Chapter 1.3 – Studying Life

Daily Objectives List the characteristics that all living things share. Identify the central themes of biology. Explain how life can be studied at different levels.

Characteristics of Living Things Biology is the science that employs the scientific method to study the living world. What are some characteristics of living things?

Characteristics of Living Things Living things share the following characteristics: Made up of units called cells Based on a universal genetic code (DNA) Obtain and use matter and energy Grow and Develop Reproduce Maintain a stable internal environment Change over time Respond to their environment

Cellular Basis of Life Organisms are composed of one or more cells, which are the smallest units that can be considered fully alive. Cells can grow, respond to their surroundings, and reproduce.

Cellular Basis of Life If an organism is composed of only a single cell it is referred to as a unicellular organism. The cells in multicellular organisms (many celled) are remarkably diverse, existing in a variety of sizes and shapes. Ex. The human body alone is made up of at least 200 types of cells.

Information and Heredity The genetic code is common, with minor variations, to every organism on Earth. That information, carried in DNA, is copied and passed from parents to offspring (Children).

Matter and Energy Matter serves as nutrients to build body structures and energy is used to fuel the processes of life.

Matter and Energy Plants obtain energy from sunlight and take up the nutrients they need from air, water, and soil. Animals must consume other organisms to obtain both nutrients and energy.

Growth and Development Growth = When an organism gets bigger or increases in size Example: Lifting Weights Development = When an organism gets more complex or specialized Example: Puberty

Reproduction All organisms produce new organisms through a process called reproduction. Sexual Reproduction – Cells from two different parents unite to produce the first cell of the new organism. Asexual Reproduction – The new cell has a single parent. Ex. Budding in Hydra

Homeostasis An organism’s ability to maintain a relatively stable internal environment.

Evolution Evolution, or the change in living things over time, explains inherited similarities as well as the diversity of life.

Structure and Function Structures evolve in ways that make particular functions possible, allowing organisms to adapt to a wide range of environments.

Interdependence in Nature All forms of life on Earth are connected together into a biosphere, which literally means “living planet.” Relationships between organisms and their environment depend on these processes: Flow of energy Cycling of matter

Science as a way of Knowing Science is not just a list of “facts.” The job of science is to use observations, questions, and experiments to explain the natural world.

Response to the Environment Organisms detect and respond to stimuli from their environment. A stimulus is a signal to which an organism responds. Ex. Temperature, light, water, movement

Branches of Biology Zoologists (Animals) Botanists (Plants) Cell Biologists (Cells) Geneticists (DNA) Ecologists (Environment)