Cosmic Origins, Earth's Forces, and Human Evolution

Cosmology and Planetary Science

The Big Bang Theory

The Big Bang Theory states that the universe was created from an explosion. Space, matter, and energy were concentrated into a point called the primeval atom, which had very high densities. This atom expanded in a big explosion, initiating the universe's expansion. Energy moved away and transformed into matter, forming subatomic particles and later atoms of hydrogen and helium. This disseminated material condensed across all dimensions, and astronomical structures emerged: nebulae, galaxies, stars, and planets.

Planets of Our Solar System

Mercury

Characterized by many craters, large and numerous lava plains, elongated escarpments, and straight features.

Venus

Its atmosphere is composed of a great amount of nitrogen, CO2, and water vapor.

Earth

Its atmosphere is composed of oxygen. Its privileged position presents ideal conditions for life.

Mars

Its atmosphere is 95% CO2 and 5% nitrogen and helium.

Jupiter

A gaseous planet with a small solid core.

Saturn

Its atmosphere is composed of hydrogen and helium. It includes thousands of ring particles formed by ice.

Uranus

It has three layers: a core, an aqueous mantle, and an atmosphere.

Neptune

Its atmosphere is composed of hydrogen and helium. It has great spin, creating distinct velocity vortices.

Earth's Geological Dynamics

Seismic Waves

P-waves (Primary Waves)

These waves compress and expand the material they pass through in the same direction as their propagation.

S-waves (Secondary Waves)

These waves deform the material's particles in a transverse direction, perpendicular to their propagation.

Surface Waves

These are the slowest waves. When they reach Earth's surface, they cause catastrophes.

Plate Tectonics

The Earth's land is divided into rigid fragments called lithospheric plates. These plates are not static; they constantly change size and position. This movement produces friction between plates and triggers various geological processes of internal origin.

Evolutionary Theories

Lamarck's Ideas on Evolution

• Simple life forms frequently arise through spontaneous generation.
• All organisms possess an inner urge to become more complex.
• The environment changes and causes new requirements, leading to the use or disuse of organs.
• Alterations achieved during an organism's development are maintained and transmitted to its offspring (inheritance of acquired characteristics).

Darwin's Theory of Evolution

• In a changing world, organisms also change. With the passage of time, some become extinct, and new ones appear.
• The process of change is gradual and continuous; there are no sudden leaps or transformations.
• Organisms that share similarities are descended from a common, related ancestor.
• The primary mechanism that gives rise to these changes is evolutionary natural selection.

Human Ancestry and Early Hominins

Key Hominid Species

• Ardipithecus ramidus
• Australopithecus anamensis
• Australopithecus afarensis

Early Human Species

Homo habilis

Known for a skull volume higher than Australopithecus, human-like teeth, beginning to lose body hair, and a diet that included tough plant-based foods.

Homo ergaster

Characterized by a larger skull, smaller teeth, a diet of meat, animal fats, and softer foods. Its skeleton was similar to modern humans.

Homo erectus

Had a more elongated skull with thicker walls, a low and slanting face, massive jaws, and no chin.

Homo antecessor

Possessed archaic characteristics. They were hunters and practiced cannibalism.