Paleontology + Phylogeny Flashcards
What did Nicholaus Steno confirm?
fossils represent formerly living organisms
What did the discovery of Archeopteryx in 1861 provide evidence for?
transition between dinosaurs and birds, and strengthened Darwin’s theory of evolution
What did Lord Kelvin believe?
- the earth was a constantly cooling molten core
- that the earth was less than 20 million years old
How does radiometric dating of volcanic rocks work?
- magma cools to form crystal like zircons
- zircons trap elements that are a mix of stable and radioactive atoms
- over time, radioactive atoms stabilize and the ratio of the two can be used to date the rock
What is a lagerstaette?
- an area of especially well preserved fossils, notable for preserving fragile body parts or soft bodied organisms
- organisms brought to anoxic water bodies with a lack of scavengers or bacteria
What is the Burgess Shale and who discovered it?
- lagerstaette of Cambrian life, including Anomalocaris, Pikaia and Hallucigenia
- discovered by Charles Doolittle Walcott in 1909 in the Rockies
- additional species discovered in 2012
What are the different types of fossils?
- compression: remnants with a carbon film outlining the organism
- impression: imprint without carbon film
- original tissue: all organic material of organism left behind due to preservation in a medium
What can fossils tell us about animal behaviour? What are some examples of evidence
- can show parental behaviour, diet, migration patterns, habitat, herding, appearance etc
- live birth evidence of ichthyosaurs, egg sites of dinosaurs, melanosomes in feathers, trumpet crests of hadrosaurs
What are some examples of the earliest signs of life?
- biomarkers of C(12) in zircons –> life prefers C(12) over C(13)
- stromatolite fossils (3.45 bya)
How old are the oldest red and green algae fossils?
red = 1.2 bya
green = 750 mya
How old can sponges be traced back in the fossil record?
Ediacaran period (600 mya)
Describe what life in the Ediacaran looked like
- 575 - 535 mya
- sessile/slow surface feeders and filter feeding plant-like organisms that primarily burrowed
- Mistake Point, NFL = evidence of sea pen “Charnia” fossils
Describe what life during the Cambrian explosion looked like
- 510 - 505 mya
- active soft bodied marine animals
- diversification of organisms
- introduction of predator-prey relationship and co-evolution
- prey developed harder exoskeletons and other defensive structures while predators developed structures for hunting proficiently
- evidence of examples of early lineages (molluscs, worms, crustaceans)
What trait defines the phylum Chordata?
notochord (stiff rod on back)
When did the first plants and fungi emerge?
- bryophyte-like plants = 475 mya (Ordovician)
- forests = 100 mya
What traits are shared among the synapsids?
- one orbital skull hole
- differentiated teeth
What synapsid jaw bones become the incus, malleus and tympanic bones of the inner ear?
incus = quadrate
malleus = articular
tympanic = angular
What did the reduction of synapsid jaw bones help mammals achieve?
allowed for hearing air vibrations as opposed to ground
What is homoplasy
similar traits evolving in different lineages as a result of convergent or parallel evolution
What homoplasous bone do avian dinosaurs and humans share?
semi-lunate carpal (for a flexible wrist)
Who hypothesized the link between dinosaurs and birds?
Thomas Huxley
What are some examples of feathered fossilized dinosaurs?
- Zhenyualong
- Archaeornis
- Archeopteryx
Define a clade
a common ancestor + all its descendents
What synapomorphy is shared among all members of Carnivora?
carnassial teeth
What other taxa share a clade with cats?
hyenas and civets (cats + hyenas = sister taxa)
What are two methods behind homoplasy?
convergent evolution = independent evolution of similar traits (i.e streamline body of ichthyosaurs, whales, sharks)
evolutionary reversal = loss of derived traits (i.e reduced limbs in snake)
What is the name of the fossilized snake that showed hindlimbs?
tetrapodophis
Which fossil showed evidence of the transition from water to land?
Tiktaalik (found at Ellesmere Island)
How are lobe finned fish like coelacanths similar to tetrapods?
similar pectoral/shoulder bone
What is the Devonian age known for?
- dominance of fish
- first trees
What is the name of the fossilized lobefinned fish that showed early signs of a transition to land?
Eusthenopteron (found in QB)
Describe tiktaalik
- weak hindlimbs separated from pelvic bones
- strong forelimbs
- mobile neck + wrist (tetrapod synapomorphy)
What was the first true amphibian?
Ichthyostega
What is the name of the ankle bone that archaeocetes and artiodactyls share similarities in?
astragalus
