Characteristics of Living Things

How do you know if something is alive? All living things… Are made up of units called cells Reproduce Are based on a universal genetic code Grow and develop Obtain and use materials and energy Respond to the environment Maintain a stable internal environment As a group, living things change over time

What is a cell? A collection of living matter enclosed by a barrier that separates the cell from its surrounding. Cells are the smallest units of an organism that can be considered alive. Unicellular = one cell Multi-cellular = many cells

Reproduction Producing new organisms Sexual reproduction= cells from 2 different parents unite to produce the first cell of the new organism. Asexual reproduction= the new organism has a single parent

Based on a Genetic code Offspring resemble their parents because they inherited traits from their parents. The directions for inheritance are carried on DNA. This genetic code determines the inherited traits of every organism on earth.

Growth and Development All organisms grow during at least part of their lives Single celled organisms simply grow in size Multi-cellular organisms grow by development.

Need for materials and energy Organisms use energy and materials to grow and stay alive Metabolism = the combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes

Response to the environment Organisms detect and respond to stimuli from their environment. Stimulus = a signal to which an organism responds

Maintaining internal balance Even though conditions in the external environment vary, most organism must keep internal conditions fairly constant to survive Homeostasis = maintaining internal stability.

Evolution A group of organisms will change over time As the environment changes a group of organism will change to adapt through the passing of traits from one generation to the next generation