lec142 invertebrates (lecture 3+4)

phylum porifera species no.

5500

phylum porifera aquatic or terrestrial

aquatic

phylum porifera larvae

sessile but free swimming

phylum porifera symmetry

asymetrical

phylum porifera internal arrangement

no tissue or organs only walls with attached cells

phylum porifera cells

flagellated collar cells

phylum porifera sex

mostly hermaphrodite

phylum cnidaria species

10000

phylum cnidaria examples

jellyfish, anemones and corals

phylum cnidaria terrestrial or aquatic

aquatic

phylum cnidaria symmetry

radial symmetry

phylum cnidaria body form

sessile polyps and mobile medusae

phylum cnidaria role in food web

all predators

hydra have…

polyps and medusa

jellyfish have

medusa

corals and anemones have…

polyps

phylum platyhelminthes species

20000

phylum platyhelminthes examples

flatworms, flukes, tapeworms

phylum platyhelminthes lifestyle

free living or parasitic

phylum platyhelminthes symmetry

bilateral

phylum platyhelminthes body form

acoelomates

phylum platyhelminthes sex

most hermaphodites, asexual reproduction ability

tapeworm needs…

2 hosts to complete the cycle

benefits of 2 hosts (parasitic tapeworm)

• increased reproduction potential

• increased range of parasite in time and space

• intermediate host can promote infection of definitive host

phylum mollusca species

93000 species

phylum mollusca examples

snails, clams, octopuses

phylum mollusca symmetry

bilateral (some have secondary symmetry (from shell torsion))

phylum mollusca body plan

coelomates, membrane, mantle, radula, muscular foot

phylum mollusca shell

secreted by mantle membrane

phylum mollusca habitat

most aquatic, some can live on land

phylum mollusca class bivalvia

• oysters and clams

• 2 shells (bilateral)

• mostly sedentary or burrowing

• expanded gills for filter feeding and respiration

• sepeate sexes - external fertilisation

phylum mollusca class gastropoda

• snails 

• terrestrial and aquatic

• head well developed (eyes and tentacles)

• assymetrical from shell coiling and torsion

• herbivores, carnivores, scavengers

• seperate sexes or hermaphrodite

• cnetidia = gill needs humidity

phylum mollusca class cephalopoda

• marine predators

• integral head and foot , tentacles with suckers

• shell internal

• some have elongated body for swimming and jet propulsion

• brain in braincase

• seperate sexes with courtshipe displayes

• highly developed brain

phylum annelida examples

fan worms, bristle worms, earthworms, leeches

phylum annelida species

16500

phylum annelida symmetry

bilateral

phylum annelida body plan

coelomates, and segmented body, covered in chaetae

coelomates advantages

• hydrostatic skeleton - soft bodied

• transport of excretory and sexual products

phylum annelida class errantia

• marine

• crawl or burrow on sea floor

• well defined head with eyes and jaws 

• each body segment with prominent parapodia

• sexual reproduction with seperate sexes

phylum annelida class sedentaria

• aquatic or terrestrial

• earthworms are burrowers

• lug/fan worms are filter feeders

• leeches are ectoparasites or predators

• parapodia small or not present and few chaetae

• regeneration

phylum nemotoda example

roundworms

phylum nemotoda species

25000 but maybe up to 1M

phylum nemotoda body plan and symmetry

• bilateral symmetry

• round body with tapering ends

• pseudocoelomates

• no antagonistic muscles only longitudinal

phylum nemotoda lifestyle

free living and parasitic

phylum nemotoda reproduction

sexual with sperate sexes

phylum echinodermata development

deuterostome

phylum echinodermata examples

sea lillies, sea urchins, starfihs, sea cucumbers

phylum echinodermata habitat

marine

phylum echinodermata body plan and symmetry

• bilateral in larvae, 5 fold radial in adults

• coelomates

phylum echinodermata reproduction

• sexual reproduction with seperate sexes

• free swimming larvae

phylum echinodermata species

7000