Evolution - EVOLUT ION I Natural selection a Darwin i Lived...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: EVOLUT ION I. Natural selection: a. Darwin: i. Lived from 1809-1882 ii. Was asked to go on a t rip around the world on the HMS Beagle from 1831-1836 as a naturalist. 1. Purpose of the journey was to chart the waters near land so British ships could know where to dock. 2. Along the way he was a collector, a theorist, and an observer. 3. Went to the Galapagos Islands for 6 weeks on the t rip: a. Noted that there were slight differences in the organisms between those on the islands and those on the mainland. b. Furthermore, he noted that there were slight differences between organisms on different islands in the island chain. iii. When he returned, he was ill and spent his time talking, reading, thinking, etc. 1. Read and spoke with scientists who had influenced his thinking: a. Thomas Malthus: 1798 Essay on Principle of Population b. Charles Lyell: Scottish geologist. i. Wrote Principles of Geology in 1830 ii. Darwin gained from this the idea that the earth is far older than people of the time thought. c. Many others 2. In 1842, he wrote his “Essay of 1842” in which he summarized what eventually became the ideas of natural selection and evolution. a. He showed it to very few people, and did not publish it. 3. In 1858 he got a letter from Alfred Russell Wallace who was also an English naturalist, and was working in the south pacific. a. Turned out, Wallace had also discovered natural selection 4. Darwin and Wallace both gave a (verbal) paper on July 1, 1858. 5. In 1859, Darwin published his famous book The Origin of Species iv. Summary of Darwin’s thought: 1. The world is not static, but ever changing 2. This change (evolution) is gradual 3. There is a process called natural selection which results in evolution b. Terminology i. Genotype ii. Phenotype iii. Population—a group of individuals of one species that live together and interbreed. iv. Gene pool—all of the genes in a population v. Environment 1. Biotic factors 2. Abiotic factors vi. Variation that comes from mutation. c. Natural Selection i. The differential perpetuation of genotypes. I.e. some genotypes do better in the wild than others. ii. Prerequisites: 1. Organisms must be capable of sexual reproduction. a. This is necessary for variability in genotypes 2. Organisms must show genetically based variability 3. Organisms must be tested by their environments. iii. E.g. Mice: 1. Alleles: D, d. D = good at “darting around”; d = less good at “darting around” a. Possible combinations: DD, Dd, dd 2. In an environment with predators, dd would theoretically get eaten before DD and Dd through natural selection. iv. A result of the process of natural selection: 1. Change in allele frequency, which is the basic definition of microevolution....
View Full Document

{[ snackBarMessage ]}

Page1 / 14

Evolution - EVOLUT ION I Natural selection a Darwin i Lived...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online