Module 12 Flashcards
what creature characterize the Cambrian?
Cambrian is often characterized by trilobites and Burgess Shale type organisms.
what joined Cambrian creature in the Ordovician that would characterize the Paleozoic oceans
brachiopods, echinoderms on fixed stalks (crinoids) and corals (in particular forms called rugose and tabulate corals)
How did the oceans change after the Permian extinction
- look
- important shelly fauna
- cephalopods
- coral
- echinoderms
- top predator
- look more modern
- instead brachiopods, bivalves (clams) and gastropods (snails) become the important shelly fossils
- cephalopods become even more common
- rugose and tabulate corals have become extinct, other creature produce reefs
- echinoderms there is a move away from the stalked crinoids to more mobile star fish and echinoids (sea urchins).
- Large marine reptiles take on the role of top predators
how may species echinoids (sea urchins survived Permian extinctions
6 species
When did boney fish evolve? where the abundant in the Mesozoic
Devonian, yes abundant in the Mesozoic
what group was in Mesozoic oceans in vast numbers
- group mollusk called cephalopods “head foot”
related to squid/octopuses
- When where Cephalopods present?
- example in Ordovician
- By the Mesozoic, cephalopods ______ even further and had evolved into ___of different forms.
- example
- Paleozoic
- in the Ordovician, Orthoconic Nautiloids, one of the top predators in the ocean, had straight shells
-By the Mesozoic, cephalopods diversified even further and had evolved into lots of different forms.
- Belemnites were like modern squid, except they had 10 arms with a double row of hooks but no suckers
Ammonites often have _______ shells meaning they coil in single _________ planes
Ammonites often have planispiral shells meaning they coil in single horizontal planes
why are ammonites biostratigraphic tool of choice during the Mesozoic
- what does that mean
very very common
- are used to split geological time in to various ‘ammonite zones’, characterized by particular definitive and widespread species that can be used in correlation.
how did ammonites move
- what is a hyponome
- did they move together?
- moved backwards through the water by jet propulsion, created when they squirted water through a tube called the hyponome.
- They may have moved through the ocean in large groups
ammonites (and similarly Nautilus)
- what is there shell like?
- what is a septum
- how do they grow?
- what is a siphuncle/ what’s it used for
- shell with a spiral form that included many different chambers, with a much longer body chamber at the end
- internal chamber is divided from the next chamber by a chamber wall called a ‘septum’
- grow by moving forward in their body chamber and adding a new chamber to the back of their existing body chamber when they become too large
- tube called a siphuncle runs the full length of all the chambers and attaches on to the living creature in the body chamber. The animals use the siphuncle to vary the amount of fluid in each chamber, allowing them to control their buoyancy in the water column.
- first ammonites?
- suture pattern?
- when did the become extinct/what took over?
- first ammonoids to evolve were the goniatites
- possess the simple suture lines you see here in this zig zag pattern
- Mesozoic, the goniatites had become extinct and the ammonites with the more complex suture line style were one of the main cephalopod groups present in the oceans
where ammoniates fast swimmers?
yes, had hydrodynamic shells used to slice through water
1.What type of asymmetry is found in planispiral ammonite shells in the earliest Jurassic?
2.What is the name and function of the tube that is offset from the centre line of the venter in this research project?
3.How widespread is the asymmetry within the genera shown in the phylogeny of the earliest Jurassic ammonites?
- siphuncle to the left?
- siphuncle and used to help with buoyancy
- very widespread
*check
- what environment where ammonites found in?
- how big can they grow?
-found in a number of environments, probably including the open ocean, as many of their shells are found in sediments where few other types of fossils are present with virtually no shallow marine species.
- Some ammonites got very big with shells over 2m in diameter
1.What should you look for in an ammonite fossil to see if it is complete?
2.What should you look for in an ammonite fossil to see if it is mature?
3.The size discrepancy is very large between the males and females of the same species. How do we know they belong to the same species?
4.Is the smaller or larger fossil the male?
5.Biologically speaking, how does ammonite reproduction work? (e.g. Do they give birth to live young?)
1.rostrum
- rostrum
- similar morphology
- smaller male
- live young
- when did ammonites become extinct?
- what was happening to ammonite diversity before extinction?
- what shapes did ammonites take then
- end Cre
- diversity alredy declining before
- some started to uncoil and take unusual shapes
- what happen to coral after Permian, how long
- what coral went extinct
- what new coral evolved in Tri and from what
- 10 mil yr coral gap
- tabulate and rugose corals, had both become extinct
- scleractinian corals, still fill important roles in today’s reefs
- parts of coral
- how do they grow
- soft, living coral polyp w/in hard CaCO3 cups
- put more CaCO3 down to grow up