Introduction:
The oldest economic activity known is gathering. Gathering refers to the collection of wild plants, fruits, nuts, and other natural resources from the environment for sustenance and survival. This activity predates the development of agriculture and animal domestication.

Explanation:
Gathering was the primary means of obtaining food and resources for early human societies. It involved the search and collection of edible plants, medicinal herbs, and other useful materials from the surrounding environment. This economic activity was prevalent among hunter-gatherer societies, which relied on the natural resources available in their surroundings.

Advantages of Gathering:
1. Abundance of resources: The natural environment offered a wide variety of edible plants, fruits, nuts, and other resources that could be gathered for food and sustenance.
2. Sustainability: Gathering is a sustainable activity as it does not involve the cultivation of crops or the rearing of animals. It relies on the natural regeneration of resources.
3. Minimal environmental impact: Gathering did not require the clearing of land or the use of intensive agricultural practices, resulting in minimal disturbance to the ecosystem.

Challenges of Gathering:
1. Seasonal availability: The availability of resources for gathering varied with the seasons. Certain plants and fruits were only available during specific times of the year, limiting the availability of food and resources.
2. Competition with other species: Humans had to compete with other animals for the same resources, leading to potential conflicts and challenges in accessing abundant food sources.
3. Mobility: Gathering often required mobility as resources could be scattered across different areas. Hunter-gatherer societies had to be nomadic or semi-nomadic to follow the availability of resources.

Transition to Agriculture and Animal Rearing:
Over time, as human societies became more sedentary and developed agricultural techniques, gathering gave way to agriculture and animal rearing. The domestication of crops and animals allowed for a more reliable and controlled food supply, leading to the establishment of settled civilizations.

Conclusion:
Gathering, as the oldest economic activity known, played a crucial role in human survival and the development of early societies. It provided sustenance and resources before the advent of agriculture and animal domestication, laying the foundation for the subsequent economic activities that shaped human civilization.