Origin of Life and Biological Evolution
The Origin of Life
Spontaneous Generation: It was previously thought that living things arose from decaying organic matter, and any small demonstrations against that idea were rejected.
Pasteur’s Demonstration: Louis Pasteur demonstrated the falsehood of the traditional beliefs. His experiments showed that air contains organisms that break down organic matter, concluding: Every living thing comes from another living being.
Biological Evolution: The Origin of Biodiversity
Biological evolution is the
Read MoreCellular and Tissue Biology: An Overview
Atom: Chemical parts, mainly carbon, hydrogen, oxygen, and nitrogen.
Molecules: Components from cells that form structures, including proteins, carbohydrates, and lipids, transported through cells and the bloodstream.
Cell: The basic unit of living beings, capable of manufacturing its own components.
Bone: A collection of cells.
Body: Formed by different tissues with specific functions.
Apparatus or System: An association of organs working together to perform a vital function.
Homeostasis: The balance
Read MoreFrom First Cells to Modern Humans: Life’s Evolution
1. The Origin of Life
Spontaneous Generation Theory
- Aristotle (384–322 BC): Life can arise from nonliving matter (e.g., frogs from mud, mice from grain).
- Theory persisted until the 17th century.
Refutation of Spontaneous Generation
- Francesco Redi (1626–1697): Experiment with meat and maggots.
- Louis Pasteur (1822–1895): Swan-neck flask experiment disproved spontaneous generation.
Panspermia Hypothesis
- Anaxagoras (500–428 BC): Life exists throughout the universe and spreads via space.
- Svante Arrhenius
Understanding the Human Heart and Blood Vessels
The Heart’s Chambers and Valves
The heart, located between the lungs and slightly to the left within the chest cavity, comprises four chambers surrounded by thick muscular walls. The lower portion of the heart is divided into two chambers: the left and right ventricles, responsible for expelling blood. These ventricles are separated by a wall known as the intraventricular septum.
The upper portion of the heart consists of the right and left atria, which receive blood entering the heart. The atria
Classification and Diversity of Living Organisms
Concept and Use of a Classificatory System
Binomial System
A system of naming species in which the scientific name of an organism is made up of two parts showing the genus (starting with a capital letter) and species (starting with a lower case letter), written in italics when printed (therefore underlined when handwritten) e.g. Homo sapiens
Classes of Animals
Class Fish
Moist skin, fins, gills, scaly skin, poikilothermic (cold-blooded), lays eggs with jelly coat.
Class Amphibia
Poikilothermic (cold-blooded)
Read MoreHuman Body Systems: Functions and Diseases
Human Body Systems: Functions & Diseases
Apparatus and Their Functions
| Apparatus | Function |
|---|---|
| Digestive | Responsible for digesting food and converting it into simpler substances (nutrients) (digestion). |
| Respiratory | Provides for the exchange of gases, i.e., oxygen intake and carbon dioxide removal. |
| Circulatory | Transports oxygen and substances throughout the body via the blood. |
| Excretory | Removes waste substances carried by the blood. |
Anatomy of the Digestive System
Digestive Tract: Mouth, pharynx, esophagus, stomach,
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