Natural and Artificial Selection

Vocabulary (in Sections 10.1, 10.2, 10.3)
• Evolution
• Natural Selection
• Artificial Selection
• Species
• Genetic Variation
• Adaptation
• Fitness
• Population

• Evolution is simply change over time.
– The change usually creates more complexity but not necessarily.
– In biology, evolution is associated with the change in genetic composition of a population over successive generations.
– For biological evolution to take place, there has to be a form of genetic inheritance. In today’s world, inheritance is through DNA, though there are other molecules (RNA for example) capable of doing DNA’s job.

• In order for biological evolution to take place, there has to be genetic variation.
• Genetic variation is defined as the differences in genomes (the genes) found among members of a species.
• The variation in genes within a population is a of genetic mutation.
– Without genetic mutation, eventually, due to genetic drift, there would be no variation.

• Natural selection is the creative force that makes biological evolution possible.
• Natural selection is defined as the process by which heritable traits that increase an organism’s chances of survival and reproduction are favored than less beneficial ones.
– The traits are encoded in genes and natural selection
“selects” which genes are most adaptive in a given environment (defined by habitat and ecological niche).

• Those individuals whose genes are more well
adapted to an environment are more fit and more likely to pass on their genes.
• Over time, through the process of genetic mutation and natural selection, species evolve
(called speciation) – giving rise to new species.
– Eventually, the original species might go extinct at the hands of the “new,” potentially better adapted
(more fit), species they have spawned.

• http://myweb.rollins
.edu/jsiry/TheOrigin
1859_2_12.html#1

• 1829–1832. [Records of captured insects, in] Stephens, J. F., Illustrations of British entomology [1]
• 1835: Extracts from letters to Professor Henslow (read at a meeting of the
Cambridge Philosophical Society on 16 November 1835, with comments by John
Stevens Henslow and Adam Sedgwick, and printed for private distribution dated
1 December 1835.[2] Selected remarks had been read by Sedgwick to the
Geological Society of London on 18 November 1835, and these were summarised in Proceedings of the Geological Society published in 1836.[3] Further extracts were published in the Entomological Magazine and, with a review, in the
Magazine of natural history.[2])
• 1836: A LETTER, Containing Remarks on the Moral State of TAHITI, NEW
ZEALAND, &c. – BY CAPT. R. FITZROY AND C. DARWIN, ESQ. OF H.M.S. 'Beagle.'[4]
• 1838-43: Zoology of the Voyage of H.M.S. Beagle: published between 1839 and
1843 in five Parts (and nineteen numbers) by various authors, edited and superintended by Charles Darwin, who contributed sections to two of the Parts:
• 1838: Part 1 No. 1 Fossil Mammalia, by Richard Owen (Preface and Geological introduction by Darwin)

• 1838: Part 2 No. 1 Mammalia, by George R. Waterhouse (Geographical introduction and A notice of their habits and ranges by Darwin)
• 1839: Journal and Remarks (The Voyage of the Beagle)
• 1842: The Structure and Distribution of Coral Reefs
• 1844: Geological Observations on the Volcanic Islands visited during the voyage of
H.M.S. Beagle
• 1846: Geological Observations on South America
• 1849: Geology from A Manual of scientific enquiry; prepared for the use of Her
Majesty's Navy: and adapted for travellers in general., John F.W. Herschel ed.
• 1851: A Monograph of the Sub-class Cirripedia, with Figures of all the Species. The
Lepadidae; or, Pedunculated Cirripedes.
• 1851: A Monograph on the Fossil Lepadidae, or, Pedunculated Cirripedes of Great
Britain
• 1854: A Monograph of the Sub-class Cirripedia, with Figures of all the Species. The
Balanidae (or Sessile Cirripedes); the Verrucidae, etc.
• 1854: A Monograph on the Fossil Balanidæ and Verrucidæ of Great Britain
• 1858: On the Tendency of Species to form Varieties; and on the Perpetuation of
Varieties and Species by Natural Means of Selection (Extract from an unpublished
Work on Species)

• 1859: On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life
• 1862: On the various contrivances by which British and foreign orchids are fertilised by insects
• 1865: The Movements and Habits of Climbing Plants (Linnean Society paper, published in book form in 1875)
• 1868: The Variation of Animals and Plants under Domestication
• 1871: The Descent of Man, and Selection in Relation to Sex
• 1872: The Expression of Emotions in Man and Animals
• 1875: Insectivorous Plants
• 1876: The Effects of Cross and Self Fertilisation in the Vegetable Kingdom
• 1877: The Different Forms of Flowers on Plants of the Same Species
• 1879: "Preface and 'a preliminary notice'" in Ernst Krause's Erasmus Darwin
• 1880: The Power of Movement in Plants
• 1881: The Formation of Vegetable Mould through the Action of Worms