Process of Evolution CHAPTER 15

Transcription

1 Process of Evolution CHAPTER 15

2 Key Concepts 15.1 Evolution Is Both Factual and the Basis of Broader Theory 15.2 Mutation, Selection, Gene Flow, Genetic Drift, and Nonrandom Mating Result in Evolution 15.3 Evolution Can Be Measured by Changes in Allele Frequencies 15.4 Selection Can Be Stabilizing, Directional, or Disruptive 15.5 Genomes Reveal Both Neutral and Selective Processes of Evolution 15.6 Recombination, Lateral Gene Transfer, and Gene Duplication Can Result in New Features 15.7 Evolutionary Theory Has Practical Applications

3 Intro In there was an unusually high death rate associated with the influenza pandemic This flu virus had an interesting evolutionary nature as soldiers contracted a virus that was especially intense to the human immune system. Viruses are continually changing and therefore humans need to build up resistance but will never truly be immune as these viruses continue to change Flu vaccines continually change top 5 from the previous year.

4 Evolution is Both Factual and the Basis of Broader Theory 15.1

5 Background Evolution is the change in genetic composition of populations over time. Evolutionary change is observed in laboratory experiments, in natural populations, and in the fossil record. These underlying genetic changes drive the origin and extinction of species and fuel the diversification of life. Watching Evolution in Real Time

6 Evolution Evolutionary theory is the understanding and application of the processes of evolutionary change to biological problems. Applications: Study and treatment of diseases Development of crops and industrial processes Understanding the diversification of life It also allows us to make predictions about the biological world.

7 Evolution Theory in everyday speech, an untested hypothesis or a guess Evolutionary theory is not a single hypothesis It refers to our understanding of the processes that result in genetic changes in populations over time and to our use of that understanding to interpret changes we observe in natural populations.

8 Darwin Even before Darwin, biologists had suggested that species had changed over time, but no one had proposed a convincing mechanism for evolution. Jean-Baptiste Lamarck presented strong evidence for the fact of evolution but his ideas were not convincing In the 1820s, Charles Darwin was interested in geology and natural history, but despite his passion, his father wanted him to become a doctor

9 Darwin It was because Darwin required surgery, he was not given anesthesia, he became nauseated and he gave up the idea of medicine and decided to take up a career as a clergyman in the Church or England Because Darwin always had a passion for the sciences, he gravitated towards a botanist named John Henslow who recommended Darwin for a position on the HMS Beagle to survey the world

10 HMS Beagle In 1831, Darwin began a 5-year voyage around the world on a Navy survey vessel, the HMS Beagle. Whenever possible, Darwin went ashore to study rocks and observe and collect plants and animals From here he explored the Galapagos islands, west of Ecuador.

11 The Voyage of the Beagle 3 Min - Theory of Evolution Crash Course Natural Selection Bozeman - Natural Selection Bozeman - Examples of Natural Selection The Making of a Theory: Darwin, Wallace, and Natural Selection HHMI BioInteractive Video

12 The Framework From the observations and insights made on the voyage and new ideas from geologists, like Charles Lyell, about how the Earth has been shaped by slow acting forces that are still active today. From this Darwin developed a framework of an explanatory theory for evolutionary change: Species are not immutable, they change over time Divergent species share a common ancestor (descent with modification) The mechanism that produces change is natural selection; the increased survival and reproduction of some individuals compared with others, based on differences in their traits.

13 Darwin In 1858, Darwin received a paper from Alfred Russel Wallace with an explanation of natural selection nearly identical to Darwin s. Both men are credited for the idea of natural selection. Darwin s book, The Origin of Species, was published in Natural Selection Animated Tutorial Bozeman - Evolution

14 Modern Synthesis By 1900, the fact of evolution was established, but the genetic basis of evolution was not yet understood. Then the work of Gregor Mendel was rediscovered, and during the 20 th century, work continued on the genetic basis of evolution. A modern synthesis of genetics and evolution took place

15 Milestones in the Development of Evolutionary Theory What Darwin Never Knew 2hr must watch!

16 Watson and Crick The structure of DNA was established by 1953 by Watson and Crick. In the 1970s, technology developed for sequencing long stretches of DNA and amino acid sequences in proteins. Evolutionary biologists now study gene structure and evolutionary change using molecular techniques. Watson and Crick Video