Posing questions about the living world and seeking answers through scientific inquiry are the central activities of biology, the scientific study of life. Biologists’ questions can be ambitious.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
In the living world, the whole is indeed more than the sum of its parts. The emergent properties created by the interactions between levels of biological organization are new, unique characteristics. These properties are governed by the laws of chemistry and physics.
Sylvia S. Mader, Biology (10th ed., 2010), Ch. 1. A View of Life
These emergent properties are due to the arrangement and interactions of parts as complexity increases.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
In life’s structural hierarchy, the cell is the smallest unit of organization that can perform all activities required for life. In fact, the actions of organisms are all based on the functioning of cells.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
The way DNA encodes information is analogous to how we arrange the letters of the alphabet into words and phrases with specific meanings. The word rat, for example, evokes a rodent; the words tarand art, which contain the same letters, mean very different things. We can think of nucleotides as a four-letter alphabet. Specific sequences of these four nucleotides encode the information in genes. Many genes provide the blueprints for making proteins, which are the major players in building and maintaining the cell and carrying out its activities.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
The entire “library” of genetic instructions that an organ ism inherits is called its genome. A typical human cell has two similar sets of chromosomes, and each set has approximately 3 billion nucleotide pairs of DNA. If the one-letter abbreviations for the nucleotides of a set were written in letters the size of those you are now reading, the genetic text would fill about 700 biology textbooks.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
Three important research developments have made the genomic and proteomic approaches possible. One is “high-throughput” technology, tools that can analyze many biological samples very rapidly. The second major development is bioinformatics, the use of computational tools to store, organize, and analyze the huge volume of data that results from high-throughput methods. The third development is the formation of interdisciplinary research teams—groups of diverse specialists that may include computer scientists, mathematicians, engineers, chemists, physicists, and, of course, biologists from a variety of fields.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
There is consensus among biologists that evolution is the core theme of biology. The evolutionary changes seen in the fossil record are observable facts. Furthermore, as we’ll describe, evolutionary mechanisms account for the unity and diversity of all species on Earth.
Jane B. Reece, Lisa A. Urry, et al. Campbell Biology (10th ed., 2014), Ch. 1. Evolution, the Themes of Biology, and Scientific Inquiry
The phrase “common descent with modification” sums up the process of evolution because it means that, as descent occurs from common ancestors, so do modifications that cause organisms to be adapted to the environment. Through many observations and experiments, Charles Darwin came to the conclusion that natural selection was the process that made modification—that is, adaptation—possible.
Sylvia S. Mader, Biology (10th ed., 2010), Ch. 1. A View of Life
Natural selection tends to sculpt a species to fit its environment and lifestyle and can create new species from existing ones. The end result is the diversity of life classified into the three domains of life.
Sylvia S. Mader, Biology (10th ed., 2010), Ch. 1. A View of Life
