In this Grade 7 Life Science lesson from Chapter 6, students learn how fossils provide evidence of Earth's 3.8-billion-year history of life, exploring different types of fossils including bone, mineral replacement, and preserved remains. Students also examine how scientists determine the age of fossils using relative dating and absolute dating methods, including radioactivity measurements. The lesson also introduces key concepts such as unicellular and multicellular organisms and mass extinctions as patterns in the fossil record.
Section 1
Scientists Decode Earth's Past Through Fossils
Fossils, the preserved remains of organisms, help scientists reconstruct Earth's history. Dating techniques determine relative positioning and absolute age, allowing researchers to assemble a timeline of life on Earth.
Section 2
Living Things Evolve From Simple to Complex
Life began as unicellular organisms in oceans about 3.8 billion years ago. Over time, multicellular organisms developed with specialized cells that perform specific tasks, eventually leading to complex life forms.
Section 3
Species Move From Water to Land
Around 500 million years ago, organisms began adapting to life on land. Plants developed roots to obtain water from soil, while animals evolved new structures. This migration created diverse ecosystems beyond oceans.
Section 4
Mass Extinctions Reset Life on Earth
Throughout history, catastrophic events caused numerous species to vanish simultaneously. The Permian Extinction wiped out 90% of ocean species, while the Cretaceous Extinction eliminated dinosaurs, allowing mammals to diversify and thrive.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
Scientists Decode Earth's Past Through Fossils
Fossils, the preserved remains of organisms, help scientists reconstruct Earth's history. Dating techniques determine relative positioning and absolute age, allowing researchers to assemble a timeline of life on Earth.
Section 2
Living Things Evolve From Simple to Complex
Life began as unicellular organisms in oceans about 3.8 billion years ago. Over time, multicellular organisms developed with specialized cells that perform specific tasks, eventually leading to complex life forms.
Section 3
Species Move From Water to Land
Around 500 million years ago, organisms began adapting to life on land. Plants developed roots to obtain water from soil, while animals evolved new structures. This migration created diverse ecosystems beyond oceans.
Section 4
Mass Extinctions Reset Life on Earth
Throughout history, catastrophic events caused numerous species to vanish simultaneously. The Permian Extinction wiped out 90% of ocean species, while the Cretaceous Extinction eliminated dinosaurs, allowing mammals to diversify and thrive.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter