Appropriate tools and techniques are used to gather data during scientific investigations. Measurements are collected using the International System of Units (metric units) of measurement. Mental and physical models, including computer and other simulations, can be helpful in explaining events or sequences of events that occur. They can be used as part of scientific explanations to support data or represent phenomena, especially those that are not easily seen directly or must be inferred from data. Potential sources of error in the experimental design must be identified. To communicate the plan of an experiment accurately, the independent variable, dependent variable, and constants must be explicitly defined. To establish that the events of an experiment are the result of manipulating the independent variable, the experiment must be controlled by observing the effects without the application of the independent variable. The results can be compared with this standard or control. Not all experiments have a control. Multiple trials of an experiment must be conducted to verify the results. Analysis of observed results of systematic investigations includes analyze the variables in an experiment and decide which ones must be held constant (not allowed to change) in order for the investigation to represent a fair test. This requires students to comprehend what “variables” are and to apply that idea in new situations related to the Life Science Standards of Learning concepts. determine the specific component of an experiment to be changed as an independent variable and control the experiment by conducting trials for the experiment in which the independent variable is not applied. This requires the student to set up a standard to which the experimental results can be compared. The student must use the results of the controlled trials to determine whether the hypothesized results were indeed due to the independent variable. construct appropriate graphs, using data sets from investigations. This requires the student to recognize that a line graph is most appropriate for reporting continuous or real-time data. This also requires a student to comprehend that points along the line that are not actual data points can be used to make predictions. Students should be able to interpret and analyze these graphs. distinguish between observational and experimental investigations. develop conclusions based on a data set and verify whether the data set truly supports the conclusion. This requires students to cite references to the data that specifically support their conclusions.
LS.10 The student will investigate and understand that ecosystems, communities, populations, and organisms are dynamic, change over time, and respond to daily, seasonal, and long-term changes in their environment. Key concepts include phototropism, hibernation, and dormancy; factors that increase or decrease population size; and eutrophication, climate changes, and catastrophic disturbances. Essential Understandings Essential Knowledge, Skills, and Processes The concepts developed in this standard include the following: Organisms may exist as members of a population; populations interact with other populations in a community; and communities together with the physical environment form ecosystems. Changes that affect organisms over time may be daily, seasonal, or long term. Plants may respond to light by growing toward it or away from it, a behavior known as phototropism. Animals may respond to cold conditions with a period of lowered metabolism, a behavior known as hibernation. Organisms may respond to adverse conditions with a period of lowered or suspended metabolism, a behavior known as dormancy. A variety of environmental factors may cause the size of a population to increase or decrease. (This requires students to brainstorm examples of factors and predict the possible effects.) Long-term changes may affect entire communities and ecosystems. Such large-scale changes include the addition of excess nutrients to the system (eutrophication), which alters environmental balance; dramatic changes in climate; and catastrophic events, such as fire, drought, flood, and earthquakes. In order to meet this standard, it is expected that students will relate the responses of organisms to daily, seasonal, or long-term events. differentiate between ecosystems, communities, populations, and organisms. predict the effect of climate change on ecosystems, communities, populations, and organisms. predict the effect of eutrophication on ecosystems, communities, populations, and organisms. compare and contrast the factors that increase or decrease population size. classify the various types of changes that occur over time in ecosystems, communities, populations, and organisms, as long term, short term, or seasonal. design an investigation from a testable question related to change over time in ecosystems, communities, populations, or organisms. The investigation may be a complete experimental design or may focus on systematic observation, description, measurement, and/or data collection and analysis. analyze and critique the experimental design of basic investigations related to change over time in ecosystems, communities, populations, and organisms.
LS.13 The student will investigate and understand that populations of organisms change over time. Key concepts include the relationships of mutation, adaptation, natural selection, and extinction; evidence of evolution of different species in the fossil record; and how environmental influences, as well as genetic variation, can lead to diversity of organisms. Essential Understandings Essential Knowledge, Skills, and Processes The concepts developed in this standard include the following: The mechanisms through which evolution takes place are a related set of processes that include mutation, adaptation, natural selection, and extinction. This results in changes in populations of organisms over time. Mutations are inheritable changes because a mutation is a change in the DNA code. Adaptations are structures, functions, or behaviors that enable a species to survive. Natural selection is the survival and reproduction of the individuals in a population that exhibit the traits that best enable them to survive in their environment. A mutation may result in a favorable change or adaptation in genetic information that improves a species’ ability to exist in its environment, or a mutation may result in an unfavorable change that does not improve or impedes a species’ ability to exist in its environment. The evidence for evolution is drawn from a variety of sources of data, including the fossil record, radiometric dating, genetic information, the distribution of organisms, and anatomical and developmental similarities across species. Individuals of a population each exhibit a range of variations in a trait as a result of the variations in their genetic codes. These variations may or may not help them survive and reproduce in their environment. If a species does not include traits that enable it to survive in its environment or to survive changes in the environment, then the species may become extinct. In order to meet this standard, it is expected that students will interpret data from simulations that demonstrate selection for a trait belonging to species in various environments. describe how changes in the environment can bring about changes in a species (adaptation, extinction) through natural selection. describe and explain how fossils are records of organisms and events in Earth’s history. explain the evidence for evolution from a variety of sources of scientific data. explain how genetic variations in offspring, which lead to variations in successive generations, can result from the same two parents. analyze and evaluate data from investigations on variations within a local population. explain how environmental influences, as well as genetic variation, can lead to diversity of organisms.