By Momina Shehzadi | BS Zoology Graduate, Pakistan In this article, we will learn Fungi - Morphology, Reproduction, Physiology and Importance - in simple words with diagram. This topic is very important for BS Zoology and Microbiology students. Fungi are found everywhere around us. They are present in soil, in water, in air, on dead plants, on dead animals, on our food, on our skin and even inside our body. When bread becomes old, green or black spots appear on it. These spots are fungi. When we see mushroom growing after rain, that is also a fungus. When yeast is used to make bread soft, that is also a fungus. Fungi are very different from bacteria and plants. They are eukaryotic organisms. It means their cells have a true nucleus and other membrane bound organelles. They do not have chlorophyll, so they cannot make their own food like plants. They get their food from other living or dead things. That is why they are called heterotrophic organisms. The study of fungi is called mycolog...
By Momina Shehzadi | BS Zoology Graduate from Pakistan
In this article, we will learn about the Levels of Organization in Biology in simple words. This topic is very important for BS Zoology, BSc Zoology, and FSc Pre-Medical students.
1 . Cell-The basic Unit of life
The cell is the smallest and most basic unit of life. All living things are made of one or more cells. For example, your body has trillions of cells. Bacteria has only one cell. A cell is like a single brick of a building. Without a brick, building cannot be made, same without cell, life cannot exist.
The study of cell is called cytology . Each cell has a nucleus, cytoplasm and cell membrane. It performs all life functions like respiration and reproduction.
Example:A nerve cell, a muscle cell, a red blood cell, an egg cell.
2.Tissue - Group of similar cells
When similar cells work together to do the same job, they form a tissue. Study of tissues is called histology. There are 4 main types of tissues in animals: Epithelial tissue, Connective tissue, Muscle tissue and Nervous tissue.
Example:Muscle tissue helps us move, nervous tissue helps us feel pain and cold, blood is also a connective tissue, xylem tissue in plants.
3.Organ - Group of different Tissues
When different types of tissues work together, they form an organ. Each organ has a special and specific function and shape. Organ is a more complex level than tissue.
Example: Heart, Brain, Lungs, Stomach, Kidney, Liver. Your heart is made of muscle tissue, nerve tissue, connective tissue and blood tissue. Leaf is an organ of plant.
4.Organ system - Group of Organs working Together
When different organs work together for a major and common function, they form an organ system. Human body has 11 organ systems. Each system is connected to others.
Example:
-Digestive System(stomach + intestine + liver + pancreas) for digestion.
- Respiratory System (lungs + trachea + nose) for breathing.
- Nervous System (brain + spinal cord + nerves) for control.
- Circulatory System (heart + blood vessels) for blood transport.
5.Organism- A Complete Living Being
All organ systems together make a complete organism - a single living being. An organism can live independently, take food, respire, reproduce and respond to environment. It is the end of body-level organization.
Example: A human, a dog, a fish, a mango tree, a bacteria. All are organisms.
Now we move to the nature-level organization which is studied in Ecology.
6.Population - Same organisms in an Area
A group of the same kind (same species) of organisms living in one place at one time is called a population. They can interbreed with each other.
Example:All humans in Sargodha form a human population, all peacocks in a forest, all mango trees in a farm, all students in your BS Zoology class.
7.Community - Different Populations Together
When different populations of animals, plants and microbes live together and interact in a defined area, they form a community. They depend on each other for food and shelter.
Example: In a pond, fish, frogs, lotus plants, algae and insects live together - that's a pond community. In a forest, lions, deer, trees and birds make a forest community.
8.Ecosystem - Community+Non living Environment
When a community interacts with its non-living or abiotic environment like water, air, sunlight, temperature and soil, it is called an ecosystem. Ecosystem is the basic functional unit of ecology. Term Ecosystem was given by A.G. Tansley.
There are two types: Natural ecosystem (forest, desert) and Artificial ecosystem (aquarium, crop field).
Example: A forest ecosystem, a desert ecosystem, a pond ecosystem, a grassland ecosystem.
9. Biosphere - The largest Level of organization
The biosphere is the biggest and final level! It includes all ecosystems, all living things and all places where life exists on Earth - land (lithosphere), water (hydrosphere) and air (atmosphere). It extends from deep ocean to high mountains.
Example:
Our whole planet Earth is a single biosphere. Biosphere is also called Ecosphere.
Quick Summary Table for Exams
Level What it is? Example
*Cell* Basic unit of life Nerve cell
*Tissue* Group of similar cells Muscle tissue
*Organ* Group of tissues Heart
*Organ System* Group of organs Digestive system
*Organism* One complete living being Human
*Population* Same species in an area All dogs in a city
*Community* Different populations together Pond community
*Ecosystem* Community + Environment Forest ecosystem
*Biosphere* All life on Earth Planet Earth
Conclusion
So, life starts from a very small microscopic cell and goes up to the huge biosphere. Each level is important and connected to the next one like stairs. Lower level makes the higher level. Understanding this ladder helps us to understand how life works, how organisms interact, and why we need to protect our biosphere from pollution.
I hope this easy explanation helped you! If you want to learn about Vertebrates and Invertebrates, read our previous article.
FAQs for Levels of Organization
Q1: What are the 9 levels of organization in biology in order?
Ans: In order they are: Cell, Tissue, Organ, Organ System, Organism, Population, Community, Ecosystem, Biosphere. This is from simplest to most complex. My trick to remember is C T O O O P C E B.
Q2: What is the smallest level of organization?
Ans: Cell is the smallest and basic unit of life. Atom and molecule are smaller but cell is considered smallest living unit.
Q3: What is the largest level of organization?
Ans: Biosphere is the largest level which includes all life on Earth and all ecosystems.
Q4: What is the difference between population and community?
Ans: Population is group of same species living in one area, like all humans in Sargodha. While community is group of different species living together, like fish, frogs and plants in a pond.
Written by Momina Shehzadi from Pakistan. I made these notes for my exams.
Also read previous complete topic what is zoology and branches of zoology
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