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CMCBiologyTest4
Evolution
| Question | Answer |
|---|---|
| Definition of Evolution | Gradual accumulation of adaptations over time. |
| Facts About Darwin | Darwin sailed on the H.M.S. Beagle in 1831, and studied finches on the Galapagos Islands. He wrote "The Origin of Species." |
| Darwin's Main Theories: 1 | All life on Earth has an earlier form. |
| Darwin's Main Theories: 2 | Populations accumulate changes over time. |
| Darwin's Main Theories: 3 | All life is a branching tree and shares common ancestors. |
| Natural Selection | Process by which traits become more or less common in a population due to the ability of that trait to help an organism survive. |
| Components of Natural Selection: 1 | Genetic Variation - Individuals have variation in their genes. |
| Components of Natural Selection: 2 | Population produces more offspring than can survive. |
| Components of Natural Selection: 3 | Organisms better fit for the current environment survive. |
| Components of Natural Selection: 4 | The trait that makes the parent a better fit for the environment gets passed to the offspring. |
| Stabilizing Selection | Favors average individuals, reduces variations in the population. |
| Directional Selection | Favors one extreme (high or low), rapid change. |
| Disruptive Selection | Favors both extremes in the population, average is weeded out, leads to evolution of two species. |
| List 6 Evidences of Evolution | Structural adaptations, Physiological adaptations, Fossils, Anatomy, Embryology, Biochemistry. |
| Structural Adaptation | Part or all of an organism changes/adapts to allow organism to survive better in their environment. Gradual process occurring over generations. |
| Structural Adaptation: Example 1 | Mimicry: Where on species resembles or mimics another species. |
| Structural Adaptation: Example 2 | Camouflage: Where an organism blends with their surroundings so they are not easily found by predators. |
| Physiological Adaptation | Adaptations that occur much faster than structural. Changes to an organism's metabolic processes. |
| Physiological Adaptation: Example | Antibiotic resistance in bacteria. Those bacteria not killed by the antibiotic survive to reproduce. They pass their resistance to their offspring and after several generations there is a large population of resistant bacteria. |
| Fossils | Evidence of an organism that lived long ago. Can give overall picture of how species evolved. By comparing fossils from different time periods, paleontologists can start to discover which organisms are related and how evolution has occurred. |
| Relative Dating | Looks at what fossils are found in different layers of the earth. Youngest fossils will be found at the top and oldest at the bottom. Used for determining appearance and extinction of the species. |
| Absolute Dating | Each fossil contains a radioactive isotope that decays over time. Over time, that decay forms a new element. Scientists measure how much of the fossil is decayed and how much is normal to find the "half-life." |
| Homologous Structures | Show evidence that organisms have a common ancestor. It would be unlikely for so many animals to have similarities if each species arose separately. |
| Homologous Structures: Example | Forelimb bones. |
| Analogous Structures | These organisms DO NOT HAVE COMMON ANCESTORS, but have adapted to a similar way of life. |
| Analogous Structures: Example | Bird wings and insects. |
| Vestigial Structures | Body structures that have no function in the present day but were probably useful to an ancestor. |
| Vestigial Structures: Example | Ostriches and penguins have wings but don't fly, humans have a tail bone but no tail, humans have an appendix but it isn't needed. |
| Embryology | An embryo is the earliest stage of development and young embryos are relatively indistinguishable. The similarities suggest a distant, common ancestor. |
| Biochemistry | Similarities between RNA and DNA sequences show how species are related. The closer the DNA sequence, the more similar the species. |
| What is a Species? | A group of organisms that look alike and can interbreed to produce fertile offspring in nature. |
| Speciation | Evolution of a new species. It occurs when member of a similar population no longer interbreeds to produce fertile offspring in nature. |
| Geographic Isolation | When part of a population of the same species becomes geographically isolated from the remainder by change in ocean level, mountains, canyons, volcanoes. |
| Reproductive Isolation | When the genetic material becomes so different that they can no longer mate and produce fertile offspring. Behavior differences can keep them from interbreeding - mating at different times of the year. |
| Change in Chromosome Number | Mistake during cell division can cause too many genes and a mutation occurs, making a mutant. |
| Divergent Evolution | Occurs when a species that was once similar to ancestral species becomes increasingly different. |
| Convergent Evolution | Occurs when two unrelated species evolves similar traits because they live in similar environments in different parts of the world. |
| Populations: 1 | A population is defined as members of a species that live in one area. |
| Populations: 2 | Populations evolve, not individuals. |
| Populations: 3 | Populations are always either evolving or are in a state of genetic equilibrium. |
| Gene Flow | The movement of individuals in and out of the population. This can introduce or remove alleles in the gene pool. |
| Genetic Drift | The alteration of allele frequencies by chance events. This occurs when populations become isolated. |
| Mutations | Mutations caused by chance or environmental factors can introduce new alleles to the gene pool. Can be good or bad. |
| Genetic Drift: Example | Amish populations - recessive alleles are more common. |
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UtauxIkuto
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