January 14 – Happy Birthday, Adolphe-Theodore Brongniart

Postednon January 14, 2015

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nThenfather of paleobotany. n

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nThat’snquite a title! But Adolphe-Theodore Brongniart (who was born innParis, France, on this date in 1801) was a pioneer in his efforts toncompare extinct and existing plants.

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nSince paleo- means “ancient” and botany means “the study of plants,” paleobotany is the name for the study of remains of ancient plants.

nBrongniartndid two things very well indeed:

nHen investigated his subject thoroughly. That means that he studied manyn different plant fossils as well as extant plant species (kinds of plantsn that are living today).

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nHen wrote a lot. He wrote books and memoirs. Because of his careful noten taking during his investigations, scientists were able to publishn his findings on fossil seeds even though Brongniart had died beforen he could do so.

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nSomenpeople think of fossils as hard things like bones and teeth andnshells…and they might wonder how plants could ever become fossils. After all, theyndon’t have bones or teeth or shells!

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nIndeed, most plants do not become fossilized. Mostnorganisms (including plants and animals) that have lived and died do not become fossils because theynare either eaten by animals or decomposed by microorganisms. The hardnparts like shells are less likely to be eaten and also decompose morenslowly. If a dead organism is quickly buried before it is eaten orndecomposed, then it has a much better chance of becoming a fossil.nSometimes even the soft parts of an organism is fossilized becausenthe animal or plant was buried so quickly.

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nIt’s important to also understand that fossils are generally not the actual bones, teeth, ornshells, but are instead rocks in which the structures of the organismnare preserved because organic molecules that made up the organism were replaced by minerals, one molecule at a time. This mineral replacementnprocess can happen with trees or other plants, in the rightnconditions. Many people call fossilized trees “petrified wood.”

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nHerenare some of the ways that plants can become fossils:

nImpressions.

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nThen most common sort of plant fossil is an impression of a flattenedn plant or plant part. These sorts of fossils often show a lot of anatomical detailn of the plant.

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nMoldsn and casts.

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nSomenseeds, cones, or woody stems can be preserved (at least partly) by sedimentnentering hollow portions of the plant, creating a sort of mold and cast. Generally these sorts ofnfossils do not provide much evidence of internal structures or detailed anatomy.

nPetrification.

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n Thisnis that slow mineralization process I talked about above.

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nFussain.

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nAlthoughn fire usually destroys plant tissues, sometimes there are delicate “charcoalified” remains that reveal plant structures such as flowers.

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