Levels of Cellular Organization

Into Cells

An organism is a living thing that can carry out life processes by itself. Unicellular organisms are made up of just one cell that performs all of the functions necessary for life. Unicellular organisms do not have levels of organization.

Into Cells

Being unicellular has advantages and disadvantages. Unicellular organisms need fewer resources, and some can live in harsh conditions. A disadvantage would be that the entire organism dies if that one cell dies.

Into Cells

Multicellular organisms are made up of more than one cell. These cells are grouped into different levels of organization, including tissues, organs, and organ systems. The cells that make up a multicellular organism, such as humans and plants, are specialized to perform specific functions.

Into Cells

Characteristics of multicellular organisms are larger size and longer lifespan than unicellular organisms. Disadvantages for multicellular organisms would be requiring more resources and also that the cells of multicellular organisms perform specialized functions and depend on each other to perform all functions required for the organism to live.

Into Tissues

A tissue is a group of similar cells that perform a common function. Humans and many other animals are made up of four basic types of tissue: Nervous, epithelial, connective, and muscle.

Into Tissues

Nervous tissue functions as a messaging system within the body.

Epithelial tissue is protective and forms boundaries, such as skin.

Into Tissues

Connective tissue, including bones and blood, holds parts of the body together and provides support and nourishment to organs.

Muscle tissue helps produce movement.

Into Tissues

Plants have three types of tissue: transport, protective, and ground.
Transport tissue moves water and nutrients
Protective tissue protects the outside of the plant.
Ground tissue provides internal support and storage and absorbs light energy to make food.

Into Organs

A structure made up of a collection of tissues that carries out a specialized function is called an organ. The stomach is an organ that breaks down food for digestion. Different types of tissues work together to accomplish this function. Nervous tissue works to tell the muscle tissue to contract, food and stomach acid is mixed, and food breaks down.

Organs

Plants also have organs that are made up of differnt tissues working together. A leaf is an organ that contains protective tissue to reduce water loss, ground tissue for photosynthesis, and transport tissue to move nutrients from leaves to stems.

Organ Systems

An organ system is a group of organs that work together to perform body functions. Each organ system has a specific job to do for the organism. The digestive system is composed of the stomach, esophagus, and the small and large intestines.

Connection Between Structure & Function

Cells, tissues, organs, and organ systems make up the structure of a multicellular organism. Structure is the arrangement of parts in an organism or object. The structure of a cell, tissue, organ, or organ determines its function. In fact -
The structure of any object determines its function.

Structure Determines Function

Cells, tissues, and organs vary in structure. For example bone cells look different from plant leaf cells. A lung differs from a stomach because they have different functions.

Systems Perform Tasks That Meet The Need of Cells

Groups of cells that work together form tissues. Groups of tissues that work together form organs. Groups of organs that work together form organ systems, and systems work with other systems (circulatory, digestive, respiratory, etc)