Paleozoic Period by Niana G

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Slide Notes

Paleozoic Period

Published on Nov 18, 2015

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PRESENTATION OUTLINE

PALEOZOIC PERIOD(CAMBRIAN)

JULIANA GOTGOTAO

Cambrian period:
Specie: Brachiopods

Brachiopods were diverse sea-floor dwellers during the Cambrian period. Brachiopods were invertebrates that had clam-like shells, although they are not related to the modern clam. Some brachiopods had a long fleshy appendage which they used to anchor themselves to the sea bed. All brachiopods are filter-feeders. More brachiopods than trilobites survived after the end of the Cambrian period and brachiopods have a greater number of living descendants.

Read more : http://www.ehow.com/info_7878061_plants-animals-cambrian-period.html

Habitat:
SEA

Brachiopods are filter-feeders. They eat the dirt in the sea.

EXTINCTION:
The Devonian Extinction
Toward the end of the Devonian, nearly 70% of all invertebrate species vanished during the Late Devonian extinction. Marine species (especially tropical ones) suffered the most extinctions, followed by freshwater species, whereas terrestrial species were hardly affected. Inparticular, tabulate coral/stromatoporoid reefs vanished entirely, leading to a great decline in worldwide coral reef-building until the Triassic Period. Many species of brachiopods, trilobites, and early fishes went extinct, as did the planktonic graptolites. These extinctions were not the result of a single major extinction event, but rather smaller extinction events that occurred over a period of more than 20 million years.

The Devonian Extinction

The causes of the extinctions are uncertain, although there are several viable hypotheses. Most of these focus on the theory that the expansion of terrestrial plants decreased the amount of carbon dioxide in the atmosphere through two separate processes. One process is chemical weathering, a process that uses up carbon dioxide from the atmosphere, and that plants accelerate. The second process is carbon storage. Plants fix carbon dioxide from the atmosphere and convert it to organic carbon, stored in their stems, roots, and leaves. After plants die the organic carbon can be released to the soils. Both of these processes would have increased as terrestrial vegetation spread, reducing the amount of carbon dioxide in the atmosphere, triggering global cooling and eventually glaciation. An asteroid impact may also have occurred at this time.

http://paleobiology.si.edu/geotime/main/devonian4.html

Niana G