Karl Ernst von Baer

Karl Ernst von Baer was born into the <a href="/facts/Baltic_nobility/8x5lw6ox">Baltic German noble</a> Baer family (et) in the Piep Manor (et), <a href="/facts/Jerwen_County/qEnPqL7F">Jerwen County</a>, <a href="/facts/Governorate_of_Estonia/CdJ7skUj">Governorate of Estonia</a> (in present-day <a href="/facts/L%25C3%25A4%25C3%25A4ne-Viru_County/zcHbTEle">Lääne-Viru County</a>, <a href="/facts/Estonia/PVjB16TI">Estonia</a>), as a <a href="/facts/Ritter/YRcQEsnA">knight</a> by birthright. His patrilineal ancestors were of <a href="/facts/Westphalia/tHtm9cTt">Westphalian</a> origin and originated in <a href="/facts/Osnabr%25C3%25BCck/XWVNrKM8">Osnabrück</a>. He spent his early childhood at <a href="/facts/Lasila/HWG1pBnW">Lasila manor</a>, Estonia.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a><a class="footnote-ref" id="fnref:4" href="#fn:4">4</a><a class="footnote-ref" id="fnref:5" href="#fn:5">5</a><a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> He was educated at the Knight and Cathedral School in <a href="/facts/Reval/IBLBVtHt">Reval</a> (Tallinn) and the <a href="/facts/Imperial_University_of_Dorpat/eVN4IExF">Imperial University of Dorpat</a> (<a href="/facts/Tartu/zL0hGPDe">Tartu</a>). In 1812, during his tenure at the university, he was sent to <a href="/facts/Riga/PCWbJn2h">Riga</a> to aid the city after <a href="/facts/French_invasion_of_Russia/EK8zjEhY">Napoleon's armies</a> had laid siege to it. As he attempted to help the sick and wounded, he realized that his education at Dorpat had been inadequate, and upon his graduation, he notified his father that he would need to go abroad to "finish" his education. In his autobiography, his discontent with his education at Dorpat inspired him to write a lengthy appraisal of education in general, a summary that dominated the content of the book. After leaving Tartu, he continued his education in Berlin, <a href="/facts/Vienna/NSpIURsA">Vienna</a>, and <a href="/facts/W%25C3%25BCrzburg/y2ok8SaL">Würzburg</a>, where <a href="/facts/Ignaz_D%25C3%25B6llinger/nDcq11RL">Ignaz Döllinger</a> introduced him to the new field of <a href="/facts/Embryology/4mvpSkhC">embryology</a>.
In 1817, he became a professor at <a href="/facts/K%25C3%25B6nigsberg_University/3NL3eavc">Königsberg University</a> and full professor of <a href="/facts/Zoology/6Kj13mBt">zoology</a> in 1821, and of <a href="/facts/Anatomy/p8TCWJuV">anatomy</a> in 1826. In 1829, he taught briefly in <a href="/facts/St_Petersburg/pNuCBxaM">St Petersburg</a>, but returned to <a href="/facts/K%25C3%25B6nigsberg/veeajbNW">Königsberg</a> (Kaliningrad). In 1834, Baer moved back to St Petersburg and joined the <a href="/facts/St_Petersburg_Academy_of_Sciences/RuUqhtFb">St Petersburg Academy of Sciences</a>, first in zoology (1834–46) and then in <a href="/facts/Comparative_anatomy/UycBTvDH">comparative anatomy</a> and <a href="/facts/Physiology/fh25y2pQ">physiology</a> (1846–62). His interests while there were anatomy, <a href="/facts/Ichthyology/S2MCul1h">ichthyology</a>, <a href="/facts/Ethnography/qxJRLSwJ">ethnography</a>, <a href="/facts/Anthropology/W6WK1C3a">anthropology</a>, and <a href="/facts/Geography/TRd1Toyo">geography</a>. While embryology had kept his attention in Königsberg, then in Russia von Baer engaged in a great deal of field research, including the exploration of the island <a href="/facts/Novaya_Zemlya/2CDJsNQK">Novaya Zemlya</a>. The last years of his life (1867–76) were spent in Dorpat, where he became a major critic of <a href="/facts/Charles_Darwin/uwDLGItY">Charles Darwin</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a>

<h2 id="contributions">Contributions</h2>
<h3>Embryology</h3>
See also: <a href="/facts/Recapitulation_theory/Fc8dFDpy">Recapitulation theory</a>
Von Baer studied the embryonic development of animals, discovering the <a href="/facts/Blastula/sJVSBmbH">blastula</a> stage of development and the <a href="/facts/Notochord/wvmmQPj1">notochord</a>. Together with <a href="/facts/Heinz_Christian_Pander/w2GakecU">Heinz Christian Pander</a> and based on the work by <a href="/facts/Caspar_Friedrich_Wolff/WUE5MytE">Caspar Friedrich Wolff</a>, he described the <a href="/facts/Germ_layer/eSUTuH7F">germ layer</a> theory of development (<a href="/facts/Ectoderm/lg5p0jTL">ectoderm</a>, <a href="/facts/Mesoderm/kf77vcNA">mesoderm</a>, and <a href="/facts/Endoderm/6UhPjVnt">endoderm</a>) as a principle in a variety of species, laying the foundation for <a href="/facts/Comparative_embryology/EaHxUY5L">comparative embryology</a> in the book Über Entwickelungsgeschichte der Thiere (1828). In 1826, Baer discovered the mammalian <a href="/facts/Ovum/gJyW3W3W">ovum</a>. The human ovum was first described by <a href="/facts/Edgar_Allen/0Xpo17AJ">Edgar Allen</a> in 1928. In 1827, he completed research Ovi Mammalium et Hominis genesi for St Petersburg's Academy of Science (published at Leipzig<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a><a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>). In 1827 von Baer became the first person to observe human <a href="/facts/Egg_cell/gJyW3W3W">ova</a>.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a><a class="footnote-ref" id="fnref:11" href="#fn:11">11</a> Only in 1876 did <a href="/facts/Oscar_Hertwig/SvIWoUbI">Oscar Hertwig</a> prove that fertilization is due to fusion of an egg and sperm cell.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a>
von Baer formulated what became known as <a href="/facts/Von_Baer%2527s_law_(biology)/FM8DfXL1">Baer's laws of embryology</a>:

<ol><li>General characteristics of the group to which an embryo belongs develop before special characteristics.</li>
<li>General structural relations are likewise formed before the most specific appear.</li>
<li>The form of any given embryo does not converge upon other definite forms, but separates itself from them.</li>
<li>The embryo of a higher animal form never resembles the adult of another animal form, such as one less evolved, but only its embryo.</li></ol>
<h3>Permafrost research</h3>

Baer was a genius scientist covering not only the topics of embryology and ethnology, he also was especially interested in the geography of the northern parts of Russia, and explored <a href="/facts/Novaya_Zemlya/2CDJsNQK">Novaya Zemlya</a> in 1837. In these <a href="/facts/Arctic/bxbuUz7Q">arctic</a> environments, he was studying <a href="/facts/Periglacial/sWDGDrCw">periglacial</a> features, <a href="/facts/Permafrost/SkFC7LMT">permafrost</a> occurrences, and collecting biological specimens. Other travels led him to <a href="/facts/Subarctic/cGeg5Al2">subarctic</a> regions of the <a href="/facts/North_Cape_(Norway)/KNnjJfwn">North Cape</a> and <a href="/facts/S%25C3%25A1pmi/tDbtp6ag">Lapland</a>, but also to the <a href="/facts/Caspian_Sea/Ymc08gkR">Caspian Sea</a>. He was one of the founders of the <a href="/facts/Russian_Geographical_Society/uWYNgxKS">Russian Geographical Society</a>.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a>
Thanks to Baer's research expeditions, the scientific investigation of permafrost began in Russia. Baer recorded the importance of permafrost research even before 1837 when observing in detail the <a href="/facts/Geothermal_gradient/KWeCJ0M0">geothermal gradient</a> from a 116.7 m deep shaft in <a href="/facts/Yakutsk/QnDgGCwX">Yakutsk</a>. At the end of the 1830s, he recommended sending expeditions to explore permafrost in Siberia and suggested <a href="/facts/Alexander_von_Middendorff/XSFCdX91">Alexander von Middendorff</a> as leader. Baer's expedition instructions written for Middendorff comprised over 200 pages. Baer summarized his knowledge in 1842/43 in a print-ready typescript. The German title is „Materialien zur Kenntniss des unvergänglichen Boden-Eises in Sibirien“ (=materials for the knowledge of the perennial ground ice in Siberia). This world's first permafrost textbook was conceived as a complete work for printing. But it remained lost for more than 150 years. However, from 1838 onwards, Baer published a larger number of small publications on permafrost. Numerous of Baer's papers on permafrost were already published as early as 1837 and 1838. Well known was his paper "On the Ground Ice or Frozen Soil of Siberia", published in the Journal of the Royal Geographical Society of London (1838, pp. 210–213)<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> and reprinted 1839 in the American Journal of Sciences and Arts by S. Silliman.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a> There are many other publications and small notes on permafrost by Baer, as shown in the Karl Ernst von Baer museum in <a href="/facts/Tartu/zL0hGPDe">Tartu</a> (<a href="/facts/Estonia/PVjB16TI">Estonia</a>), now part of the <a href="/facts/Estonian_University_of_Life_Sciences/v0VhTH65">Estonian University of Life Sciences</a>.
There are quite a number of studies in Russian about the origin of permafrost research. Russian authors usually relate with it the name <a href="/facts/Alexander_von_Middendorff/XSFCdX91">Alexander von Middendorff</a> (1815–1894), as he did much scientific work during the years 1842–1845 concerning permafrost on <a href="/facts/Taimyr_Peninsula/Jk6EXYSL">Taimyr Peninsula</a> and in East-<a href="/facts/Siberia/oaCoPEjF">Siberia</a>. However, Russian scientists during the 1940s also realized, that it was K. E. Baer who initiated this expedition and that the origin of scientific permafrost research must be fixed with Baer's thorough earlier scientific work. They even believed, that the scepticism about the permafrost findings and publications of Middendorff would not have risen, if Baer's original "materials for the study of the perennial ground-ice" would have been published in 1842 as intended. This was realized also by the Russian Academy of Sciences that honoured Baer with the publication of a tentative Russian translation done already in 1842 by Sumgin. These facts were completely forgotten until after the Second World War.
In North America, permafrost research started after the Second World War with the creation of the <a href="/facts/Cold_Regions_Research_and_Engineering_Laboratory/vPLuYuT5">Cold Regions Research and Engineering Laboratory</a> (CRREL), a division of the US army. It was realized that the understanding of frozen ground and permafrost are essential factors in strategic northern areas during the <a href="/facts/Cold_War/spJdJQ3q">Cold War</a>. In the Soviet Union, the <a href="/facts/Melnikov_Permafrost_Institute/xXDKKIAT">Melnikov Permafrost Institute</a> in <a href="/facts/Yakutsk/QnDgGCwX">Yakutsk</a> had similar aims. The first post-World War major contact between groups of senior Russian and American frozen ground researchers took place in November 1963 in Yakutsk.However, Baer's permafrost textbook remained still undiscovered.
Thus in 2001 the discovery and annotated publication of the typescript from 1843 in the library <a href="/facts/Archive/BgCG3dxa">archives</a> of the <a href="/facts/University_of_Giessen/gbtWeYuD">University of Giessen</a> was a scientific sensation. The full text of Baer's work is available online (234 pages).<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a> The editor Lorenz King added to the <a href="/facts/Facsimile/KYVNIArp">facsimile</a> reprint a preface in English, two colour permafrost maps of Eurasia and some figures of permafrost features. Baer's text is introduced with detailed comments and references on additional 66 pages written by the <a href="/facts/Estonia/PVjB16TI">Estonian</a> historian Erki Tammiksaar.
The work is fascinating to read, because both Baer's observations on permafrost distribution and his periglacial morphological descriptions are largely still correct today. He distinguished between "continental" and "insular" permafrost, saw the temporary existence of permafrost and postulated the formation and further development of permafrost as a result of the complex <a href="/facts/Physical_geography/NByHKLCQ">physio-geographical</a>, <a href="/facts/Geology/WGvVRIYF">geological</a> and <a href="/facts/Flora/2xkcTn2d">floristic</a> site conditions. With his permafrost classification Baer laid the foundation for the modern permafrost terminology of the <a href="/facts/International_Permafrost_Association/xtlhF5qt">International Permafrost Association</a>. With his compilation and analysis of all available data on ground ice and permafrost, Karl Ernst von Baer must be given the attribute "founder of scientific permafrost research".

<h3>Evolution</h3>

From his studies of comparative embryology, Baer had believed in the <a href="/facts/Transmutation_of_species/aoHxUErV">transmutation of species</a> but rejected later in his career the theory of <a href="/facts/Natural_selection/JXTte6en">natural selection</a> proposed by <a href="/facts/Charles_Darwin/uwDLGItY">Charles Darwin</a>. He produced an early tree-like branching diagram illustrating the sequential origins of derived character states in vertebrate embryos during ontogeny that implies a pattern of phylogenetic relationship.<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a>
In the fifth edition of <a href="/facts/On_the_Origin_of_Species/zTMxkKVY">On the Origin of Species</a> published in 1869, Charles Darwin added a Historical Sketch giving due credit to naturalists who had preceded him in publishing the opinion that species undergo modification, and that the existing forms of life have descended by true generation from pre-existing forms. According to Darwin:

"Von Baer, towards whom all zoologists feel so profound a respect, expressed about the year 1859... his conviction, chiefly grounded on the laws of geographical distribution, that forms now perfectly distinct have descended from a single parent-form."<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a> He was a pioneer in studying biological time – the <a href="/facts/Time_perception/9xxfx8gb">perception of time</a> in different organisms.<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a>
Baer believed in a <a href="/facts/Teleology/8YR2sPUf">teleological</a> force in nature which directed evolution (<a href="/facts/Orthogenesis/TKjwUPmA">orthogenesis</a>).<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a><a class="footnote-ref" id="fnref:21" href="#fn:21">21</a>

<h3>Other topics</h3>

The term <a href="/facts/Baer%2527s_law/52gRcRh5">Baer's law</a> is also applied to the unconfirmed proposition that in the <a href="/facts/Northern_Hemisphere/EFwyqL25">Northern Hemisphere</a>, <a href="/facts/Erosion/gaGJXy0W">erosion</a> occurs mostly on the right banks of rivers, and in the <a href="/facts/Southern_Hemisphere/QfJ4z9L5">Southern Hemisphere</a> on the left banks. In its more thorough formulation, which Baer never formulated himself, the erosion of rivers depends on the direction of flow, as well. For example, in the Northern Hemisphere, a section of river flowing in a north–south direction, according to the theory, erodes on its right bank due to the <a href="/facts/Coriolis_effect/SqCyUY6d">coriolis effect</a>,<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a> while in an east–west section there is no preference. However, this was repudiated by <a href="/facts/Albert_Einstein/CNTet8qu">Albert Einstein</a>'s <a href="/facts/Tea_leaf_paradox/tpvGfh5r">tea leaf paradox</a>.

<h2 id="awards-and-distinctions">Awards and distinctions</h2>
In 1849, he was elected a foreign honorary of the <a href="/facts/American_Academy_of_Arts_and_Sciences/KptWYgz4">American Academy of Arts and Sciences</a>.<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> He was elected a foreign member of the <a href="/facts/Royal_Swedish_Academy_of_Sciences/QazgtP1n">Royal Swedish Academy of Sciences</a> in 1850. He was the president of the <a href="/facts/Estonian_Naturalists%2527_Society/DX1lzKx8">Estonian Naturalists' Society</a> in 1869–1876, and was a co-founder and first president of the <a href="/facts/Russian_Entomological_Society/Q1hwJoyo">Russian Entomological Society</a>.<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a><a class="footnote-ref" id="fnref:25" href="#fn:25">25</a><a class="footnote-ref" id="fnref:26" href="#fn:26">26</a><a class="footnote-ref" id="fnref:27" href="#fn:27">27</a> In 1875, he became a foreign member of the <a href="/facts/Royal_Netherlands_Academy_of_Arts_and_Sciences/3kMPbFAD">Royal Netherlands Academy of Arts and Sciences</a>.<a class="footnote-ref" id="fnref:28" href="#fn:28">28</a>

<h2 id="legacy">Legacy</h2>
A statue honouring him can be found on <a href="/facts/Toome_Hill/zL0hGPDe">Toome Hill</a> in Tartu, as well as at <a href="/facts/Lasila/HWG1pBnW">Lasila manor</a>, Estonia, and at the <a href="/facts/Zoological_Museum_of_the_Zoological_Institute_of_the_Russian_Academy_of_Sciences/82D3J9J9">Zoological Museum in St Petersburg</a>, Russia. In Tartu, there is also located Baer House which also functions as <a href="/facts/Baer_Museum/AgzrerLK">Baer Museum</a>.<a class="footnote-ref" id="fnref:29" href="#fn:29">29</a>
Before the Estonian conversion to the euro, the <a href="/facts/2_krooni/v8Rnzobm">2-kroon</a> bank note bore his portrait. <a href="/facts/Taymyr_Gulf/AfntIpTy">Baer Island</a> in the Kara Sea was named after Karl Ernst von Baer for his important contributions to the research of arctic meteorology between 1830 and 1840.<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a> A duck, <a href="/facts/Baer%2527s_pochard/UmTGQouU">Baer's pochard</a>, was also named after him.

<h2 id="works">Works</h2>
<ul><li>Karl Ernst von Baer, <a href="/facts/Gregor_von_Helmersen/XM9ugg2e">Gregor von Helmersen</a>. <a href="/facts/Beitr%25C3%25A4ge_zur_Kenntniss_des_Russischen_Reiches_und_der_angr%25C3%25A4nzenden_L%25C3%25A4nder_Asiens/I3V3DShr">Beiträge zur Kenntniss des Russischen Reiches und der angränzenden Länder Asiens</a>, 2 vols. Kaiserlichen Akademie der Wissenschaften, 1839. <a href="https://books.google.com/books?id=uN0GAAAAYAAJ">Google Books</a>.</li>
<li>Karl Ernst von Baer, Welche Auffassung der lebenden Natur ist die richtige? Berlin, 1862<a class="footnote-ref" id="fnref:31" href="#fn:31">31</a></li></ul>

<h3>Further reading</h3>
<ul><li>Oppenheimer, Jane (1970). "Baer, Karl Ernst von". <a href="/facts/Dictionary_of_Scientific_Biography/qMA96GhQ">Dictionary of Scientific Biography</a>. Vol. 1. New York: Charles Scribner's Sons. pp. 385–389. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-684-10114-9.</li>
<li>Wood C, Trounson A. Clinical in Vitro Fertilization. Springer-Verlag, Berlin 1984, Page 6.</li>
<li>Baer, K E v. "Über ein allgemeines Gesetz in der Gestaltung der Flußbetten", Kaspische Studien, 1860, VIII, S. 1–6.</li></ul>
<h2 id="external-links">External links</h2>

Wikimedia Commons has media related to Karl Ernst von Baer.

<a href="/facts/Wikisource/TrMdylNf">Wikisource</a> has the text of the <a href="/facts/Encyclop%25C3%25A6dia_Britannica_Eleventh_Edition/mPElbCRY">1911 Encyclopædia Britannica</a> article "Baer, Karl Ernst von".

<ul><li><a href="https://www.biodiversitylibrary.org/creator/2018">Works by Karl Ernst von Baer</a> at the <a href="/facts/Biodiversity_Heritage_Library/NqePUljt">Biodiversity Heritage Library</a></li>
<li><a href="http://vlp.mpiwg-berlin.mpg.de/references?id=per44">Bibliography and links</a> at <a href="/facts/Max_Planck_Institute_for_the_History_of_Science/oLRU6F2n">Max Planck Institute</a></li>
<li><a href="http://www.mois.ee/jarva/piibe.shtml">Overview of Piibe (Piep) manor (with photo of memorial stone)</a> <a href="https://web.archive.org/web/20200803004756/http://www.mois.ee/jarva/piibe.shtml">Archived</a> 3 August 2020 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li>
<li><a href="http://www.zbi.ee/baer/biography.htm">Short biography</a> <a href="https://web.archive.org/web/20130616004912/http://www.zbi.ee/baer/biography.htm">Archived</a> 16 June 2013 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li>
<li><a href="https://ipa.arcticportal.org/publications/glossary/">Glossary of Permafrost and Related Ground-Ice Terms (IPA)</a> <a href="https://web.archive.org/web/20210514025808/https://ipa.arcticportal.org/publications/glossary">Archived</a> 14 May 2021 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li>
<li><a href="https://ipa.arcticportal.org/meetings/international-conferences/">International Conferences on Permafrost</a> <a href="https://web.archive.org/web/20210305135541/https://ipa.arcticportal.org/meetings/international-conferences">Archived</a> 5 March 2021 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li>
<li><a href="https://web.archive.org/web/20060212043202/http://www.bankofestonia.info/pub/en/yldine/pangatahed/pangatahed/_2.html">Estonian banknotes</a></li>
<li><a href="https://archive.today/20140104091028/http://uudised.err.ee/index.php?06190711">Ajaloolane: Karl Ernst von Baer oli Venemaa luure asutaja</a> (in Estonian)</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Regarding personal names: Ritter is a title, translated approximately as 'Sir' (denoting a knight), not a first or middle name. There is no equivalent female form. <a href="/wiki/Ritter" target="_blank">/wiki/Ritter</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Regarding personal names: Edler is a rank of nobility, not a first or middle name. The female form is Edle. <a href="/wiki/Edler" target="_blank">/wiki/Edler</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">K. J. Betteridge (1981). "An historical look at embryo transfer". Reproduction. 62 (1): 1–13. doi:10.1530/jrf.0.0620001. PMID 7014855. Three years later, the Estonian, Karl Ernst von Baer, finally found the true mammalian egg in a pet dog (von Baer, 1827). <a href="https://doi.org/10.1530%2Fjrf.0.0620001" target="_blank">https://doi.org/10.1530%2Fjrf.0.0620001</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Karl Clausberg (2006). "Karl Ernst von Baer". Zwischen den Sternen: Lichtbildarchive. Was Einstein und Uexküll, Benjamin und das Kino der Astronomie des 19. Jahrhunderts verdanken (in German). Berlin: Akademie Verlag. p. 47. ISBN 978-3-05-004043-1. ...- dreizehn Jahre später von dem berühmten Estländer Biologen Karl Ernst von Baer...[permanent dead link] <a href="978-3-05-004043-1" target="_blank">978-3-05-004043-1</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">J.M.S. Pearce, M.D. (2010). "Evolution from recapitulation theory to Neural Darwinism". Hektoen International. A Journal of Medical Humanities. 2 (2). Archived from the original on 29 March 2012. <a href="https://web.archive.org/web/20120329104606/http://hektoeninternational.org/HektoenInternational.NeuralDarwinism2.html" target="_blank">https://web.archive.org/web/20120329104606/http://hektoeninternational.org/HektoenInternational.NeuralDarwinism2.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Hein, Ants (2009). Eesti Mõisad – Herrenhäuser in Estland – Estonian Manor Houses (in Estonian, German, and English). Tallinn: Tänapäev. p. 126. ISBN 978-9985-62-765-5. <a href="978-9985-62-765-5" target="_blank">978-9985-62-765-5</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Alexander Vucinich (1988). Darwin in Russian thought. University of California Press. pp. 92–99. ISBN 978-0-520-06283-2. Archived from the original on 27 September 2012. Retrieved 1 September 2011. <a href="978-0-520-06283-2" target="_blank">978-0-520-06283-2</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">"Bibliographic Index – Baer Carl". Archived from the original on 21 May 2006.{{cite web}}: CS1 maint: bot: original URL status unknown (link) via Google Translate <a href="https://web.archive.org/web/20060521214120/http://safety.spbstu.ru/book/hrono/hrono/biograf/bio_b/ber_karl.html" target="_blank">https://web.archive.org/web/20060521214120/http://safety.spbstu.ru/book/hrono/hrono/biograf/bio_b/ber_karl.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">"Biography Karl Maximovych". Archived from the original on 19 March 2008.{{cite web}}: CS1 maint: bot: original URL status unknown (link) via Google Translate <a href="https://web.archive.org/web/20080319143038/http://www.allpersona.ru/people/72032.html" target="_blank">https://web.archive.org/web/20080319143038/http://www.allpersona.ru/people/72032.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Cobb M (2012). "An amazing 10 years: the discovery of egg and sperm in the 17th century". Reprod Domest Anim. 47 (Suppl 4): 2–6. doi:10.1111/j.1439-0531.2012.02105.x. PMID 22827343. <a href="https://doi.org/10.1111%2Fj.1439-0531.2012.02105.x" target="_blank">https://doi.org/10.1111%2Fj.1439-0531.2012.02105.x</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">""Conclusio" from Carl Ernst von Baer's De Ovi Mammalium et..." (jpeg). Archived from the original on 24 May 2019. Retrieved 2 February 2015. <a href="https://commons.wikimedia.org/wiki/File:%22Conclusio%22_from_Carl_Ernst_von_Baer%27s_De_Ovi_Mammalium_et..._Wellcome_L0013369.jpg" target="_blank">https://commons.wikimedia.org/wiki/File:%22Conclusio%22_from_Carl_Ernst_von_Baer%27s_De_Ovi_Mammalium_et..._Wellcome_L0013369.jpg</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Clift D, Schuh M (2013). "Restarting life: fertilization and the transition from meiosis to mitosis (Box 1)". Nature Reviews Molecular Cell Biology. 14 (9): 549–62. doi:10.1038/nrm3643. PMC 4021448. PMID 23942453. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4021448" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4021448</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"Founders of the Russian Geographical Society". Archived from the original on 11 February 2017. Retrieved 10 February 2017. <a href="https://www.rgo.ru/en/founders-society" target="_blank">https://www.rgo.ru/en/founders-society</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">Baer, Karl Ernst von (1838). "On the Ground Ice or Frozen Soil of Siberia". The Journal of the Royal Geographical Society of London. 8: 210–213. doi:10.2307/1797797. JSTOR 1797797. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">Baer, Karl Ernst von (1838). "On the Ground Ice or Frozen Soil of Siberia". The American Journal of Science and Arts by B. Silliman. 36: 210–212. <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">King, Lorenz (2001). "Materialien zur Kenntniss des unvergänglichen Boden-Eises in Sibirien, compiled by Baer in 1843" (PDF). Berichte und Arbeiten aus der Universitätsbibliothek und dem Universitätsarchiv Giessen (in German). 51: 1–315. Archived (PDF) from the original on 24 January 2021. Retrieved 27 March 2021. <a href="http://geb.uni-giessen.de/geb/volltexte/2006/3649/pdf/BaerMaterialien-2001.pdf" target="_blank">http://geb.uni-giessen.de/geb/volltexte/2006/3649/pdf/BaerMaterialien-2001.pdf</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Brauckmann, Sabine (2012). "Karl Ernst von Baer (1792–1876) and Evolution". Int. J. Dev. Biol. 56 (9): 653–660. doi:10.1387/ijdb.120018sb. PMID 23319342. <a href="https://doi.org/10.1387%2Fijdb.120018sb" target="_blank">https://doi.org/10.1387%2Fijdb.120018sb</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">"The Origin of Species" Archived 29 October 2015 at the Wayback Machine. Preface to the Third Edition. <a href="http://www.talkorigins.org/faqs/origin/preface.html" target="_blank">http://www.talkorigins.org/faqs/origin/preface.html</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Karl Ernst von Baer, Welche Auffassung der lebenden Natur ist die richtige?, Berlin, 1862 <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Barbieri, Marcello. (2013). Biosemiotics: Information, Codes and Signs in Living Systems. Nova Science Publishers. p. 7. ISBN 978-1-60021-612-1 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Jacobsen, Eric Paul. (2005). From Cosmology to Ecology: The Monist World-view in Germany from 1770 to 1930. p. 100. Peter Lang Pub Inc. ISBN 978-0-8204-7231-7 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Zoltan, Balla (2007). "The Influence of the Coriolis Force on Rivers and the Baer Law. Historical Review" (PDF). Geological Institute of Hungary. pp. 53–62. Archived (PDF) from the original on 18 September 2017. Retrieved 16 May 2017. <a href="http://epa.oszk.hu/02900/02934/00034/pdf/EPA02934_mafi_evi_jelentes_2007_053-062.pdf" target="_blank">http://epa.oszk.hu/02900/02934/00034/pdf/EPA02934_mafi_evi_jelentes_2007_053-062.pdf</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">"Book of Members, 1780–2010: Chapter B" (PDF). American Academy of Arts and Sciences. Archived (PDF) from the original on 25 July 2011. Retrieved 5 May 2011. <a href="http://www.amacad.org/publications/BookofMembers/ChapterB.pdf" target="_blank">http://www.amacad.org/publications/BookofMembers/ChapterB.pdf</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">Hodgson, Geoffrey M. (2001). How economics forgot history: the problem of historical specificity in social science. New York: Routledge. p. 331. ISBN 978-0-415-25717-6. <a href="978-0-415-25717-6" target="_blank">978-0-415-25717-6</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">Barbieri, Marcello (2007). Biosemiotics: Information, Codes and Signs in Living Systems. Nova Publishers. p. 6. ISBN 978-1-60021-612-1. <a href="978-1-60021-612-1" target="_blank">978-1-60021-612-1</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">Lockwood, Michael (2005). The labyrinth of time: introducing the universe. Oxford [Oxfordshire]: Oxford University Press. p. 374. ISBN 978-0-19-924995-4. <a href="978-0-19-924995-4" target="_blank">978-0-19-924995-4</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">Herrmann, Debra S.; Williams, Nicola; Kemp, Cathryn (2003). Lonely Planet Estonia Latvia & Lithuania (Lonely Planet Estonia, Latvia and Lithuania). Hawthorn, Vic., Australia: Lonely Planet Publications. p. 159. ISBN 978-1-74059-132-4. <a href="978-1-74059-132-4" target="_blank">978-1-74059-132-4</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">"Karl Ernst Ritter von Baer (1792–1876)". Royal Netherlands Academy of Arts and Sciences. Archived from the original on 18 September 2017. Retrieved 26 January 2016. <a href="http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00000412" target="_blank">http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00000412</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">"Baer House in Tartu, Estonia". Visitestonia.com. Archived from the original on 10 January 2021. Retrieved 8 January 2021. <a href="https://www.visitestonia.com/en/baer-house-in-tartu" target="_blank">https://www.visitestonia.com/en/baer-house-in-tartu</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">Meteo History Archived 9 February 2012 at the Wayback Machine, 2004. <a href="http://www.meteohistory.org/2004polling_preprints/docs/abstracts/tammiksaar_abstract.pdf" target="_blank">http://www.meteohistory.org/2004polling_preprints/docs/abstracts/tammiksaar_abstract.pdf</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
<li id="fn:31">Karl Ernst von Baer, Welche Auffassung der lebenden Natur ist die richtige?, Berlin, 1862 <a href="#fnref:31" class="footnote-back-ref">↩</a></li>
</ol>

Karl Ernst von Baer open-in-new

Karl Ernst von Baer