Living Systems 7th Grade Science

Living Systems Every living thing has parts that work together. From cells to organs, each part of the system has a job. The parts are called structures, and the kinds of work they do are called functions.

What is a Living System? All living systems are made up of cells, the basic unit of life. Many cells working together at the same job form tissues. Different tissues work together to form organs. Organs work together to form organ systems. Organ systems work together in the body or larger organism.

The Structure of Life Each organism has unique structures suited to its particular way of life. Different organisms may use similar and different structures to do the same job.

Structure and Function For example, tiny hair-like cilia surround the microscopic organism known as a paramecium. The cilia move back-and-forth like the oars of a boat to move the paramecium through water. Can you think of an organism that has similar methods of movement? .

CELLS A cell is the basic unit of structure and function of life. A cell is a living unit. Cells make up living things and carry out the activities that keep a living thing alive.

CELLS Cells have different sizes and shapes, based on their JOB Some can be very SMALL and some can be very LARGE

Brainpop—Cell Specialization . What kind of cells are humans made of: prokaryotic or eukaryotic? . Which organelle gives plant cells their green color? . How long are the LONGEST nerve cells?

TISSUES Tissues are composed of many cells working together to do the same function.

4 Tissue Types of Animals Epithelial Covers the outside of the body and lines inner surfaces of the body. Forms glands Found in your skin Connective Fills in spaces and connects other tissues together; supports, protects, nourishes, and insulates organs. Found in ligaments, cartilage, blood Muscular Contracts and relaxes to allow movement; makes up some organs. Found in your diaphragm, heart, biceps, triceps Nervous Transmits messages through the body. Found in your brain, spinal cord, nerves

4 Tissue Types of Animals

ORGANS Organs are structures that are composed of two or more different types of tissues. They have specific functions and have recognizable shapes. Examples of organs are: Stomach, Liver, Heart, Lungs, and Brain

Organs make up Organ Systems Organs systems consist of related organs that have a common function.

Organs make up Organ Systems Function Skeletal Supports the body

Organs make up Organ Systems Function Muscular Makes the body move

Organs make up Organ Systems Function Digestive Breaks down food and takes in nutrients

Organs make up Organ Systems Function Immune Protects the body from infection and fights disease

Organs make up Organ Systems Function Circulatory Carries oxygen and nutrients to cells as well as picks up carbon dioxide from the body

Organs make up Organ Systems Function Respiratory Takes in oxygen from air and releases carbon dioxide from the body

Organs make up Organ Systems Function Nervous Controls body activities through the brain, spine and nerves

Organs make up Organ Systems Function Excretory Removes wastes

Organs make up Organ Systems Function Endocrine Controls body activities through hormones