Learning Intention: 8.ESS2.1 Science 8th Grade Notes: Standard 16 Learning Intention: 8.ESS2.1 Analyze and interpret data to support the assertion that rapid or gradual geographic changes lead to drastic population changes and extinction events. Terms/phrases to Investigate geographic changes, population changes, extinction events Crosscutting Concepts Patterns, Cause and Effect, Stability and Change Success Criteria/I Can Statement By the end of this unit I will be able to say... ...I can explain how geological changes can effect populations and/or cause extinctions.

Environments always change over time Science 8th Grade Notes: Standard 16 Environments always change over time These changes can happen rapidly (fast) or gradually (slow). It is easier to adapt to slow changes than fast changes. Organisms that cannot adapt to these changes die. If too many individuals die, then the entire species goes extinct. Gradual Change Ice Age to Warm Period Rapid Change Asteroid Impact Dinosaurs Mammoths Extinct Extinct

Geologic Periods Science 8th Grade Notes: Standard 16 There have been (at least) five major extinction events in our planet’s history. There have been many minor extinction events. 5 1) Ordovician-Silurian Event (439 million yrs ago) ---approx. 86% of all life on Earth went extinct. 2) Devonian Event (364 million yrs ago) ---approx. 75% of all life on Earth went extinct 4 3 3) Permian-Triassic Event (250 million yrs ago) ---approx. 96% of all life on Earth went extinct 2 4) Triassic-Jurassic Event (210 million yrs ago) ---approx. 50% of all life on Earth went extinct 1 5) Cretaceous-Paleogen event (65 million yrs ago) ---approx. 76% of all life on Earth went extinct

Gradual Change: Continental Drift As part of Pangaea, Antarctica was once further North. It was much warmer, and dinosaurs lived there. Tectonic plates broke apart and Antarctica moved south. This movement changed Antarctica’s climate. Flora (plants) and fauna (animals) had to adapt or die. Pangaea Present Past Video Link 02 (1 min 36 sec): Continental Drift-600 Million Years

Gradual Change: Continental Drift Tectonic plate movement can uplift or drive down entire continents. About 100 million yrs ago, the Pacific & North American plates collided. This formed a shallow ocean called the North American Inland Sea. Events like this force organisms to adapt or go extinct.

Rapid Change: Volcanic Eruptions Super-volcanoes or large numbers of smaller volcanoes can erupt throwing huge amounts of ash up into the atmosphere. This blocks sunlight which reduces global temperatures. Due to less sunlight, plants begin to die. Then plant eaters (herbivores) start to starve and die. Next, animals that eat herbivores (carnivores) start to starve & die. This has caused the extinction of many species. Video Link (20 seconds): Volcanic Eruption

Permian-Triassic Extinction Event A.K.A. “The Great Dying” About 250 million years ago, massive flood basalt eruptions occurred in Russia (the Siberian Traps). Flood Basalts are high volume eruptions that flood vast areas. This caused the extinction of approx. 96% of all life on Earth.

Gradual Change: Ice Ages and Warming Periods Another cause of environmental change is due to the way the Earth orbits (revolves) the sun. In reoccurring cycles, the Earth wanders in its orbital path. When it wanders closer to the sun, the planet gets warmer. When it wanders away from the sun, the planet gets colder. Species must adapt to these warmer or colder conditions or go extinct. Distance These cold times are called glacial periods These warmer periods are called inter-glacials. As the distance increases or decreases, the Earth becomes colder or hotter.

Rapid Change: Asteroid Impacts Impacts from large asteroids can propel huge amounts of rock-dust into the atmosphere which will block sunlight. With less sunlight, plants begin to die and global temperature drop. Then plant eaters (herbivores) start to starve and die. Next, animals that eat herbivores (carnivores) start to starve & die. Video Link (1 min 15 sec): Asteroid Strike (In the Past)

Rapid Change: Asteroid Impacts Evidence that an asteroid impact caused the dinosaur extinction. A massive crater was found in Mexico (Yucatan Peninsula) With dinosaurs gone, mammals diversified and expanded across the planet in a process called adaptive radiation. Video Link (1 min 19 sec): Asteroid Strike (In the Future?)

Review Questions Notes: Standard 16

Review Questions Notes: Standard 16

Review Questions Notes: Standard 16

Review Questions Notes: Standard 16

Review Questions Notes: Standard 16