The Worm Phyla
What is the name of the class of the marine annelids?
Class Polycheate
What are 3 classes in Phylum Mollusca? Give an example of an animal from each group.
Gastropods-snails, slugs, nudibranchs
Cephalopods- octopus, squid, cuttlefish, chambered nautilus
Bivalves-clams, mussels, oysters, scallops
List 4 of the defining characteristics of Phylum Arthropoda.
Arthropoda means jointed feet.
All Arthropods have jointed appendages (paired).
All Arthropods have an exoskeleton.
Segmented body.
Do echinoderms have a brain?
No
What are the five characteristics that distinguish the different phyla of marine invertebrates?
Body Symmetry
Cephalization
Type of Gut
Type of Body Cavity
Segmentation
List 5 defining characteristics of Phylum Platyhelminthes.
Sac-like Gut- single opening for ingesting food and excreting waste.
most primitive species to have cephalization
Protostome development
Bilateral Symmetry
3 Tissue Layer
Acoelom- no body cavity
Unsegmented body
Found in oceans, freshwater and in moist terrestrial habitats and a few are parasitic.
List 5 of the defining characteristics of Phylum Mollusca.
Visceral Mass- contains the organs- the “soft bodied” part
Mantle- makes a shell in most organisms.
Foot- muscular lower part used for movement
Radula - tongue-like structure, sharp
Head area- that contains the brain and sense organs
List 3 characteristics of Class Crustacea.
Bilateral Symmetry
Two main body segments: Cephalothorax and Abdomen
Have gills to breath
Describe 3 of the ecological roles of Echinoderms.
Sand dollars and sea cucumbers burrow into the sand, providing more oxygen at greater depths of the sea floor. This allows more organisms to live there.
Many sea cucumbers provide a habitat for parasites such as crabs, worms, and snails.
Recently, some marine ecosystems have been overrun by seaweed. Excess seaweed can destroy entire reefs. Scientists believe that the extinction of large quantities of echinoderms has caused this destruction.
What are the 8 major phyla of Marine Invertebrates?
Porifera (sponges)
Cnidaria (jellyfish, corals)
Platyhelminthes (flatworms, tapeworms)
Nematoda (roundworms)
Mollusca (snails, clams, squids)
Annelida (earthworms, leeches, marine worms)
Arthropoda (insects, spiders, crustaceans)
Echinodermata (sea stars, sea urchin)
Provide an example of how worms reproduce sexually and asexually.
Several species of the non-parasitic flatworms undergo transverse fission, in which a single organism splits up into smaller fragments through transverse division (Asexual Reproduction).
Sexual reproduction occurs in earthworms when hermaphrodites fertilize each other's eggs.
What are 4 of the defining characteristics of Class Gastropoda?
Gastropod means “stomach footed”; a typical gastropod is a coiled mass of organs enclosed by a dorsal shell, which rests on the foot
Sensory structures on head (tentacles and eye spots)
Operculum: trap door, pulls in snail to shell
The shell of a gastropod is always one piece (univalve) and may be coiled or uncoiled.
Radula- a tongue like structure with teeth
Describe 3 of the ecological roles of Crustaceans.
Are an important food source for other marine organisms.
Krill are the most important part of the food chain in the Antarctic animal communities.
Crabs are important predators, and the continuing struggle between them and their prey prompts the evolution of newer adaptation.
Some eat dead animals and scraps, which is important because they are cleaners of the ocean.
List 5 of the defining characteristics of Echinoderms.
Radial symmetry (usually five-point)
Endoskeleton
Spiny projections from skin
No head region or brain
Water vascular system for movement
All organisms are marine organisms
Classification involves grouping organisms into a series of hierarchical categories. List these categories in order.
kingdom, phylum, class, order, family, genus, and species
What are the two ways that worms can breath (respiration)?
Through absorption through body wall or skin
Gills
Describe how species in Phylum Mollusca respire (breath)?
Usually consists of paired gills
Water is drawn into organisms through incurrent siphon.
Water passes over the gills
Oxygen from the water diffuses into the blood.
Describe the 3 different types of feeding methods of Crustaceans.
Filter Feeding
Krill have long legs with “feeding baskets” that branch out to collect food particles from the water.
Scavengers
Some Crabs, shrimp, and prawns feed on scraps and dead creatures.
Active Hunters.
Some crabs and lobsters are active predators, seizing prey in their powerful claws.
Compare and contrast how echinoderms reproduce asexually and sexually.
Asexual Reproduction
Asexual reproduction in echinoderms usually involves the division of the body into two or more parts (fragmentation) and the regeneration of missing body parts.
Sexual Reproduction
Echinoderms have separates sexes.
Fertilization takes place externally when both male and female release their gametes into the water.
The larvae float and eventually settle to the ocean floor.
What are the 6 kingdoms of life?
Animalia, Plantae, Fungi, Bacteria, Protista, Archaea.
Give one similarity and one difference between the three groups of worms?
Similarities: body shape, bilateral symmetry, flatworms and roundworms respire through body wall and are both unsegmented, all have cephalization
Differences: Annelids are segmented, flatworms have sac-like gut, some annelids have gills and a closed circulatory system
Compare and contrast the nervous system and sensory structures of the 3 different classes of Phylum Mollusca.
Gastropods: eye spots (on stalks at base of tentacles or on tentacles) and chemical sensors in tentacles
Bivalves: photoreceptor and vibration cells
Cephalopods: Best developed brain of all invertebrates- can detect light, vibrations, chemicals
Describe an example of how Crustaceans reproduce asexually and an example how they reproduce sexually.
Sexual Reproduction
Sperm and egg released into water (broadcast spawning)
Cephalopods and most snails use internal fertilization.
Asexual Reproduction
Describe 3 of the different feeding methods of Echinoderms.
Provide an example of each one.
Crinoids and some brittle stars tend to be passive filter-feeders, enmeshing suspended particles from passing water
Most sea urchins are grazers.
Sea cucumbers deposit feeders and the majority of starfish are active hunters.
Coevolution occurs when different species interact with one another in a way that results in reciprocal adaptation. That is, impose natural selection on each other. How does Vermeij’s data exhibit this phenomenon (hint: think “arms race”?
Vermeij's data shows use that the increase in shell-breaking predators occurred around the same time that we started to see traits that would help to foil would be predators in in Gastropods, Cephalopods, and Bivalves. Gastropods increased in percent of taxa with high spires and narrow apertures. As well, as a decrease in taxa with weak shell designs. Shelled Cephalopods with coiled and sculptured shells also increased. For Bivalves there was an increase of burrowing and rock boring species. This evidence supports the theory that one species could affect the evolution of another species.