primal origin of the freshwater invertebrates jerry l. kaster what is the geologic time-scale...

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),

Gastropoda (0.821), Annelida (0.973), Pelecypoda (0.423), Porifera (0.560), Ectoprocta (0.504), Echindermata (0.270), and Brachiopoda (0.015).

Extant FW Invertebrate Probability Signature

(Kaster, various data)

0

0.1

0.2

0.3

0.4

0.5

0.6

Br Ec Bz Po Pe An Ga Cr

Taxon

Pro

ba

bili

ty Known FWProbability



y = 5E-05x4.4233

R2 = 0.9302

0

0.1

0.2

0.3

0.4

0.5

0.6


Taxon

Pro

ba

bili

ty



y = 5E-05x4.4233

R2 = 0.9302

0

0.1

0.2

0.3

0.4

0.5

0.6


Taxon

Pro

ba

bili

ty

Extant

Predicted

Pow er Function

Cenozoic FW Invertebrate Probability Signature

(Raup, 1900 -1970 data)

y = 0.0004e0.9056x

R2 = 0.7886

0

0.1

0.2

0.3

0.4

0.5

0.6


Taxon

Pro

bab

ility

Mesozoic FW Invertebrate Probability Signature

(Raup, 1900-1970 data)

y = 0.0008e0.7131x

R2 = 0.6345

0

0.1

0.2

0.3

0.4

0.5

0.6


Taxon

Pro

bab

ilit

y

Paleozoic FW Invertebrate Probability Signature

(Raup, 1900-1970 data)

y = 0.0028e0.5252x

R2 = 0.8103

00.10.20.30.40.50.6


Taxon

Pro

bab

ilit

y

Precambrain FW Invertebrate Probability Signature

(Raup, 1900-1970 data)

y = 8E-05e0.927x

R2 = 0.7311

00.10.20.30.40.50.6


Taxon

Pro

bab

ilit

y

Paleozoic Fauna 600 - 230

Mesozoic Fauna 230 - 63

Ordovician22%

Devonian21%

Permian95%

Triassic20%

Cretaceous75%

TIME

2

2.1

2.2

2.3

2.4

2.5

2.6

2.7

Sh

an

no

n D

ive

rsit

y

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


Taxon

Pro

bab

ilit

y

Pre-extinction

Post-extinction

K-T Extinction FW Probability Signature

(Raup, 1900-1970 data)

0

0.1

0.2


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.

Continental Corridors

Immigration RoutesRoute associated competitive strategies

Polar

Equatorial

Continent

BROODING

FAUNA

SHEDDING

FAUNA

85%

85%

15%

15%

Lake

Lake

Polar

Equatorial

Continent

BROODING

FAUNA

SHEDDING

FAUNA

85%

85%15%

15%

“Regression Period”

Lake

Lake

K

IncreasedHabitat

DecreasedHabitat

r

Polar

Equatorial

Continent

BROODINGFAUNA

SHEDDING

FAUNA

85%

85%15%

15%

“Transgression Period”

Lake

Lake

K

DecreasedHabitat

IncreasedHabitat

r

Why do freshwater forms lack pelagic larvae?

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

medium:Freshwater = 0.03 mM/l vs. inverts = 4.75 mM/l (ratio = 0.0063)

Benthic sediment K+ = 13.8 mM/l vs. 4.75mM/l (ratio = 2.9)

K+ is necessary for membrane function, especially in excitatory tissue such as muscle and nervous tissue.

Bottleneck is at the late embryo (yolk K+ cache depleted) or at the earlylarval stage (must shift to high [K+] particle feeding).

Immigration of K-strategist, marine brooding invertebrates to freshwater largely followed a polar corridor.

The de novo evolution of muscle and nervous systems of the primal metazoans (protozoan-metazoan megaleap) required high benthic K+.

Metazoan de novo “K+ scavenging” may have lead to herbivory and “K+ predation” to predation.

A “K+ bottleneck” during early life history stages is suggestedas a critical factor that regulates freshwater colonization success.

primal origin of the freshwater invertebrates jerry l. kaster what is the geologic time-scale...

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