Welcome to Biology Notes Online! We are the BNO Team, dedicated to providing high-quality, accessible biology study notes for students and teachers alike. Our goal is to simplify complex biological concepts and present them in an easy-to-understand format, entirely free of charge. Whether you're preparing for exams, teaching a class, or simply passionate about biology, our comprehensive notes are designed to support your learning and teaching journey.
What Is Ecology? Ecology is the scientific discipline that focuses on understanding the interactions between living organisms and their environment. It explores how organisms, both plants and animals, interact with each other and their surroundings, including the physical and biological components of their environment. Ecology draws upon various scientific fields, such as biology, geography, geology, … Read more
What is Population? Definition of Population Population can be defined as the total number of individuals, whether human, animal, plant, or microorganism, residing in a specific area or ecosystem. Features/Characteristics Of Population Population characteristics are fundamental in understanding ecological dynamics, encompassing various aspects such as size, density, dispersion patterns, and dispersal mechanisms. The properties of … Read more
Gause’s Principle, also known as the competitive exclusion principle or Gause’s law, is a fundamental concept in ecology that describes the competition between species for limited resources. It states that two species that compete for the same resources cannot coexist in the long term at constant population values. When one species has even a slight … Read more
The history of the Lotka-Volterra predator-prey model can be traced back to the early 20th century. Alfred J. Lotka, an American mathematician and biophysicist, first proposed the model in 1910 in the context of autocatalytic chemical reactions. The model was essentially a logistic equation, initially derived by Pierre François Verhulst. In 1920, Lotka extended the … Read more
What is Community in Ecology? Types of Community Types of community can be classified based on their size and self-regulatory capabilities. Here are the main types of communities: Communities can also be classified based on their openness or closedness: Understanding the types of communities helps ecologists study the dynamics, interactions, and adaptations within different ecological … Read more
A microscope condenser is an integral optical component in the realm of microscopy, designed to focus and direct light onto the specimen being examined. This specialized lens system is strategically positioned beneath the microscope stage, a placement crucial for optimal illumination. The primary function of the condenser is to gather light from the microscope’s light … Read more
What is Phylum Platyhelminthes? Definition of Phylum Platyhelminthes Phylum Platyhelminthes, also known as flatworms, comprises bilaterally symmetrical, triploblastic, dorsoventrally flattened invertebrates lacking circulatory, respiratory, and skeletal systems, characterized by a simple digestive system with a single opening and a protonephridial excretory system. Characteristics of Phylum Platyhelminthes Classification of Phylum Platyhelminthes Class 1- Turbellaria (L., turbella= a little … Read more
What is Phylum Porifera? – Definition of Phylum Porifera Phylum Porifera refers to a group of simple, sessile aquatic animals commonly known as sponges. Sponges lack true tissues and organs and have a porous body structure with numerous channels and chambers that allow water to flow through them. They feed by filtering small particles from … Read more
Origin of Parazoa Choanoflagellate: Link to sponges Sponges’ internal chambers are bordered by a series of specialised cells known as choanocytes (choano = collar; cyte =cell). These are the cells that feed sponges. Each choanocyte, like choanoflagellates, possesses a collar of tentacles enclosing a single anterior flagellum. By undulating dozens of flagella, choanocytes generate a … Read more
Reproduction in Protista Methods of Reproduction in Protists The following paragraphs emphasise the two essential reproductive strategies of protists. The procedures are: A. Asexual Reproduction in Protists Mode of Asexual Reproduction In Protista 1. Binary Fission Mitosis is the division of the parent cell into two identical daughter cells. Examples: Amoeba, Euglena and Paramecium. 2. … Read more
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