CHAPTER 8: THE HISTORY OF LIFE ON EARTH
OBJECTIVE: Investigate the diversity of living organisms and how they can be compared scientifically.
SECTION 1 Vocabulary: EVIDENCE OF THE PAST
* FOSSIL- the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock.
* RELATIVE DATING- any method of determining whether an event or object is older or younger than other events or objects.
* ABSOLUTE DATING- any method of measuring the age of an object or event in years.
* GEOLOGIC TIME SCALE- the standard method used to divide the Earth's long natural history into manageable parts.
* EXTINCT- describes a species that has died out completely.
* PLATE TECTONICS- the theory that explains how large pieces of the Earth's outermost layer move and change shape.
SECTION 1 Summary: EVIDENCE OF THE PAST
- Fossils are formed most often in sedimentary rock. The age of a fossil can be determined using relative and absolute dating.
- The geologic time scale is a time line that is used by scientists to outline the history of Earth and life on Earth.
- Conditions for life on Earth have changed many times. Rapid changes might have caused mass extinctions. But many groups of organisms have adapted to changes like these.
SECTION 1 Vocabulary: EVIDENCE OF THE PAST
* FOSSIL- the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock.
* RELATIVE DATING- any method of determining whether an event or object is older or younger than other events or objects.
* ABSOLUTE DATING- any method of measuring the age of an object or event in years.
* GEOLOGIC TIME SCALE- the standard method used to divide the Earth's long natural history into manageable parts.
* EXTINCT- describes a species that has died out completely.
* PLATE TECTONICS- the theory that explains how large pieces of the Earth's outermost layer move and change shape.
SECTION 1 Summary: EVIDENCE OF THE PAST
- Fossils are formed most often in sedimentary rock. The age of a fossil can be determined using relative and absolute dating.
- The geologic time scale is a time line that is used by scientists to outline the history of Earth and life on Earth.
- Conditions for life on Earth have changed many times. Rapid changes might have caused mass extinctions. But many groups of organisms have adapted to changes like these.
GEOLOGIC TIME SCALE
The geologic time scale is a scale that shows the different times and periods that the Earth has had. The geological time scale has four time periods, the Precambrian time, the Paleozoic Era, the Mesozoic Era, and the Cenozoic Era.
SECTION 2 Vocabulary: ERAS OF THE GEOLOGIC TIME SCALE
* THE PRECAMBRIAN TIME- the period on the geological time scale from the formation of the Earth to the beginning of the Paleozoic Era.
* THE PALEOZOIC ERA- the geological era that followed the Precambrian time.
* THE MESOZOIC ERA- the geologic era that lasted for about 251 million years ago to about 65.5 million years ago. : also called the age of reptiles.
* THE CENOZOIC ERA- the most recent geologic era, beginning 65 million years ago: also called the age of mammals.
* THE PRECAMBRIAN TIME- the period on the geological time scale from the formation of the Earth to the beginning of the Paleozoic Era.
* THE PALEOZOIC ERA- the geological era that followed the Precambrian time.
* THE MESOZOIC ERA- the geologic era that lasted for about 251 million years ago to about 65.5 million years ago. : also called the age of reptiles.
* THE CENOZOIC ERA- the most recent geologic era, beginning 65 million years ago: also called the age of mammals.
THE CENOZOIC ERA
The Cenozoic Era is the age of mammals. We currently live in the Cenozoic Era.
SECTION 3 Vocabulary: HUMANS AND OTHER PRIMATES
* PRIMATE- a type of mammal characterized by opposable thumbs and binocular vision.
* HOMINID- a type of primate characterized by bipedalism, relatively long lower limbs, and lack of a tail.
* HOMO SAPIENS- the species of hominids that includes modern humans and their closest ancestors.
SECTION 3 Summary: HUMANS AND OTHER PRIMATES
- Humans, apes, and monkeys are primates. Almost all primates have opposable thumbs and binocular vision.
- Hominids include humans and their humanlike ancestors. Early hominids included austrsapithecines and the homo group.
- Early homo sapiens did not differ from the modern day humans.
* PRIMATE- a type of mammal characterized by opposable thumbs and binocular vision.
* HOMINID- a type of primate characterized by bipedalism, relatively long lower limbs, and lack of a tail.
* HOMO SAPIENS- the species of hominids that includes modern humans and their closest ancestors.
SECTION 3 Summary: HUMANS AND OTHER PRIMATES
- Humans, apes, and monkeys are primates. Almost all primates have opposable thumbs and binocular vision.
- Hominids include humans and their humanlike ancestors. Early hominids included austrsapithecines and the homo group.
- Early homo sapiens did not differ from the modern day humans.
HOMINIDS- HOMO ERECTUS
Hominids lived in the late Cenozoic Era. We humans evolved
from the hominids Homo- Erectus
from the hominids Homo- Erectus