Question

Please help ASAP! Describe at least one way in which each of Earth’s subsystems was altered during the Precambrian era.

Answer 1

The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.

The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.

At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.

Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.

Answer 2

The Precambrian Era is the largest on Earth, voering about 600m years, which is around 90% of Earth's age. Nota that this isn't an official era or period, so I recommend calling it "time".

A susystem is system, that functions independently, within another bigger system.

Given all that, let's work trough the differences:

During the precambrian time, some subsystems where not existent.

In the beginning, oceans, lakes and rivers didn't exist, since there still wasn't liquid $H_{2} O$ on Earth.

Since there wasn't a source of water, trees where also inexistant and started develpoing only later on, when soil was adequate (but still in the precambrian era, remember, it covers about 600 million years).

The geopshere was also different at the start of the Precambrian time. It was more active, there still wasn't inactive volcanoes and these where more common and frequent.

The atmosphere was also very different. Gases at that time where different, and the concentration of these as well.

Hope it helped,

BioTeacher101