invertebrates - cabrillo collegencrane/bio11b/documents/invertspart1.pdfinvertebrates • animals...
TRANSCRIPT
10/3/13
1
Invertebrates • Animals without
backbones • We’ll cover
characteristics of major phyla and some to class level (KPCOFGS)
• We’ll also cover some natural history
• Refer to your notes that I posted on-line!
• Levels of complexity change (become more complex) as we move ‘up’ the evolutionary tree
• ‘Ancient’ animals are no better or worse adapted than ‘more complex’ animals. Its all about survival.
Ctenophores here too
Lophophorates
• No real symmetry, associations of loosely aggregated cells - very simple!
• Coanocytes (flagellated), collar cells, allow for food intake and O2. Osculum is excurrent pore (can have several), pore cells intake water
• Skeleton Spicules (CaCO3, or SiO2), or spongin (household sponges)
• Ecology: sessile, benthic, filter feeder. Encrusting and upright, and boring
• Most are hermaphrodites: eggs and sperm (broadcast). Fertilization is internal. Also have asexual reproduction: budding, re-aggregation
Sponges: Porifera ‘pore bearer’ Sponges are Suspension Feeders Choanocytes or Collar cells - flagellated
food-trapping cells of a sponge that generate a current through the pores
Water out through Osculum
Water in through Pore Cells
Water
10/3/13
2
Cnidaria • Radial symmetry – similar parts of the body are repeated around the
center. No front or back, No head • Oral surface (mouth side) • aboral surface (opposite of mouth side)
• Two Body Forms – Polyp -cylindrical and usually attached
• Corals, • Anemones • many colonial hydroids
– Medusa - umbrella-like swimming form • upside-down polyp adapted for swimming
Polyp
Medusa
Feeding Polyps on colonial hydroid
Phylum Cnidaria
• Diverse forms: jellyfish, corals, anemones, sea fans etc. Stinging cells = nematocysts
• Gastrovascular cavity digestion and absorbtion of nutrients. Waste through mouth! Respiration occurs through diffusion.
• Hydrostatic (water) skeleton • Ecology: sessile and benthic, as well as free swimming
(planktonic). Filter feeders and predators. Some are colonial animals. (corals, sea fans, gorgonians, man-o-war). Some like man-o-war and by the wind sailors have sails to aid in movement!
10/3/13
3
Phylum Cnidaria
• Symbiosis is common with zooxanthellae: 95% of food and formation of calcareous skeleton.
• Sex: Two phase life cycle (polymorphism)=sessile polyp phase and mobile medusa phase. Sexual rep is usually by medusa (eggs and sperm by broadcast spawning, or internal fertilization). Polyp also undergoes asexual budding
Phylum Cnidaria
• Some have a two phase life cycle! Polyp and medusa
Phylum Cnidaria
• Some have a two phase life cycle! Polyp and medusa
Aurelia: one of ‘our’ Jellyfish (scyphozoan)
Phylum Cnidaria Class Hydrozoa:�siphonophores
10/3/13
4
Phylum Cnidaria - Class Hydrozoa Phylum Cnidaria, class scyphozoa�Jellyfish and friends
Stinging cells - unique to Cnidaria
Fluid filled capsule
• Nematocysts discharge on contact and with other stimuli (e.g. fresh water!)
Nematocysts
Anthozoa - corals and anemones
10/3/13
5
Coral Polyp • Zooxanthellae
– photosynthetic dinoflagellates (Kingdom: Protista) that are adapted to live within corals.
Mouth
Tentacles
Gut
Zooxanthellae
Phylum Cnidaria - Class Anthozoa
Metridium giganteum, Urticina lofotensis, Urticina piscivora White plumed anemone, White spotted rose a., Fish eating anemone
Phylum Ctenophora Phylum: Ctenophora
• Characteristics of Comb Jellies About 100 species - more???? 8 rows of ciliary combs (ctenes) Bi-radial symmetry Cilia beat continuously
• Light is refracted off the cilia giving a prism-like color effect
Respiration occurs at body surface some have tentacles with sticky cells called
colloblasts used to capture prey cells and tissues are organized into organs
(rudimentary) simple Gut (single opening)
10/3/13
6
Phylum: Ctenophora • Natural history of Comb Jellies
– No segmentation; No circulatory system
– length from a few mm (sea gooseberry) to 2 meters long (venus’s girdle)
– Most are pelagic, Found in warm and cold oceans - many are deep sea and bioluminescent
– Carnivores (e.g. eat fish larvae) – Hermaphrodites – broadcast – Lots we don’t know!
Flatworms:�Phylum: Platyhelmenthes�
Class Turbellaria
Phylum Platyhelminthes: flatworms
• As many as 20,000 species! • CNS, Brain (agg. Of nerve cells in head region).
Nerve cords and muscular system. • Many (such as flukes) are parasites (eg.
tapeworms – one is 40 feet long – in sperm whales)
• Bilateral • Organs and organ systems, nerves, brain, CNS,
muscles • No skeleton • Variety of functions (parasites, free living etc.) • Sexual, most have larval stage
Flatworms:�Phylum: Platyhelmenthes�
Class Turbellaria
10/3/13
7
Ph Nemertea (ribbon worms),� Ph Nematoda (roundworms)
Phylum Nematoda (roundworms) • Bilateral symmetry • dig tract, and true organs. • Hydrostatic skeleton • Huge #s in sediments, decomposers, parasites, • Sexual reproduction with larvae. • Can be seen in fish flesh!
Lophophorates: bilateral symmetry
Bugula turbinata
Lichenopora hispida
Plumatella fungosa
10/3/13
8
Lophophorates: Lophophore=set of ciliated tentacles arranged in a horseshoe).
• Suspension feeders, mostly colonial (individual zooids), live in area of low sedimentation
• Bilateral • Unsegmented, colonial. U shaped gut • Exoskeleton of a variety of shapes • Benthic filterfeeders • Sexual and asexual.
• Phylum Bryozoa: look like colonial hydrozoans. 4000 species, delicate colonies. Retractable lophophore. Zooids show task specialization.
Bryozoans (moss animals)
Polychaete worms (Phylum Annelida)
10/3/13
9
Phylum Annelida: segmented worms
• bilateral • Segmentation • Gut cavity, complex movement and systems. Makes them
good crawlers and burrowers. • 2 Ventral nerve cords : peristaltic movement. Each
segment has ‘kidneys’ for nitrogenous waste, and parapodia with setae for movement.
• Closed circulatory system. • Have gills • Hydrostatic skeleton - many have tubes etc! • See ploychaeta: deposit feeders and suspension feeders:
active and passive, and carnivorous. Some crawl. • Sexual. Trochophore larvae. often timed with phases of
moon.
Diopatra ornata Ornate Tube Worm
Phylum Annelida - Class Polychaeta
Class Polychaeta: most annelid species are here. 6,000 sp. Mostly marine. 5-10 cm long. Live singly or in aggregations. Build tubes made with lots of different things. Cilia and mucus aid in feeding.
Phylum sipuncula: peanut worms Phylum Sipuncula (peanut worms). • All marine. 350 sp, benthic. Most intertidal, few
deep sea. • Bilateral • Unsegmented. Can curl in to look like peanut.
Mouth and anus at same end • Hydrostatic • Burrows (open at one end). Calcarous tubes or
burrows. • Sexual: gametes released through temporary
gonads. External fertilization
10/3/13
10
Ph. Echiura: fat innkeeper worm Phylum Echiura: spoon worms. About 100 sp. Fat innkeeper (Urechis Caupo). Burrow with
commenal creatures in mud. Sweep detritus with proboscis and urechis uses a mucus net. Pumps water through burrow and through net. Close relatives of annelids.