Phylum Annelida: summary of characteristicsPhylum AnnelidaSegmentationSlide 4Slide 5MovementSlide 7Slide 8AnnelidsSlide 10Slide 11Slide 12Annelid ClassificationClass PolychaetaPolychaetesSlide 16Slide 17Slide 18Slide 19FanwormsSlide 21Slide 22Burrowing polychaetesSlide 24Burrowing PolychaetesSlide 26Slide 27Predatory polychaetesSlide 29Slide 30Slide 31Slide 32Class OligochaetaSlide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Excretory organsSlide 43Reproduction in earthwormsSlide 45Slide 46Class HirudineaSlide 48Slide 49Slide 50Slide 51Slide 52Slide 53Class Siboglinidae (pogonophorans)Slide 55Slide 56Slide 57Slide 58Slide 59Phylum EchiuraSlide 61Slide 62Slide 63Phylum Annelida: summary of Phylum Annelida: summary of characteristicscharacteristicsName from Latin aName from Latin annulusnnulus meaning a ring. meaning a ring.Vermiform. Possess tissues and organs.Vermiform. Possess tissues and organs.Muscular gut with mouth and anus.Muscular gut with mouth and anus.Body divided into segments.Body divided into segments.Outer epithelium with clumps of bristles (except in forms Outer epithelium with clumps of bristles (except in forms with suckers). May be covered with a cuticle.with suckers). May be covered with a cuticle.Body wall muscular with both circular and longitudinal Body wall muscular with both circular and longitudinal muscles.muscles.Closed circulatory system.Closed circulatory system.Nervous system with supraoesophageal ganglion, Nervous system with supraoesophageal ganglion, circum-oesophageal ring and ventral nerve cord.circum-oesophageal ring and ventral nerve cord.Nephridia responsible for most excretionNephridia responsible for most excretionPhylum AnnelidaPhylum AnnelidaThe annelids (L. The annelids (L. annelusannelus: a little ring) are the : a little ring) are the segmented worms.segmented worms.Annelids are coelomate, protostomes and the Annelids are coelomate, protostomes and the body is metameric being composed of serially body is metameric being composed of serially repeated segments or metameres.repeated segments or metameres.Each segment is separate from the next Each segment is separate from the next segments being divided by partitions or septa.segments being divided by partitions or septa.SegmentationSegmentationWithin each segment are components of Within each segment are components of most organ systems such as the most organ systems such as the circulatory, nervous and excretory circulatory, nervous and excretory systems.systems.Thus, there is a degree of redundancy in Thus, there is a degree of redundancy in annelids so that if a segment is damaged annelids so that if a segment is damaged it need not be fatal.it need not be fatal.SegmentationSegmentationThe evolution of segmentation is the great The evolution of segmentation is the great evolutionary innovation of the annelids.evolutionary innovation of the annelids.Segmentation allows annelids to make Segmentation allows annelids to make more precise body movements than more precise body movements than organisms that have a hydrostatic organisms that have a hydrostatic skeleton, but lack segmentation e.g. the skeleton, but lack segmentation e.g. the pseudocoelomate nematodes.pseudocoelomate nematodes.SegmentationSegmentationBecause the coelom is divided by septa the Because the coelom is divided by septa the force of muscle contraction in a segment is not force of muscle contraction in a segment is not transmitted throughout the body, but instead is transmitted throughout the body, but instead is confined to the single segment. confined to the single segment. Thus, one segment may elongate while the Thus, one segment may elongate while the adjacent one contracts and this allows the adjacent one contracts and this allows the animal to make fine, controlled movements.animal to make fine, controlled movements.MovementMovementWith the exception of the leeches, the coelom is With the exception of the leeches, the coelom is filled with fluid and acts as a hydrostatic filled with fluid and acts as a hydrostatic skeleton. skeleton. Annelids possess circular and longitudinal Annelids possess circular and longitudinal muscles and this enables individual segment to muscles and this enables individual segment to be elongated or contracted. be elongated or contracted. Crawling is achieved by alternating waves of Crawling is achieved by alternating waves of contraction by circular and longitudinal muscles contraction by circular and longitudinal muscles passing down the body (peristalsis).passing down the body (peristalsis).MovementMovementBecause they have fine control of movement Because they have fine control of movement annelids have evolved a relatively sophisticated annelids have evolved a relatively sophisticated nervous system.nervous system.Most annelids are burrowing forms and as an Most annelids are burrowing forms and as an adaptation to this lifestyle bear short chitinous adaptation to this lifestyle bear short chitinous bristles called setae on each segment. The bristles called setae on each segment. The setae enable the annelid to gain traction against setae enable the annelid to gain traction against the side of the burrow.the side of the burrow.MovementMovementIn other annelids longer hair-like setae In other annelids longer hair-like setae assist the animal in swimming.assist the animal in swimming.For the annelids that live in burrows or in For the annelids that live in burrows or in tubes the setae help to prevent the animal tubes the setae help to prevent the animal from being pulled out.from being pulled out.AnnelidsAnnelidsAnnelids occur worldwide being found in Annelids occur worldwide being found in the sea, freshwater, and in the soil.the sea, freshwater, and in the soil.They feed on organic matter in the mud or They feed on organic matter in the mud or soil, by filtering suspended particles from soil, by filtering suspended particles from the water, act as predators, or suck blood.the water, act as predators, or suck blood.AnnelidsAnnelidsThe typical annelid body has a two part head The typical annelid body has a two part head made up of a made up of a prostomiumprostomium and a and a peristomiumperistomium, a , a series of segments, and a terminal series of segments, and a terminal pygidiumpygidium which contains the anus.which contains the anus.Neither the head nor the