BS1116 Intro PDF

Dr. Atittaya Tandhanskul BS1116 Basic Biology INTRODUCTION Learning outcomes Briefly describe the unifying themes that characterize the biological sciences Distinguish among the three domains of life, and the eukaryotic kingdoms eukaryote, any cell or organism that possesses a...

Dr. Atittaya Tandhanskul BS1116 Basic Biology INTRODUCTION Learning outcomes Briefly describe the unifying themes that characterize the biological sciences Distinguish among the three domains of life, and the eukaryotic kingdoms eukaryote, any cell or organism that possesses a clearly defined nucleus. Distinguish between the following pairs of terms: discovery science and hypothesis-based science, quantitative and qualitative data, science and technology Overview: Inquiring About the World of Life Evolution is the process of change that has transformed life on Earth Biology is the scientific study of life Biologists ask questions such as: – How a single cell develops into an organism – How the human mind works – How living things interact in communities What properties of life are demonstrated in this flower? A magnolia tree in early spring Connect the concepts of biology What is life? Life is recognized by what living things do The essence of life, therefore, is a complex orchestration of chemistry and information management that allows organisms to adapt and persist through inheritance. Evolution the Overarching Theme of Biology Evolution makes sense of everything we know about living organisms Organisms living on Earth are modified descendants of common ancestors Life can be studied at different levels from molecules to the entire living planet The study of life can be divided into different levels of biological organization Levels of biological organization Emergent properties Emergent properties are properties that are not evident in the individual components of a system, but show up when combining those components, so they might also be called surprises. for example: Bike, you disemble it, and different parts are no use. But when you put all the parts tgh it become sth use full. Emergent properties result from the arrangement and interaction of parts within a system Emergent properties characterize nonbiological entities as well – For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way Emergent properties Reductionism Reductionism The Power and Limitations of Reductionism Reductionism is the reduction of complex systems to simpler components that are more manageable to study – For example, the molecular structure of DNA An understanding of biology balances reductionism with the study of emergent properties –For example, new understanding comes from studying the interactions of DNA with other molecules Systems Biology A system is a combination of components that function together Systems biology constructs models for the dynamic behavior of whole biological systems The systems approach poses questions such as: – How does a drug for blood pressure affect other organs? – How does increasing CO2 alter the biosphere? Organisms interact with their environments, exchanging matter and energy Every organism interacts with its environment, including nonliving factors and other organisms Both organisms and their environments are affected by the interactions between them – For example, a tree takes up water and minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil. Ecosystem Dynamics The dynamics of an ecosystem include two major processes: – Cycling of nutrients, in which materials acquired by plants eventually return to the soil – The flow of energy from sunlight to producers to consumers Energy Conversion Work requires a source of energy Energy can be stored in different forms, for example, light, chemical, kinetic, or thermal The energy exchange between an organism and its environment often involves energy transformations Energy flows through an ecosystem, usually entering as light and exiting as heat Structure and function are correlated at all levels of biological organization Structure and function of living organisms are closely related – For example, a leaf is thin and flat, maximizing the capture of light by chloroplasts Structure and function at different levels of biological organization Cells are an organism’s basic units of structure and function The cell is the lowest level of organization that can perform all activities required for life All cells: – Are enclosed by a membrane – Use DNA as their genetic information The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms A lung cell divides into two smaller cells that will grow and divide again. Eukaryotic and prokaryotic cells A eukaryotic cell has membrane- enclosed organelles, the largest of which is usually the nucleus By comparison, a prokaryotic cell is simpler and usually smaller, and does not contain a nucleus or other membrane-enclosed organelles Bacteria and Archaea are prokaryotic; plants, animals, fungi, and all other forms of life are eukaryotic. The continuity of life is based on heritable information in the form of DNA Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid) DNA is the substance of genes Genes are the units of inheritance that transmit information from parents to offspring DNA Structure and Function Each chromosome has one long DNA molecule with hundreds or thousands of genes DNA is inherited by offspring from their parents DNA controls the development and maintenance of organisms DNA Structure and Function Each DNA molecule is made up of two long chains arranged in a double helix Each link of a chain is one of four kinds of chemical building blocks called nucleotides DNA Structure and Function Genes control protein production indirectly DNA is transcribed into RNA then translated into a protein The process of DNA transcribe to RNA and translate to proteincentral dogma An organism’s genome is its entire set of genetic instructions Advances in systems biology at the cellular and molecular level depend on: “High-throughput” technology, which yields enormous amounts of data Bioinformatics, which is the use of computational tools to process a large volume of data Interdisciplinary research teams The Human Genome Project Feedback mechanisms regulate biological systems Negative feedback Positive feedback as more of a product accumulates, the process that as more of a product accumulates, the process that creates it speeds up and more of the product is creates it slows and less of the product is produced produced Evolution accounts for the unity and diversity of life Evolution accounts for the unity and diversity of life “Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky Evolution unifies biology at different scales of size throughout the history of life on Earth Approximately 1.8 million species have been identified and named to date, and thousands more are identified each year Estimates of the total number of species that actually exist range from 10 million to over 100 million Classifying life The Three Domains of Life Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth Domains, followed by kingdoms, are the broadest units of classification The three-domain system is currently used, and replaces the old five-kingdom system Domain Bacteria and domain Archaea comprise the prokaryotes Domain Eukarya includes all eukaryotic organisms Classifying life Classifying life Classifying life  Unity in the Diversity of Life A striking unity underlies the diversity of life; for example: – DNA is the universal genetic language common to all organisms – Unity is evident in many features of cell structure the architecture of cilia in eukaryotes Charles Darwin and the Theory of Natural Selection Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 Darwin made two main points: – Species showed evidence of “descent with modification” from common ancestors – Natural selection is the mechanism behind “descent with modification” Darwin’s theory explained the duality of Sir. Charles Darwin unity and diversity Example of natural selection natural selection could cause an ancestral species to give rise to two or more descendant species: the finch species of the Galápagos Islands Scientists use two main forms of inquiry in their study of nature Scientists use two main forms of inquiry in their study of nature The word Science is derived from Latin and means “to know” Inquiry is the search for information and explanation There are two main types of scientific inquiry: discovery science and hypothesis-based science 1. Discovery Science Discovery science describes natural structures and processes This approach is based on observation and the analysis of data Data fall into two categories – Qualitative, or descriptions rather than measurements – Quantitative, or recorded measurements, which are sometimes organized into tables and graphs 2. Hypothesis-Based Science Observations can lead us to ask questions and propose hypothetical explanations called hypotheses A hypothesis is a tentative answer to a well-framed question A scientific hypothesis leads to predictions that can be tested by observation or experimentation For example, – Observation: Your flashlight doesn’t work – Question: Why doesn’t your flashlight work? Hypothesis 1: The batteries are dead Hypothesis 2: The bulb is burnt out Both these hypotheses are testable Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent Biology is marked by “discoveries,” while technology is marked by “inventions” Science, Technology, and Society The combination of science and technology has dramatic effects on society – For example, the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases Ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology Dr. Atittaya Tandhanskul Thank you