Cells as basic unit of living organisms - Session 1

The word biology is derived from the Greek words bios meaning life, and logos meaning study or knowledge. Therefore, the literal meaning of biology is the study or knowledge of life. Biology is a natural science that focuses on the study of living organisms and their interactions with each other and their environment. Biologists use a variety of tools and techniques to study living things, from microscopes and DNA sequencing to field observations and experiments. The study of biology is crucial to our understanding of the natural world. It has important applications in fields such as medicine, agriculture, and environmental conservation.

Life is a fundamental aspect of our existence, but what defines it? At its core, life is characterized by a range of interconnected attributes, including the ability to grow, reproduce, adapt, and respond to stimuli. These characteristics are seen in all living organisms, from the tiniest bacteria to the largest mammals. In addition to these core features, living things also exhibit complex behaviours, from the intricate social interactions of ants to the self-awareness of humans.

However, despite decades of exploration, many questions about the nature of life remain unanswered. What drives living things to persist and evolve, and what secrets do they hold that are yet to be discovered? The mysteries of life continue to captivate and inspire us, driving us to explore and understand the world around us.

Biology is organized into levels of increasing complexity. At the lowest level are subatomic particles, such as electrons, protons, and neutrons. Atoms are the basic unit of matter and make up all living and non-living things. Molecules are groups of atoms that are joined together by chemical bonds to form compounds. The basic unit of life is the cell, which is capable of carrying out all of the functions necessary for survival. Tissues are groups of similar cells that work together to perform a specific function.

Organs are composed of multiple tissues that work together to perform a specific function in the body. Organ systems are groups of organs that work together to carry out a particular function, such as digestion or circulation. At the highest level, organisms are individual living things that can carry out all of the necessary life functions on their own. Finally, populations are groups of individuals of the same species that live in the same area and interact with each other.

Cell theory is the idea that all living things are made up of cells, which are the basic units of life. This theory was first proposed by Matthias Schleiden and Theodor Schwann in the 19th century. The theory has three main principles. First principle states that all living things are composed of one or more cells. Second principle states thatthe cell is the basic unit of life. Third principle is that all cells arise from pre-existing cells. Cells have a specific structure that allows them to carry out their functions. The basic structure of a cell includes a cell membrane, which surrounds the cell and separates its contents from the external environment.

Inside the cell, there is a fluid called cytoplasm, which contains various organelles that perform specific functions. These organelles include the nucleus, which contains genetic material, the mitochondria, which produce energy, and the endoplasmic reticulum and Golgi apparatus, which are involved in protein synthesis and transport. Plant cells also contain additional organelles, such as chloroplasts for photosynthesis and a cell wall for structural support. Understanding cell theory and cell structure is essential for understanding the complex processes that occur within living organisms.

Have you ever wondered how different traits are passed-down from parents to offspring? This is due presence of DNA in living organisms. DNA short for deoxyribonucleic acid is a molecule found in every living organism that carries genetic information. Genetics is the study of how traits are passed-down from one generation to the next through DNA. Each individual has two copies of every gene, one inherited from each parent. A gene is a segment of DNA that contains information. Some traits, such as eye color, are determined by a single gene, while others, such as height, are influenced by multiple genes.

Natural selection is the process by which particular traits become more common in a population over time due to their reproductive advantage. This process is driven by the fact that organisms with advantageous traits are more likely to survive and reproduce, passing on those traits to their offspring. For example, if a population of birds lives in an area with trees of different heights, the birds with longer beaks might be better able to reach food sources on the taller trees. Over time, the birds with longer beaks would be more successful at reproducing and passing on their long-beaked trait to their offspring, while birds with shorter beaks would be at a disadvantage and have fewer offspring.

This gradual process of natural selection can result in significant changes in a population over time, ultimately resulting in the formation of new species. However, it's important to note that natural selection is simply one of several mechanisms of evolution, and the process of evolution is complex.

Ecology is the study of how living organisms interact with each other and their environment. It encompasses the relationships between different organisms, as well as their relationships with abiotic factors like water, soil, and climate. An ecosystem refers to a community of living organisms in a particular area, as well as the physical environment in which they live. Ecosystems can be as small as a puddle or as large as a forest or a desert. They can be classified into different types based on their physical characteristics and the dominant types of organisms that inhabit them.

Biology has played a crucial role in the development of new treatments and drugs for a wide range of diseases. From vaccines to antibiotics, biology has helped to improve human health and extend life expectancy. Understanding how living organisms interact with the environment is critical for protecting ecosystems and biodiversity. Biology helps us understand the effect of human activities on the natural world. For example, Biology is crucial to the development of new crops and farming techniques that can improve food security. It also helps reduce the environmental-impact of agriculture.

Biology has enabled the development of new technologies that have revolutionized fields like genetics and medicine. Biology helps us understand how the human body works, from the molecular level to the systems level. This knowledge is crucial for the development of new medical treatments and for promoting public health.