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Paleozoic Era Facts & Worksheets

Throughout the Paleozoic Era, or Paleozoic (541 to 251.9 million years ago), there was a significant increase in fish species diversity, and marine organisms were plentiful. During the Paleozoic era in North America, there were frequent movements of shallow oceans and numerous collisions of continents that led to the formation of the Appalachian Mountains.

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Throughout the Paleozoic Era, or Paleozoic (541 to 251.9 million years ago), there was a significant increase in fish species diversity, and marine organisms were plentiful. During the Paleozoic era in North America, there were frequent movements of shallow oceans and numerous collisions of continents that led to the formation of the Appalachian Mountains. Trilobites, cephalopods, insects, and ferns are common Paleozoic fossils. This era concluded with the most significant mass extinction in Earth’s history.

See the fact file below for more information about the Paleozoic Era, or you can download our 23-page Paleozoic Era worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

BOUNDARIES OF THE ERA

  • The Paleozoic base is a significant geological time division marking the transition between the Proterozoic and Phanerozoic eons, the Paleozoic and Neoproterozoic eras, and the Ediacaran and Cambrian periods.
  • In 1835, British geologist Adam Sedgwick identified the base of the Paleozoic as the first occurrence of complex life in the rock record, shown by the dominance of trilobite fauna.
  • The transition between the Paleozoic and Mesozoic eras and the Permian and Triassic periods is identified by the initial appearance of the conodont Hindeodus parvus. This initial biostratigraphic event discovered globally links to the onset of recovery after the end-Permian mass extinctions and environmental shifts.
  • In terrestrial layers, the analogous stratum is identified by the absence of the Permian Dicynodon tetrapods. Events like the eruption of the Siberian Trap flood basalts, the beginning of a greenhouse environment, ocean anoxia and acidification, and the subsequent mass extinction were traditionally thought to indicate the Permian-Triassic boundary.
  • However, they are now considered to have occurred during the last Permian period. The Global Boundary Stratotype Section and Point (GSSP) is located near Meishan, within Zhejiang Province in southern China. The age of the border is determined to be 251.902+/-0.024 million years based on the radiometric dating of volcanic clay layers above and below it.

PERIODS OF THE PALEOZOIC ERA

  • The Paleozoic Era commenced approximately 297 million years following the Precambrian period and concluded with the onset of the Mesozoic period around 250 million years ago. Each significant era on the Geologic Time Scale has been subdivided into periods characterized by the specific living forms that developed during that period.
  • The initial period of the Paleozoic Era is called the Cambrian Period. Many of the ancestors of modern animals originated during the Cambrian Explosion in the early Cambrian era. Although the rapid diversification of life spans millions of years, this timeframe is somewhat brief in the context of Earth’s history.
  • During the Cambrian Period, most life existed in the waters, with any life on land limited to unicellular bacteria. Fossils from the Cambrian period have been discovered worldwide, with the majority concentrated in three main fossil beds. The fossil deposits are located in Canada, Greenland, and China.
  • The Ordovician Period follows the Cambrian Period. The second stage of the Paleozoic Era lasted around 44 million years and witnessed increasing diversification of aquatic organisms. Large predatory mollusks consumed smaller species on the ocean floor.
  • Multiple and abrupt environmental changes took place during the Ordovician Period. Glaciers expanded from the poles onto the continents, causing a substantial reduction in water levels.
  • Following the great extinction during the Ordovician Period, Earth’s biodiversity had to recover gradually. One significant alteration in Earth’s configuration was the merging of continents, which resulted in increased continuous ocean space for the evolution and diversification of marine life. Animals could now swim and feed at shallower depths than ever before in the history of life on Earth.  
  • Diversification occurred quickly and extensively throughout the Devonian Period. Terrestrial vegetation expanded to encompass ferns, mosses, and seeded plants. The roots of these primitive terrestrial plants facilitated the transformation of weathered rock into soil, providing a favorable environment for plant growth on land. 
  • The Devonian Period concluded due to the impact of massive meteorites on Earth. The meteorite impact is thought to have caused a global extinction, resulting in the loss of approximately 75% of the developed aquatic animal species.
  • The Carboniferous Period was characterized by a need for species variety to recover following a prior catastrophic extinction event. During the Devonian Period, while a mass extinction occurred mainly in the waters, terrestrial flora and animals thrived and evolved rapidly. During the Carboniferous Period, amphibians further adapted and diverged into the early predecessors of reptiles. 
  • The continents were still converging, and glaciers covered the southernmost countries once again.
  • During the Permian Period, all the continents on Earth merged to create the supercontinent Pangaea. Life continued to evolve, and new species emerged in the early stages of this time. Reptiles were well-developed and eventually evolved into a branch that led to the emergence of mammals during the Mesozoic Era. Saltwater fish adapted to survive in freshwater pockets on the Pangaea continent, leading to the emergence of freshwater aquatic creatures.

FLORA AND FAUNA IN THE PALEOZOIC ERA

  • Macroscopic plant life emerged in the Paleozoic Era and potentially in the late Neoproterozoic Era of the previous eon. However, plants primarily existed in aquatic environments until about 420 million years ago during the Silurian Period, when they started to move onto dry land. 
  • During the Carboniferous period, terrestrial plant life peaked, with towering lycopsid rainforests dominating the tropical region of Euramerica. The Carboniferous Rainforest Collapse, triggered by climate change, led to the fragmentation of this environment, resulting in reduced plant diversity during the late Carboniferous and Permian periods.
  • A significant characteristic of Paleozoic life is the abrupt emergence of almost all invertebrate animal species in considerable numbers at the start of the Cambrian period. Primitive fish were the earliest vertebrates to emerge and underwent significant diversification during the Silurian and Devonian Periods.
  • Arthropods were the first animals to explore terrestrial environments. Some fish have lungs and robust bone fins that enabled them to transition onto land during the late Devonian period, approximately 367.5 million years ago. 
  • Over time, the bones in their fins transformed into legs, marking the emergence of the earliest tetrapods 390 million years ago, which also led to the development of lungs. Amphibians were the primary tetrapods until the mid-Carboniferous era when climatic change significantly decreased their variety. Reptiles thrived and multiplied during the late Permian epoch.

CLIMATE IN THE PALEOZOIC ERA

  • The Ordovician and Silurian periods were characterized by warm greenhouse conditions and the highest sea levels of the Paleozoic Era, reaching 200 meters above current levels. This warm climate was briefly interrupted by a 30 million-year icy period known as the Early Palaeozoic Icehouse, which culminated in the Hirnantian glaciation around 445 million years ago at the end of the Ordovician period.
  • The middle Paleozoic was characterized by significant stability. During the ice age, sea levels decreased and gradually rose again over the Silurian and Devonian periods. The gradual fusion of Baltica and Laurentia and the northward displacement of fragments of Gondwana led to the formation of multiple new regions with relatively warm and shallow oceanic floors. 
  • As vegetation established itself on the edges of the continents, oxygen levels rose, and carbon dioxide decreased, albeit to a lesser extent. The temperature difference between north and south regions has decreased, maybe due to metazoan life evolving to be more resilient or combining both factors. 
  • The southern continental borders of Antarctica and West Gondwana have become less barren over time, and the Devonian period concluded with a sequence of turnover events that contributed to the extinction of a significant portion of middle Paleozoic vertebrate species. However, it did not significantly decrease total species diversity.

Paleozoic Era Worksheets

This fantastic bundle includes everything you need to know about the Paleozoic Era across 23 in-depth pages. These ready-to-use worksheets are perfect for teaching kids about the Paleozoic Era. During the Paleozoic era in North America, there were frequent movements of shallow oceans and numerous collisions of continents that led to the formation of the Appalachian Mountains. Trilobites, cephalopods, insects, and ferns are common Paleozoic fossils. This era concluded with the most significant mass extinction in Earth’s history.

Complete List of Included Worksheets

Below is a list of all the worksheets included in this document.

  1. Paleozoic Era Facts
  2. Paleozoic Profiling
  3. Jumbled Letters
  4. Match the Period
  5. Short Quiz
  6. Story Time
  7. Research Time!
  8. What if?
  9. As a Scientist
  10. PopMedia
  11. Memory of Paleozoic

Frequently Asked Questions

What geological events characterized the Paleozoic Era?

The Paleozoic Era, lasting from approximately 541 to 252 million years ago, was marked by significant geological events such as the Cambrian Explosion, the assembly and breakup of supercontinents (like Pangaea), extensive mountain-building episodes (orogenies), and widespread glaciations.

What was the dominant life form during the Paleozoic Era?

The Paleozoic Era saw the emergence and dominance of various life forms, notably marine invertebrates during the early Cambrian period, followed by the rise of jawless fish, jawed fish, and early tetrapods during subsequent periods. Additionally, this era witnessed the diversification and proliferation of plants and insects.

What major evolutionary milestones occurred during the Paleozoic Era?

One of the most significant evolutionary milestones was the Cambrian Explosion, during which a rapid diversification of multicellular life occurred, resulting in the appearance of diverse body plans and the earliest known representatives of many animal phyla. Additionally, the Paleozoic Era saw the evolution of vertebrates from fish to amphibians, the colonization of land by plants and early tetrapods, and the development of terrestrial ecosystems.

How did the climate change throughout the Paleozoic Era?

The Paleozoic Era experienced fluctuations in climate, ranging from warm periods with high sea levels and extensive shallow seas to ice ages marked by glaciations. During the late Paleozoic, the Earth entered a prolonged cooling trend, culminating in the Carboniferous-Permian glaciation, which significantly impacted global climates and contributed to the formation of extensive coal deposits.

What significant mass extinction events occurred during the Paleozoic Era?

The end of the Ordovician period and the end of the Permian period were marked by major mass extinction events. The Ordovician-Silurian extinction event, one of the five largest extinction events in Earth’s history, resulted in the loss of around 85% of marine species. The Permian-Triassic extinction event, also known as the “Great Dying,” was the most severe extinction event in Earth’s history, wiping out over 90% of marine species and approximately 70% of terrestrial vertebrate species.

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Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

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