Question

1. Filter-feeding is ubiquitous in the marine realm and absent entirely from the terrestrial realm. Name some phyla that we encountered in the course (including several that you saw alive) that are filter-feeders, give specific examples as much as possible. Name as many different phyla as you can (even if you did not see them in the course) that exhibit this feeding mode and name or describe the structures in that group that are used for filter feeding. Why do you think there are no terrestrial filter-feeders given the great success of this lifestyle in aquatic environments? Be specific in your answer to this last question.

1. Name two marine invertebrate taxa from two different phyla that derive nutrition at least partially from photosynthesis. Explain how this works in some detail.

Answer 1

Phyla win which animals are filter feeders:-

a) Sponges b)Cnidarians c) Ctenophora d)Molluscs- bivalves e)Arthropoda- Crustacean f)Vertebrates- fish, bird,marine reptiles.

Structure for filter-feeding:-

Sponges- Water Canal System e.g Leuconia

Cnidarian- tentacles and mouth e.g moon jellyfish, sea pen, sea fan

Ctenophora-Tentacles and cilia e.g Pleurobrachia

Molluscs- suspended food is trapped in the mucus of gill and transported to the mouth eg. Unio, Teredo

Arthropoda- collect food by the filter basket

Vertebrate- mouth e.g flamingos, most fish

An ecosystem that can afford terrestrial filter feeder need pollen, spore, and seed production throughout the year and it needs minimum seasonal variations and a high degree of competition. It also suggests there aren't enough pollinators to do the job manually, or the dispersal of pollen/spore to the air is done to combat "pollinators" that eat far more than they spread about.

Photosynthesis in invertebrates

Sponges and cnidarians exhibit photosynthesis due to presence of symbiotic algae on their surface.