantic issue: "changé plus" = "changed more" suggests quantitative comparison, not just descriptive listing.

User observes contradiction: "l'âge des poissons" naming vs. terrestrial plant emergence. → Need to resolve apparent paradox.

### 1. Contextualization

Devonian Period: 419-359 Ma. ● High confidence timeframe.

Geological setting: First major terrestrialization phase. Preceded by Ordovician-Silurian marine diversification. Followed by Carboniferous-Permian terrestrial dominance.

→ Critical transition period, not endpoint either way.

### 2. Information Retrieval Challenge

Need comparative data across:
- Ichthyofauna evolution metrics
- Terrestrial flora emergence patterns  
- Quantitative biodiversity changes
- Ecological impact assessments

? Key question: How to measure "change"? Species count? Ecological dominance? Morphological innovation?

### 3. Fish Evolution Analysis

"Âge des poissons" justified by:
- Jawed fish radiation ●
- Placoderm dominance (Dunkleosteus, etc.) ●  
- Cartilaginous fish proliferation ●
- Predator-prey marine food web establishment ●

But: ◐ Partial data on exact species counts/rates.

### 4. Plant Terrestrialization Patterns

Critical innovations:
- Lignin production → vascular support ●
- True roots development ●
- Seed formation ●
- Extensive forest ecosystems ●

Timeline progression:
├─ Early Devonian: simple vascular plants
├─ Mid-Devonian: first forests
└─ Late Devonian: seed plants

∴ Gradual but fundamental terrestrial ecosystem establishment.

### 5. Comparative Impact Assessment

⟨H≈0.8⟩ Which changed "more"? Depends on metrics... species count? ecological transformation? temporal duration? Fish diversity certainly accelerated mid-Devonian but terrestrial plants established foundational innovations... lignin for soil formation, seed reproduction, atmospheric oxygenation... these seem more... transformative in long-term Earth system sense... but fish dominated actual ecosystem dynamics...

Back to structured analysis:

**Quantitative approaches:**
- Species count: ○ Low confidence, incomplete fossil record
- Ecological dominance: Fish clearly dominated marine systems ●
- Evolutionary innovation: Plants developed key terrestrial adaptations ●
- Ecosystem transformation: Both major but different domains ●

### 6. Resolution Strategy

The paradox dissolves when recognizing:

Fish = marine ecological dominance (visible, measurable)
Plants = terrestrial ecosystem foundations (invisible initially, long-term)

∴ "Age of Fishes" reflects observable marine biodiversity surge.
But plant innovations = more fundamental terrestrial ecosystem establishment.

**Conclusion synthesis:**
Both groups underwent significant change. Fish diversification was more immediately visible/measurable. Plant innovations were foundational for terrestrial ecosystem evolution. User's observation of contradiction = false dichotomy between marine/terrestrial domains.

NB: Response should emphasize this complementary rather than competitive evolution pattern.

### Answer###
Votre observation est tout à fait justifiée ! Le Dévonien a effectivement été une période de transformations majeures pour les poissons, mais aussi pour la vie terrestre.

Pour répondre à votre question : les poissons ont probablement évolué de manière plus spectaculaire en termes de diversité et de nouvelles formes. C'est d'ailleurs pour cette raison que le Dévonien est souvent appelé "l'Âge des Poissons". Les poissons à mâchoires ont particulièrement prospéré, avec les poissons blindés comme Dunkleosteus qui dominaient presque tous les environnements aquatiques connus, et les poissons à nageoires lobées qui évolueraient finalement en premiers tétrapodes. Les requins cartilagineux sont devenus plus nombreux qu'à l'Ordovicien supérieur, et les premiers ammonites sont apparus.

Cependant, les changements chez les plantes étaient tout aussi fondamentaux mais sur une autre échelle. Durant ce que l'on appelle l'explosion dévonienne, les plantes ont connu une diversification rapide : elles ont développé la lignine, produit des premiers arbres, formé des forêts étendues, puis les premières graines sont apparues. Ces innovations terrestres comprenaient aussi l'apparition de vraies racines et de feuilles.

Le Dévonien a été marqué par la première radiation évolutive significative de la vie sur terre, avec l'établissement des premiers animaux terrestres et l'émergence des premiers amphibiens. Les deux groupes ont donc évolué de manière complémentaire : les poissons dominaient les écosystèmes marins, tandis que les plantes terrestres établissaient les fondations des écosystèmes continentaux.