6.2 Neogene period

The Neogene period, spanning from 23.03 to 2.58 million years ago, marked significant changes in Earth's climate, geography, and life forms. This second period of the Cenozoic Era saw the expansion of grasslands, diversification of mammals, and evolution of early hominins.

Divided into the Miocene and Pliocene epochs, the Neogene witnessed global cooling trends, sea level fluctuations, and tectonic events. These changes shaped modern ecosystems, leading to the emergence of C4 plants, grazing mammals, and the foundation for human evolution.

Neogene period overview

• The Neogene period is the second period of the Cenozoic Era, spanning from 23.03 million years ago to 2.58 million years ago
• It follows the Paleogene period and is succeeded by the Quaternary period
• The Neogene period witnessed significant changes in climate, geography, and biotic evolution that shaped the modern world

Miocene and Pliocene epochs

Top images from around the web for Miocene and Pliocene epochs

• 

  4.2.4 Phylogenetic Trees and Classification | Digital Atlas of Ancient Life View original

  Is this image relevant?

• 

  Palaeos Cenozoic: Miocene: The Miocene Epoch View original

  Is this image relevant?

• 

  File:An evolutionary tree of mammals.jpeg - Wikimedia Commons View original

  Is this image relevant?

• 

  4.2.4 Phylogenetic Trees and Classification | Digital Atlas of Ancient Life View original

  Is this image relevant?

• 

  Palaeos Cenozoic: Miocene: The Miocene Epoch View original

  Is this image relevant?

1 of 3

Top images from around the web for Miocene and Pliocene epochs

• 

  4.2.4 Phylogenetic Trees and Classification | Digital Atlas of Ancient Life View original

  Is this image relevant?

• 

  Palaeos Cenozoic: Miocene: The Miocene Epoch View original

  Is this image relevant?

• 

  File:An evolutionary tree of mammals.jpeg - Wikimedia Commons View original

  Is this image relevant?

• 

  4.2.4 Phylogenetic Trees and Classification | Digital Atlas of Ancient Life View original

  Is this image relevant?

• 

  Palaeos Cenozoic: Miocene: The Miocene Epoch View original

  Is this image relevant?

1 of 3

• The Neogene period is divided into two epochs: the Miocene (23.03 to 5.333 million years ago) and the Pliocene (5.333 to 2.58 million years ago)
• The Miocene epoch is characterized by warmer climates, the expansion of grasslands, and the diversification of mammals
• The Pliocene epoch saw a gradual cooling trend, the emergence of modern biomes, and the evolution of early hominins

Neogene climate and geography

• The Neogene period experienced significant climatic and geographic changes that influenced the distribution and evolution of flora and fauna
• These changes included global cooling, sea level fluctuations, and tectonic events that altered landscapes and created new habitats

Miocene climatic optimum

• The Miocene climatic optimum occurred around 17 to 15 million years ago, characterized by warm temperatures and high sea levels
• This period supported the expansion of tropical and subtropical forests and the diversification of plant and animal species adapted to these environments

Mid-Miocene disruption

• The mid-Miocene disruption, around 14 million years ago, marked a shift towards cooler and drier conditions
• This event led to the expansion of grasslands and savannas, particularly in the Northern Hemisphere, and the evolution of grazing mammals

Late Miocene cooling

• The late Miocene, from around 11 to 5 million years ago, saw a gradual cooling trend and increasing aridity
• This period witnessed the further expansion of grasslands, the evolution of C4 photosynthesis in plants, and the diversification of mammals adapted to open environments

Messinian salinity crisis

• The Messinian salinity crisis occurred during the late Miocene, around 6 million years ago, when the Mediterranean Sea became isolated from the Atlantic Ocean
• This event led to the desiccation of the Mediterranean basin, the deposition of thick evaporite layers, and significant changes in the regional climate and biota

Pliocene climate

• The Pliocene epoch was characterized by a gradual cooling trend, with intermittent warm periods
• The global climate was generally warmer and more humid than the present, with higher sea levels and a reduced extent of polar ice caps
• The Pliocene climate supported the expansion of grasslands and savannas, as well as the evolution of modern biomes and ecosystems

Neogene flora and fauna

• The Neogene period witnessed significant changes in flora and fauna, driven by climatic and geographic factors
• The diversification and evolution of plants and animals during this period laid the foundation for modern ecosystems and biodiversity

Miocene flora

• The Miocene epoch saw the expansion of grasslands and savannas, particularly in the Northern Hemisphere, due to increasing aridity and cooling temperatures
• C4 photosynthesis evolved in plants during the late Miocene, enabling them to thrive in warm, dry conditions
• Examples of Miocene flora include the spread of grasses (Poaceae), the diversification of legumes (Fabaceae), and the evolution of succulent plants (Cactaceae)

Pliocene flora

• The Pliocene epoch witnessed the further expansion of grasslands and savannas, as well as the development of modern biomes and plant communities
• The cooler and drier climate favored the evolution of plants adapted to seasonal changes and water stress
• Examples of Pliocene flora include the spread of C4 grasses, the diversification of herbaceous plants, and the evolution of modern tree genera (Quercus, Pinus)

Miocene fauna

• The Miocene epoch saw the diversification of mammals, particularly those adapted to grassland and savanna habitats
• This period witnessed the evolution of large herbivores (proboscideans, perissodactyls, artiodactyls), carnivores, and primates
• Examples of Miocene fauna include the giant ground sloth (Megatherium), the saber-toothed cat (Smilodon), and the early horse (Merychippus)

Pliocene fauna

• The Pliocene epoch was characterized by the continued diversification of mammals and the emergence of modern faunal assemblages
• This period saw the evolution of early hominins, as well as the spread of megafauna adapted to cooler climates
• Examples of Pliocene fauna include the woolly mammoth (Mammuthus primigenius), the giant short-faced bear (Arctodus simus), and the early hominin (Australopithecus afarensis)

Mammalian evolution in the Neogene

• The Neogene period witnessed significant evolutionary changes in mammals, driven by climatic and environmental factors
• Key mammalian groups, such as proboscideans, perissodactyls, artiodactyls, carnivorans, and primates, underwent diversification and adaptation to new habitats

Proboscidean diversity and distribution

• Proboscideans, including elephants and their relatives, diversified during the Neogene period
• The Miocene epoch saw the evolution of various proboscidean lineages, such as gomphotheres, mammutids, and deinotheres, adapted to different habitats and diets
• During the Pliocene, proboscideans spread to new regions, including Africa, Asia, and the Americas, and evolved into modern forms like the woolly mammoth (Mammuthus primigenius)

Perissodactyl evolution

• Perissodactyls, including horses, rhinoceroses, and tapirs, underwent significant evolutionary changes during the Neogene
• The Miocene epoch witnessed the diversification of equids, with the evolution of grazing adaptations and the emergence of the modern horse lineage (Equus)
• Rhinoceroses and tapirs also evolved and spread to new regions during the Miocene and Pliocene, adapting to various habitats and climates

Artiodactyl diversification

• Artiodactyls, including cattle, deer, and pigs, diversified during the Neogene in response to the expansion of grasslands and savannas
• The Miocene saw the evolution of various artiodactyl lineages, such as bovids, cervids, and suids, with adaptations for grazing and browsing
• During the Pliocene, artiodactyls continued to evolve and spread to new regions, with the emergence of modern genera and species

Carnivoran adaptations

• Carnivorans, including cats, dogs, and bears, underwent evolutionary adaptations during the Neogene to exploit new prey resources and habitats
• The Miocene witnessed the evolution of saber-toothed cats (Machairodontinae), adapted for hunting large prey in open environments
• During the Pliocene, carnivorans continued to diversify, with the emergence of modern lineages like wolves, foxes, and big cats

Primate evolution and hominins

• Primates, including monkeys, apes, and early hominins, evolved and diversified during the Neogene period
• The Miocene saw the evolution of various primate lineages, such as the first apes (Proconsulidae) and the ancestors of modern monkeys and gibbons
• The Pliocene witnessed the emergence of early hominins, such as Ardipithecus and Australopithecus, setting the stage for human evolution

Neogene mass extinctions and turnovers

• The Neogene period experienced several mass extinction events and faunal turnovers, driven by climatic and environmental changes
• These events shaped the composition and distribution of flora and fauna, leading to the emergence of modern ecosystems

Mid-Miocene extinction events

• The mid-Miocene disruption, around 14 million years ago, coincided with extinctions and faunal turnovers in various regions
• This event affected marine and terrestrial ecosystems, with the decline of reef-building corals and the turnover of mammalian faunas in Europe and Asia

Late Miocene extinctions

• The late Miocene, particularly the Messinian stage, witnessed significant extinctions and faunal changes
• The Messinian salinity crisis in the Mediterranean region led to the extinction of many marine species and the turnover of terrestrial faunas
• Late Miocene cooling and aridification also contributed to the decline and extinction of various mammalian lineages

Pliocene extinctions and faunal changes

• The Pliocene epoch saw further extinctions and faunal turnovers, particularly during the Pliocene-Pleistocene transition
• Cooling climates and the onset of glacial-interglacial cycles led to the extinction of many species adapted to warmer conditions
• The Pliocene also witnessed the turnover of mammalian faunas, with the decline of archaic forms and the spread of modern lineages

Neogene marine life

• The Neogene period witnessed significant changes in marine ecosystems, driven by climatic, oceanographic, and evolutionary factors
• Marine biota adapted to changing conditions, with the evolution of new species and the restructuring of marine communities

Miocene marine biota

• The Miocene epoch saw the diversification of various marine groups, such as mollusks, echinoderms, and foraminifera
• Reef ecosystems flourished during the Miocene climatic optimum, with the expansion of coral reefs and associated marine life
• The mid-Miocene disruption and the Messinian salinity crisis led to extinctions and turnover in marine faunas

Pliocene marine ecosystems

• The Pliocene epoch witnessed the recovery and restructuring of marine ecosystems following the Messinian salinity crisis
• Cooler climates and changes in ocean circulation patterns influenced the distribution and composition of marine biota
• The Pliocene saw the evolution of modern marine species and the establishment of present-day marine biogeographic patterns

Evolution of marine mammals

• Marine mammals, including cetaceans (whales, dolphins) and pinnipeds (seals, sea lions), underwent significant evolution during the Neogene
• The Miocene epoch saw the diversification of various cetacean lineages, such as baleen whales (Mysticeti) and toothed whales (Odontoceti)
• Pinnipeds also evolved and diversified during the Miocene and Pliocene, adapting to different marine habitats and climates

Neogene geological events and processes

• The Neogene period was characterized by significant geological events and processes that shaped the Earth's surface and influenced biotic evolution
• These events included tectonic activity, volcanic episodes, and sea level fluctuations

Tectonic activity and orogeny

• The Neogene witnessed ongoing tectonic activity and mountain building (orogeny) in various regions
• The formation of the Himalayan-Tibetan plateau intensified during the Miocene, influencing regional and global climate patterns
• Other notable tectonic events included the uplift of the Andes, the opening of the Gulf of California, and the collision of the African and Eurasian plates

Volcanic episodes and impacts

• Volcanic activity and impacts from extraterrestrial bodies occurred during the Neogene, affecting climate and biota
• The Miocene epoch saw significant volcanic eruptions, such as the Columbia River Basalt Group in North America and the Yellowstone hotspot
• The Pliocene witnessed the formation of the Yellowstone Caldera and the eruption of the Huckleberry Ridge Tuff

Sea level fluctuations

• The Neogene period experienced significant sea level fluctuations, driven by changes in global climate and ice volume
• The Miocene climatic optimum was characterized by high sea levels, leading to the expansion of shallow marine habitats and the diversification of marine biota
• The late Miocene and Pliocene saw a gradual fall in sea levels, punctuated by short-term fluctuations related to glacial-interglacial cycles

Neogene fossil record and localities

• The Neogene period has a rich and diverse fossil record, providing insights into the evolution and paleoecology of flora and fauna
• Numerous fossil localities around the world have yielded important Miocene and Pliocene fossils, contributing to our understanding of this period

Key Miocene fossil sites

• The Miocene epoch has several notable fossil localities, such as the Messel Pit in Germany, known for its exceptionally preserved fossils of early Miocene plants and animals
• The Siwalik Hills in Pakistan and India have yielded a rich record of Miocene mammals, including early primates and proboscideans
• The Ashfall Fossil Beds in Nebraska, USA, preserve a unique assemblage of Miocene mammals killed by volcanic ash

Important Pliocene fossil localities

• The Pliocene epoch also has significant fossil sites, such as the Turkana Basin in Kenya, which has yielded fossils of early hominins and a diverse mammalian fauna
• The Hagerman Fossil Beds in Idaho, USA, are known for their well-preserved Pliocene horses and other mammals
• The Yushe Basin in China has provided insights into Pliocene mammalian evolution and biogeography in Asia

Taphonomy and preservation in the Neogene

• Taphonomy, the study of how organisms become fossilized, plays a crucial role in understanding the Neogene fossil record
• Various taphonomic processes, such as burial, diagenesis, and weathering, influence the preservation and distribution of Neogene fossils
• Exceptional preservation, such as that found in Lagerstätten like the Messel Pit, provides detailed insights into the anatomy and paleoecology of Neogene organisms

Transition to the Quaternary

• The end of the Neogene period marks the transition to the Quaternary, a time of significant climatic and biotic changes
• This transition is characterized by the onset of glacial-interglacial cycles and the evolution of modern ecosystems and species

Pliocene-Pleistocene boundary

• The Pliocene-Pleistocene boundary, set at 2.58 million years ago, marks the beginning of the Quaternary period
• This boundary is defined by the appearance of the planktonic foraminifer Globorotalia truncatulinoides in marine sediments
• The Pliocene-Pleistocene boundary coincides with significant changes in global climate, sea levels, and biotic turnover

Onset of glacial-interglacial cycles

• The transition from the Pliocene to the Pleistocene is marked by the onset of large-scale glacial-interglacial cycles
• These cycles, driven by variations in Earth's orbital parameters (Milankovitch cycles), led to the repeated growth and decay of continental ice sheets
• The onset of glacial-interglacial cycles had profound impacts on global climate, sea levels, and the distribution and evolution of flora and fauna
• The Quaternary period, which follows the Neogene, is characterized by the continued influence of these glacial-interglacial cycles on Earth's ecosystems and biota