Organization of Tissues
Unicellular organisms,
like bacteria and protozoans though made of single cells act as a site for
diverse life activities such as digestion, respiration, excretion and
reproduction. On the other hand, multicellular organisms, like higher plants
and animals, are composed of millions of different types of cells that are
grouped into different levels of organization. Multicellular organisms have
specialized cells, tissues, organs and organ systems that perform specific
functions. In this chapter, you will learn different types of plant and animal
tissues and how they are modified to coordinate life activities.
Multicellular organisms
usually develop from the zygote. Each zygote divides by the process of mitotic
cell division. Repeated cell divisions produce large number of cells which
undergo cellular differentiation. The process of cell division and cell
differentiation lead to the development of specific organs consisting of
specific groups of cells to perform specific functions in the body. Group of
cells positioned and designed to perform a particular function is called a
tissue. An organ is a structure made up of a collection of tissues that carry
out specialized functions for example in plants the root, stem and leaves are
organs; wherein tissues of leaves include epidermis, palisade tissue, spongy
tissue, xylem and phloem. Similarly in animals stomach for example, is an organ
that consists of tissues made of epithelial cells, gland cells and muscle
cells.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2024 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.