Introduction to Biology PDF - Handout

Summary

This handout is an introduction to key concepts in biology. It covers topics like the branches of biology, the origin and properties of life, and the regulation of blood sugar. It is suitable for high school students learning introductory biology concepts.

Full Transcript

# Introduction to Biology - Handout ## Biology * Greek word "bios" means life, and "logos" which means to study * Also known as life science * Coined by Jean Baptiste-Lamarck * Studies living things including their structure, composition, characteristics, functions and classification. *...

# Introduction to Biology - Handout ## Biology * Greek word "bios" means life, and "logos" which means to study * Also known as life science * Coined by Jean Baptiste-Lamarck * Studies living things including their structure, composition, characteristics, functions and classification. * Aristotle - Father of Biology ## Branches of Biology * Anatomy - internal structures * Bacteriology - bacteria * Biotechnology - using biological processes for industrial production * Botany - study of plants * Conchology - shells * Cytology - cell * Ecology - relationship between living and non-living things * Embryology - developmental patterns of an organism from zygote to birth * Endocrinology - endocrine glands and their corresponding hormones * Entomology - insects * Ethology - animal behavior * Evolution - change over time * Genetics - heredity, genes and variations * Helminthology - parasitic worms * Histology - tissues * Ichthyology - fishes * Immunology - immune system * Malacology - mollusks * Mammalogy - mammals * Medicine - preventing, treating, or reducing disease * Microbiology - microscopic organism * Morphology - Form and shape * Mycology - fungi * Ornithology - birds * Paleontology - fossil * Parasitology - parasites * Pathology - diseases * Physiology - functions of organ and body systems * Virology - virus * Zoology - animals ## Life * The culmination of all organism' physiological activities. Sometimes, it is an energetic force that can express all the various domains of action ## Origin of Life * **Divine or Special Creation Theory** * Life was created by a supernatural being or force. * It is often associated with religious beliefs that attribute the creation of life to a divine entity. * **Cosmozoic or Interplanetary Theory (Panspermia)** * Life did not originate on Earth but was brought to our planet from extraterrestrial sources, such as comets or meteorites. * Suggests that life's building blocks or even simple lifeforms may have existed elsewhere in the universe. * **Abiogenesis or Spontaneous Generation** * Life arose from non-living matter through natural processes. * Suggests that under certain conditions, simple organic molecules could have formed and eventually led to the development of living organisms. * **Philosophical Theory of Eternity** * Life has always existed, and there was no specific point of origin. * Often more philosophical than scientific, posits that life is eternal and has continuously existed in some form. * **Marine Theory** * Life originated in the Earth's oceans. * Suggests that the conditions in the early oceans, including the presence of various chemicals and minerals, were conducive to the formation of simple life forms. * **Naturalistic, Evolutionary, or Physico-Chemical Theory (Chemosynthetic Theory)** * Life evolved from simple to complex forms through natural processes and the principles of chemistry and physics. * Associated with the scientific understanding of evolution, posits that life originated from simpler organic molecules and gradually evolved into more complex organisms. ## Properties of Life (HOMAGRR) ### Homeostasis * The ability to maintain internal balance, or normal state of a body * Examples: body temperature regulation, blood sugar level regulation * Relies on feedback mechanisms: * Negative feedback * Positive feedback ### Basic Component of Feedback Mechanism * Stimulus - any change in the environment * Sensor (Receptor) - detects the change and sends information to the control center. * Control center - processes the information and decides how to respond. * Effector - executes the response to restore balance. * Response - the action taken by the effector to reduce or amplify the stimulus. ### Negative Feedback * A negative feedback mechanism reduces or counteracts a change in the body, bringing conditions back to a normal range or "set point." This ensures stability and balance in physiological systems. The image represents a diagram illustrating the concept of homeostasis with the caption "HOMEOSTASIS". The diagram includes two scenarios: one depicting the body cooling down and another depicting the body warming up.. * Left pathway: Too hot, stimulus leads to sweat glands increasing secretion, resulting in evaporative cooling. This leads to body temperature decreasing. * Right pathway: Too cold, stimulus leads to shivering, causing increased heat production. This leads to body temperature increasing. Below the diagram, the following text can be found: "Your sweat glands are signaled to produce perspiration in order to cool you off when your hypothalamus determines that you are too hot. The hypothalamus delivers messages to your muscles when it detects that you are too cold, causing you to shiver and generate heat." ### Regulation of Blood Sugar The Regulation of Blood Sugar is controlled by feedback mechanisms involving the pancreas, liver and body cells. When there are high glucose levels in the blood, the pancreas will release a hormone called insulin that facilitates glucose transport into the cells. This process lowers blood glucose levels. On the other hand, when there are low glucose levels in the blood, the pancreas will release the hormone called glucagon to stimulate the breakdown of glycogen into glucose thereby raising blood glucose levels. ### Positive Feedback * A positive feedback mechanism amplifies or intensifies a change in the body rather than reversing it. This process drives events to completion, often in situations that require a rapid or significant outcome. ### Positive Feedback - Childbirth The image illustrates a positive feedback loop during childbirth. A stimulus(Stess) triggers a sensor(Cervix of uterus), which in turn triggers a control center(brain). The birth of the child will bring the process to a close. * When a baby moves down into the mother's birth canal, it stretches the cervix. This stretching sends signals to the brain (control center), which tells the pituitary gland to release a hormone called oxytocin. Oxytocin makes the uterus contract, pushing the baby further down. These stronger contractions stretch the cervix even more, sending more signals to the brain, which releases more oxytocin. This loop continues until the baby is born, at which point the process stops. It's a cycle that amplifies until the goal - childbirth - is achieved. ## Organization * Made up of one or more cells with complex structures and chemical processes. * Atom - it is the building block of matter. With subatomic particles: * Proton - positively charged particles * Neutron - no charge particles * Electron - negatively charged particles * Molecules/Compound - two or more atoms joined in chemical bonds. * Organelles - tiny organs of the cells that have specific function. They are known as little organs and they are found inside the cell. * Cells - they are the building blocks of life. Basic unit of life. All organisms are made up of cells. * Tissue - when cells of the same structure and function combine together. * Organ - when tissues of the same structure and function combine together. * Organ System - when organs of the same structure and function combine. * Organism - individual living things. * Population - it is a group of the same species living in the same area. * Community - different populations living in the same area. * Ecosystem - it is composed of living and non-living things interacting with one another. * Biomes - it is a region that is divided into categories based on the plants and animals that call it home; Scientists can identify a biome by defining the temperature range, soil type, and amounts of light and water that are peculiar to that location and create niches for various species. * Biosphere - entire planet is thought of as an ecosystem ## Metabolism * The sum of all chemical reactions that occur within an organism. * The process of converting and releasing energy ### Processes of metabolism: * Ingestion - process of taking in food substances * Digestion - process by which the body breaks down food into small molecules through mechanical and chemical means * Respiration - process that delivers oxygen from the air to the body's tissues and removes carbon dioxide. * Excretion - process of removing metabolic wastes from the body, which are byproducts of metabolism. ### Types of metabolism: * Catabolism (Cut) - breakdown of large molecules * Anabolism (Add) - synthesis of large molecules ## Adaptation * Organism's mechanism to be better fit and to survive the conditions of their environment. * Mimicry - resemblance between on organism and another object or species. ### Types of mimicry: * Batesian mimicry - harmless mimics harmful * Mullerian mimicry - harmful mimics another harmful * Aggressive mimicry - predators or parasites share some of the characteristics of a harmless species ## Evolution * Evolution - it is a change over time. It is responsible for variation and biodiversity. ### Types of evolution: * Divergent evolution - occurs when two or more related species become more dissimilar over time * Convergent evolution - occurs when two different organisms develop similar characteristics as a result of the same needs in the environment * Parallel evolution - occurs when related species develop similar traits independently because they have similar ancestral traits ### Evidence of evolution: * Biogeography - similar species are often found in geographically close but ecologically different regions, suggesting a graphic common ancestry. * Fossil Records or Paleontology - fossilized organisms are found in specific layers of rock, and the sequence of these layers reflects the chronological order of species over time. * Molecular Biology - species with a more recent common ancestor tend to have more similar DNA sequences. ### Structures * Homologous Structures - structures with a common evolutionary origin but may have different functions * Analogous Structures - structures with similar functions but different evolutionary origins * Vestigial structures - structures that exist in organisms that have no known function which are believed to be remaining parts from ancestor * Embryology - similarities in the early stages of development among different species suggest common ancestry ### Mechanisms of evolution: * Artificial Selection - mechanism of evolution where humans consciously select for or against particular features in organisms. * Natural Selection - mechanism of evolution where individuals with heritable traits that favor survival and reproduction tend to leave more offspring ### Types of Natural Selection * Stabilizing - favors the intermediate variants in a population and acts against extreme phenotypes at both ends * Disruptive - favors the extreme variants of a trait over the intermediate variants. * Directional - favors one extreme variant of a trait over the other, leading to a shift in the mean of the population ### Genetic Drift * Genetic Drift - evolutionary mechanism where allele frequencies in a population change over generations due to chance events. #### Types of Genetic Drift: * Bottleneck effect - occurs when a sudden sharp decline in the population * Founder Effect - there is a loss of genetic variation due to migration of a small subgroup in the population * Mutation - random changes in an organism's genetic makeup, resulting in new alleles and contributing to genetic variation in a population. * Recombination - mechanism in evolution that introduces genetic variation into populations. This process naturally occurs during the crossing over stage in meiosis. * Speciation - the evolution of new species. Occurs via allopatric (other place) or sympatric (same place) speciation ## Growth and Development * Increase in size and complexity respectively ## Response to Stimuli * Ability to respond to stimulus * Irritability * Stimulus - causes to organism to react. * Response - reaction. * tAxis - directional movement of Animals as a response to a stimulus. * troPism - directional response of Plants toward (positive) or away (negative) from an environmental stimulus ### Types of Stimulus - Response of Organism | Stimulus | Response | | :---------------------- | :---------------------------- | | Phototropism/Phototaxis | Growth response to light | | Geotropism/Geotaxis | Response to gravity | | Thigmotropism/Thigmotaxis | Response to touch | | Chemotropism/Chemotaxis | Response to chemical stimulus | | Hydrotropism/Hydrotaxis | Response to water or soil moisture | | Cryotropism/Cryotaxis | Growth response to cold | | Galvanotropism/Galvanotaxis | Response to electricity | | Rheotropism/Rheotaxis | Response to air or water current | | Chromotropism/Chromotaxis | Response to color | ## Reproduction * Process by which living organisms produce offspring ### Sexual Reproduction * Sexual Reproduction - Involves sex cells (fertilization). Egg cell and a sperm cell combine to produce offspring. Results in genetic variation ### Types of Fertilization: * In vitro fertilization (IVF) - medical procedure where an egg is fertilized with sperm outside the body. (Test tube babies) * In vivo fertilization - natural internal fertilization where the sperm meets and fuses with the egg inside the female's body, typically within the fallopian tubes * Internal fertilization - occurs inside the female's body, where the male's sperm fuses with the female's egg ### Three ways of Internal fertilization: * Oviparity: Offspring develop in eggs outside the mother's body. * Ovoviviparity: Offspring develop in eggs that are retained within the mother's body until they are ready to hatch. * Viviparity: Offspring develop inside the mother and gain nutrients directly from her * External fertilization - happens outside the female's body, commonly in water, where eggs and sperm are released and meet in the external environment ### Asexual Reproduction * Asexual Reproduction - Does not utilize gametes. Only single parent. Identical to parent (clone) ### Types of Asexual Reproduction: * Budding - outgrowth or bud from parents (e.g. hydra) * Binary Fission - living organism splits into two * Fragmentation - breaking of the parent body or cell into many parts (e.g. planaria) * Regeneration - ability to regrow its lost part * Parthenogenesis - an egg develops into a complete individual without being fertilized (e.g. bees)