Problem Overview:
The task involves interpreting a timeline of Earth's history and matching specific life events to their corresponding physical events. The timeline provides approximate dates for significant physical events, and we need to identify the most appropriate "Life Events" (a–d) that align with these physical events.
Timeline and Life Events:
#### Timeline:
1.
2.5 billion years ago: Oxygen gas is released into seas, then enters atmosphere.
2.
444 million years ago: Protective ozone shield in place in upper atmosphere.
3.
318 million years ago: Widespread drought.
4.
65 million years ago: Earth's climate becomes moist.
#### Life Events:
-
a. Reptiles appear.
-
b. Mammals become dominant on land.
-
c. Plants appear on land.
-
d. Cyanobacteria first begin to carry out photosynthesis.
Solution Approach:
We will analyze each physical event in the timeline and match it with the most appropriate life event based on historical context and scientific understanding.
---
#### 1.
2.5 billion years ago: Oxygen gas is released into seas, then enters atmosphere.
- This event is associated with the
Great Oxidation Event, which occurred when cyanobacteria began producing oxygen through photosynthesis. This was a major turning point in Earth's history as it led to the oxygenation of the atmosphere.
-
Most appropriate life event:
d. Cyanobacteria first begin to carry out photosynthesis.
---
#### 2.
444 million years ago: Protective ozone shield in place in upper atmosphere.
- The formation of the ozone layer provided protection from harmful UV radiation, allowing life to diversify and move onto land.
- This period is also known for the colonization of land by plants, which marks a significant transition in Earth's history.
-
Most appropriate life event:
c. Plants appear on land.
---
#### 3.
318 million years ago: Widespread drought.
- This period corresponds to the late Carboniferous era, which was characterized by extensive coal-forming swamps and forests. However, it was followed by a significant drying trend, leading to the Permian period.
- During this time, reptiles evolved and became more diverse, adapting to the changing environments.
-
Most appropriate life event:
a. Reptiles appear.
---
#### 4.
65 million years ago: Earth's climate becomes moist.
- This period follows the Cretaceous-Paleogene extinction event, which wiped out the dinosaurs. After this event, the climate became more humid and favorable for the rise of mammals.
- Mammals diversified rapidly during this time, becoming the dominant terrestrial vertebrates.
-
Most appropriate life event:
b. Mammals become dominant on land.
---
Final Answer:
Matching the physical events with the life events:
1.
2.5 billion years ago: d. Cyanobacteria first begin to carry out photosynthesis.
2.
444 million years ago: c. Plants appear on land.
3.
318 million years ago: a. Reptiles appear.
4.
65 million years ago: b. Mammals become dominant on land.
Boxed Answer:
\[
\boxed{d, c, a, b}
\]
Parent Tip: Review the logic above to help your child master the concept of skills worksheet science skills.
