Chapter 21 - Paleozoic Life History Flashcards Preview

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Flashcards in Chapter 21 - Paleozoic Life History Deck (25)
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What is the Cambrian explosion? When did it happen? date

Metaphor; all of a sudden had a huge variety of life forms that come on to planet
-555-525 M.y ago
-all these species appeared at once


What are cnidarians? When did they come?

Aquatic invertebrate animal of phylum Cnidaria
-suddenly appearing in fossil record in Cambrian explosion


When were the first land plants on earth?date

about 470M.y ago - 444 M.y ago (spores)


When did the major diversification of vascular plants start? date

416 M.y ago


When did the first seeds start to grow? date

385 M.y ago


When did reptiles first grow? What can we infer off this? period

Pennsylvanian (carboniferous) period
-can only live on land if theres something to eat, so there has to be land vegetation
-reptiles have the amniotic egg-egg with shell/yolk/egg white
-this makes evolutions of reptiles possible
-does not need water source to reproduce


What period was the biggest for plant growth? period

Devonian period


What are vascular plants? period

They have a tissue system of specialized cells for the movement of water and nutrients


When were First amphibians on earth? How big are they period

middle to late Devonian
-first land vertebrates, amphibians
-~1m long
-must go to the water to reproduce


When were first spores on earth? (first land plants)

~470m.y years ago
Upper Ordovician period (first land plants)


What are echinoderms?

starfish, sea urchin, etc..
-marine invertebrate of phylum echinodermata


Most famous location for "Cambrian explosion" ? What is it the home of?

Burgess shale, Yoho national park, BC
-fossil deposit, so much evidence
-home of most famous quarry, "Walcott Quarry". The quarry is the Unesco world heritage site


Importnat Fossils from the burgess shale;

Hallucigenia (a velvet worm)
Opabina (predator)


Cambrian marine community. Name an important wun, and say when it came?

Back then, almost all life was In the ocean
Land wasn't colonized in the beginning
(Late) Cambrian marine diversity
-PIKAIA (Cambrian)


Sulurian life diversity

started in silurian period:
Lobe finned fish


Devonian marine life diversity

Reef growth
-make good oil reservoirs


When was the age of fishes? date + period

415 to 355 m.y ago
-Devonian time


Great moment in evolution for fish

Silurian period (lobe finned fish came) -> Devonian period(lobe-finned fish --> lung fish evolved)
-lobe finned fish evolved into lung fish in Devonian period
-elongated body and paired fins so they can move on land


Devonian period wrt vegetation

Relatively sparse vegetation mostly hollow trunks


Pennsylvanian period wrt vegetation

lush vegetation forming extensive coal swamps, solid trunks
-this is why reptiles can flourish on land, lots of vegetation for them to eat


Adaptive radiations and mass extinctions through time

Cambrian explosion (600M.y ago) flourished with species
Then 250M.y Ago, late Permian period, greatest mass extinction of all time


Adaptive radiation graph

Number of families (Y-axis) vs geologic time (million years, x-axis)
-positive slope means a lot of new life forms appearing, called adaptive radiations
-should know the geologic time scale, Cambrian ,o, s, d, carb, mperm, tri, jur, cret, tert, know these times


% of species extinct in late Permian mass extinction?



Findings from rock record of information of late permain mass extinction; duration, an steps of the extinction

Duration of extinction ~ 10000

Steps of extinction:
1) First effected, land animals
2) Massive marine extinction
3)Massive land extinction


Probable causes of mass extinction

Supercontinent (Pangea) --> superplume, loading atmosphere with CO2 ---> Heating ----> CH4-hydrate melting ----> heating + O2 depletion