Introductory Botany 1 Lecture One 2023/24 PDF

**INTRODUCTORY BOTANY 1** **BOT 101: LECTURE ONE** **FIRST SEMESTER, 2023/2024 SESSION** **General Biology** Biology is a branch of science that deals with living organisms and their vital processes. Biology encompasses diverse fields, including botany, conservation, ecology, evolution, genetics...

**INTRODUCTORY BOTANY 1** **BOT 101: LECTURE ONE** **FIRST SEMESTER, 2023/2024 SESSION** **General Biology** Biology is a branch of science that deals with living organisms and their vital processes. Biology encompasses diverse fields, including botany, conservation, ecology, evolution, genetics, marine biology, medicine, microbiology, molecular biology, physiology, and zoology. Biology is subdivided into separate branches for convenience of study, though all the subdivisions are interrelated by basic principles. Thus, while it is customary to separate the study of [[plants]](https://www.britannica.com/plant/plant) ([[botany]](https://www.britannica.com/science/botany)) from that of [[animals]](https://www.britannica.com/animal/animal) ([[zoology]](https://www.britannica.com/science/zoology)), and the study of the structure of organisms ([[morphology]](https://www.britannica.com/science/morphology-biology)) from that of function ([[physiology]](https://www.britannica.com/science/physiology)), all living things share in common certain biological phenomena---for example, various means of [[reproduction]](https://www.britannica.com/science/reproduction-biology), [[cell division]](https://www.britannica.com/science/cell-division), and the transmission of genetic material. **Properties of living organisms** Living things include the visible world of animals, plants, and fungi and the invisible world of [**bacteria**](https://www.thoughtco.com/bacterial-reproduction-373273) and **[viruses](https://www.thoughtco.com/viruses-373893).** All living organisms, regardless of their uniqueness, have certain biological, chemical, and physical characteristics in common. All living organisms share several key properties: order, sensitivity or response to stimuli, reproduction, growth and development, regulation, homeostasis, and energy processing. When viewed together, these eight characteristics serve to define life. These characteristics form the basis of the study of biology. **Order** Organisms are highly organized, coordinated structures with one or more cells. Even very simple, single-celled organisms are remarkably complex: inside each cell, atoms make up molecules; these, in turn, make up cell organelles and other cellular inclusions. In multicellular organisms, similar cells form tissues. Tissues, in turn, collaborate to create organs (body structures with distinct functions). Organs work together to form organ systems. Multicellular Organisms: A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. image **Multicellular Organisms**: A toad represents a highly organized structure of cells, tissues, organs, and organ systems.  **Multicellular Organisms**: A Dicot plant represents a highly organized structure of cells, tissues, organs, and organ systems. **Sensitivity or Response to Stimuli** Organisms can respond to diverse stimuli. For example, plants can grow toward a light source, climb on fences and walls, or respond to touch. Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response. image **Response to Stimuli**: The leaves of this sensitive plant (*Mimosa pudica*) will instantly droop and fold when touched. After a few minutes, the plant returns to normal. **Reproduction** Single-celled organisms reproduce by first duplicating their DNA. They then divide it equally as the cell prepares to divide to form two new cells. Multicellular organisms often produce specialized reproductive germline cells that will form new individuals. When reproduction occurs, genes containing DNA are passed along to an organism's offspring. These genes ensure that the offspring will belong to the same species and will have similar characteristics, such as size and shape.  **Reproduction:** Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics **Growth and Development** All organisms grow and develop following specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species' young will grow up to exhibit many of the same characteristics as its parents. **Regulation** Ability to maintain a constant internal environment in response to environmental changes. Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Two examples of internal functions regulated in an organism are nutrient transport and blood flow. Organs (groups of tissues working together) perform specific functions, such as carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body. **Energy Processing** Energy is constant and energy transformation is not completely efficient. All organisms use a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemical energy in food; others use chemical energy in molecules they take in as food. **Evolution** Evolution i**s a**ny genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable. Finally, **life can adapt and respond** to the demands placed on it by the environment. As a population of organisms interacts with the environment, individuals with traits contributing to reproduction and survival in that particular environment will leave more offspring. Over time, those advantageous traits (called adaptations) will become more common in the population. This process changes over time, is called evolution, and it is one of the processes that explain the diverse species seen in biology. Adaptations help organisms survive in their ecological niches, and adaptive traits may be structural, behavioral, or physiological; adaptations frequently involve other properties of organisms, such as homeostasis, reproduction, and growth and development. **Key Points** - Order can include highly organized structures such as cells, tissues, organs, and organ systems. - Interaction with the environment is shown by response to stimuli. - The ability to reproduce, grow and develop are defining features of life. - The concepts of biological regulation and maintenance of homeostasis are key to survival and define major properties of life. - Organisms use energy to maintain their metabolic processes. - Populations of organisms evolve to produce individuals that are adapted to their specific environment. ***LECTURER: Professor S. Olajide OKE*** ***Department of Botany***