SWBAT illustrate the vast diversity of life that has been present on Earth over time by using
the geologic time scale.
SWBAT explain how Earth’s history has been influenced by catastrophes (including the
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.
Paleozoic Era
There is little known about this era but there are a couple of things that are for certain.
During the Paleozoic Era, warm, shallow seas covered a lot of the continents. Because of
this, many of the life forms scientists have found are marine (living in the ocean). Trilobites
were very common and eventually other organisms formed shells. These shells were
preserved as fossils and are a part of how scientists know about
this era. Most of the fossil record (layer of fossil in the earth).
Both vertebrates and invertebrates were able to live during this
time. Towards the end of this era, forests began to develop. In
addition, fish like creatures inhabited the shallow seas.
Eventually, these fishlike creatures were able to adapt to become
land animals. During the end of this era, Pangaea formed.
Mountains came together, the seas lost water and many of the
organisms became extinct because they were unable to adapt to
the changing landscapes of Earth.
Mesozoic Era
During the Mesozoic Era, Pangaea broke up. It split into two separate continents, Laurasia
and Gwondaland. Reptiles became the most common animal on land during this era and
dinosaurs came to be in existence as well. Dinosaurs not only
existed but evolved to become bigger and have other characteristics
through the Mesozoic Era. These dinosaurs were both warm and
cold blooded. Birds began to appear during this time, as did small
mammals. The mammals resembled mice and were warm blooded
vertebrates. In addition, plants that produce flowers (called gymnosperms) appeared. The
different kinds of mammals increased as the era continued on. At the end of Mesozoic Era, it
is believed that an asteroid collided with the Earth, and the resulting dust and smoke blocked
the Sun. The plants died and all the animals that ate plants died as well.
Cenozoic Era
This is called the “Era of Recent Life” and this era is still
continuing today. This era is sectioned into two different periods,
the Tertiary and the Quaternary Period, which is still going on
today. Many mountain ranged began to form throughout the
continents. In the late Cenozoic era, the Ice Age occurred, when
the climates cooled greatly. It is believed that the mountains were part of the reason that the
climate was able to cool so much. During this era, the grasslands expanded on the lands and
life forms on Earth became more diverse (more types of life forms started to exist).
Mammals that existed became larger and some mammals moved to live to the sea (ex:
dolphins and whales). Humans (called homo sapiens) appeared around 140,000 years ago and
continued to live today. Flowering plants became more common during this time and
eventually became the most common type of plant.
Related Questions:
1.
What type of life lived during the Paleozoic Era?
2. How did the climate during the Paleozoic Era allow marine life to live?
3.
Why did climate change and the lowering of sea level cause mass extinction?
4. How are the end of the Paleozoic and the Mesozoic era similar? Different?
5. Why did the asteroid that collided with Earth cause mass extinction?
6. What happened to the diversity of life forms during the Cenozoic Era?
7. Did all animals become land animals? If not, which ones were marine life?
8.
How did plants change over time?