enotes outline: introduction to zoology history

7/30/2019 enotes outline: Introduction to Zoology History

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established in his Principles of Geology(1830 to 1833) the principle of uniformitarianism.

natural forces, acting over long periods of time, could explain the formation of fossil-bearingrocks.

geological studies led him to conclude that the earths age must be measured in millions ofyears.

Sir Charles Lyell (1797 to 1875)

Darwins Theory ofEvolution

published his famous bookOn the Origin of Species by Means of Natural Selection in England in1859

neo-Darwinism to describe Darwins theories as modified by chromosomal theory of

inheritance by Gregor Mendel in 1900s Natural selection

rests on three propositions.

First, there is variation among organisms (within populations) for anatomical, behavioral, andphysiological traits.

Second, the variation is at least partly heritable so that offspring tend to resemble theirparents.

Third, organisms with different variant forms are expected to leave different numbers of

offspring to future generations. Variants that permit their possessors most effectively to exploit their environments will

preferentially survive to be transmitted to future generations.

Over many generations, favorable new traits will spread throughout a population.

Accumulation of such changes leads, over long periods of time, to production of neworganismal characteristics and new species.

Natural selection is therefore a creative process that generates novel forms from the small

i di id l i ti th t i ithi l ti

Charles Darwin (1809-82)


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individual varia tions that occur among organisms within a population

co-discovered the process of evolution by natural selection with CharlesDarwin.

Wallace's Standard wing Bird of Paradise, Semioptera wallaceii, discovered byAlfred Russel Wallace in South east Asia and named after him

This specimen of the butterfly Asterope sapphira was collected by Henry WalterBates, the travelling companion of Alfred Russel Wallace, in the Amazon in the1850s.

Alfred Russel Wallace (1823-1913)

Hennig proposed the practice of taxonomy as a series of tests of hypotheses.

Introduced cladistics

A clade is a group of organisms that share characters, and by extension, acommon ancestor.

1960's when Hennig's bookPhylogenetic Systematics (it was published in 1950in German as Grundzge einer Theorie der Phylogenetischen Systematik) wasfirst translated into English and came into British and American academiccircles.

lead to the discovery that birds and dinosaurs are more closely related to eachother than either is to reptiles.

Willi Hennig (1913-76)


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Linnaeus and the birth of modern taxonomy

Developed sexual system of plants as basis of classifying plants

In 1753 he published a book called Species Plantarum

Systema Naturae 1759 for animal naming Specimen of red maple, Acer rubrum, used by Linnaeus.

Rubus idaeus L.

Rubus (the genus name) idaeus (the species name) Linnaeus (the botanist who coinedthe name, often abbreviated).

Homo sapiens, which means 'thinking man

Carolus Linnaeus (1707-78)

French naturalist who offered the first scientific explanation of evolution. Lamarckshypothesis that evolution proceeds by inheritance of acquired characteristics has beenrejected and replaced by neo-Darwinian theories.

Inheritance of acquired characteristics

organisms, by striving to meet the demands of their environments, acquireadaptations and pass them by heredity to their offspring.

According to Lamarck, the giraffe evolved its long neck because its ancestorslengthened their necks by stretching to obtain food and then passed the lengthenedneck to their offspring. Over many generations, these changes accumulated toproduce the long necks of modern giraffes.

- theory of use and disuse

Jean Baptiste de Lamarck (1744 to 1829)

enotes outline: introduction to zoology history

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