QUESTIONS:
1. Describe the conditions before our planet earth was born. (1 mark). How and when was
earth’s moon formed? (1 mark).
There is sun before our earth is born, but its surrounded by dust and rocks and there is no clue of life existing. The whole solar system is chaotic and filled with gas and dust. However, the solar nebula is gradually condensing which forms the primary model of the solar system. After that, the solar dust and gas collide and merge with each other, then creating larger body of planets.
The Earth’s moon is primarily considered as born 4.5 million years ago.
According to the giant-impact model, there are two body collide in the early earth. (How did the moon form? (n.d.). Retrieved from https://www.nhm.ac.uk/discover/how-did-the-moon-form.html) These two body which is Earth and Theia they become one body and part of it spin and becomes moon of the earth. People tend to consider Earth and Theia comes from the same place and having the same ingredients in the beginning. This also explains why the Earth and Moon have the similar mineral ingredients and the Moon tells us a lot about what is happening to Earth 4 million years ago.
2. What are stromatolites? (1 mark). Why are they considered significant in shaping our
planet? (1 mark).
Stromatolites is originally comes from accumulation of carbon compounds and captured by cyanobacteria which along with photosynthesis. The existing of cyanobacteria can be considered as the first life form with photosynthesis which brings the boom of oxygen level in the earth which builds the foundation of more complex oxygen based life beings. Its changing the earth environment and make it more hospitalize to life in nowadays.
Stromatolites cyanobacteria and Oxygen. Fossils Facts and Finds.com. (n.d.). https://www.fossils-facts-and-finds.com/stromatolites.html
3. Dragonflies, spiders, and other bugs that we see today, were the first creatures to crawl in the land. In what way were they different from today’s bugs and why? (1 mark).
The first is the size, as mentioned before, the oxygen level in million years ago is way much higher which makes these bugs have larger size and brings them greater respiratory efficiency.
Secondly, in order to adapt harsh environment at that time, most of these insects are having really hard, thick shell to protect them from damage of nature disasters.
Thirdly is there habit, those insects are mostly produce their eggs in dark and moisture places to prevent them from drying out and we still can see that from nowadays.
4. How was ozone gas formed around planet earth? (1 mark). Why is it considered a
significant event in the formation of earth’s climate? (1 mark).
Ozone gas (O₃) was formed around planet Earth through the interaction of oxygen molecules (O₂) with ultraviolet (UV) light from the Sun. In the upper atmosphere, particularly in the stratosphere, UV light splits some oxygen molecules into individual oxygen atoms. These free oxygen atoms then combine with other oxygen molecules to form ozone. This process is part of the natural oxygen cycle in the Earth’s atmosphere.
Ozone formation is considered a significant event in the formation of Earth’s climate because it plays a critical role in shielding the surface of the Earth from the Sun’s harmful ultraviolet radiation. By absorbing the majority of the sun’s high-energy UV light, the ozone layer prevents these rays from reaching the surface, protecting living organisms from genetic damage and other harmful effects. This protective layer made it possible for life to develop and thrive on land, influencing the evolution of biological diversity on Earth and helping to stabilize the planet’s climate.
5. One and half billion years ago, mysterious forces hidden beneath the surface was shaping our planet. What were the processes at work and how did they shape our planet? (2 marks).
About one and a half billion years ago, the key geological processes at work beneath the Earth’s surface included plate tectonics and volcanic activity. These processes were crucial in shaping the planet’s surface and its environment.
Plate Tectonics: The movement of Earth’s lithospheric plates over the semi-fluid asthenosphere beneath them drove the formation and rearrangement of continents and oceans. This movement led to phenomena such as the creation of mountain ranges through continental collision, the opening and closing of oceanic basins, and the formation of deep ocean trenches and mid-ocean ridges. Plate tectonics also influenced the distribution of various climatic zones and helped facilitate cycles of supercontinents such as Rodinia, which is believed to have existed around that time.
Volcanic Activity: Associated with plate boundaries and hotspots, volcanic activity contributed to the formation of new crust and the emission of gases like carbon dioxide and water vapor, which are critical for the greenhouse effect that regulates Earth’s temperature. Volcanism also played a role in the chemical differentiation of the Earth’s surface, leading to the formation of diverse rock and mineral types.
These processes not only molded the physical landscape of Earth but also had profound impacts on its atmospheric composition and climate, setting the stage for later biological evolution.
6. Approximately 4 million years ago, explain what conditions led to human evolution and
migration out of Africa? (2 marks)
Approximately 4 million years ago, the conditions that led to human evolution and the eventual migration out of Africa were primarily driven by climatic changes and environmental factors.
**Climatic Changes:** The Earth underwent significant climatic fluctuations around 4 million years ago, with patterns of gradual cooling and drying. These changes altered the African landscape, transforming dense forests into mixed woodlands and grasslands. This shift forced our early ancestors to adapt to new environments, leading to evolutionary changes. For example, bipedalism (walking upright on two legs) is thought to have developed as a means to move more efficiently across open landscapes, which allowed for better heat regulation, wider visual surveillance, and energy-efficient long-distance travel.
**Environmental Factors:** The changing environments created new challenges and opportunities, including diverse diets and new ecological niches. As forests receded, early humans had to travel longer distances to gather food, which fostered improvements in locomotion and increased brain size for better tool use, social interaction, and problem-solving skills. These adaptations were crucial for survival and facilitated cultural and technological innovations.
These evolutionary advancements not only allowed early humans to thrive in various African environments but also equipped them with the skills necessary for migration. As populations grew and climates continued to change, humans began migrating out of Africa in search of new territories, which they were now more adept at colonizing due to their advanced tool use and social structures. This migration was a gradual process that occurred over thousands of years, leading to the eventual global distribution of human populations.
7. What are the three major events that created and shaped our planet as we know it today?
(4 marks) Hint: The documentary explicitly states the most important event that helped
create our planet, please discuss the event, followed by two other important events, based
on your opinion.
The three major events that have significantly created and shaped our planet as we know it today are:
1. **The Formation of the Moon:** Around 4.5 billion years ago, a Mars-sized body collided with the early Earth. This catastrophic event led to the formation of the Moon, which is believed to have played a crucial role in stabilizing Earth’s axis and moderating its climate, enabling a more stable environment that favored the evolution of life. The Moon’s gravitational pull also influences Earth’s tides, which have implications for marine life and weather patterns.
2. **The Great Oxygenation Event:** Approximately 2.4 billion years ago, photosynthesizing cyanobacteria began releasing oxygen as a byproduct, leading to the Great Oxygenation Event. This significant increase in atmospheric oxygen drastically changed the chemical composition of the atmosphere and the oceans, leading to the oxidation of iron and the precipitation of banded iron formations. It also enabled the development of the ozone layer, which protected living organisms from harmful ultraviolet radiation, paving the way for more complex life forms to evolve.
3. **The Development of Plate Tectonics:** The process of plate tectonics, which began more than 3 billion years ago but became well-established by about 2 billion years ago, has had a profound impact on the planet’s landscape, climate, and biological diversity. The movement of tectonic plates has resulted in the formation and breakup of continents, the creation of mountain ranges, and the regulation of carbon dioxide through weathering processes. These dynamics have influenced climate patterns, ocean currents, and the distribution of life on Earth.
These events, each unique and powerful, have interactively shaped the Earth, affecting its physical structure, atmosphere, and life forms, ultimately creating the complex and dynamic planet we live on today.
