Homework Questions PG. 287 Q3: Explain why harmful mutations do not accumulate over time and cause harm to populations. ANSWER: Harmful mutations cause harm to the individual and evolution will select against individuals with harmful mutations. These individuals will not breed with others, causing the harmful mutation to disappear from the population.

Homework Questions PG. 287 Q9: How do the genetic diversity of a population and mutation rates limit the ability of breeders to create organisms with desired traits? ANSWER: Hint: Think of the blue rose. Breeders can only work with the genetic diversity that is already present in the organisms population. If a trait does not exist in an organisms genome, a breeder cannot just create that mutation. Mutations are random and rare. This means that beneficial mutations are unlikely to happen.

Homework Questions PG. 319 Q28: What is artifical selection, and why is it called artificial? ANSWER: Artificial selection is directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation. It’s called artificial because it is controlled by human choice, not by nature.

The Modern Synthesis: Evolution and Genetics

Charles Darwin - Born in Shrewsbury, England on February 12, 1809 - Born into a wealthy family as the 5th of 6 children Grandfather, Erasmus Darwin, had proposed that all life came from a single organism, “the Great First Cause” Darwin was encouraged to become a doctor, but was fascinated with the natural world

The Voyage of the Beagle December 27, 1831, he joins the HMS Beagle as a naturalist on a five year voyage The ship’s mission was to map the coast of South America for Britain As a naturalist, Darwin was to observe and collect specimens

How did he begin to craft his theory of evolution?

Observations in South America In Argentina, Darwin uncovered fossils of the Megatherium and Glyptodon These fossils looked like giant sloths and armadillos The fossils were found in the same geological range as these modern animals Fossils of marine organisms also found in the Andes Mountains

Observations in the Galapagos Islands Island chain 1000 km west of Ecuador Discovered many new species with many similarities to species found on South America No native amphibians or large land mammals why?

Observations in the Galapagos Islands Marine Iguana: Closely resembles iguanas from the South American Mainland Is the only known lizard able to dive and forage in water

Observations in the Galapagos Islands Giant land tortoises At least five unique species were found on different islands

Darwin’s Finches Darwin at first thought they were one species with variation 13 species with distinct characteristics Their beaks show variation in shape and size Why?

Forming the Theory After leaving the Beagle in 1836, Darwin spent more than 20 years gathering evidence on evolution He knew that his theories would be controversial By the time he presented his theory, Darwin was able to not only explain that evolution had happened, but also how it occurred…mostly

On the Origin of Species By 1844 Darwin had prepared an essay on his theory of Evolution, but did not publish it 1858 - received a letter from Alfred Russell Wallace, who had also concluded that evolution must be true This pressure led Darwin to publish his theory as On the Origin of Species in 1859

Backlash

Please read 294-295 and complete #1-4