EVOLUTIONARY THEORY The change of species over time

EVOLUTIONARY THEORY The change of species over time References: Understanding Evolution. 2014. University of California Museum of Paleontology. 22 August 2008. <http: //evolution. berkeley. edu/>. Understanding Science. 2014. University of California Museum of Paleontology. 3 January 2014. <http: //www. understandingscience. org>.

HABITS OF THE MIND Managing Impulsivity Refrain from making judgments about an idea despite personal views Listen to other points of view Questioning and Posing Problems Know what questions to ask to find out the information needed Ask a range of questions to get a more complete picture of topic

HABITS OF THE MIND Thinking Flexibly Can see things from many points of view Can adjust thinking, as needed, based on new information Remaining Open to Continuous Learning Keep an open mind

TITAN CREED Titans endeavor to recognize and pursue truth, beauty, and goodness.

OBJECTIVES Define evolution as related to biology. Identify basic differences between microevolution and macroevolution. Analyze the mechanisms for microevolution.

VOCABULARY Fact Charles Darwin Law Evolution (biology) Hypothesis Microevolution Theory Mechanism Descent Mutation Species Migration Population Genetic drift Variation Natural selection Macroevolution

EVOLUTION – 2 MAIN QUESTIONS 1. Why are there so many different kinds of plants and animals? 2. How can the similarities among organisms be explained?

EVOLUTIONARY THEORY (BIOLOGY) Definition: change in the hereditary characteristics of groups of organisms over the course of generations ("descent with modification") Evolutionary biologists say that organisms undergo changes in gene frequency in a population from one generation to the next (microevolution). Population - a group of organisms of one species that interbreed and live in the same place at the same time (e. g. deer population) Specie - the major subdivision of a genus or subgenus, regarded as the basic category of biological classification, composed of related individuals that resemble one another, are able to breed among themselves, but are not able to breed with members of another species It is thought that some organisms can undergo so much change that they become a whole new species (macroevolution). Large-scale evolution is the descent of different species from a common ancestor over many generations.

CHARLES ROBERT DARWIN 12 FEBRUARY 1809 – 19 APRIL 1882 Father of Evolution English naturalist Revolutionary theory laid the foundation for both the modern theory of evolution and the principle of common descent by proposing natural selection as a mechanism. A worldwide sea voyage aboard HMS Beagle and observations on the Galapagos Islands in particular provided inspiration and much of the data on which he based his theory. Published proposal 1859 - The Origin of Species

KEY QUESTION TO PONDER How is the genetic variation of a population changed over time (evolution)?

MICROEVOLUTION A change in gene frequency within a single population over time Video: What is Evolution?

DETECTING MICROEVOLUTIONARY CHANGE Individuals of one beetle species live on a particular mountaintop. Year 1: Data collected determines that 80% of the genes in the population are for green coloration; 20% of them are for brown coloration. Year 2: Repeat the procedure; new ratio: 60% green genes to 40% brown genes. A microevolutionary pattern has been detected - a change in gene frequency. • Question: How did it happen?

MECHANISMS OF MICROEVOLUTION 4 Mechanisms that Influence Gene Frequency: Mutation Migration Genetic drift Natural selection Mechanism - the fundamental processes involved in or responsible for natural phenomenon

MUTATION Definition: a change in DNA, the hereditary material of life; To pass from one generation to another, the mutation must be contained in the gamete cells Example: Some ‘green genes’ randomly mutated to ‘brown genes’ This process alone cannot account for a big change in allele frequency. Why? Video: Mutations (Amoeba Sisters - 7 minutes) VIDEO: HHMI Malaria and Sickle Cell Anemia (14 minutes)

MIGRATION (OR GENE FLOW) Definition: any movement of genes from one population to another Pollen being blown to a new destination People moving to new cities or countries. If genes are carried to a population where those genes previously did not exist, gene flow can be a very important source of genetic variation (different gene versions that are present in a population). Example: Some beetles with brown genes immigrated from another population, or some beetles carrying green genes emigrated.

GENETIC DRIFT Definition: In each generation, some individuals may, just by chance, leave behind a few more descendants (and genes, of course!) than other individuals. The genes of the next generation will be the genes of the "lucky" individuals, not necessarily the healthier or "better" individuals. Example: When the beetles reproduced, just by random luck more brown genes than green genes ended up in the offspring. In the diagram, brown genes occur slightly more frequently in the offspring (29%) than in the parent generation (25%).

NATURAL SELECTION Definition: The process in nature by which, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations while those less adapted tend to be eliminated. Example: Beetles with brown genes escaped predation and survived to reproduce more frequently than beetles with green genes, so that more brown genes got into the next generation. Video: Natural Selection (Amoeba Sisters - 7 minutes) Video: What is Natural Selection (9 minutes) Video: When will the next mass extinction occur? (Ted. Ed)

DEFINITION EVOLUTION Evolution is the process by which species of organisms arise from earlier life forms and undergo change over time through natural selection. The modern understanding of the origins of species is based on theories of Charles Darwin combined with a modern knowledge of genetics based on the work of Gregor Mendel. Darwin observed there is a certain amount of variation of traits or characteristics among the different individuals belonging to a population. Some of these traits confer fitness—they allow the individual organism that possesses them to survive in their environment better than other individuals who do not possess them and to leave more offspring. The offspring then inherit the beneficial traits, and over time the adaptive trait spreads through the population. In twentieth century, the development of the science of genetics helped explain the origin of the variation of the traits between individual organisms and the way in which they are passed from generation to generation. This basic model of evolution has since been further refined, and the role of genetic drift and sexual selection in the evolution of populations has been recognized. Video: Evidence for Evolution (11 minute Video: The 12 Days of Evolution (18 minut The American Heritage® Science Dictionary

WHICH ONE IS AN EXAMPLE OF EVOLUTION? Evolution only occurs when there is a change in gene frequency within a population over time. These genetic differences are heritable and can be passed on to the next generation. 1. Beetles on a diet - Imagine a year or two of drought in which there are few plants that these beetles can eat. All the beetles have the same chances of survival and reproduction, but because of food restrictions, the beetles in the population are a little smaller than the preceding generation of beetles. 2. Beetles of a different color - Most of the beetles in the population (say 90%) have the genes for bright green coloration and a few of them (10%) have a gene that makes them more brown. Some number of generations later, things have changed: brown beetles are more common than they used to be and make up 70% of the population. Evolution or Not?

KEY QUESTION TO ANSWER How is the genetic variation of a population changed over time (evolution)? VIDEO: HHMI Galapagos Finch Evolution

NEXT GENERATION SCIENCE STANDARDS MS-LS 4 -4: Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individual’s probability of surviving and reproducing in a specific environment. MS-LS 4 -6: Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

A Framework for K-12 Science Education LS 4. B: Natural Selection • Natural selection leads to the predominance of certain traits in a population and the suppression of others. (MS-LS 4 -4) LS 4. C: Adaptation • Adaptation by natural selection acting over generations is one important process by which species change over time in response to changes in environmental conditions. Traits that support successful survival and reproduction in the new environment become more common; those that do not become less common. Thus, the distribution of traits in a population changes. (MS-LS 4 -6)

American Association for the Advancement of WHEN INHERITED TRAITS ARE FAVORABLE TO INDIVIDUAL ORGANISMS, THE PROPORTION OF INDIVIDUALS IN A POPULATION THAT HAVE THOSE TRAITS WILL TEND TO INCREASE OVER Science SUCCESSIVE GENERATIONS. Students are expected to know that: There is variation in the inherited traits of organisms of the same species, including traits that affect their ability to find food, avoid predators, and attract mates. Some inherited traits (e. g. bacterial resistance to antibiotics, skin pigmentation in some organisms) may give individuals of a species an advantage in surviving and reproducing in their environment compared to other individuals of the same species (e. g. increased ability to find food or nesting sites, avoid predators, attract mates, resist diseases). Conversely, the individuals that do not have advantageous trait(s) are more likely to be unable to survive and reproduce. An organism’s survival influences its reproductive success. Usually, the longer an organism lives (during its reproductive years), the more chances it has to reproduce; therefore traits that improve chances of survival (such as finding food or avoiding predators) also increase chances of success in reproduction. Changes in environmental conditions (such as the appearance of a new predator, a slight change in temperature, or changes due to the eruption of a volcano) can change which traits are more advantageous (or less detrimental) in the new environment.

American Association for the Advancement of WHEN INHERITED TRAITS ARE FAVORABLE TO INDIVIDUAL ORGANISMS, THE PROPORTION OF INDIVIDUALS IN A POPULATION THAT HAVE THOSE TRAITS WILL TEND TO INCREASE OVER Science SUCCESSIVE GENERATIONS. Students are expected to know that: Because more of the individuals with favorable inherited traits survive and reproduce than those that do not have them, and because the favorable traits are passed on to the offspring, the proportion of individuals with the favorable inherited traits increases in each subsequent generation. This process is called natural selection. There is no guarantee that any members of a population will be able to survive and reproduce in a changed environment. Sometimes changes in environmental conditions may cause an entire population of organisms to die, or even an entire species to become extinct. The process of natural selection does not lead to changes in the characteristics of individual organisms. It only changes the characteristics of populations (i. e. the proportion of individuals in the population having certain inherited traits) over time. After natural selection has operated on many successive generations of a population, the descendants can be very different from their original ancestors. Even though organisms can be very different in both appearance and behavior from their ancestors of many generations ago, they retain some of the inherited traits of those early ancestors.

BENCHMARKS FOR SCIENCE LITERACY PROJECT 2061 Small differences between parents and offspring can accumulate (through selective breeding) in successive generations so that descendants are very different from their ancestors. 5 F/M 1 Individual organisms with certain traits are more likely than others to survive and have offspring. 5 F/M 2 a Changes in environmental conditions can affect the survival of individual organisms and entire species. 5 F/M 2 b Benchmarks for Science Literacy - Project 2061

STANDARD: 2. LIFE SCIENCE Prepared Graduates: Explain how biological evolution accounts for the unity and diversity of living organisms Grade Level Expectation: Seventh Grade Concepts and skills students master: 1. Individual organisms with certain traits are more likely than others to survive and have offspring in a specific environment Evidence Outcomes 21 st Century Skills and Readiness Competencies Students can: a. Develop, communicate, and justify an evidence-based explanation for why a given organism with specific traits will or will not survive to have offspring in a given environment (DOK 1 -3) b. Analyze and interpret data about specific adaptations to provide evidence and develop claims about differential survival and reproductive success (DOK 1 -3) c. Use information and communication technology tools to gather information from credible sources, analyze findings, and draw conclusions to create and justify an evidence-based scientific explanation (DOK 1 -2) d. Use computer simulations to model differential survival and reproductive success associated with specific traits in a given environment (DOK 1 -2) Inquiry Questions: 1. What is the relationship between an organism’s traits and its potential for survival and reproduction? 2. How is the use of the word “adaptation” different in everyday usage than in biology? Relevance and Application: 1. Bacteria have evolved to survive in the presence of the environmental pressure of antibiotics – giving rise to antibiotic resistance. 2. Species that can live with humans –such as rats and pigeons – are more common around towns and cities. Nature of Science: 1. Create and use sound experimental designs to collect data around survival and genetic traits. (DOK 2 -3) 2. Describe several ways in which scientists would study genetics, and suggest ways that this has contributed to our understanding of survival and populations. (DOK 1 -2)

STANDARD: 2. LIFE SCIENCE Prepared Graduates: Explain and illustrate with examples how living systems interact with the biotic and abiotic environment Grade Level Expectation: Sixth Grade Concepts and skills students master: 1. Changes in environmental conditions can affect the survival of individual organisms, populations, and entire species Evidence Outcomes 21 st Century Skills and Readiness Competencies Students can: a. Interpret and analyze data about changes in environmental conditions – such as climate change – and populations that support a claim describing why a specific population might be increasing or decreasing b. Develop, communicate, and justify an evidence-based explanation about how ecosystems interact with and impact the global environment (DOK 1 -3) c. Model equilibrium in an ecosystem, including basic inputs and outputs, to predict how a change to that ecosystem such as climate change might impact the organisms, populations, and species within it such as the removal of a top predator or introduction of a new species d. Examine, evaluate, question, and ethically use information from a variety of sources and media to investigate how environmental conditions affect the survival of individual organisms (DOK 1 -2) Inquiry Questions: 1. How do ecosystem changes affect biodiversity? 2. How does biodiversity contribute to an ecosystem’s equilibrium? Relevance and Application: 1. The development and application of technologies intended to aid some populations and ecosystems. Nature of Science: 1. Ask testable questions and make a falsifiable hypothesis about how environmental conditions affect organisms, populations, or entire species and design a method to find the answer. (DOK 2 -4) 2. Recognize and describe the ethical traditions of science: value peer review; truthful reporting of methods and outcomes; making work public; and sharing a lens of professional skepticism when reviewing the work of others. 3. Use models and technology tools to show what might happen to individuals, populations, and species as environmental conditions change. (DOK 1 -2)