Lecture 5 - Paleoecology & Paleoclimate Flashcards
miocene
23-5.3 Ma
- slightly warming trend, then cooling, with increasing aridity in Africa
- Tethys Sea contracts, dries up at least once
- Himalayas rise, creates Gobi desert eventually, because of rain shadow
- Apes diversify
- higher sea levels, but similar earth plan compared to now
pliocene
5.3 - 2.58 Ma
- lots of early hominins (some late Miocene)
- climate getting cooler and drier
- Panama forms, affecting ocean circulation
pleistocene
2.58 Ma - 10 Ka
- ice age!
- Homo appears at Plio-Pleistocene boundary
- Onset of Northern Hemisphere Glaciation
- massive variability in climate - glacial and interglacial period cycles on northern continents
- Neanderthals, modern humans appear towards the end
holocene
10Ka - present
- relatively stable climate
- minimal glaciation, habitable zones extensive
- modern humans show rapid technological, and social evolution
O2
isotopes of oxygen
16O - common, light
18O - rare, heavy
both stable
microorganisms and chemical clues
microorganisms and chemical clues
microorganisms create skeletons using CaCO3 –> in shallow ocean limestone sedimentary rocks deposited from skeletons –> chemical sedimentary rock = long-term microorganism tombs
microorganisms and chemical clues
hydrolgic cycle
during non-glacial = complete cycle, all water comes back down
during glacial = some water never makes it back down, leaving heavy oxygen in the sea water
how to understand fossil record of terrestrial environments?
- characterization based on adaptations & functional traits
- carbon isotopes in enamel & soil
terrestrial adaptations
community structure - size
- forested habitats have more small-bodied animals
- open habitats have a bigger distribution of animals in large-bodied
terrestrial adaptations
community structure - adaptations
can tell apart different environments based on what adaptations species have
ex: diet, locomotion, morphology
terrestrial adaptations
ecomorphology
aims to link morphology with ecological characteristics/categories
terrestrial adaptations
hypsodonty
bigger teeth
- allows for more enamel wear
- can help predict avg precipitation of environments
terrestrial adaptations
herbivore craniodental adaptations
grazers - wide, U shaped mandibles, expanded cheek tooth rows
browsers - opposite of grazers, narrow V shaped mandibles
terrestrial adaptations
carnivoran craniodental adaptations
identified based on carnassial teeth
aka teeth that sheer back & forth
terrestrial adaptations
types of carnivorans
hypercarnivores - well developed carnassials, little to no crushing teeth, cats
omnivorous carnivoran - eats anything, not predatory, black bears
herbivorous carnivoran - pandas
bone-crushing carnivoran - hyena
terrestrial adaptations
postcranial ecomorphology
links features of the limbs with habitat-specific patterns of locomotion
terrestrial adaptations
suspensory locomotions
postcranial morphology
allows for suspension from branches etc
ex: primates
terrestrial adaptations
crypsis
postcranial morphology
hide & don’t detect
terrestrial adaptations
cursoriality
postcranial morphology
run away, fast animals
in environments where it’s not possible to hide (open grasslands etc)
terrestrial carbon record
carbon isotopes
C4 - take up more 13C during photosynthesis = grasses
C3 - takes up less 13C = trees/shrubs
terrestrial carbon record
dental enamel
carbon is entomed when teeth are forming during juvenile period
enamel of teeth is a resevoir of carbon that is a time capsule
diet over time (bottom to top = oldest to youngest)
terrestrial carbon record
carbon in soil
soil develops on rock surfaces as rock surfaces degrade and organic material comes from above
ex: crushed up leaves eventually become soil
terrestrial carbon record
carbonates form during soil formation
carbonates form naturally as rock minerals react with water
can build up in dry soils and preserve a record of 13C profile vegetation
terrestrial carbon record
problems with soil carbon
if climate fluctuates on a smaller scale, it won’t be reflected in the soil
soil takes thousands of years to form
terrestrial carbon record
paleosols
ancient soils that preserve record of vegetation cover
can be millions of years old
