Chapter 1: An Introduction To Biology PDF

CHAPTER 1 AN INTRODUCTION TO BIOLOGY 1  What is Biology? Biology is the study of life Is it important to study Biology? Absolutely! Investigation of living organisms leads to unforeseen discoveries that  Characteristics of Life 1. Cells and organi...

CHAPTER 1 AN INTRODUCTION TO BIOLOGY 1  What is Biology? Biology is the study of life Is it important to study Biology? Absolutely! Investigation of living organisms leads to unforeseen discoveries that  Characteristics of Life 1. Cells and organization 2. Energy use and metabolism 3. Response to environmental stimuli (changes) 4. Regulation and homeostasis 5. Growth and development 6. Reproduction 7. Evolution 3 1. Cells are the simplest units of life. https://youtu.be/7pR7TNzJ_pA https://www.youtube.com/watch?v=WFpBRfL tbIo https://www.youtube.com/watch?v=W7c1dA OVbvw 4  2. Living organisms use energy. Metabolism includes all the chemical reactions that occur in the cell. All organisms use energy, and energy needs to be converted (changed) to useful energy for the cells. Most of these reactions involve converting energy from one form to another. This includes photosynthesis, but also getting energy by eating (consuming) other organisms and converting the energy in the food to useful energy for the cells by cellular respiration 5  3. Living organisms interact with. their environment. amples: Plants start flowering in response to changes in daylight or temperature Venus flytrap (a carnivorous plant) closes its leaves to catch insects in response to to The stems of plants grow upwards in response to light Roots of plants grow downward in response to gravity Response to environmental stimuli: https://www.youtube.com/watch?v=pCFstSMvAMI 6 4. Living organisms maintain homeostasis. Homeostasis is about maintaining a balance inside the body/cells: All organisms, including humans need to maintain a certain internal temperature (e.g. about 40 oC for humans) water, glucose, pH, etc. https://www.youtube.com/watch?v=LSgEJSlk6W4 7 5. Living organisms grow and develop. Development of salamander—from fertilized egg cell: https://www.youtube.com/watch?v=SEejivHRIbE&t=238s 8  6. The genetic material provides a blueprint for reproduction. The genetic material (DNA) provides blueprint (all the information) for the development and functioning of all organisms. Reproduction: All organisms reproduce—they produce ‘offspring’ (new organism Asexual reproduction (e.g. protists, bacteria): ttps://www.youtube.com/watch?v=X7Qz9oc4DsA Sexual reproduction (e.g. plants, animals): https://www.youtube.com/watch?v=Ji2vDBPm3P4 9  7. Populations of organisms evolve from one generation to the next. Biological evolution is the process of organisms (populations) changing over several generations. In order for this change to happen, also the genetic makeup (DNA) of the organisms (populations) need to change. Changes in the DNA sequence are called genetic mutations. New species can evolve as a results of many genetic mutations. 10  Levels of Biological Organization From smallest to largest! For example, 5. organs include all other lower levels: tissues, cells, molecules, atoms. Organs are made up of tissues, tissues are made up of cells, cells are made up of…) 1. Atoms 6. Organism 2. Molecules 7. Population 3. Cells 8. Community 4. Tissues 9. Ecosystem 5. Organs 10. Biosphere Cells are common to all life (all organisms)! (This is also true for atoms and molecules, of course, but non-living things have molecules and atoms too.) 11.  Levels of Organization 1. Atoms are the smallest unit of matter. 2. Molecules are a group of atoms bonded with each other. Macromolecules are formed when many molecules bond together to form a polymer (carbohydrates, DNA, RNA etc.). 3. The cell is the smallest unit of biological organization that biologists consider alive. All organisms consist of cells! Molecules and macromolecules associate with each other to form larger structures such as membranes. Cells are surrounded by a plasma membrane, carry out complex chemical reactions, and are at least potentially capable of self reproduction. Cells come in a wide variety of shapes and sizes. Not all cells have a nucleus, but again all true cells have genetic material in the form of DNA. 4. Tissue is a group of similar cells that associate with each other to carry out a specific set of functions. For example:. Muscle tissue is for contraction.. Connective tissue is tissue consisting of cells surrounded by a large amount of non living material.. Nerve tissue is for the conduction of nerve impulses and secretion of specialized chemicals called neurotransmitters. 5. Organs are groups of two or more types of tissues organized together to carry out a particular set of functions. Organs typically have several kinds of tissue. For example, the heart is and organ, which is composed of several type of tissues, including muscle, nervous and connective tissue. But also plants have organs. The flower is the reproductive organ of flowering plants.  Levels of Organization 6. The organism or individual is that level of biological organization that has its own distinct existence as a complex, self reproducing unit. All living things can be called organisms. We are multicellular organisms in that we are made of many highly specialized cells which cannot exist independently of other cells in the organism. Many organisms are unicellular, that is consist of a single independent cell. Organisms are classifies as belonging to a particular species, which is a related group of organims. The members of the same species are closely related genetically. 7. Population is group of freely interacting and breeding individuals of the same species that occupies (live in) the same environment. 8. Community is all the populations of different species living and interacting together in a distinct area. (e.g: all the species in a prairie). The type of species that are found in a community are determined by the environment and by the interactions of species with each other. But a community does NOT include the physical (non-living environment). 9. Ecosystem is a community of organisms that interact with their physical (non-living) environment, such as the water, air, soil, rocks, etc. 10. Biosphere is the region on (land), below (water), and above (air) the Earth's surface where life exists. Living things can be found well into the atmosphere, the deepest parts of the ocean, and at least in some areas, microbes live in rock several kilometers below the surface of the earth.  Classification Taxonomy is the grouping (or classification) of species based on common ancestry Three domains of life Bacteria- unicellular prokaryote Archaea- unicellular prokaryote Eukarya- unicellular and multicellular eukaryotes Complex cells with a nucleus Four kingdoms: Protista, Plantae, Fungi, and Animalia 15 1. Bacteria 2. Archaea 3. Eukarya The 3 Domains ssification of Living Organisms (continue Taxonomy involves multiple levels in which particular species are placed into progressively smaller and smaller groups of organisms that are more closely related to each other. From the most inclusive (general) to least inclusive (general): Domain Kingdom Phylum Class Order Family Genus (Panthera) Species (Panthera onca) King Phillip Comes Over For Great 17 (Example: Jaguar) Spaghetti  Scientific Names Binomial – First word represents genus. – Second word is specific epithet or species name within the genus. Genus species (Panthera onca) Universal Latin-based 18  Domain Bacteria: Mostly unicellular prokaryotes that. inhabit many diverse environments on Earth. Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill 19 Education. Domain Archaea: Unicellular prokaryotes that often live. in extreme environments, such as hot springs. 20 Domain Eukarya: Unicellular and multicellular organisms having cells with internal compartments that serve various functions. 4 multicellular kingdoms In the Eukarya: 1.) Protista (Protists): Unicellular (1 cell only) Eukaryotic (with nucleus) 2.) Plantae (Plants): Multicellular (many cells); all can do photosynthesis 3.) Fungi: Multicellular; Absorb nutrients from substrate (e.g. soil) 4.) Animalia (Animals): Multicellular; obtain food by eating and digesting others 21  Classification A species is placed into progressively smaller groups that are more closely related Emphasizes the unity and diversity of different species Example: Clownfish (Amphiprion ocellaris) 22 Figure 1.11. 23  Classification continued Binomial nomenclature Each species has a unique scientific name Genus name capitalized Species descriptor is not capitalized Both names are italicized Amphiprion ocellaris = Ocellaris clownfish 24  Genomes and Proteomes Genome The complete genetic makeup (composition) of an organism. It encodes (codes for) all proteins in the cells. Genomics  Techniques used to analyze DNA sequences  Comparison of genomes of different species Proteome The complete complement (set) of proteins of an organism Proteomics  Techniques used to analyze the proteins of a species  Comparison of proteomes of different species 25 The genome carries the information to make the proteome. In other words, the genome encodes (codes) for all the proteins in all the cells of an organism. Genomic and proteome analysis illuminate the evolutionary history and relatedness of all living organisms. 26 Biology is an experimental science. 27  Biologists investigate life at different levels Different branches of biology study life at different levels using a variety of tools. Ecology, anatomy, physiology, cell biology, molecular biology, etc. As new tools become available, they allow scientists to ask new questions Systems biology aims to understand how emergent properties arise, at any level 28 Investigate life at different levels Different branches of biology study life at different levels using a variety of tools. As new tools become available, they allow scientists to ask new questions 29  Understanding Curiosity is the key. biology Two general approaches: 1. Discovery-based science (WITHOUT hypothesis). Collection and analysis of data without the need for a preconceived hypothesis. Goal is to gather information - Test drugs to look for action against disease - Sequence genomes and proteomes. Often leads to hypothesis testing 2. Hypothesis testing/Scientific method Test the validity of a hypothesis and comprise Five stages: a. Observations are made regarding natural phenomena. b. These observations lead to a hypothesis that tries to explain the phenomena. Remember, a scientific hypothesis is one that is testable c. Experimentation is conducted to determine if the predictions are correct. d. The data from the experiment are analyzed. 30 e. The hypothesis is accepted (‘verified’) or rejected  Hypothesis or Theory? Hypothesis  A proposed explanation for a natural phenomenon  Based on previous observations or experiments  Hypotheses must make predictions that can be shown to be correct or incorrect (must be testable)  Additional observations or experiments can support or reject a hypothesis, but a hypothesis is never really proven Example:  “Maple trees drop their leaves in autumn because of shortened hours of sunlight” 31  Hypothesis or Theory? Theory continued – Broad explanation of some aspect of the natural world that is substantiated (backed up)by a large body of evidence – Allows us to make many predictions – Also can never be proved true, but due to overwhelming evidence, may be very likely to be true Two key attributes of a theory: 1. Consistent with a vast amount of known data 2. Able to make many correct predictions Example – “DNA is the genetic material” – Overwhelming body of evidence supports this 32 theory  Hypothesis Testing Five stages 1. Observations are made regarding natural phenomena. 2. These observations lead to a testable hypothesis that tries to explain the phenomena. 3. Experiments are conducted to determine if the predictions are correct. 4. The data are analyzed. 5. The hypothesis is accepted or rejected. These steps comprise the Scientific Method 33 Hypothesis testing/Scientific method 34  Common features Data are often collected in parallel Control and experimental groups Differ by only a single variable Data analysis Apply statistical analysis to determine if the control and experimental groups are different because of the single variable that is different Are differences statistically significant? If the two sets are found not to be significantly different, we must reject our hypothesis. If the two sets of data are significantly different, we accept our hypothesis (though it is not proven) 35  Example: Cystic Fibrosis Affects about 1 in every 3,500 Americans Persons with cystic fibrosis (CF) produce abnormally thick and sticky mucus that obstructs the lungs and pancreas Average lifespan for people with CF is currently 36  Example: Cystic Fibrosis In 1945, Dorothy Anderson determined that cystic fibrosis (CF) is a genetic disorder In 1989, research groups headed by Lap-Chi Tsui, Francis Collins, and John Riordan identified the CF gene Discovery-based science, not 37  Hypothesis for function of CF gene Hypothesis: The CF gene encodes a protein that transports chloride ions (Cl-) across the membrane of cells Led to experiments to test normal cells and cells from CF patients for ability to transport Cl-  CF cells were found defective in chloride transport  Transferring a normal CF gene into cells in the lab corrects this defect Chloride transport hypothesis is accepted 38 CF Gene Hypothesis 39  Hypothesis for function of CF gene continued Results supported the hypothesis that the CF gene encodes a protein that transports Cl- across the plasma membrane A mutation in this gene causes it to encode a defective transporter protein, leading to a salt imbalance This imbalance affects water levels outside the cell, which explains the thick and sticky mucus in CF patients In this example, hypothesis testing has provided a way to accept or reject an idea regarding how a disease is caused by a genetic change 40