Exploring the Characteristics of Living Things

1. Lesson Overview 1.3 Studying Life

2. THINK ABOUT IT • Think about important news stories you’ve heard. Ebola coming to the US. Users of certain illegal drugs experience permanent damage to their brains and nervous systems. Reports surface about efforts to clone human cells. • These and many other stories involve biology—the science that employs scientific methodology to study living things. The Greek word bios means “life,” and -logy means “study of.” • The study of life!

3. Characteristics of Living Things • What characteristics do all living things share? • Living things: made up of cells • based universal genetic code (DNA) • obtain and use materials and energy (metabolism) • grow and develop • reproduce • respond to their environment (stimulus) • maintain a stable internal environment (homeostasis) • change over time (evolve)

4. Characteristics of Living Things • Biology is the study of life. But what is life? • No single characteristic is enough to describe a living thing. Also, some nonliving things share one or more traits with organisms. • Some things, such as viruses, exist at the border between organisms and nonliving things. • song

5. Characteristics of Living Things • Despite these difficulties, we can list characteristics that most living things have in common. Both fish and coral, for example, show all the characteristics common to living things.

6. Characteristics of Living Things • Living things are based on a universal genetic code. • All organisms store the complex information they need to live, grow, and reproduce in a genetic code written in a molecule called DNA. • That information is copied and passed from parent to offspring and is almost identical in every organism on Earth.

7. Characteristics of Living Things • Living things grow and develop. • During development, a single fertilized egg divides again and again. • As these cells divide, they differentiate, which means they begin to look different from one another and to perform different functions.

8. Characteristics of Living Things • Living things respond to their environment. • A stimulus is a signal to which an organism responds. • For example, some plants can produce unsavory chemicals to ward off caterpillars that feed on their leaves.

9. Characteristics of Living Things • Living things reproduce, which means that they produce new similar organisms. • Most plants and animals engage in sexual reproduction, in which cells from two parents unite to form the first cell of a new organism.

10. Characteristics of Living Things • Other organisms reproduce through asexual reproduction, in which a single organism produces offspring identical to itself. • Beautiful blossoms are part of an apple tree’s cycle of sexual reproduction.

11. Characteristics of Living Things Living things maintain a relatively stable internal environment, even when external conditions change dramatically. All living organisms expend energy to keep conditions inside their cells within certain limits. This condition process is called homeostasis. For example: specialized cells help leaves regulate gases that enter and leave the plant. when blood pressure rises, the heart slows down when glucose levels in the blood are too high, the pancreas secretes insulin to stimulate the absorption of glucose A fish exchanging gases through its gills to regulate oxygen levels

12. Characteristics of Living Things • Living things obtain and use material and energy to grow, develop, and reproduce. • The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism. • Anabolism- building • Catabolism-breaking down

13. Characteristics of Living Things • Living things are made up of one or more cells—the smallest units considered fully alive. • Many living things consist of only a single cell and are called unicellular organisms. • Plants and animals are multicellular. Cells in multicellular organisms display many different sizes, shapes, and functions. • Despite their small size, cells are complex and highly organized. • .

14. Characteristics of Living Things • Over generations, groups of organisms evolve, or change over time. • Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago.

15. Characteristics of Living Things • All living organisms store genetic information using the same molecules — DNA and RNA. Written in the genetic code of these molecules is compelling evidence of the shared ancestry of all living things.

16. Big Ideas in Biology • All biological sciences are tied together by “big ideas” that overlap and interlock with one another. • Cellular Basis of life • Information & Heredity • Matter & Energy • Growth, Development & Reproduction • Homeostasis • Evolution • Structure & Function • Unity & Diversity of Life • Interdependence • Science as a way of Knowing

17. Scientific Measurement • The metric system is the world standard for measurement. Not only is it used by scientists throughout the world, but most nations have adopted it as their standard of measurement. • The metric system is a decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10. • Most scientists use the metric system when collecting data and performing experiments.

18. Metric System • The following list shows five important basic units in the metric system.

19. Scientific Measurement: Common Metric Units

20. Scientific Measurement • The basic unit of length, the meter, can be multiplied or divided to measure objects and distances much larger or smaller than a meter. The same process can be used when measuring volume and mass. • For example, scientists in Alaska want to measure the mass of a polar bear. What unit of measurement should the scientists use to express the mass?

21. Dimensional Analysis • How many feet in 24 inches?