Organisms are living systems Organisms A bacterium a
Organisms are living systems
Organisms • A bacterium, a tree and a rat are all living things, yet they look very different and perform different activities. What characteristics do they all have in common? • All living things, or organisms perform basic life functions. • An organism is a living system made up of one or more cells that perform all the functions needed for life and growth.
Subsystems • The body of complex organisms like humans can be organized into subsystems that interact and perform functions. • For example: The human body has the circulatory system and the respiratory system that work together to bring oxygen and nutrients to all cells of your body.
cells • All organisms are made up of cells • A cell is the smallest subsystem of an organism. • The human body has over 200 types of cells.
Unicellular organisms • Organisms made up of a single cell are called unicellular organisms. • Each cell in unicellular organisms perform all the functions required for that organism to stay alive.
Multicellular organisms • Multicellular organisms are made up of more than one cell. • The cells of these organisms are specialized and organized to carry out specific functions.
Tissue • A tissue is a subsystem made up of a group of similar cells that are organized to perform a specific function. • For example: Certain cells in a plant are small and hollow. These cells come together to form a tissue called vascular tissue, that transport water throughout the plant.
Organs • An organ is a subsystem made up of different tissue types that work together to perform a function. • For example: Blood vessels are organs in animals made up of epithelial tissue that controls the passage of blood cells, layers of smooth muscle tissue control the diameter of the vessel, and a tough wall of connective tissue. Connective tissue Epithelial tissue (inside) Smooth muscle Red blood cells
Organ system • Organ system is a subsystem made up of a group of organs that work together to perform body functions. • For example, in animals the heart, lungs and blood vessels are organs of the circulatory system that takes in oxygen from the air through the process of respiration and deliver it to all the cells in the body. • Draw a model that shows the relationship between cells, tissue, organs and organ systems.
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