There is evidence to support the changes in life forms over Earth's history (additions and extinctions) are often accompanied by changes in environmental conditions on Earth. Impacts, climate changes, and volcanism can produce sudden and rapid changes to environmental conditions. Many organisms cannot adapt to these sudden and rapid changes resulting in the extinction of those species. When these events are global in nature then mass extinctions occur.
Volcanic Activity
From the earliest days while Earth was forming to today, volcanic activity has been part of the nature of our ever changing planet.
- During the Precambrian time (the earliest part of Earth's history billions of years ago) volcanic activity was one of the most natural events. Lava flows, ash clouds in the atmosphere, and heat made conditions for life forms extremely difficult. Even the simplest life forms did not survive these conditions.
- As continents collided and mountains began to build up due to plate tectonics, volcanoes continued to form throughout the Paleozoic Era.
- During the rapid movement of tectonic plates in the Mesozoic era, collision and subduction produced extensive volcanic activity around plate boundaries. Plate boundaries are still the location of much of Earth's volcanic activity today.
Very explosive volcanic activity can send ash and dust high into the atmosphere where it is carried great distances around the Earth. The Sun can be blocked for very long periods of time. This violent type of activity can disrupt many of Earth's processes such as food chains and ultimately the life forms that depend on those processes.
Video Guide:
|
|
Topic Tips
- Volcanic activity can affect the climate on Earth by decreasing the amount of sunlight that reaches the surface for long periods of time.
- Volcanic activity can also quickly alter the chemistry of the atmosphere and oceans.
- Volcanic activity can last for millions of years and have potentially caused the greatest extinctions the Earth has ever known.