SS 3 Biology (1st, 2nd & 3rd Term)

Fighting the political apathy Political apathy, a prevalent phenomenon in contemporary society, encapsulates the passive and disengaged attitude or, in some cases, outright refusal of citizens to actively participate in the multifaceted realm of their state’s political affairs. This widespread phenomenon manifests itself through a conspicuous absence of enthusiasm, curiosity, and eagerness when it comes […]

Theories of Evolution Organic Evolution Organic evolution is the sum total of adaptive changes from pre–existing or old forms that has taken place over a long time resulting in diversity of forms, structures and functions among organism. The basis of evolution is that all organisms have pre–existing ancestors. Evidences of Evolution Fossil record: A fossil

Social animals are those in which individuals of the same species live together cooperatively in organized communities known as societies (colonies). Examples of social animals are: social insects (like termites, honey bees or wasps, ants etc), wolves, foxes, baboons etc. Characteristics of Social Insects They live together They display division of labour They show distinct

VARIATION IN POPULATION A population represents a dynamic assembly of organisms belonging to the same species, coexisting within a defined geographical region over a specific duration. This collection of individuals, whether of plants, animals, or microorganisms, forms a vital ecological unit that undergoes continual changes and interactions. Variation, on the other hand, encompasses the array

GENETIC TERMINOLOGY Genetics, the scientific study of heredity and variation in all living organisms, was termed by Dilliam Bateson in 1906. Heredity/Inheritance pertains to the passage and manifestation of traits from parents to offspring, accounting for the common resemblances between them. Variation encompasses the dissimilarities existing among parents, offspring, and siblings. Genes are hereditary units

Courtship Behaviour in Animals and Territoriality: Courtship behaviour in animals refers to a set of behaviours and displays that individuals of a species engage in to attract potential mates and establish a reproductive partnership. This behaviour often involves various signals, sounds, postures, and movements that communicate the fitness and availability of an individual for mating.

STRUCTURE OF A FRUIT A fruit is a matured fertilized ovary of a flower containing one or more seeds. Contrary to this, some plants do not undergo fertilization for the formation of their fruit. Such fruits are called parthenocarpic fruits e.g. banana and pineapple. Such fruits are seedless. A typical fruit has the following parts

Development of Zygotes in Plants In flowering plants, the process of pollination is followed by fertilization, leading to the development of the zygote. This development eventually transforms the flower into a fruit that encloses the seeds. The male and female sex cells responsible for zygote formation are the pollen grain and the ovule, respectively. The

The reproductive system in humans is a complex and vital system responsible for the creation of new life. It plays a fundamental role in the perpetuation of the human species and involves a series of intricate processes that culminate in reproduction. Let’s delve into the various aspects of the reproductive system and the process of

NATURAL DYNAMIC BALANCE: In the realm of nature, a state of dynamic equilibrium prevails. When environmental conditions influenced by population dynamics, encompassing both abiotic and biotic elements, are propitious, growth is encouraged. Conversely, when these conditions turn unfavourable, growth is hindered. A constraining element that curbs population expansion is termed a “limiting factor.” The amalgamation

1. Ecology of Population An ecological population refers to a group of individuals of the same species that live in the same area and interact with each other. This concept is fundamental to the field of ecology, which is the study of how organisms interact with each other and their environment. A population is defined

SENSORY RECEPTORS Living organisms have the ability to respond to changes in their environment, known as stimuli. These stimuli can be of various types, including mechanical, electromagnetic, chemical, or thermal. While most cells in an organism’s body are capable of sensing stimuli, certain cells specialize in detecting specific types of stimuli. These specialized cells are

Structure of The Kidney The mammalian kidney is a reddish-brown, bean-shaped organ located at the posterior end of the abdomen. The right kidney is slightly lower than the left. On cutting a kidney longitudinally, two distinct regions are observed: an outer cortex and an inner medulla. Narrow tubules called urinary tubules (nephrons) pass through these

What are Hormones? Hormones are chemical substances produced or secreted by endocrine glands, which are ductless glands in the body. They are released into the bloodstream and travel to target organs to exert their effects. Hormones can speed up or slow down biological reactions in the body. They act as chemical messengers, produced in one

LOCATION AND STRUCTURE OF CHROMOSOMES Chromatin granules (thread – like structures) found in the nucleus of eucaryotic cells are the precursors or raw materials of chromosomes.   Chromosomes occur in pairs known as homologous chromosomes. Each chromosome is made up of two threads called chromatids joined at a point called centromere. Each human somatic cell

Genetics is the scientific study of heredity and variation in all living things. The word genetics was coined by Dilliam Bateson (1906

ORGANIC EVOLUTION Organic evolution is the sum total of adaptive changes from pre–existing or old forms that has taken place over a long time resulting in diversity of forms, structures and functions among organism. The basis of evolution is that all organisms have pre–existing ancestors.   Evidences of evolution Fossil record: A fossil is an

ADAPTIVE COLOURATION This is the possession by an organism of a colour which enables it to catch its prey, avoid its predators or enemies, secure mates and ensure their survival. Adaptive colouration may be grouped into Concealing (cryptic) colouration to help organisms blend with their background and remain unnoticed by predators Colour blendingwith the environment

COMPETITION Competition is the process by which living organisms in the habitat struggle with one another for limited essential needs in the environment. Such scarce resources in plants include; light, space, nutrient and water while animals complete for food, space or mate. Competition finally results in survival of the fittest and elimination of the unfit.