Earths History
EARTH’S HISTORY
Academic Standard 8-2
Study Guide
8-2.1 Explain how biological adaptations of populations enhance their survival in a particular environment
There are variations among species of similar populations. Organisms of a species differ from one another in many of their traits. A trait that helps an organism survive and reproduce is an adaptation. Species in a particular environment that are better adapted to living conditions there and are therefore able to meet their survival needs are more likely to survive and reproduce offspring with those traits.
Natural selection is the process that explains this survival and shows how species can change over time.
8-2.2 Summarize how scientists study Earth’s past environment and diverse life-forms by examining different types of fossils (including molds, casts, petrified fossils, preserved and carbonized remains of plants and animals, and trace fossils).
Mold fossil – forms when sediments bury an organism and the sediments change into rock, the organism decays leaving a cavity in the shape of the organism.
Petrified fossils – form when minerals soak into the buried remains, replacing the remains, and changing them into rock.
Preserved fossils – forms when entire organisms or parts of organisms are trapped in ice, tar or amber and are prevented from decaying.
Carbonized fossil – forms when organisms or parts, like leaves, stems, flowers, or fish, are pressed between layers of soft mud or clay that hardens squeezing almost all the decaying organism away leaving the carbon imprint in the rock.
Trace fossil – forms when the mud or sand hardens to stone where a footprint, tral or burrow of an organism was left behind.
8-2.3 Explain how Earth’s history has been influenced by catastrophes (including impact of an asteroid or comet, climate changes, and volcanic activity) that have affected the conditions on Earth and the diversity of its life-forms.
Earliest life forms
Academic Standard 8-2
Study Guide
8-2.1 Explain how biological adaptations of populations enhance their survival in a particular environment
There are variations among species of similar populations. Organisms of a species differ from one another in many of their traits. A trait that helps an organism survive and reproduce is an adaptation. Species in a particular environment that are better adapted to living conditions there and are therefore able to meet their survival needs are more likely to survive and reproduce offspring with those traits.
Natural selection is the process that explains this survival and shows how species can change over time.
8-2.2 Summarize how scientists study Earth’s past environment and diverse life-forms by examining different types of fossils (including molds, casts, petrified fossils, preserved and carbonized remains of plants and animals, and trace fossils).
Mold fossil – forms when sediments bury an organism and the sediments change into rock, the organism decays leaving a cavity in the shape of the organism.
Petrified fossils – form when minerals soak into the buried remains, replacing the remains, and changing them into rock.
Preserved fossils – forms when entire organisms or parts of organisms are trapped in ice, tar or amber and are prevented from decaying.
Carbonized fossil – forms when organisms or parts, like leaves, stems, flowers, or fish, are pressed between layers of soft mud or clay that hardens squeezing almost all the decaying organism away leaving the carbon imprint in the rock.
Trace fossil – forms when the mud or sand hardens to stone where a footprint, tral or burrow of an organism was left behind.
8-2.3 Explain how Earth’s history has been influenced by catastrophes (including impact of an asteroid or comet, climate changes, and volcanic activity) that have affected the conditions on Earth and the diversity of its life-forms.
Earliest life forms