User:Phlebas/sandbox

Introduction

Ostracoda is a class of the Crustacea, sometimes known as the seed shrimp because of their appearance. Some 50,000 extinct and extant species have been identified, grouped into several orders.

Ostracods are small crustaceans, typically around one mm in size, but varying between 0,2 to 3 mm, laterally compressed and protected by a bivalve-like, chitinous or calcareous valve or "shell". The hinge of the two valves is in the upper, dorsal region of the body.

Ecologically ostracods can be part of the zooplankton, or (most commonly) they are part of the benthos, living on or inside the upper layer of the sea floor. Some groups of ostracods are also found in fresh waters and in humid continental soils (normally in humid forests).

Ostracods are particularly useful for the biozonation of marine strata on a local or regional scale, and they are invaluable indicators of ancient shorelines, salinities and relative sea-floor depths. They have a long and well documented fossil record from the Cambrian to the present day. An outline microfaunal zonal scheme based on both foraminifera and ostracoda was compiled by M.B. Hart (1972).

Morphology

The body of an ostracod is encased by two valves, which together form the duplicature. A distinction is made between the valve (hard parts) and the body with its appendages (soft parts).

Soft parts and ontogeny

The body consists of a cephalon (head), separated from the thorax by a slight constriction. The segmentation is unclear. The abdomen is regressed or absent whereas the adult gonads are relatively large. There are 5-8 pairs of appendages. The branchial plates are responsible for oxygenation.

During the ontogeny the epidermis (containing mesodermal tissue invaginates ventrolaterally near the cephalon/thorax area. This invagination proceeds upwards and tailwards, until the whole animal is enveloped by a double tissue layer on both sides: this forms the duplicature. The dorsal region never becomes invaginated, and is called the isthmus. The mesodermal tissue in the duplicature develops into the vestibulum. The vestibulum makes contact with the body near the isthmus. It plays a role in oxygenation. In paleo-ecology, the size of the vestibulum can be cautiously interpreted as an environmental indicator. The two double tissue layers surrounding the animal each have an inner and an outer lamella, which surrounds the vestibulum. These lamellae are surrounded by a chitinous cuticle, that is secreted by the epidermal cells.

Like all arthropods, ostracods develop discontinually. Before reaching maturity 8 larval stages (instars) are passed.

Hard parts

The epidermal cells may also secrete calcium carbonate after the chitinous layer is formed, resulting in a chalk layer enveloped by chitin. This calcification is not equally pronounced in all orders. During every instar transition, the calcified layer gets thicker. The outer lamella calcifies completely, while the inner lamella calcifies partially, with the rest remaining chitinous. The partial inner lamella calcification occurs when the ostracod becomes adult. The partial inner lamella calcification is most strongly developed frontally (see electron micrograph). The marginal zone is the area where inner and outer lamella meet, and includes part of the vestibulum. The edge of the marginal zone is called the fused zone, and in this area inner and outer lamella join. The fused zone can contain marginal pore canals. These, along with non-marginal pore canals (that are dispersed evenly along the ostracod's valve) connect the vestibulum to the outer world. The line of concrescence is the visible line between the vestibulum and the fused zone. In many cases, this line is wavering and follows the marginal pore canals. On the inner lamella, a selvage may be present.

External link

• Introduction to Ostracoda

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German steam locomotive classification

Class until 1968	Class from 1968	Original	Whyte notation	Operation Type	Remarks	Links
01.0-2	001	DRG standard design	4-6-2	S 36.20
01.0-2	001	DRG standard design rebuilt	4-6-2	S 36.20	with Henschel-Mischvorwärmer
01.0-2	001	DRG standard design rebuilt	4-6-2	S 36.20	with Hochleistungskessel
01.10		DRG standard design	4-6-2	S 36.20	de-streamlined
01.10	011	Rebuilt	4-6-2	S 36.20	de-streamlined
01.10	012	Rebuilt	4-6-2	S 36.20	de-streamlined with oil as fuel
03.0-2	003	DRG standard design	4-6-2	S 36.17, S 36.18
03.10		DRG standard design	4-6-2	S 36.18	de-streamlined
03.10		Rekolok	4-6-2	S 36.18	de-streamlined
05		DRG standard design	4-6-4	S 37.19	de-streamlined
10	010	New DB design	4-6-2	S 36.22	partially streamlined
17.11-12		Prussian S10.1, Bauart 1914	4-6-0	S 35.17
18.1		Württemberg C	4-6-2	S 36.16
18.3		Baden IV h (1-3)	4-6-2	S 36.17
18.4-5		Bavarian S3/6	4-6-2	S 36.16, S 36.17, S 36.18	partial DRG reproduction
18.6	018	Rekolok	4-6-2	S 36.18	from Bavarian S3/6
23	023	New DB design	2-6-2	P 35.18
24		DRG standard design	2-6-0	P 34.15
38.4		Bavarian P3/5 H	4-6-0	P 35.15
38.10-40	038	Prussian P8	4-6-0	P 35.17
39.0-2		Prussian P10	2-8-2	P 46.19
41		DRG standard design	2-8-2	G 46.18/20
41	041	Rekolok	2-8-2	G 46.18
41	042	Rekolok	2-8-2	G 46.18	with oil as fuel
42		War locomotive	2-10-0	G 56.17
42.90		War locomotive	2-10-0	G 56.18	Converted BR 52 with Franco-Crosti-boiler
44	044	DRG standard design	2-10-0	G 56.20	auch als ÜK (Übergangskriegslok) beschafft
44	043	DRG standard design	2-10-0	G 56.20	with oil as fuel
45	045	DRG standard design	2-10-2	G 57.18/20
50	050 - 053	DRG standard design	2-10-0	G 56.15	auch als ÜK (Übergangskriegslok) beschafft
50.40		DRG standard design rebuilt	2-10-0	G 56.15	with Franco-Crosti-boiler
52		War locomotive	2-10-0	G 56.15
54.15-17		Bavarian G3/4 H	2-6-0	G 34.16
55.0-6		Prussian G7.1	0-8-0	G 44.13
55.16-22		Prussian G8	0-8-0	G 44.14
55.25-56	055	Prussian G8.1	0-8-0	G 44.17
56.1		Prussian G8.3	2-8-0	G 45.17
56.2-8		Prussian G8.1 mit Laufachse	0-8-0	G 45.16	Converted G8.1 by DRG
56.20-29		Prussian G8.2	2-8-0	G 45.17
57.5		Bavarian G5/5	0-10-0	G 55.17
57.10-35		Prussian G10	0-10-0	G 55.15
58.2-3		Baden G12.1-7	2-10-0	G 56.16
58.4		Saxon XIII H	2-10-0	G 56.16
58.5		Württemberg G12	2-10-0	G 56.16
58.10-21		Prussian G12.	2-10-0	G 56.16
59		Württemberg K	2-12-0	G 67.16
61		DRG standard design	4-6-4	St 37.18
62		DRG standard design	4-6-4	Pt 37.20
64	064	DRG standard design	2-6-2	Pt 35.15
65	065	New DB design	2-8-4	Pt 47.17
66		New DB design	2-6-4	Pt 36.16
70.0		Bavarian Pt2/3	2-4-0	Pt 23.14
70.1		Baden Ig.1-2	2-4-0	Pt 23.14, Pt 23.15	partially DRG reproduction
71		DRG standard design	2-4-2	Pt 24.15
74.0-3		Prussian T 11	2-6-0	Pt 34.16
74.4-13		Prussian T 12	2-6-0	Pt 34.17
75.0		Württemberg T 5	2-6-2	Pt 35.15
75.1-3		Baden VI b.1-11	2-6-2	Pt 35.14
75.4		Baden VI c.1-7	2-6-2	Pt 35.16
75.10-11		Baden VI c.8-9	2-6-2	Pt 35.16
76.0		Prussian T10	4-6-0	Pt 35.16
77.0		Pfalz P5	2-6-4	Pt 36.16
77.1		Pfalz and Bavarian Pt3/6	2-6-4	Pt 36.16
78.0-5	078	Prussian T18, Württemberg T18	4-6-4	Pt 37.17
78.10	078	DB rebuilt 3810-40	4-6-4	Pt 37.17	from Prussian P8
80		DRG standard design	0-6-0	Gt 33.17
81		DRG standard design	0-8-0	Gt 44.17
82	082	New DB design	0-10-0	Gt 55.18
85		DRG standard design	2-10-2	Gt 57.20	for the Höllentalbahn
86		DRG standard design	2-8-2	Gt 46.15	auch als ÜK (Übergangskriegslok) beschafft
87		DRG standard design	0-10-0	Gt 55.17	mit zahnradgekuppelten Endkuppelachsen
89.1		Pfalz T3	0-6-0	Gt 33.14
89.3		Württemberg T3	0-6-0	Gt 33.10, Gt 33.12
89.6		Bavarian DII.II	0-6-0	Gt 33.15
89.7		Bavarian R3/3	0-6-0	Gt 33.15
89.8		Bavarian R3/3	0-6-0	Gt 33.16	reproduction DRG
89.70-75		Prussian T3	0-6-0	Gt 33.10, Gt 33.11, Gt 33.12
91.3-18		Prussian T9.3	2-6-0	Gt 34.15
91.19		Mecklenburg T4	2-6-0	Gt 34.11, Gt 34.12, Gt 34.13
91.20		Württemberg T9	2-6-0	Gt 34.15
92.2-3		Baden X b.1-7	0-8-0	Gt 44.15, Gt 44.16
92.5-10		Prussian T13	0-8-0	Gt 44.15, Gt 44.16
92.20		Pfalz R4/4, Bavarian R4/4	0-8-0	Gt 44.16
93.0-4		Prussian T14	0-8-0	Gt 46.16
93.5-12	093	Prussian T14.1	0-8-0	Gt 46.17
94.1		Württemberg Tn	0-10-0	Gt 55.13
94.2-4		Prussian T16	0-10-0	Gt 55.15
94.5-17	094	Prussian T16.1	0-10-0	Gt 55.17
95.0		Prussian T20	2-10-2	Gt 57.19
97.1		Bavarian PtzL 3/4	0-6-2	Z 34.15	Cog locomotives
97.5		Württemberg Hz	0-10-0	Z 55.15	Cog locomotives newly designed by DRG
98.3		Bavarian PtL 2/2	0-4-0	L 22.11	local locomotives Glaskasten
98.4-5		Bavarian 0-8-0 XI	0-6-2	L 34.10, L 34.11	local locomotives
98.5		Bavarian PtL 3/4	0-6-2	L 34.11	local locomotives
98.6		Pfalz 0-8-0 VIII	0-6-2	L 34.13	local locomotives
98.8-9	098	Bavarian GtL 4/4	0-8-0	L 44.11, L 44.12	local locomotives z.T. reproduction der DRG
98.10		Newly built by DRG	0-8-2	L 45.11	local locomotives
98.11	097	rebuilt DRG - Bavarian GtL 4/5	0-8-2	L 45.11	local locomotives rebuilt aus bay. GtL 4/4
99	099		several		narrow gauge locomotives

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Creationist welcome template

Welcome again, Phlebas/sandbox. It appears you are a creationist, but thank you for your contributions anyway. I sincerely hope you like the place and decide to stay. Here are a few good links for newcomers like yourself:

• Evolution
• Logic
• Occam's Razor
• Physical cosmology
• Biology
• Common descent
• Population genetics
• Molecular evolution
• Cladistics

Stone Age

This period is part of the Stone Age.

Paleolithic

:Lower Palaeolithic

:Middle Palaeolithic

:Upper Palaeolithic

Mesolithic

Neolithic