* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Darwin and Natural Selection
Survey
Document related concepts
Unilineal evolution wikipedia , lookup
Sexual selection wikipedia , lookup
Evolving digital ecological networks wikipedia , lookup
Evolutionary mismatch wikipedia , lookup
Evolution of sexual reproduction wikipedia , lookup
Inclusive fitness in humans wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Theistic evolution wikipedia , lookup
Sociobiology wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Natural selection wikipedia , lookup
Genetic drift wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Saltation (biology) wikipedia , lookup
Transcript
Learning Targets: Darwin and Natural Selection Evolution is a Theory – Just like Einstein's Theory of General Relativity, which helps to explain gravity! Evolution is a well-supported explanation of phenomena that have occurred in the natural world A theory in science is a well-tested hypothesis, not just a guess Charles Darwin (___________________________________) Sailed around the world 1831-1836 What did Darwin’s travels reveal The diversity of living species was far greater than anyone had previously known!! These observations led him to develop the theory of evolution!! Diversity on the Galapagos Each island had ____________________________________________ ___________________________________________________________ Influences on Darwin’s Theories Theories of geologic change set the stage for Darwin’s theory: Fossils: traces of organisms that existed in the past. Theory of ___________________________ states that natural disasters like floods and volcanic eruptions have shaped landforms and caused species to go extinct. Theory of ___________________________ states that changes in landforms resulted from slow changes over a long period of time. Theory of ___________________________ states that the geologic processes that shape Earth are uniform through time (Charles Lyell’s theory). Lyell argued that the earth is many millions of years o layers of rock take time to form o processes such as volcanoes and earthquakes shaped the earth and still occur today Jean-Baptiste Lamarck: o ___________________________________________________ Organisms acquired traits by using their bodies in new ways These new characteristics were passed to offspring _________________________________________________________! Thomas Malthus o If the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone. Artifical Selection: Process in which humans change a species by breeding it for certain traits. Darwin’s The Origin of Species (1859) Other naturalists, like Alfred Wallace, were developing the same theory as Darwin’s. Even though Darwin was afraid of the Church’s reaction to his book he wanted to get credit for his work. Summary of Darwin’s Theory of Natural Selection 1. Organisms differ; _______________________________________________ 2. Organisms produce more offspring than survive 3. Organisms ____________________________________________________ 4. Organisms with advantages survive to pass those advantages to their children (“_________________________________________”) 5. ______________________________________________________________ ________________________________________________________________ What is evolution? o ____________________________________________________ o explains how modern organisms have descended from ancient organisms Fitness and Adaptation Organisms ______________________________________________ and some organisms are more ______ than others Fitness – ___________________________________________________ ________________________________________________________ ________________________________________________________ Adaptation – ________________________________________________ ________________________________________________________ ________________________________________________________ What determines survival? o Traits that help individuals survive survive _____________________ survive _____________________ compete for _________________ compete for _________________ o Traits that help individuals reproduce attracting a ___________ compete for _____________________ successfully _____________________ Natural Selection There is ___________________________ (difference in the physical traits of an individual from those of other individuals in the group) in traits. o For example, some beetles are green and some are brown. There is ___________________ . o Since the environment can’t support unlimited population growth, to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do. There is___________________________ o The surviving brown beetles have brown baby beetles because this trait has a genetic basis (trait is passed down from one generation to the next). End result: ___________________________ o The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown Over time, ______________________ results in changes in the _______ _____________________________of a population. These changes __________________________ in its ________________. Species: Group of organisms so similar to one another that they can reproduce and have fertile offspring. Sources of Genetic Variation Genetic Variation is stored in a populations _________________, which is the combined alleles of all of the individuals in a population. Each allele exists at a certain rate in a population. ___________________, is a measure of how common a certain allele is in the population Gene flow: movement of __________ from ______________________ (migration) Mutation: __________________________________________________ o Some mutations can affect an ____________________ while others have __________________________. Recombination (occurs during meiosis): __________________________ o Independent ________________ o ________________ over o _______________ reproduction Evolution as Genetic Change Natural selection determines which alleles are passed from one generation to the next. As a result, it can change the relative frequencies of alleles in a population over time. Evolution is __________________________________ in a population’s gene pool. Evolution acts on ____________________, not on _________________. * Remember: Populations include individuals of the same species living in an area. Genetic Drift Natural selection is not the only source of evolutionary change. Genetic drift: _______________________________________________ In __________ populations, individuals that carry a _________________ may leave more descendants than other individuals, just by ___________. Over time, a series of chance occurrences of this type can cause an allele to become common in a population. Bottleneck Effect _________________________ of genetic drift, occurs after an event drastically _______________________ the size of a population. This causes the population to have _____________________________ variation. The reason for this is that certain alleles have become fixed in the population and others have been lost. Founder Effect Occurs when a ______________ of individuals _________ a new ____________. Members of the colony may carry alleles in different relative frequencies than the larger population from which they came. If so, the population that they found will be genetically different from the parent population. Sexual Selection Certain traits increase mating success, so these traits will be passed down from generation to generation. Summary: