Question

Form Hypotheses Suggest some reasons why trilobites might have become extinct at the end of the Paleozoic Era.

Short answer

Trilobites may have gone extinct due to environmental changes or increased competition.

Step-by-step solution

Understanding Extinction

First, we need to recognize what 'extinction' means. Extinction is when a species, such as trilobites, disappears completely from Earth.

Historical Context

Trilobites became extinct at the end of the Paleozoic Era, around 252 million years ago, during a period known as the Permian-Triassic extinction event.

Investigating Possible Causes

Examine possible reasons for the extinction. Common hypotheses include dramatic changes in climate, volcanic eruptions, changes in sea levels, or an asteroid impact event.

Analyzing Environmental Changes

Consider how sudden changes in the environment, such as a dramatic temperature shift or ocean chemistry change, could have led to the extinction of trilobites by reducing their habitat or food sources.

Considering Biological Competition

Explore the possibility that trilobites faced increased competition or predators as new species evolved, making survival more difficult.

Formulating Hypotheses

Based on the previous steps, hypothesize that trilobites might have gone extinct due to environmental changes like climate shifts, volcanic activity, or competition from other species.

Key concepts

Permian-Triassic extinction event

The Permian-Triassic extinction event was a pivotal moment in Earth's history, marking the end of the Paleozoic Era. This event occurred approximately 252 million years ago and is often referred to as the "Great Dying" due to its massive impact on life forms. During this event, an estimated 90% of marine species and 70% of terrestrial vertebrate species vanished. Such widespread extinction dramatically reshaped the biosphere.

Scientists believe several factors contributed to this event. It is often thought that massive volcanic eruptions in the Siberian Traps released significant amounts of carbon dioxide and other gases into the atmosphere. This likely led to severe global warming and ocean acidification, conditions under which many species couldn't survive. Additionally, there is speculation about an asteroid impact, similar to what caused the later extinction of the dinosaurs, although this idea is not as widely supported.

Climatic upheavals and environmental disruptions would have created a hostile environment for many organisms. Trilobites, the extinct marine arthropods, were among the invertebrates unable to cope with these detrimental changes, leading to their disappearance from the fossil record.

Paleozoic Era

The Paleozoic Era is a significant era in Earth's history, lasting from about 541 to 252 million years ago. It is known for the explosion of life forms, famously highlighted by the Cambrian Explosion, when most major animal phyla appeared. This era saw the development of many life forms including the first fish, arthropods, amphibians, and reptiles.

The Paleozoic is typically divided into six geological periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. Each of these periods contributed uniquely to the advancement of life forms and ecosystems on Earth. It was during these times that trilobites thrived, especially during the Cambrian and Ordovician periods when they were very diverse.

• Trilobites were among the most common creatures of the Paleozoic seas.
• They are often used as index fossils because they were widespread and rapidly evolving.
• This helps geologists to date the layers of rock in which they're found.

By the end of the Paleozoic Era, environmental and ecological shifts, culminating in the Permian-Triassic extinction event, led to the demise of many life forms, including the trilobites.

Environmental changes

Environmental changes played a crucial role in the extinction events occurring throughout Earth’s history, especially during the transition from the Paleozoic Era to the Mesozoic Era. These changes can range from rapid climate shifts to alterations in ocean chemistry and sea levels.

During the Permian period, significant volcanic eruptions and associated phenomena led to increased greenhouse gases like CO2, resulting in global warming. This warming, in turn, may have led to oxygen-poor oceans, affecting aquatic life chains fundamentally. High temperatures could hinder many species' survival that needed more oxygenated environments, leaving predators like trilobites at a disadvantage.

Moreover, these severe changes could also impact food availability. As marine environments became more hostile, the organisms dependent on these ecosystems likely suffered, including trilobites. Habitat loss was a significant factor, as suitable living conditions shrank dramatically during tumultuous environmental fluctuations.

• Such environmental transformations often lead to habitat destruction, affecting biodiversity.
• Organisms less adaptable to rapid changes found survival increasingly tricky.
• These combined factors could explain the substantial loss of life during major extinction events.