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Biology 181 Book Notes

Biology 181 Book Notes - Biology 181 Book Notes An...

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Biology 181 Book Notes An Introduction to Evolution Biological evolution : heritable change in one or more characteristics of a population or species across many generations Small scale: changes in a single gene in a population over time Large scale: the formation of a new species or groups of related species Species : a group of related organisms that share a distinctive form Members of the same species are capable of interbreeding to produce viable and fertile offspring Population : members of the same species that are likely to encounter each other, and have the opportunity to interbreed Although evolutionary theory has been refined over the past 150 years, the fundamental principle remains unchanged The theory is supported by substantial evidence and explains a wide range of observations Molecular evolution: molecular changes in genetic material that underlie the phenotypic changes associated with evolution The Theory of Evolution Many of the earliest ideas of evolution were influenced by religion and philosophy Suggested that all forms of life have remained the same since their creation Empirical thought (started in Europe in 1600s): relies on observation to form an idea or hypothesis, rather than trying to understand life from a nonphysical or spiritual point of view Encouraged scholars to look for the basic rationale behind a given object or phenomenon John Ray (mid- to late-1600s): the first scientists to carry out a thorough study of the natural world Developed an early classification system for plants and animals based on anatomy and physiology Established the modern concept of a species organisms of the one species do not interbreed with members of another Ray’s ideas were extended by Swedish naturalist Carolus Linnaeus Neither Linnaeus nor Ray proposed that evolutionary change promotes the formation of new species Their classification system helped scholars perceive similarities and differences among living organisms Late 1700s, European scientists began to suggest that life forms are not fixed George Buffon ( a French zoologist) said that living things to change over time Jean-Baptiste Lamarck ( a French naturalist) hypothesized that species change over the course of many generations by adapting to new environments Believed that living things evolve in a continuously upward direction from dead matter, through simple to complex forms towards “human perfection” Thought behavioral changes modified traits Inheritance of acquired characteristics : modified traits were inherited by offspring Ex. Giraffes developed elongated necks and front legs by feeding on high tree leaves and then passed those traits on to offspring Erasmus Darwin (physician, plant biologist, grandfather to Charles): was an early advocate of evolutionary change Was aware that many fossil types were different from modern species Saw how animal and plant breeders used breeding practices to change the traits of a domesticated species
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Knew that offspring inherited features from their parents
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