Author: <span>sammardelhi141988</span>

CLASS XII – CHAPTER 7 (NOTES 7.2)

IMMUNITY Introduction The human body is constantly exposed to infectious agents, but not all exposures lead to disease. Immunity is the body's ability to defend itself against disease-causing organisms. Types…

CLASS XII – CHAPTER 7 (NOTES 7.1)

COMMON DISEASES IN HUMANS Introduction Various pathogens cause diseases in humans. Pathogens can enter the body, multiply, and disrupt normal functions. Bacterial Diseases Salmonella Typhi and Typhoid Fever Pathogenic bacterium…

CLASS XII – CHAPTER 6 (NOTES 6.5)

Biological Evolution: Key Concepts and Natural Selection Origin of Evolution: Biological evolution, driven by natural selection, began when cellular life forms with variations in metabolic capabilities emerged on Earth. Darwinian…

CLASS XII – CHAPTER 6 (NOTES 6.6)

Mechanism of Evolution: Variation and Speciation Origin of Variation: The question arises regarding the origin of variation within populations and how speciation occurs. Although Gregor Mendel had discussed inheritable factors…

CLASS XII – CHAPTER 6 (NOTES 6.7)

HARDY-WEINBERG PRINCIPLE Gene Allele Frequencies: In a population, the frequency of alleles for a specific gene or locus can be determined. These allele frequencies are expected to remain constant and…

CLASS XII – CHAPTER 6 (NOTES 6.8)

A Brief Account of Evolution Early Cellular Life (2000 mya): Approximately 2 billion years ago, the first cellular forms of life appeared on Earth. The mechanism by which non-cellular aggregates…

CLASS XII – CHAPTER 6 (NOTES 6.9)

ORIGIN AND EVOLUTION OF MAN 15 Million Years Ago (mya): Around 15 million years ago, primates called Dryopithecus and Ramapithecus existed. They were covered in hair and walked like gorillas…

CLASS XII – CHAPTER 6 (NOTES 6.4)

WHAT IS ADAPTIVE RADIATION? Definition: Adaptive radiation is a biological phenomenon where a single ancestral species diversifies into multiple, distinct species, each uniquely adapted to exploit specific ecological niches or…

CLASS XII – CHAPTER 6 (NOTES 6.2)

EVOLUTION OF LIFE FORMS – A THEORY Traditional religious literature promotes the theory of special creation, which suggests that all living organisms were created in their current forms and that…

I wish there were something for comparison here - this thing is literally 12 inches (30cm) across.

CLASS XII – CHAPTER 6 (NOTES 6.3)

WHAT ARE THE EVIDENCES FOR EVOLUTION? 1. Paleontological Evidence Fossils found in rocks, remains of hard parts of life-forms. Different-aged rock sediments contain fossils of different life-forms. Fossils provide evidence…