Lab 6 (inverts 1) Flashcards
Describe members of phylum Porifera
- Sponges are the simplest animals
- multicellular but are not true eumetazoans (do not have true tissues)
- Filter feeders: have special cells called Choanocytes and Amoebocytes
- Work together to catch food particles and distribute the nutrients throughout the animal
what are the true tissues
True tissues:
- ectoderm
- endoderm
- mesoderm
how does tissue develop
zygote cleavages to 8 cells, then a lot more into a blastula. The blastula is hollow with a cavity called the Blastocoel inside. It undergoes Gastulation where it caves to make the inner cavity that is the digestive tract. Opening = Blastopore.
Describe phylum Cnidaria
- Cnidarians (anemones, corals, jellies, etc.) are eumetazoans - have true tissues (are diploblastic)
- All have stinging cells called cnidocytes
- Two body forms: polyp and medusa
- Usually, the polyp stage is asexual and the medusa stage is sexual but this varies
Cnidarians exhibit radial symmetry
what are bilaterians
- bilaterial symmetry
- Triploblastic
- other features
describe phylum Platyhelminthes
- this group contains flatworms like planarians, trematodes (flukes) and Cestodes (tape worms)
- Cephalization
- Planarians are free living but cestodes and trematodes are obligate parasites
- There are many human parasites in this group
describe the mollusks are their 4 main parts
- mollusca is a large and very diverse phylum
- It contains some of the largest, fastest, and strongest invertebrates including octopuses and squids
Muscular foot → usually for movement
Visceral mass:
Contains internal organs
Gill and anus open into mantle cavity
Mantle:
Secretes shell: calcium carbonate in protein matrix
Mantle cavity: houses gills, anus, excretory pores
Radula:
tooted scraping tool
what are Annelids
- true segmented worms
- contain terrestrial, freshwater, and marine species
- We divide annelids into two clades:
- errantia
- Sedentaria
how do animals vary
Animals vary in a lot of ways
- habit: free living vs symbiotic, sedentary vs motile, predator vs prey
- Habitat: living in water, on land, etc
- Embryonic development, Protostomes or Deuterostomes
- Organs, gut may be in the form of a cavity of a complete tube
- Organ systems
- Blood vascular system may be open or closed
- Nervous system together with sense organs is highly variable
- reproductive system may be modified to accommodate external or internal fertilization and development
- Secondary body cavity: presence of absence of Coelom
- Segmentation or metamerism and arrangement of adult body parts
- Symmetry: radial or bilateral
- tissue organization
describe the morphology of a sponge
Body organized around a series of holes and channels that accommodate water flow. The current of water enters the animal via a series of many tiny openings (the ostia/ostium) flows through many passage ways and exits via a large opening called the osculum. Water current is maintained by specialized flagellated cells called Choanocytes, that line the passage ways and trap microscopic food particles.
Spong body may be either simply organized with a relatively simple system of water channels or it may be complex with vast numbers of chambers that give the body a ‘spongy’ texture. Can be up to 2 m tall.
what is typical of Cnidarians
Cnidocytes are typical of this group, as are polyp and medusa body forms. They are diploblastic (have ectoderm and endoderm) that give rise to the epidermis and gastrodermis.
Alternate between asexual polyps and sexual medusae during life cycle.
Cnidocytes are stinging cells which house a mini needle-like stinger and are used for defence and predation.
what are Platyhelminthes like
Dorso-ventrally flattened animals that vary in size, habitat, and habit.
Triplobastic, having ectoderm, mesoderm, and endoderm. Can have connective tissues, and muscle tissues.
Includes Turbellarians (planaria) which are abundant freshwater predators, Trematodes (blood flukes) and Cestodes (tapeworms) which are both endoparasitic with often complex lifecycles with sexually + asexually lifecycles which involve 1 or more hosts.
what are bivalves like
Class Bivalvia: marine and freshwater with laterally compressed bodies enclosed by a shell in two hinged parts. Included clams, oysters, mussels, scallops, etc. Mostly filter feeders with no head or radula. GIlls evolved into ctenidia, specialised organs for feeding and breathing. Shell made of calcium cabronate, two similar parts called valved, joined by flexible ligament that forms the hinge.
what are Gastropods like
Class Gastropoda: stomach foot, snails, slugs, conchs, sea hares, sea butterflies. Includes shell-bearing species, and some with reduced shell. Foot modified for crawling. Usually bear a head with tentacles, eyes, and a style. Complex radula used for ingestion.
what are Cephalopods like
Class Cephalopoda: Head food, octopi, squids, cuttlefish, nautilus. Some have a shell, most don’t. Active carnivores, beak like jaw. Well developed nervous system, closed circulatory system. Foot made into tentacles, arms, and a funnel.
