practical 4 Flashcards
Animals: Metazoa
- Multicellularity with division of labor: (different cells for different tasks= first step in tissue/organ development)
- Collagen (Most abundant protein in animals, connective material)
-heterotrophic
Porifera (sponges) apomorphies (2)
- Aquiferous system: water drawn in then pumped out
- Spicules: fibers of silica or calcium carbonate, make up skeleton of sponge
Porifera Aquiferous System functions
- Water drawn in through ostia
- Water pumped out through osculum
- Choanocyte cell (collar cell):
produces current that draws water
into the ostia by beating flagella
Porifera (sponges) facts
- Aquatic (mostly marine) = sessile: attached to substrate, benthic: bottom dwelling
- Earliest lineage of animals
- Only animals lacking true tissues
Cnidaria (anemones, jellies, corals, sea pens) (Animalia: Eumetozoa)
- radial symmetry, incomplete gut (one opening)
- Apomorphy = Cnidae - Nematocysts = stinging organelles that activate with touch or chemical signals
- Capture prey, defense
Cnidarian diplontic life cycle
- Polyp = sessile, can be singular or colonial, Polyps produce medusae through asexual budding (except
in Hydra and sea anemones) - Medusa = pelagic, reproduce sexually (egg and sperm) - planula larva - settle on ocean floor and grow into a polyp
Hydrozoans
- generally experience both polyp and
medusa phases - Hydra: will see today, polyp stage most conspicuous
Scyphozoans
true jellyfish
* Polyp stage reduced/absent, medusa phase dominant
Anthozoans
sea anemones, sea pens, corals
* Lack medusoid stage
* Marine
* Solitary or colonial
* Can form large skeletal structures housing many polyps
* Corals: symbiotic relationships with zooxanthellae
Animalia: Eumetozoa: Ctenophora
- Complete gut (two openings rather than one like in Cnidarians)
- largest animal that uses cilia to move
Platyhelminthes (flatworms)
- Most are parasitic: Cestodes: endoparasitic = tapeworms, Trematodes: endoparasitic, Monogeneans: primarily ectoparasitic with one host in their life
- Trocophore larvae: ciliated larvae
- flattened dorsoventrally
- No complex organ systems
- Incomplete gut (single opening)
Rotifera (rotifers)
Complete gut: two openings, Cilia around mouth: Swirl like a buzz saw
(circular saw)
Bryozoans
all marine, lophophores: ciliated tentacles around the mouth = gas exchange and feeding
Mollusca types
- Polyplacophora
- Gastropoda
- Bivalvia
- Cephalopoda
Mollusca apomorphies
- Radula: toothed “rasping” tongue-like organ, used to scrape food, absent in bivalves
- Calcium carbonate calcareous spicules make up the shell, laid down in layers, coated with periostracum layer (surface coating), can be adapted to different ecologies (bivalves)
- Muscular foot = often with a flat creeping sole, produce mucous trail and the animal glides along it, lined with many cilia
- Fleshy mantle = outer dorsal body wall
Polyplacophora (chitons)
- shell made of 7-8 distinct plates (articulating shell plates)
- Mantle fused to shell plates
- Strictly marine, intertidal regions
Gastropoda (snails and slugs)
- habitat: marine, freshwater, terrestrial
- some have lost shells
- aposematic coloration: Nudibranchs = brightly colored to show predators they are toxic
Bivalvia (clams, oysters, mussels, scallops)
- shell with 2 valves
- no radula, instead gills for filter feeding
Cephalopoda (octopus, squid, nautilus, cuttlefish)
- all lost external shell except nautilus
- cuttlefish and squid have internal shell
- octopus have no shell at all
cephalopoda apomorphies
- beak-like jaws
- siphon = propulsion, reproduction, ink release
- ink sac = defense
- muscular foot modified into arms/tentacles
- siphuncle = used for flotation
Annelida (segmented worms)
- Serial homology of body segments = segmentation
- Coelom cavity partitioned by septa, digestive tract and blood vessels run the length of the body (through the septa)
- Apomorphy = Setae bundles: bristly hair-like structures used to anchor the worm while it is moving
- basic annelid movement = hydrostatic skeleton: changes body shape to anchor or release setae along different regions of the body
Polychaete worms
Can be free living or sedentary residing in a tube, most are marine, Sensory system: complex eyes, antennae, parapodia: act as legs or
paddles to assist in movement or gas exchange
Lumbricidae (e.g., earthworms)
- burrowers
- freshwater or terrestrial
- external clitellum = worms attach at this region for reproduction
- loss of trocophore larval stage: adaptation to more terrestrial environment
Hirudinea (e.g., leeches)
- Fresh and salt water, some terrestrial
- many parasitic
- apomorphy = Posterior sucker
- Internal clitellum
