Chapter 1: Evolution, Themes of Biology, and Scientific Inquiry – Study Notes

Life: Organization & Characteristics of Living Things

1.1 A View of Life

Biology is the scientific study of life. Biologists seek to understand the diversity and complexity of living organisms, constantly acquiring new knowledge that leads to discoveries about millions of species on Earth.

• Biology: The science that studies living organisms and their interactions with one another and their environments.

• Modern biology uses advanced techniques, such as CRISPR for genome editing, to explore genetic material and cellular processes.

• Biological research provides insights into health, ecology, evolution, and biotechnology.

1.2 Characteristics of Life

All living organisms share a set of fundamental characteristics that distinguish them from non-living matter.

• Composed of cells: The cell is the basic unit of life. Organisms may be unicellular (single-celled) or multicellular (many cells).

• Grow and develop: Organisms increase in size and complexity through cell division and differentiation.

• Regulate their metabolic processes: Organisms carry out chemical reactions (metabolism) to maintain life, including energy use, growth, and repair.

• Respond to stimuli: Organisms detect and react to changes in their environment (e.g., light, temperature, chemicals).

• Reproduce: Organisms produce new individuals, either asexually (without gametes) or sexually (involving gametes and genetic recombination).

• Adapt to the environment: Organisms evolve over generations, developing traits that enhance survival and reproduction in specific environments.

Example: A Paramecium (unicellular organism) moves using cilia and performs all life functions within one cell, while an African buffalo (multicellular organism) has specialized cells and organs for different functions.