Chapter 1 Section 3 Studying Life

The word biology means the study of Life. The Greek word “bio” means “Life,” and “ology” means “study of.”

Biology is the science that seeks to understand the living world.

A biologist is someone who uses a scientific method to study living things.

Characteristics of Living Things Living things share several characteristics. These characteristics include the following: Living things are made up of units called cells.

Living things reproduce.

Living things are based on a universal genetic code.

Living things grow and develop.

Living things obtain and use materials and energy.

Living things respond to their environment.

Living things maintain a stable internal environment.

Taken as a group, living things change over time.

Made up of cells A Cell is a collection of living matter enclosed by a barrier that separates the cell from its surroundings.

Unicellular=single celled. Multicellular=many celled.

Cells are the smallest units of an organism that can be considered alive.

Cells can grow, respond to their surrounding, and reproduce.

Despite their small size, cells are complex and highly organized.

Many living things consist of only a single cell and are therefore called Unicellular organisms.

Multicellular organisms contain hundreds, thousands, or even trillions of cells.

In some multicellular organisms, each type of cell is specialized to perform a different function.

Mid-Section Review Define Biology. What does unicellular mean? Define cell. Define multicellular. List the characteristics of living things. The Greek words “bio” and “ology” mean what? Living things are made up of units called? Complex and highly organized? The smallest unit of Life. In some multicellular organisms, each type of cell is:

Reproduction All organisms produce new organisms through a process called Reproduction.

There are two basic kinds of reproduction: sexual and asexual.

In Sexual Reproduction, two cells from different parents unite to produce the first cell of the new organism.

In Asexual Reproduction, the new organism has a single parent.

In some forms of asexual reproduction, a single celled organism divides in half to form two new organisms.

Based on a Genetic Code Biologists now know that the directions for inheritance are carried by a molecule called Deoxyribonucleic Acid or DNA.

The DNA genetic code determines the inherited traits of every organism on Earth.

Growth and Development All organisms grow during at least part of their lives.

Check Point Give 5 Examples of Growth and Development.

Answer Egg, Lizard. Larva, Fly. Human Baby, Human Adult. Tadpole, Bullfrog. Caterpillars, cocoon, Butterfly.

Need for Materials and Energy The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called Metabolism.

Response to the Environment Each organism responds to changes in its own way.

Maintaining Internal Balance The process by which organisms keep their internal conditions relatively stable is called Homeostasis.

Mid-Section Review Describe the process of asexual reproduction. The DNA genetic code determines? What kinds of reproduction are there? Define Homeostasis. How does Metabolism work? What is an organisms response to its environment? Give 5 examples of how an organism responds to its environment. Define Sexual Reproduction. What is the importance of DNA?

Check Point What is the relationship between Metabolism and Homeostasis?

Key Term Evolve: Change over time.

Branches of Biology The diversity of life is so great that no biologist can study everything, so biology is often organized into branches, or divisions.

The many levels at which life can be studied include molecules, cells, organisms, populations of a single organism, communities of populations living in the same area, and the biosphere.

Levels of Organization Biosphere: The part of Earth that contains all ecosystems.

Ecosystem: Community and its nonliving surroundings.

Community: Populations that live together in a defined area.

Population: Group of organisms of one type that live in the same area.

Organism: Individual living thing.

Section Review Page 22, 1-6

Think, Pair, Share Figures 1-15 & 1-16, What characteristics of life do both of these organisms exhibit? How are these two living things similar, and how are they different? Figure 1-18, How does the Chameleon obtain the energy it needs to live? Where do you think the grasshopper obtained the energy it needed to live? Where did the plants the grasshopper ate obtain the energy they needed to live?

Think, Pair, Share Figure 1-20: What does it mean in your everyday life when you become “Adapted” to a situation? How could an organism such as a plant become “Adapted” to a changing environment? Figure 1-22

Quiz What are the 8 characteristics of living things? What does it mean to evolve? What is homeostasis? Describe the process of Metabolism. What is the Greek word breakdown of Biology? Describe Multi-cellular organisms. Describe uni-cellular organisms. Describe the cell. What are the levels of organization? The diversity of life is so great that: