Introduction to Biology Chapter 1 August 26, 2015

Think about it: What is life?

No single characteristic is enough to describe a living thing

Living Things Based on Genetic Code Grow and Develop Respond to Environment Cells Reproduce Stable Internal Environment Obtain and Use Materials Evolve

Characteristics of Living Things  Living things are based on a universal genetic code.  All organisms store the information needed to live, grow, and reproduce in DNA.  This information can be copied and passed on to offspring.  Living things grow and develop.  Every organism has a pattern of development.  A single fertilized egg divides again and again.  As cells divide, they differentiate.

Characteristics of Living Things  Living things respond to their environment.  Stimulus: signal to which an organism responds.  Living things are made up of cells.  The cell is the smallest unit considered to be alive.  Cells are small, but highly organized.

Characteristics of Living Things  Living things reproduce.  All organisms can produce new similar organisms.  Sexual reproduction: cells from two parents unite to form the first cell of a new organism.  Asexual reproduction: a single organism produces offspring identical to itself.  Living things maintain a stable internal environment.  Internal environment must remain stable, even when external conditions change dramatically.  Homeostasis!

Characteristics of Living Things  Living things obtain and use materials and energy.  For growth, development, and reproduction.  Metabolism: the combination of chemical reactions through which an organism builds up or breaks down materials.  Taken as a group, living things evolve.  Only groups change over time.  Life has a common origin.

Think-Pair-Share Imagine a working thermostat that maintains temperature in your home and an active, live animal (such as a fish). Compare and contrast the two objects, noting similarities and differences. Then, summarize why one object is living and the other is nonliving.

The study of biology revolves around several interlocking big ideas: 1.Cellular Basis of Life 2.Information and Heredity 3.Matter and Energy 4.Growth, Development, and Reproduction 5.Homeostasis 6.Evolution 7.Structure and Function 8.Unity and Diversity of Life 9.Interdependence in Nature 10.Science as a Way of Knowing