Lesson 1 - Zoology: Its History, Recent Developments and Significance PDF

LESSON 1- ZOOLOGY: IT’S HISTORY, RECENT DEVELOPMENTS AND SIGNIFICANCE  INTRODUCTION Science began the moment man wondered about his surroundings and is own existence. As man explored the vastness of his universe, his studies, the sciences, expanded in ways never before imagined....

LESSON 1- ZOOLOGY: IT’S HISTORY, RECENT DEVELOPMENTS AND SIGNIFICANCE  INTRODUCTION Science began the moment man wondered about his surroundings and is own existence. As man explored the vastness of his universe, his studies, the sciences, expanded in ways never before imagined. Now, more than ever, scientists have been learning so much and so fast in almost all the fields of science. For instance, zoology, particularly on inheritance patterns, they have constructed genetic tools that could revolutionize the living world. That field of science most related to man, known as zoology, its, branches, history, developments and significance is the focus of this lesson.  DEFINITION OF ZOOLOGY Zoology is the branch of biology concerned with the study animals and animal kingdom. It is also known as animal biology. The study of zoology includes the interaction of animal kingdom in their ecosystems such as classification, habits, structure, embryology, distribution, evolution, and extinct species. Zoology is the division of biology that deals with the animal kingdom. It is the scientific study related to the entire species of the animal kingdom.  HISTORY OF ZOOLOGY It is often difficult to appraise the historical development of any field of science since advances are made by various scientists/scholars from many different places, accumulating over several periods of time. That is also the very reason why it is difficult to decide on which year the “discovery” occurred. Many important discoveries in zoology, took place in recent years, largely due to the relentless efforts of several teams of investigations. Aristotle Aristotle, was a first-person to broadly classify the living things in the 4th century BC. Firstly he divided living things into animals and plants and then continued with his further classifications. Later the words like biology, botany, and zoology came into existence Aristotle Later, Aristotle divided animals into two classes: one with red-blood and another without such as insects and crustaceans. Then, he further classified creatures into those who were able to walk, flow and swim.  The classification by Aristotle was followed until the 16th century, during the Age of enlightenment, scientists finally began to research closely. Now, zoology has become much more complex, where the living things are divided into five kingdoms, in which animal kingdom themselves divided into several smaller categories of Phylum, Class, Order, Family, Genus and, finally, Species.  These developments were synthesized in Charles Darwin’s theory of evolution by natural selection. In the year 1859, Charles Robert Darwin presented the theory of organic evolution along with its observational evidence.  Fundamental Properties of Life Does Life Have Defining Properties? – What is life? 1-36  CHARACTERISTICS OF LIVING THINGS Life is as diverse as anyone could imagine. Yet despite all the differences, living beings exhibit attributes common to all. These thematic characteristics are present from the smallest living creature to the largest. The following are their common features that make them totally interesting as subjects of inquiry.  Fundamental Properties of Life Does Life Have Defining Properties? – What is life? No simple definition The history of life shows extensive and ongoing change called evolution Answer must be based on the common history of life on earth 1-38  Chemical uniqueness. Cellular compositon Response to stimuli Growth and development Nutrition Reproduction Release of Energy Excretion Adaptation Homeostasis  Fundamental Properties of Life Does Life Have Defining Properties? – What is life? No simple definition The history of life shows extensive and ongoing change called evolution Answer must be based on the common history of life on earth 1-40 10 Characteristics of Living Systems 1. Chemical Uniqueness: Living systems demonstrate a unique and complex molecular organization – Small molecules are assembled into macromolecules: 1. Nucleic Acids 2. Proteins 3. Carbohydrates 4. Lipids 1-41  Although living systems are composed of the same kinds of atoms obeying the same fundamental laws of chemistry as nonliving matter, the organizational structure of the macromolecules makes them unique 1-42 1-43  10 General Properties of Living Systems 2.CellularComposition/Complexity and Hierarchical Organization: All forms of life are built of cells. A cell is the basic unit of the structure and function of living things capable of performing all the activities of life. Living things may appear very different from one another on the outside, but their cells are very similar. Human cells. Onion cells  Some organisms are made up of only one cell and are called unicellular; others are composed of two or more cells and are called multicellular. Complex multicellular organisms have levels of organization as shown in Figure 2.5 below 8 General Properties of Living Systems 3. Reproduction: Living systems can reproduce themselves At each level of the biological hierarchy living forms reproduce to generate others like themselves: Genes replicated to produce new genes. Cells divide producing new cells. Organisms reproduce, sexually or asexually, to produce new organisms Populations may fragment to produce new populations Species may split to produce new species 1-47 8 General Properties of Living Systems 4. Possession of a Genetic Program: A genetic program provides fidelity of inheritance – DNA: Long, linear, chain of nucleotides containing genetic information – Sequence of nucleotide bases in DNA determines the order of amino acids in proteins – Genetic Code: correspondence between base sequences in DNA and the sequence of amino acids in a protein 1-48 1-49  10 General Properties of Living Systems 5. Metabolism: Living organisms maintain themselves by acquiring nutrients from their environments – Metabolic processes include: Digestion Energy production (Respiration) Synthesis of required molecules and structures by organisms 1-50 8 General Properties of Living Systems Metabolism is often viewed as an interaction of destructive (catabolic) and constructive (anabolic) reactions The most fundamental anabolic and catabolic chemical processes used by living systems arose early in the evolutionary history of life 1-51 1-52 1-53  10 General Properties of Living Systems 3. Response to Stimuli All animals interact with their environments – Ecology: The study of organismal interaction with an environment – All organisms respond to environmental stimuli 1-54  10 General Properties of Living Systems 4. Growth & Development: All living things grow and develop. Growth is the physical change in an organism’s size and weight, while Development is the gene-directed process by which an organism matures. Growth occurs through cell division and enlargement of cells, development occurs though cell differentiation (cell becoming different from each other; i.e. some cells become blood cells and others become bone cells) and specialization (adaptation of a cell to perform a specific function). For example, a plant seed may look like a lifeless pebble, but under the right conditions it will grow and develop into a plant. Animals also grow and develop. 1-59  10 General Properties of Living Systems 5.Nutrition – Organisms feed by taking in and assimilating materials for growth and maintenance, while others make their own food.  6.Reproduction All living things are capable of reproduction. Reproduction is the process by which living things give rise to offspring and transmit hereditary information (coded in DNA, deoxyribonucleic acid). In sexually reproducing organisms hereditary information recombines from two organisms of the same species, producing genetically different offspring. In asexually reproducing organisms hereditary information does not come from different organisms to the offspring, the offspring is genetically identical to the parent.  7.Release of energy is necessary to stay alive. This enables organisms to perform necessary activities that will sustain life.  8.Excretion is the process by which the organism eliminates toxic waste products. 9. Adaptation refers to inherited changes that occur over time and help the species survive. 1-67  10. Homeostasis. All organisms stabilize the internal conditions of their body through a process called homeostasis. This process is brought about by different feedback mechanisms.  Today zoology- in fact, all of biology-has become much more complex. Living things are now classified into six kingdoms (from five a few years back), of which Kingdom Animalia is just one. The kingdoms are further divided into smaller categories of phylum, class, order, family, genus and finally, species. Animal species are differentiated from one another based on their physical and genetic characteristics  THE SCIENTIFIC METHOD The scientific method is used by scientists to conduct experiments and research and record their findings. These recordings allow others to interpret and build upon their work. Because there is more than one way to explore science, different books, websites, and documents describe the scientific method in various ways.  STEPS IN SCIENTIFIC METHOD OBSERVATION RESEARCH HYPOTHESIS EXPERIMENTATION ANALYSIS CONCLUSION COMMUNICATION  OBSERVATION Scientists generally begin by making an observation. They explore and collect information with their senses (smell, sight, sound, touch, and taste) and ask a question that they would like to answer. This question will guide scientists in conducting research and experiments. An observation is the act of noting and recording something with instruments. Observations help scientists decide how certain variables might affect the problem.  Example: Observation When I turn on a flashlight using the on/off switch, light comes out of one end. Example: Question What makes light come out of a flashlight when I turn it on?  RESEARCH Once scientists ask a question, they generally do research. Scientists have been asking questions for thousands of years, so there is a good chance that someone has made the same observation and asked a similar question. Therefore, after asking the question, scientists spend time reading papers and books on past research to prepare for their own research. Your students should do the same! When studying prior research, it is important that the information is from a credible source, meaning that the information and the source of the information are believable and trustworthy. Conducting research helps scientists better understand their observations or questions before they conduct experiments (and will help you and your students, too!).  Example: Research Look in the flashlight’s instruction manual for tips, or conduct an online search on how flashlights work using the manufacturer’s website. You can even analyze information and past experiments or discoveries regarding the relationship between energy and light.  HYPOTHESIS With a question in mind, scientists decide on what they want to test. (The question may have changed as a result of research.) Scientists will clearly state what they expect to find out during the experiment. They’ll make an educated guess that could answer the question or explain the observation. This statement is called a hypothesis. A hypothesis guides the experiment and must be testable.  Example: Hypothesis The batteries inside a flashlight give it energy to produce light when the flashlight is turned on  EXPERIMENTATION Design and conduct an experiment that tests the hypothesis. Remember, a hypothesis is only an educated guess (a possible explanation), so it cannot be considered valid until an experiment verifies that it is valid. Example: Experimental Procedure 1. Remove the batteries from the flashlight, and try to turn it on using the on/off switch. Result: The flashlight does not produce light. 2. Reinsert the batteries into the flashlight, and try to turn it on using the on/off switch. Result: The flashlight does produce light. 3. Write down these results.  In general, it is important to design an experiment to measure only one thing at a time. This way, you know your results are directly related to the one thing that you changed. If you do not design the experiment carefully, your results may be confusing and will not tell you anything about your hypothesis.  Variables in an Experiment Variables - Factors that can be changed Controlled Variables - all the variables that remain constant Manipulated Variable - (also called the Independent Variable) - factor in an experiment that a scientist purposely changes Responding Variable- (also called the Dependent Variable) - the outcome or results, factor in an experiment that may change because of the manipulated variable…. what a scientist wants to observe  Variables in Redi’s Experiment Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat  Control and Experimental Groups Control group:used as a standard of comparison Experimental group: the group containing the factor (variable) that has been changed (manipulated or independent variable) Two groups of jars Uncovered jars Covered jars Example: Designing an Experiment Independent variable: The use of batteries. Dependent variable: Whether or not light was produced. Controlled variables: The same flashlight was used each time. The on/off switch is moved into the same positions each time.  Collect and Record Data Data are pieces of information collected before, during, or after an experiment. Types of Recorded Data – Quantitative - observations that involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters – Qualitative - observations that do not involve numbers, are of a descriptive nature i.e. white maggots covered the meat, leaves were all wilting  Data Must be organized Can be organized into charts, tables, or graphs  ANALYSIS Once the experiment is complete, the data is then analyzed to determine the results. In addition, performing an experiment multiple times can be helpful in determining the credibility of your data. Example: Analysis Record the results of the experiment in a table. Review the results that you have written down.  CONCLUSION If the hypothesis was testable and the experiment provided clear data, scientists can make a statement telling whether or not the hypothesis was correct. This statement is known as a conclusion. Conclusions must always be backed up by data. Therefore, scientists rely heavily on data so they can make an accurate conclusion If the data support the hypothesis, then the hypothesis is considered correct or valid. If the data do not support the hypothesis, then the hypothesis is considered incorrect or invalid  Example: Valid Hypothesis The flashlight did not produce light without batteries. The flashlight did produce light when batteries were inserted. Therefore, the hypothesis that batteries give the flashlight energy to produce light is valid, given that no changes are made to the flashlight during the experiment. Example: Invalid Hypothesis What if the flashlight did NOT produce light when the batteries were inserted? Then, the hypothesis would have to be modified to say something such as, “The batteries inside a flashlight give it energy to produce light when the batteries are in the correct orientation and when the flashlight is turned on.” Then, another experiment would be conducted to test the new hypothesis.  An invalid hypothesis is not a bad thing! Scientists learn something from both valid and invalid hypotheses. If a hypothesis is invalid, it must be rejected or modified. This gives scientists an opportunity to look at the initial observation in a new way. They may start over with a new hypothesis and conduct a new experiment. Doing so is simply the process of scientific learning.  COMMUNICATION Communication is an essential part of science. ▪ Scientists report their results in journals, on the internet, or at conferences ▪ This allows their experiments to be evaluated and repeated ▪ Scientists can build on previous work of other scientists True or False - Only scientists use the scientific method