13.2 Plate tectonics and its influence on past ecosystems and species distributions
3 min read•august 7, 2024
Plate tectonics shaped Earth's past ecosystems and species distributions. As continents moved, formed and broke, influencing how plants and animals spread. These changes also affected climate patterns, creating new habitats and challenges for life.
The shifting continents led to fascinating evolutionary outcomes. Isolated populations evolved into new species, while newly connected areas saw species exchanges. This dance of plate movement and life adaptation is key to understanding Earth's biodiversity history.
Supercontinent Cycles
Pangaea and Continental Drift
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- Supercontinent cycle describes the periodic assembly and breakup of supercontinents over geologic time
- is the gradual movement of Earth's continents across the surface of the planet caused by plate tectonic processes
- was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, approximately 335 to 175 million years ago
- Pangaea formed through the collision and suturing of earlier continental land masses and was centered approximately on the equator
Breakup of Pangaea
- Pangaea began to break apart due to the onset of rifting and seafloor spreading in the central Atlantic region during the (~175 million years ago)
- Breakup of Pangaea led to the formation of two smaller supercontinents: in the northern hemisphere and in the southern hemisphere
- Laurasia consisted of the present-day continents of North America and Eurasia (excluding India)
- Gondwana consisted of the present-day continents of South America, Africa, Australia, Antarctica, and the Indian subcontinent
- was an ancient ocean that separated the supercontinents of Gondwana and Laurasia during much of the Mesozoic Era (252 to 66 million years ago)
Paleogeographic Connections
Land Bridges and Biogeographic Provincialism
- Land bridges are narrow strips of land that connect two larger landmasses and allow for the exchange of flora and fauna between them (Isthmus of Panama)
- Formation and disappearance of land bridges throughout Earth's history has played a significant role in shaping biogeographic patterns and species distributions
- refers to the division of Earth's surface into distinct biogeographic regions, each characterized by unique assemblages of flora and fauna
- Paleogeographic configurations, such as the arrangement of continents and oceans, have a strong influence on biogeographic provincialism
Paleoclimatic Effects
- , or the configuration of continents and oceans in the past, has a significant impact on global and regional climate patterns
- Position of continents relative to the equator affects the distribution of solar radiation and heat across the planet's surface
- Presence or absence of land bridges and seaways influences ocean circulation patterns and the distribution of heat and moisture (Tethys Sea, Central American Seaway)
- Changes in paleogeography can lead to major climate shifts, such as the onset of or periods of
Evolutionary Consequences
Allopatric Speciation and Adaptive Radiation
- occurs when populations of a species become geographically isolated from one another, allowing them to evolve independently and diverge into separate species over time
- Plate tectonic processes, such as continental rifting and the formation of land bridges, can create opportunities for allopatric speciation by isolating populations ()
- is the rapid diversification of a single ancestral species into a wide variety of new forms, each adapted to fill a different ecological niche
- Plate tectonics can promote adaptive radiation by creating new habitats and ecological opportunities as continents split apart or collide (Cichlid fish in African Rift Lakes)
- Evolutionary consequences of plate tectonics are evident in the fossil record, which documents the appearance, diversification, and extinction of species in response to changing paleogeography and paleoclimate
Key Terms to Review (16)
Adaptive radiation: Adaptive radiation is the rapid diversification of a single ancestral lineage into a wide variety of forms, each adapted to different ecological niches. This process often occurs in response to new environmental opportunities or after mass extinction events, leading to the emergence of distinct species with unique adaptations.
Allopatric speciation: Allopatric speciation is the process by which new species arise due to geographic isolation, where populations of a single species become separated by physical barriers, leading to divergent evolution. This type of speciation highlights the impact of physical landscape changes and geographical features on the distribution and diversity of species, illustrating how isolating mechanisms can contribute to biodiversity over time.
Biogeographic Provincialism: Biogeographic provincialism refers to the phenomenon where distinct biological communities are geographically separated, leading to unique species compositions and ecological characteristics in different regions. This concept emphasizes how environmental factors, historical events, and geographical barriers can influence the distribution of organisms, creating distinct biogeographic provinces that exhibit specific flora and fauna over time.
Continental drift: Continental drift is the movement of the Earth's continents relative to each other, driven by tectonic forces beneath the Earth's crust. This theory explains how continents have shifted positions over geological time, influencing marine life evolution, species distribution, and ecological interactions across different regions.
Early Jurassic Period: The Early Jurassic Period is the first division of the Jurassic Period, spanning from approximately 201 to 174 million years ago. This era is significant for the rapid recovery and diversification of life after the mass extinction at the end of the Permian, as well as for the ongoing effects of plate tectonics on global ecosystems and the distribution of species.
Global warming: Global warming refers to the long-term increase in Earth's average surface temperature due to human activities, primarily the emission of greenhouse gases like carbon dioxide and methane. This phenomenon has significant implications for ecosystems and species distributions as climate patterns shift, leading to alterations in habitat conditions and species interactions.
Gondwana: Gondwana was a supercontinent that existed from the Late Precambrian to the Jurassic period, comprising present-day South America, Africa, Antarctica, Australia, and the Indian subcontinent. It played a crucial role in shaping the paleogeography and biodiversity of ancient terrestrial ecosystems and influenced the distribution of both vertebrate and invertebrate species across these regions.
Great American Biotic Interchange: The Great American Biotic Interchange refers to the significant exchange of fauna between North and South America that occurred around 3 million years ago during the Pleistocene epoch. This event was largely facilitated by the formation of the Isthmus of Panama, which connected the two continents and allowed various animal species to migrate, leading to a dramatic shift in ecosystems and species distributions in both regions.
Ice Ages: Ice ages are extended periods of time during which global temperatures are significantly lower than today, leading to the expansion of ice sheets and glaciers across large parts of the Earth. These climatic changes have had profound effects on ecosystems and species distributions, influencing biodiversity and the evolution of life on our planet.
Land Bridges: Land bridges are naturally occurring landforms that connect two landmasses, allowing for the movement of species between them. These geological formations have played a crucial role in shaping ecosystems and species distributions over time, particularly during periods of glaciation when sea levels dropped, exposing these connections.
Laurasia: Laurasia was a supercontinent that comprised the northern part of Pangaea, consisting of present-day North America, Europe, and Asia. It played a crucial role in shaping the Earth's geological history and had significant implications for the distribution of ecosystems and species during its existence.
Paleoclimatic effects: Paleoclimatic effects refer to the influence of past climate conditions on ecosystems, species distributions, and geological formations throughout Earth's history. These effects are crucial for understanding how changes in climate—such as temperature, precipitation, and atmospheric composition—have shaped the evolution and migration of species over time. Examining paleoclimatic effects helps reveal patterns in biodiversity and ecosystem dynamics linked to ancient climate events.
Paleogeography: Paleogeography refers to the study of historical geography, specifically how geographic features and environments have changed over geological time. It helps scientists understand the distribution of land and sea, climate variations, and the habitats of ancient organisms, which are crucial for reconstructing past ecosystems and understanding species distributions influenced by geological processes.
Pangaea: Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, approximately 335 to 175 million years ago. This massive landmass brought together nearly all of Earth's landmasses into one interconnected body, which significantly impacted the distribution of species and ecosystems. The formation and subsequent breakup of Pangaea played a crucial role in shaping the planet's biological and geological history.
Supercontinent cycles: Supercontinent cycles refer to the periodic formation and breakup of supercontinents over geological time, typically occurring every 300 to 500 million years. These cycles play a critical role in shaping Earth's geological landscape, influencing climate patterns, and impacting the distribution and evolution of ecosystems and species across the planet.
Tethys Sea: The Tethys Sea was a vast oceanic body that existed during the Mesozoic era, separating the continents of Laurasia to the north and Gondwana to the south. This ancient sea played a crucial role in shaping the distribution of marine and terrestrial life, influencing ecosystems and species interactions through its dynamic geological and climatic changes.