Biology 2601A/B Lecture 24: 2601 Organismal Physiology–Lecture 24
19 Jul 2016
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Document Summary
The living together in more or less intimate association or close union of two dissimilar organisms . More than 600 species of warm-water reef building corals are known: all house photoautotrophs, algae called zooxanthellae. Reef building corals are the foundation of coral reef ecosystems. 600,000 square miles of the earth"s surface contain 4-5% of known species highest diversity per unit area of any marine ecosystem: biodiversity hotspots. Highly productive systems: gross primary productivity of 1500-5000 gcarbon m. Zooxanthellae (algal symbiont) lives within the tissues of scleractinia coral (animal host) Phylum cnidaria; class anthazoa; subclass hexacorallia; order scleractinia. Three tissue animals: epidermis, fibrous mesoglea, gastrodermis (contains zooxanthellae) Give colouration to coral colonies due to pigment composition: chla, chlc, peridinin, fucoxanthin, diadinoxanthin, diatoxanthin. Permits existence in tropical environments (very low nutrient waters) Symbionts transfer ~90% photosynthate for inorganic nutrients (nitrogen and phosphorus) Inhabit the gastrodermal tissue of the coral polyp. Release from alga via chemical signal from host called host transmission.
