Evolution: From Fossils to Modern Synthetic Theory
Fossils
Fossils are the remains of organisms or their activity that lived on Earth in times past and became preserved. The fossil record shows that many species that existed in the past no longer exist today, i.e., they are extinct. Moreover, fossils of modern organisms are not found in ancient rocks. The study of fossils reveals a process of change in living beings over time.
Comparative Anatomy
Structural similarities inherited by organisms are called homologies, and the affected organs are called
Read MoreSolar System and Earth’s Formation: A Comprehensive View
Copernicus and the Heliocentric Theory
Nicolaus Copernicus proposed that to explain the constitution of the universe, we must acknowledge that the Sun is the center of the world, a concept known as the Heliocentric Theory.
The Sun and the Milky Way
The Sun is one among the 100,000 million stars in our galaxy, the Milky Way. The solar system resides in one arm of the Milky Way, rotating at a speed of 760,000 Km/h. It takes 230 million years to complete one orbit, known as a galactic year.
Earth’s Age
Read MoreScientific Method, Universe, and the Search for Life
Science and the Heuristic Method
Science is a collective effort, not an individual one, where progress is only possible through collaboration and control by the community. The heuristic method refers to forms of work and thought that support existing mental activities.
What Makes a Scientist? How it Works
- Monitor a phenomenon, wondering about something witnessed.
- Develop a hypothesis that can explain the phenomenon.
- Design an experiment to demonstrate whether the hypothesis is correct.
- Prepare data.
- Draw
Oceans, Seas, and Glaciers: Earth’s Water Systems
Oceans and Seas
Oceans are large bodies of water separating the continents. Planet Earth has five oceans; the largest is the Pacific, with its 180 million km2, larger in extent than all the continents combined. The other four are the Atlantic, Indian, Southern, and Arctic. Within the oceans, seas are areas near the coast, almost always located on the continental shelf.
Seafloor Relief
The average depth of the oceans is about four or five kilometers. This depth varies depending on the area:
- Continental
Human Health and Environmental Impact: A Comprehensive View
Human Health and Disease
The World Health Organization (WHO) defines health as a state of complete physical, mental, and social well-being, not merely the absence of disease. Given the agent that causes disease, diseases can be classified into:
- Infectious
- Non-infectious
Infectious Diseases
Infectious diseases are caused by a pathogen that enters the body and, in most cases, can spread to other people.
Non-infectious Diseases
In non-infectious diseases, a living organism is not directly involved in their
Read MoreWater Resources: Management and Industrial Applications
Water Supply
The oceans store 97.6% of natural water (water alone, in solid, liquid, or gas). The water available to organisms of terrestrial life represents only 0.5% of the total, most of it groundwater. While the amount of atmospheric water is relatively small, its rate of recycling in the atmosphere is relatively high, with an average atmospheric residence time of nine days. Therefore, atmospheric water vapor is renewed 40 times a year. The two human activities that consume more water are industrial
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