-
Philosophie Zoologique
In 1809 Jean-Baptiste Lamark's Philosophie Zoologique published, presenting early ideas on the mechanisms of evolution. Lamark presented stronge evidence for the fact of evolution but his ideas about how it occurred were not convincing. -
Birth of Charles Robert Darwin
Charles Robert Darwin was born on 12 February 1809 in Shrewsbury, Shropshire into a wealthy family. Later in his life, Darwin went to school to join the medical field but then decided to switch to the study of divinity. -
Period: to
Principles of Geology
Charles Lyell publishes Principles of Geology, popularizing the idea that Earth was shaped by slow-acting forces still in operation today. -
Period: to
Darwin on the HMS Beagle
A scientist named Henslow recommended Darwin for a postion on the HMS Beagle, a Royal Navy ship that was going on a survey voyage around the world. On this voyage is when Darwin made his famous Galapagos discoveries. Through these discoveries Darwin learned that animals change over time to adapt to their environments. -
Period: to
Dawrin develops ideas on evolution
Darwin develops his ideas that evolution can be explained by descent with modification and natural selection. His three major propositions were:
-Species change over time
-Divergent species share a common ancestor
-The mechanism that produces changes in species is natural selection
Natural selection is the differential survival and reproduction of individuals ina population based on variation in their traits. -
Darwin's 1st Essay
Darwin's first essay on natuarl selection. This essay was on his thrid propostion describing natural selection as the mechanism of evolution. He was reluctant to publish this essay because he wanted to gather more information first. -
Natural Selection
Parts of Darwin's 1844 essay combined with Wallace's manuscript were presented to Linnaean Society and later published so both men were credited for the idea of natural selection. They were published together because their therories were almost identical. Darwin found this out when Wallace sent him his manuscript which included an explanation of natural selection. -
The Origin of Species
Darwin publishes The Origin of Species. The publication of The Origin of Species provided evidendce from many fields supporting both the premise of evolution and the notion of natural selection as a mechanism of evolution. Its publication therefore cause many scientists to become more interested in theories of evolution. -
Pea Genetics Publication
Gregor Mendel publishes his paper on pea genetics. This publication was not really paid attention to when it was first publicated but it turned out to be the basic mechanisms of genetic inheritance.Through the selective cross-breeding of common pea plants over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics. -
Tree of Life
Haeckel publishes his diagrams of Tree of Life. Haeckel's most popular diagram is known as the pedigree of man. By creating these diagrams he added the third kingdom, the unicellular protists, to the already existing plant and animal kingdoms. His trees were also the first to depict humans as branching off from the primate lineages. -
Chromosomes and Inheritance
Thomas Hunt Morgan establishes Drosophila lab at Columbia University and clarifies role of chromosomes in inheritance. He does through examining fruit flies with a microscope and a magnifying glass and eventually Morgan confirmed the chromosomal theory of inheritance. This theory is that genes are on the same chromosome and are always inherited together. -
Period: to
Modern Synthesis
"Modern synthesis" of genetics and evolution. -
DNA Structures
james Watson and Frances Crick publish their paper on DNA structure. This opened up the door to our curretn detailed understanding of molecular evolutionary mechanisms. -
Period: to
Molecular Evolution and Protein Sequencing
By the early 1960s, techniques for protein sequencing had advanced to the point that scientists were able to find a direct comparison of homologous amino acid sequences. This was all due to scientists like Francis Crick, Charles Sibley and others who saw the potential for using biological sequences to construct phylogenies. -
Molecular Clock
Emile Zuckerkandl and Linus Pauling noticed that the number of amino acid differences in hemoglobin between different lineages changes roughly linearly with time, as estimated from fossil evidence. This caused them to believe that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages. A molecular clock is used to estimate the time of occurrence of events called speciation. -
Neutral Theory of Molecular Evolution
Motoo Kimura's neutral theory of molecular evolution. The neutral theory of molecular evolution says that at the molecular level most evolutionary changes and most of the variation within species is not caused by natural selection but by random drift of mutant alleles that are neutral. A neutral mutation is one that does not affect an organism's ability to survive and reproduce. -
Journal of Molecular Evolution
Emile Zuckerkandl and other molecular evolutionists founded the Journal of Molecular Evolution. Journal of Molecular Evolution covers experimental and theoretical work aimed at figuring out features of molecular evolution. The journal includes the evolution of macromolecules and their relation to more complex levels of biological organization. -
Sociobiology
Sociobiology by E. O. Wilson. Sociobiology is a brach of biology that deals with social behaviors. Sociobiology is based on the hypothesis that social behavior has resulted from evolution and attempts to explain and examine social behavior within that context.
