Higher plants and animals require more complex structures in order to maintain their bodily processes. Some structures found in plants are organs but these are difficult to compare with those of an animal. Such things as limbs on a tree and plant stems are organs but in the classical sense we only consider organs to be structures like the heart or brain. Just as tissues and cells grouped together to form a higher system, organs do the same. A group of organs working together to perform a task is called an organ system. An example of an organ system is the circulatory system which includes the heart, blood, blood vessels, and lymph vessels in the animal kingdom. In higher animals, there is an organ system for almost every life process that takes place.
An organism is considered the ultimate level of organization. At this level all other levels are working together to make the organism a complete living thing. Thus the definition of an organ system is: A system that is constituted to carry on the life processes by means of organs that are functionally independent but mutually dependent.
Use the following chart to help
students understand the difference between cells, tissues, and organs in
plants and animals.
TISSUES, AND ORGANS
Classifying thin sections of plants and animals.
Swift GH Microscope, prepared
1. Find slides that
represent a cell, tissue, organ, appendage and whole organism.
2. Fill in the chart below
of the slides you are observing
List the whole mount and appendage slides you will be looking at.
Draw a picture of a cell, tissue, appendage, whole organism, and
synthetic material below or on
the back of the worksheet. Try to
label any areas of the slide you can recognize.