Primal Origin of the Freshwater Invertebrates Jerry L. Kaster What is the Geologic Time-Scale History of Freshwater Invertebrates? What are the Colonization Routes of the Freshwater Invertebrates? Habitat Corridors Continental Corridors What was the Role of K + Scavenging in Establishing a Brooding Fauna? Regression-Transgression Bryant 1775 Route associated competitive strategies
Primal Origin of the Freshwater Invertebrates. Jerry L. Kaster. What is the Geologic Time-Scale History of Freshwater Invertebrates?. What are the Colonization Routes of the Freshwater Invertebrates?. Habitat Corridors. Continental Corridors. Regression-Transgression. - PowerPoint PPT Presentation
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Primal Origin of the Freshwater InvertebratesJerry L. Kaster
What is the Geologic Time-Scale History of Freshwater Invertebrates?
What are the Colonization Routes of the Freshwater Invertebrates?
Habitat Corridors
Continental Corridors
What was the Role of K+ Scavenging in Establishing a Brooding Fauna?
Regression-Transgression
Bryant 1775
Route associated competitive strategies
First, the contemporary marine and freshwater faunas are more ecesis compatible than are faunas not contemporary.
Second, marine taxa with a high survival rate (implying gene pool breadth) on a geological time scale are more likely to colonize new habitats, both marine and freshwater, than taxa with a low survival rate.
By example, the extinct trilobites would have a zero probability for a modern colonization of freshwaters; whereas extant marine forms without a contemporary freshwater counterpart, such as branchiopods or echinoderms would score a probability for a modern occurrence in freshwaters. The fact that the latter two forms do not now exist in freshwater does not rule out the possibility that they may colonize in the future.
Assumptions
Third, the predicted probability of occurrence for a ancestral freshwater fauna is a recapitulation of its descendant freshwater fauna.
What is the Geologic Time-Scale History of Freshwater Invertebrates?
PFPt = ((MPt + FPt) 2) MSP
PFPt 1 = ((MPt 1 + PFPt) 2) MSP
PFPt 2 = ((MPt 2 + PFPt 1) 2) MSP
PFPt 3 = …
Where: PFPt = Predicted freshwater probability
MPt = Extant marine taxon probability
FPt = Extant freshwater taxon probability
MPt-n = Fossil marine taxon probability (mainly Raup 1976)
t = Faunal geological period, where 1 = Cenozoic; 2 = Mesozoic; 3 = Palaeozoic; 4 = PrecambrianMSP = Marine taxon survival probability (Easton 1960): Crustacea (0.930),
Are there too many species clustered in too few Phyla?
PROBABILITY
Precambrian Fauna
Paleozoic Fauna
Mesozoic Fauna
Cenozoic Fauna
Extant Fauna
Pm=0.53Pm=0.51
Pm=0.61
Pm=0.72
Pm=0.81
Idealized Probabilistic Signature of the Freshwater Invertebrate Fauna
Permian Extinction FW Probability Signature
(Raup, 1900-1970 data)
0
0.1
0.2
Br Ec Bz Po Pe An Ga Cr
Taxon
Pro
bab
ilit
y
Pre-extinction
Post-extinction
K-T Extinction FW Probability Signature
(Raup, 1900-1970 data)
0
0.1
0.2
Br Ec Bz Po Pe An Ga Cr
Taxon
Pro
bab
ilit
y
Pre-extinction
Post-extinction
A shift along the time series is characterized by an overall rise in dominance of fewer taxa with high probable occurrence.
Communities of greater horizontal energy-material exchange have more rare species and should be distinguished by greater evolutionary innovation.
Catastrophic Permian community disruption reduced rare taxa, with common taxa gained dominance (reduced diversity). The K-T disruption increased rare taxa relative to common taxa (increased diversity).
Immigration Routes Habitat Corridors
Sea Land Freshwater (pulmonate snails, insects, mites)
Sea Estuary Freshwater (zebra mussels)
Sea Psammolittoral Phreatic Freshwater
(protozoa; micrometazoans)
Sea Marsh Freshwater(amphipods)
What were the Colonization Routes of the Freshwater Invertebrates?
Equatorial Continental Von Martens, 1857
Shotgun approach:
Typical r-strategists. Large pool of tropical species with pelagic larvae.
Polar Continental de Guerne & Richard, 1892
Finesse approach:
Typical K-strategists. Small pool of polar species with brood representing a pre-adapted life cycle to freshwater.
Broad statements (e.g., Neeham 1930; Pennak 1953, 1963, 1985) of ion/osmoregulation provided the framework for its general acceptance of the marine to freshwater transition.
Abundant suggestions:
Ionic - Osmotic gradiant imbalance
Energy expenditure to stay afloat
Poor pelagic nutrient resources
Brooding K-strategist Fauna
Keen competitors “fill the barrel”; Shedding r-strategist fauna poorly colonize a “full barrel”
Others
Most cations and anions are regenerated in the epilimnion, while K+ shunts to the benthos.
K+Ca2+ Mg2+
Na+ HCO3
CO32- SO4
2-
Cl-
K+ is preferentially incorporated into the crystaline lattice of minerals
What was the role of K+ scavenging in establishing a brooding fauna?
Ionic K+ Bottleneck
Earth leaches K+ : Na+ = 1
K+ is readily absorbed to soil particulates and thus there is less K+than Na+ in sea water (K+ : Na+ = 0.021)and freshwater (K+ : Na+ = 0.028)
Marine invertebrate K+ levels are similar to sea water medium:
Sea water K+ = 9.96 mM/l vs. inverts = 11.56 mM/l (ratio = 0.86)
Freshwater invertebrate K+ levels are much higher than the freshwater