Unit 1 Early Earth Study Guide

How would you describe accretion?

• the process by which particles come together due to gravity to create a more massive object

• how molten materials changed position in the planet based on density.

• an isotope with an unstable nucleus, which can spontaneously decay

• Cyanobacteria are prokaryotes that obtain energy via photosynthesis. Fossil cyanobacteria date back to 3.5 billion years.

How would you describe differentiation?

• upper portion of the mantle

• molten materials changed position in the planet based on density

• Cyanobacteria are prokaryotes that obtain energy via photosynthesis. Fossil cyanobacteria date back to 3.5 billion years.

• addition of material to the planet from space. Each new addition added mass to the planet

What are Earth's Layers from inside out?

• outer core, mantle, crust inner core

• mantle, crust, inner core, outer core

• inner core, outer core, mantle, crust

• crust, mantle, outer core, inner core

Which statement best describes the Iron Catastrophe?

• increase in Earth’s mass led to an increase in the planet’s gravitational force.

• universe expanded from a hot, dense initial condition at a specific point in time around 13 billion years ago

• volcanoes releasing huge amounts of water vapor and carbon dioxide

• formation of Earth's layers (very dense iron core and less dense near surface)

What led to complex life on earth?

• The layers of earth settling into their current position based on density

• an increase in atmospheric oxygen

• and increase in atmospheric carbon dioxide

• Complex life was always on earth

Which two gases were present in VERY early Earth?

• Methane and Carbon Dioxide

• Ammonia and Methane

• Helium and hydrogen

• Hydrogen and Oxygen

When did earth start to form?

• 4.5 billion years ago

• 4 billion years ago

• 4.5 million years ago

• 4 million years ago

When did earth begin to cool for the first time?

• 4.5 billion years ago

• 4 billion years ago

• 4 million years ago

• 4.5 million years ago

When did free oxygen start appear in Earth's atmosphere?

• 4.5 billion years ago

• 2.5 billion years ago

• last year :)

• 3.5 billion years ago

What gas does photosynthesis create?

• oxygen

• carbon dioxide

• Water

• carbon monoxide