{"id":741,"date":"2021-03-09T14:29:46","date_gmt":"2021-03-09T19:29:46","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/earthhistorylab\/?post_type=chapter&p=741"},"modified":"2021-03-15T11:30:58","modified_gmt":"2021-03-15T15:30:58","slug":"fossils-of-the-paleozoic-phylum-brachiopoda-the-brachiopods","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/earthhistorylab\/chapter\/fossils-of-the-paleozoic-phylum-brachiopoda-the-brachiopods\/","title":{"raw":"Fossils of the Paleozoic: Phylum Brachiopoda (The Brachiopods)","rendered":"Fossils of the Paleozoic: Phylum Brachiopoda (The Brachiopods)"},"content":{"raw":"Brachiopods (Figure 7.9) range from the Lower Cambrian to the present. They were at peak diversity in the Devonian, but most went extinct at the end of the Permian. Brachiopod fossils are often well-preserved, as well as being abundant and exhibiting diverse shell morphology (i.e., a variety of shell shapes) over time. Because of these characteristics and their long presence in the geologic record, they are perhaps the best index fossil for correlation and relative time dating.\r\n\r\n \r\n\r\n[caption id=\"attachment_745\" align=\"aligncenter\" width=\"650\"]\"\"<\/a> Figure 7.9 |<\/strong> Examples of Phylum Brachiopoda.[\/caption]\r\n\r\nBrachiopods are animals that live inside two shells (or valves) that show bilateral symmetry from side to side (i.e., if viewed from above or below). The top and bottom shells are not the same shape. To see this, look at the Side view<\/em> in Figure 7.9: the valve on the left is the top and the valve on the right is the bottom.\r\n\r\nThe animal attaches itself to the sea bottom by a pedicle (a muscle sometimes referred to as a \"foot\") that extends through an opening near the shell\u2019s hinge. The animal draws water in, filters out food (mostly phytoplankton), then expels the water. The animal must exert muscle power to open the shells, and when their muscles are relaxed the shells close. As a result, fossil brachiopods are frequently found with both sides together. This is different from the bivalves introduced in the next section.\r\n\r\nBrachiopod shells vary greatly in shape and texture. They are typically 2 to 4 cm in size, but some are 6 to 8 cm and a few reach up to 25 cm across.\r\n\r\n \r\n
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Questions a & b<\/p>\r\n\r\n<\/header>\r\n

\r\n\r\na.\u00a0\u00a0 Describe the brachiopod habit using terms from Figure 7.2<\/a>.\r\n\r\nb.\u00a0\u00a0 What environment range do brachiopods occupy? (Refer to Figure 7.4<\/a>)\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n

<\/a>A. Sample 13<\/a>: Brachiopod<\/h3>\r\nThese samples can be picked up but please treat them with care.<\/strong><\/span>\r\n\r\nThe ripples on the surface of this sample are referred to as corrugations<\/strong>. They have the same purpose as the rippled inner layer of corrugated cardboard.\r\n\r\n \r\n\r\n[h5p id=\"86\"]\r\n\r\n \r\n
\r\n

Questions c-f<\/p>\r\n\r\n<\/header>\r\n

\r\n\r\nc.\u00a0\u00a0 Make a simple sketch of Sample 13 from above (Slide 1) and from the front (the side that opened; Slide 2). Identify the plane of symmetry on your sketches.\r\n\r\nd.\u00a0\u00a0 What type of symmetry does this fossil have?\r\n\r\ne.\u00a0 Describe how this was fossil preserved, and name the preservation type.\r\n\r\nf.\u00a0 Which morphological characteristic (i.e., which aspect of the shape) of this sample indicates the strength of the shell?\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\nExamine Samples 9 and 15 below, paying special attention to the shape and structure of the shell.\r\n

B. Sample 9<\/a>: Brachiopod<\/h3>\r\nThese samples can be picked up but please treat them with care.<\/strong><\/span>\r\n\r\n \r\n\r\n[h5p id=\"87\"]\r\n\r\n \r\n
Question g<\/header>\r\n
g.\u00a0\u00a0 How was Sample 9 preserved? Explain your reasoning.<\/div>\r\n<\/div>\r\n \r\n

C. Sample 15<\/a>: Brachiopod<\/h3>\r\nThese samples can be picked up but please treat them with care.<\/strong><\/span>\r\n\r\n \r\n\r\n[h5p id=\"88\"]\r\n\r\n \r\n
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Question h<\/p>\r\n\r\n<\/header>\r\n

h.\u00a0\u00a0 Compare all three brachiopod samples (13, 9, and 15). Which most likely lived in the lowest-energy environment? Explain your reasoning by drawing the sample you chose and labelling any features important for understanding your answer. Draw which ever view of the sample works best to make your argument.<\/div>\r\n<\/div>\r\n ","rendered":"

Brachiopods (Figure 7.9) range from the Lower Cambrian to the present. They were at peak diversity in the Devonian, but most went extinct at the end of the Permian. Brachiopod fossils are often well-preserved, as well as being abundant and exhibiting diverse shell morphology (i.e., a variety of shell shapes) over time. Because of these characteristics and their long presence in the geologic record, they are perhaps the best index fossil for correlation and relative time dating.<\/p>\n

 <\/p>\n

\"\"<\/a>
Figure 7.9 |<\/strong> Examples of Phylum Brachiopoda.<\/figcaption><\/figure>\n

Brachiopods are animals that live inside two shells (or valves) that show bilateral symmetry from side to side (i.e., if viewed from above or below). The top and bottom shells are not the same shape. To see this, look at the Side view<\/em> in Figure 7.9: the valve on the left is the top and the valve on the right is the bottom.<\/p>\n

The animal attaches itself to the sea bottom by a pedicle (a muscle sometimes referred to as a “foot”) that extends through an opening near the shell\u2019s hinge. The animal draws water in, filters out food (mostly phytoplankton), then expels the water. The animal must exert muscle power to open the shells, and when their muscles are relaxed the shells close. As a result, fossil brachiopods are frequently found with both sides together. This is different from the bivalves introduced in the next section.<\/p>\n

Brachiopod shells vary greatly in shape and texture. They are typically 2 to 4 cm in size, but some are 6 to 8 cm and a few reach up to 25 cm across.<\/p>\n

 <\/p>\n

\n
\n

Questions a & b<\/p>\n<\/header>\n

\n

a.\u00a0\u00a0 Describe the brachiopod habit using terms from Figure 7.2<\/a>.<\/p>\n

b.\u00a0\u00a0 What environment range do brachiopods occupy? (Refer to Figure 7.4<\/a>)<\/p>\n<\/div>\n<\/div>\n

 <\/p>\n

<\/a>A. Sample 13<\/a>: Brachiopod<\/h3>\n

These samples can be picked up but please treat them with care.<\/strong><\/span><\/p>\n

The ripples on the surface of this sample are referred to as corrugations<\/strong>. They have the same purpose as the rippled inner layer of corrugated cardboard.<\/p>\n

 <\/p>\n

\n