Chapter 21 - Paleozoic Life History Flashcards
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)
Pikaia
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?
94%
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
