Particulate and suspension feeders

Term test answers addressed (in part)Amphioxus Branchiostoma: filtering with mucus

Lophophores: sabellid worms and sortingChaetopterus: Annelida

Hairs are branched; pollen transferred from them by brushes of basitarsus: a tarsal segment enlarged into a rectangular brush, shaped for this purpose. Cross-body use of rake at end of broad-tipped tibia draws pollen up into press. Pollen press compacts and moves pollen to pollen baskets. See account in lab outline.Posterior face honeybee metathoracic leg showing

basitarsal brush, hint of branching of hairs

There are special features in the natural world everyone should see. One of these is a coral reef. The diverse fishes and invertebrates, all living their lives for close-up viewing. The same remarkable community of animals can be seen differently at night. And in complete darkness , turn off your light at depth and shake your hand; little speckles of greenish yellow light occur wherever the water is agitated. This is the light of diatoms, tiny single-celled organisms that phosphoresce.

Noctilucalarge protozoan, a dinoflagellate (allied with the brown algae and diatoms by the presence of xanthophyll pigments that give them a brown or golden brown colour and by the absence of

chlorophyll b, chlorophylls a and c are present)

Two flagella characterize dinoflagellates, one directed posteriorly lying in a long groove called the sulcus and another transverse called the girdle

Luminescent: principal contributors to planktonic bioluminescence

Branchiostomaamphioxus

Anterior to the mouth of amphioxus is an oral hood defining a buccal cavity; arching on the underside of the hood are ciliary tracts called the wheel organ. [The metachronal beating of the cilia reminded someone of a wheel.] Buccal cirri line the edges of the lateral aspect of the hood and are used as a coarse filter to prevent large inorganic particles entering with the incoming water stream (incurrent). Mucus is discharged onto the wheel organ from Hatschek’s Pit in the midline of the hood. The mouth is at the back of the buccal cavity and is bordered by a velum with velar tentacles.

Within the cavity of the pharynx frontal cilia line the gill bars and are positioned so that their beating drives a sheet of mucus produced in the hypobranchial (ventral) groove up the inner wall of the pharynx. Projecting into the space between gill bars (gill slits) are lateral cilia whose beating creates the current . Food particles adhere to the mucus and travel in the mucus sheet [held against the pharynx wall by the current] up the pharynx walls to accumulate and travel rearward in a dorsal groove (epipharyngeal), thus reaching the intestine just beyond the pharynx.

atriopore

Buccalcirri

Oral hood

Bryozoa colonial tiny animals in their own phylum that

filter feed with lophophores, a whorl of

tentacles surrounding the mouth

Bryozoa [moss animals]: lophophoresA circular or horsehoe-shaped fold of the body wall that encircles the mouth and

bears numerous ciliated tentacles (Barnes)

A number of phyla are notable for lophophores: have been grouped together and called the ‘lophophorates’: Phylum BryozoaPhylum EntoproctaPhylum phoronidaPhylum Brachiopoda: this last being lampshells, Lingula (in lab)

Lampshell

Chaetopterus

Chaetopterus in its u-shaped burrow

Filter feeding in annelids: sabellid worms ‘fan’ or ‘feather duster’ tube-

dwelling worms