Ecosystems Through Time

How have marine ecosystems changed over time?

Apex predators shifted from giant arthropods to marine reptiles to sharks 

How have marine ecosystems stayed the same over time?

• Ancient oceans were dominated by invertebrates (e.g., trilobites, ammonites)

• Functional equivalents of coral reefs existed in different forms

How have terrestrial ecosystems changed over time?

• Carboniferous swamps vs. Mesozoic forests vs. modern grasslands. 

• Dominant plant groups shifted: ferns → gymnosperms → angiosperms

How have predator-prey relationships changed over time?

• Marine predators evolved: Giant arthropods → marine reptiles → sharks

• Terrestrial predators shifted: Amphibians → theropod dinosaurs → mammals, with ambush and pursuit strategies

How have predator-prey relationships stayed the same over time?

Prey defences repeated:

• Armor (trilobites, ankylosaurs)

• Speed (ichthyosaurs, antelope)

• Burrowing (marine worms, synapsids, rodents)

Describe how mass extinctions have shaped evolution of life over time:

• Opportunistic species flourished in empty niches. 

• Extinctions repeatedly shaped the rise of new dominant groups 

Describe how ecosystem structures have recurred over time:

• Reef systems, forests, and open plains have appeared multiple times. 

• Different dominant organisms filled similar roles in different Eras/Periods. 

• Food chains consistently rely on producers, herbivores, and predators

How has climate affected evolution of life over time?

• Warmer periods favoured forests and tropical biodiversity. 

• Ice ages shaped tundra, grasslands, and megafauna adaptations. 

• Rising CO₂ levels impacted plant dominance and growth rates