Essential Principles of Life Science and Evolution

Fundamental Biological Concepts

Energy Acquisition and Matter Cycling

Autotrophic Organisms

They produce organic matter from inorganic matter (mineral salts, water, etc.) using solar energy.

Heterotrophic Organisms

These are organisms that feed on organic material previously produced by autotrophic organisms.

Photosynthesis

This is the process by which plants, algae, and some bacteria use light energy to synthesize organic matter from carbon dioxide and water.

Cellular Respiration

This is the process in which the organic matter synthesized in photosynthesis is broken down to produce necessary energy for the organism.

The Earth and Life's Domain

Biosphere

The surface area of Earth where living matter exists.

Origins of Life and Planetary Components

Where Did Earth's Components Originate?

Carbon Reservoirs: Carbon accumulated inside the Earth where it formed when our planet originated.

Origin of Water (H₂O): The more accurate assumption is the assertion that asteroids brought water from a larger orbit to Earth.

Hypotheses for the Transformation of Inert Material into Living Matter

1. The Miller-Urey Experiment (Amino Acid Synthesis)

   Stanley Miller synthesized amino acids from ammonia vapor, H₂O, and methane (CH₄), which were assumed to be primitive atmospheric gases. This synthesis was considered the first step toward the emergence of life on early Earth.

2. The Metabolic Hypothesis

   Simple, small molecules were isolated within a membrane environment, initiating a series of chemical processes.

3. The RNA World Hypothesis

   This hypothesis suggests the chance occurrence of RNA molecules capable of replication through mutations.

Dating Rocks and Defining Life

Determining the Age of Geological Materials

We determine the age of minerals by measuring the decay of radioactive elements contained within them.

Radiogenic Elements

Elements generated through the decay of the nuclei of atoms in minerals.

Isotopes

Atoms of the same chemical element that have different masses.

Radioactive Isotopes

Isotopes that disintegrate after a certain period.

Biological Classification and Early Life Theories

Species

A set of organisms that can interbreed and produce fertile offspring.

Panspermia

The hypothesis that argues that the earliest forms of life came from space.

Evolutionary Mechanisms and History

Key Evolutionary Events

Adaptive Radiation

This occurs when new environments emerge (often involving new continents or geographical isolation), leading to the rapid diversification and growth in the number of species.

Dinosaur Extinction

This event occurred 65 million years ago. An asteroid the size of a mountain impacted southern Mexico and caused an environmental disaster (tsunamis, fires, etc.) that killed numerous species.

Theories of Evolution

Darwin and Natural Selection

Charles Darwin proposed natural selection as the mechanism to explain evolution, based on the survival of the fittest. Generation after generation, the characters that confer greater resistance to a species are maintained, while others are lost.

The most resistant individuals reproduce more successfully and transmit their characteristics to their descendants. After many generations, the accumulation of changes will make the last generation so different from the first that it forms a new species. Natural selection was not the first evolutionary theory.

Lamarckism

Lamarck proposed that species varied by acquiring new organs to address new needs or desires—a key concept of adaptation. A central tenet of Lamarckism is that acquired traits are heritable during life, which we now know to be false.

Neo-Darwinism (The Modern Synthesis)

Neo-Darwinism is the union of Darwin's original theory with modern genetics (the synthetic theory of evolution).