Volcano tops from Ocean Floor Remote Colonization Rare Adaptive Radiation of Founder Species
Origin of Island Archipelago Hot spot moves or plates move over hot spot Volcanoes build to surface then erode or subside Current islands arose after previous islands were already submerged Exceedingly limited island hopping
Island Development Island Appears Biota Establishes Biota Stabilizes Island Moves Away from Hot Spot Waif Founders Lack Competition Speciation: Adaptive Radiation to fill empty niches
Endemic Terrestrial Species
Cladistic Analysis 1960s Development of Cladistic Analysis Characters and Polarized Character States - Anatomy, Morphology, Behavior, Chemical, Gene Sequence
- Plesiomorphies-Ancestral character states
- Apomorphies-Derived character states
Construction of Cladogram-computers! - Reveal homoplasies (parallel, convergent), reversals
- Most-parsimonious (fewest steps) cladogram
- Not necessarily unique!
Cladogram
Island-Hopping Crickets!
Amazing Fruit Flies! DNA sequences show 10 MYBP arrived Necker Necker has subsided and lost habitat…now n=0 All 511 endemic species are a single clade! Analyzed by morphology, karyotype, molecular analysis
Primitive Phylogram of Drosophiloids
Drosophilid Area Cladogram
Spiders Spinning Southeast!
Honeycreepers of Hawaii
How about Plants? Hibiscadelphus
Silverswords
Silversword Origins Closest relatives are California tarweeds Fruits too thin-walled to survive bird gut Fruits do not float in sea water Fruits too heavy to float on wind Hairy and sticky sepals suggest bird attachment Preened off on Kauai, then radiated and migrated
Biotic Factors Symbioses (living together) - Mutualism: zooxanthellae/corals/forams
- Commensalism: bromeliads on trees
- Parasitism: epiphytic woevine on shrubs
Competitors: Epiphytes, Allelopathy, Exotics Herbivory - Partners required for reproduction
Abiotic Factors Light-wavelength (color), amplitude (intensity) - Water absorbs low energy wavelengths…leaving blue
- Turbidity (milkiness) vs Turbulence (mixing)
- Chlorophyll (purple, blue, yellow, red)
- Carotenoids (green)
- Phycobilins (green to red) depending on type/depth
Gas Availability (N2=78%, O2=21%, CO2<1%) - Oxygen poisons photosynthesis (photorespiration)
- CO2 highly soluble in water, O2 virtually insoluble
- Most algae are C3, many terrestrials C4 or CAM
Abiotic Factors Temperature-plants are essentially poikilotherms - Water in tidepools rises rapidly
- Eurythermal = wide tolerance, Stenothermal = narrow tolerance
- Dunes heat unless leaves shade them or burrow deeply
- Ice damage, frost, heat shock
- Large body size: thermal insulation vs heat load
- Surface:Volume ratio (Neither Fucus nor Ascophyllum here!)
Desiccation: evaporation, osmotic stress - Saccate thallus (Colpomenia or Valonia)
- Mucilaginous sheath, Waxy Cuticle, Hairy Epidermis
Abiotic Factors Salinity: osmotic stress, Na+ or Cl- toxicity - Salinity in small tidepools rises with evaporation
- Salinity in small tidepools falls with rainfall
- Euryhaline = wide tolerance, Stenohaline = narrow tolerance
- Halophytes
- Exudation: Avicennia via hydathodes (salt glands)
- Exclusion: Rhizophora ion pumps keep salt out
- Shedding: Spartina, annual dicots, leaves abscise taking salt out
- Acclimitization: mannitol, sucrose, betaine, etc.
Soil Minerals - Oligotrophic Waters are Depauperate in Minerals (N, P, Fe)
- Eutrophic Estuarine waters: Algal Blooms
Abiotic Factors Surge Stress, Drag Stress, Shear Stress - Turbulence in Rocky Intertidal
- Scouring in Sandy Intertidal
- Euryhaline = wide tolerance, Stenohaline = narrow tolerance
- Benefits
- Predator Restriction
- Parasite Removal
- Equalize Salinity and Temperature
- Adds CO2 for photosynthesis, but also adds O2
- Rhodoliths in deep waters…detached coralline red algae
- Phytoplankton in Photic Zone of open ocean only 5000 spp!
- Greater diversity and abundance in Estuarine waters
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