4.3 Multicellular Organization

4.3 Multicellular Organization

Unicellular

One cell carries out everything.

Multicellular

*Cells are differentiated to perform specific functions.

Cells make up Tissues that make up Organs that make up Organ Systems that make up Complete Organisms.

Cells The basic unit of life.

Tissues A group of

similar cells which carry out a common function.

Organ Several types of

body tissues that together form a function. Examples are stomach, lungs, heart.

Organ System

A group of organs that interact to perform a set of related tasks. Examples of organ systems are; digestive, respiratory, reproductive, endocrine, immune, urinary.

Organ SystemThe digestive

system is made up of the following organs: mouth, esophagus, stomach, large intestines, small intestines, pancreas, gall bladder.

Organism

Living things.

Specialized Tissues (“MENC”)

Muscle

*contraction

Epithelial

*surface covering

Nervous

*transmits messages

Connective

*support and link together

Specialized Tissues Example of specialized

tissues.Take cells that make

up the stomach. *muscle tissue causes

movement. *epithelial tissue secretes

enzymes. *nervous tissue transmits

messages back and forth from stomach to brain.

*connective tissue holds stomach together.

Plants have Tissues and Organs

Vascular tissue transports water and nutrients from leaves to roots and from roots to leaves.

Organs are roots, stems, leaves.

Prokaryotes *First cells on Earth. * Evidenced by fossils Did not produce own food. Depend on nutrients in environment.*Through evolution, these cells started to

compete for the environment and cells with adaptations evolved. These were eukaryotes.

Colonial Organisms

A collection of genetically identical cells that live together in a closely connected group and each cell group has its own function.

The green alga known as volvox is the evolutionary link between unicellular organisms and multicellular organisms. It still lacks tissues and organs.