Paleozoic Species

during this period, many of the present species evolved such as marine skeletonized animals, complex reptiles, and land plants. It was also a time of major extinctions especially at the end of it.

Biologic Event Paleozoic (1)

Evolution

Geologic Events Paleozoic (3)

Opening and closure of oceans Transgressions and regressions of epeiric seas Latitudinal changes in position of continents

Climate of Paleozoic (3)

Ocean circulation Atmospheric circulation Wet/dry

Cambrian Explosion

The beginning of this period is marked by the abrupt appearance of animals with skeletons in the fossil record. It's not well understood, a mechanism that would trigger this even is not agreed upon.

Emergence of Shelly Fauna

The earliest organisms with hard parts are Proterozoic calcareous tubes found associated with Ediacaran faunas. Hard body parts have many advantages - protection against UV rays allowing animals to move into shallower water, prevent drying out in an intertidal environment, provides protection against predators, and skeleton support for muscles -> larger animals

Life habits of organisms (7)

Pelagic, Nektonic, Planktonic, Benthic, Epifauna/Epiflora, Infauna, and Semi-infauna.

Four basic feeding groups

Suspension feeders - remove or consume microscopic plants and animals and dissolved nutrients from water. Herbivores - plant eaters. Carnivore-scavengers - meat eaters. Sediment-deposit feeders - ingest sediment and extract the nutrients from it.

Trophic levels which describe the levels of food production and consumption within a feeding hierarchy.

Primary producers - manufacture their own food. Primary consumers - feed on primary producers and are mostly suspension feeders. Secondary consumers Predators Transformers and decomposers

Late ordovician mass extinction

occured about 440-450 million years ago, the second most devastating extinction to marine communities in earth history cause by the disappearance of one third of all brachiopod and bryozoan families, as well as numerous groups of conodonts, trilobites, and graptolites.

Speculated causes of the Ordovician extinction

Glaciation and sea-level lowering hypothesis - the glaciation of the continent gondwana at the end of the period.

Late Devonian Mass Extinction

Worst for tropical marine taxa at Famenian boundary. Extinguished most conodonts, most graptolites, many trilobites, placoderm fish, armored jawless fish, and pentamerid brachiopods.

Possible causes of Late Devonian extinction

1. Glaciation - oxygen and carbon isotopes suggest oceanographic changes. 2. Meteorite Impact

Carboniferous land

Swamp forests as well as terrestrial habitats became common and widespread - Coal forming period. The first land snails appeared and insects with wings that can't fold back such as dragonflies and mayflies flourished and radiated.

End Permian Mass Extinction

Greatest recorded mass extinction to affect earth "Mother of mass extinctions". 50% of all marine invertebrate families died, 90% of all marine invertebrate species died, 65% of all amphibians and reptiles died, and 33% of all insects died. Species that did not survive the end of Permian are Trilobites, Fusulinids, Rugose and Tabulate corals, many Brachiopod orders and Blastoids.

Vertebrate Evolution

Chordates have, during at least past of their life, a notochord, dorsal hollow nerve chord, and gill slits. Vertebrates are animals with backbones and a sub-phylum of chordates. Ancestors were soft-bodied and left few fossils.

Fish

The oldest vertebrates are fish. Fish range from the Late Cambrian to the present and consist of five classes. All five classes were in existence by the Silurian. The earliest fish are found in shallow nearshore environments. Earliest freshwater fish are from the Silurian. Devonian is sometimes called the "age of fish"

Amphibians

The first vertebrates to live on land (preceded by plants, insects and snails). Oldest amphibian fossils are found within late devonian sandstone in Greenland (Ichthyostega). Evolved from lobe-finned fish, for which muscles extend into the fin allowing greater flexibility of movement.

Barriers amphibians overcame

Desiccation, reproduction, effects of gravity, and extraction of oxygen by lungs rather than gills.

Reptile Evolution

They evolved in the late mississippian from amphibians. Amphibians had to return to water to lay their eggs. REptiles on the other hand evolved the amniote egg freeing them from the constraint of returning to water to reproduce. REptiles were able to colonize all parts of the land.

Early Reptiles

The earliest ones were small, agile, and fed on grubs and insects. During the Permian, reptiles diversified and began displacing amphibians. Success due to advanced reproductive methods, more advanced jews and teeth, and ability to more rapidly on land.

Pelycosaurs

Evolved from Reptiles and were the dominant ones by the Permian. They later became extinct during the Permian. They were mammal-like reptiles that quickly evolved into herbivorous and carnivorous forms. They displayed fewer bones in the skull, enlargement of the lower jawbone, differentiation of the teeth, and a more vertical position of their legs for grater flexibility.

Silurian and Devonian Floras

Seedless vascular plants require moisture for fertilization (the sperm must travel to the egg on the surface of the gametophyte to produce a successful sporophyte). Seed bearing plants (gymnosperms produce male cones which provide sperm in pollen to an egg in the female cone).