- Attachment: mini-baseball animals?
- See the attached photo. The fossils look like mini-baseballs, or soccer balls. There are three theories as to what living creatures these fossils really were?
---------------------- (1) bacteria
---------------------- (2) protists
---------------------- (3) metazoan embryos.
- (3) It these mini-baseballs are truly embryos they represent the oldest records of animal evolutionary lineage.
- (2) We know plants evolved before animals. Protists could be either. Protists are single cell organisms that lack a structured cellular arrangement. Protists include:
------------------- (a) bacteria
------------------ (b) algae
----------------- (c ) diatoms
----------------- (d) fungi
- Protists are not animals yet but they may have given rise to both plants and animals on Earth.
- (2a) Bacteria was the strongest theory until the mini-baseballs were studied using a particle accelerator. Using the power of the accelerator resolution was imaged down to 250 nanometers. Samples were sliced into sections so thin that they were transulent. Microscopic examinations revealed a myriad of eggs and embryos that confirmed the presence of tiny adult sponges and cnidarians. Several bilaterians were discovered ranging from 100,000 to 200,000 nanometers across. The extreme close-ups of these specimens revealed that the fossils and bacteria were far too different. The theory that mini-baseballs ere bacteria was shot down.
- These fossils from the Dousantuo formation in South China were preserved in a chance formation of calcium phosphate. The fossil deposit is 26 feet thick and each single grain is a fossil, a mini-baseball. The phosphate acted as a preservative for the remains of these soft-bodied animals.
- Preservation of fossils in types of rock and chemistry are spectacularly rare. Another one of these rare finds is in Solnhofen Limestone in Germany. There a 150,000,000 year-old feathered specimen was found believed to be the earliest bird, “Archaeopteryx”.
- Other fossils at the South China site include Vernaimalcula, which means “small spring animal”. It first appeared at the end of the era known as “ Snowball Earth”. This fossil is the first known animal having body symmetry. “ Bilaterians” are celled animals comprising species from worms to humans. Their symmetry displays a left-right balance yet a multilayered body that typically has a mouth, a gut and anus.
- Bilaterians as microscopic animals are surprisingly complex including the three major tissue layers you learned in high school biology, endoderm, mesoderm and extoderm. The presence of a gut and a mouth and anus and paired coeloms ( body cavities) surrounding the gut. The Vernaimalcula’s oval shaped body scooted along the seafloor to feed. At one end of the oval, the mouth sucked up microbes. Pits on either side of the mouth were likely sense organs. In life this animal was the size of a period at the end of this sentence “.”
- “Kimberella” are soft-bodied sea dwellers some 10 centimeters in length that were likely the ancestors to mollusks and today’ clams, snails, and squid. This link to the bilaterians is still waiting discovery.
- Other similar fossils have been found at Flinders Ranges in South Australia. Both sites were dated at 570,000,000 years old. Accordingly at that time South China and South Australia were connected as one continent , called “ Gondwana”. The Cambrian explosion of life began about 542,000,000 years ago and science now believes that complex animals existed at least 50,000,000 years earlier.
- Using DNA differences in organisms science tries to measure the date at which two lineages split from a common ancestor, each group going its separate way and accumulating its own distinctive mutations. The idea is that over millions of years mutations in the DNA of genes occurs at a steady rate. Using this technique theories have bilaterians diverging from more primitive animals 1,200,000,000 years ago.
- Exactly what the mini-baseball fossils in the picture represent remains to be determined. They have something to do with the evolution of life on Earth. We just to not know what that is? An announcement will be made shortly, stay tuned. In the meantime , they are mini-baseballs fossils.
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(1) Cradle of life, the discovery of Earth’s earliest fossils, by j. William Schopf
(2) Evolution, the triumph of an idea, by Carl Zimmer.
(3) Life on a Young Planet, the first 3 billion years of evolution on Earth. by Andrew H. Knoll.
(4) On the origin of Phyla, James W. Valentine
(5) www.ucmp.berkeley.edu
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707-536-3272, Tuesday, December 13, 2011
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