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Marine Invertebrates. Main Ideas. Classification and Comparison of all invertebrates Sponges are asymmetric, sessile animals that filter food from the water circulating through their bodies. Sponges provide habitats for other animals. Main Ideas.
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Main Ideas • Classification and Comparison of all invertebrates • Sponges are asymmetric, sessile animals that filter food from the water circulating through their bodies. • Sponges provide habitats for other animals.
Main Ideas • Cnidarians and ctenophores exhibit radial symmetry. • Cnidarians posses a high specialized stinging cell used to capture prey and for protection.
Main Ideas • Marine Worms exhibit bilateral symmetry. • Turbellarians are free living flatworms; flukes and tapeworms are parasitic. • Nematodes are abundant and important members of the meio-fauna
Main Ideas • Several other worm-like animals like ribbon worms, spiny headed worms, peanut worms, acorn worms and beard worms play important ecological roles in the marine environment.
What are animals? • Multi-cellular • Eukaryotic cells with no cell walls • Cannot produce their own food • All animals, with the exception of adult sponges can actively move.
Classification of Animals • Living creatures inhabit almost every part of our waters and land, and they exist in an astonishing variety of shapes and sizes. • Over a million kinds of animals and plants are known, and probably millions more are yet to be discovered and described.
Classification of Animals • To study this vast number of life forms, biologists classify organisms into groups and subgroups that have similar anatomy (body parts) and physiology (the workings of those parts).
Classification of Animals • All animals are members of the animal kingdom. • A kingdom is divided into smaller groups, the most inclusive being the phyla (the singular is phylum). • A phylum is successively divided into classes, orders, families, genus, and species. • Each group may be further divided into subgroups, such as subphyla or subclasses.
Classification of Animals • Kingdom- Phylum-Class-Order-Family- Genus-Species • When talking about an animal you are just naming the genus and species. • Use Latin and Greek roots for unfamiliar names. • Example: lobster is Homarus (genus) gammarus (species)
Classification System • Using this classification system, we can study the characteristics of one kind of organism or compare the common characteristics of several groups.
Classification System • In the phylum Chordata is a subphylum Vertebrata, which includes all animals with backbones. • Among its members are animals such as fish, frogs, lizards, birds, and humans. • Animals are often divided into two groups, vertebrates and invertebrates. Although this division is convenient, it is confusing because invertebrates do not make up a formal scientific group.
Classification System • The term invertebrate does not refer to a strictly defined scientific group, it is a handy term meaning “any animal without a backbone.” • All kinds of animals except vertebrates are invertebrates. • Invertebrates are far more abundant in the ocean and on land than vertebrates are.
Sponges or Porifera • Come in an variety of colors and an amazing array of shapes. • The shapes are determined by the bottom sediment, the material they are growing in and ocean currents. • Red, yellow, green, orange and purple are extremely common.
Sponges • They are predominantly marine • Exception family of Spongillidae who live in freshwater. • Sponges are benthic creatures, found at all latitudes beneath the world's oceans, and from the intertidal to the deep-sea.
Sponges • They are sessile- means doesn’t move much. • It has been shown that some younger sponges are able to move slowly (up to 4 mm per day).
Sponges • Some sponges bore into the shells of bivalves (mussels and clams) gastropods, and the colonial skeletons of corals by slowly etching away chips of calcareous material.
Sponges • A sponge can settle on a snail shell that is being used by a hermit crab; an unusual association can be formed. • This sponge/crab association results in a mobile sponge.
Generalized Anatomy of a Sponge • Body is built around a system of water canals. • Body full of tiny pores called ostia in which water passes through. • Water is source of nutrients and oxygen, and carries away wastes. • Water is like the blood of the human body, circulating food and nutrients throughout the sponge.
Generalized Anatomy of a Sponge • Water comes in through ostia, and enters large cavity called spongocoel. • Water exits out the osculum. • See handout: Anatomy of a sponge.
Sponge Size and Body Forms • Asconoid sponge: the simplest form, tubular and small. • Usually found in clusters. • During evolution, sponges found it helped out if they could grow by folding over areas of the sponge. • This increased the amount of volume of water it could filter (thus get nutrients)
Sponge Size and Body Forms • Syconoid Sponges: has body wall folding to it, but only a small amount. • Leuconoid Sponges: many folds to these types of sponges. • Largest type of sponges.
Nutrition and Digestion • Suspension Feeders: feed on food suspended in water. • Filter feeders: because they filter their food from the water. • Collar cells trap the food that is flowing in with the water. • Collar cells have flagella, which will push the water through the cells. • Flowing water also takes out wastes produced by the sponge. • Water: digestive system
Sponge Reproduction • Depends on type of sponge. • Sexually: egg and sperm released into the water and hope to god that they combine. • Sponges are hermaphrodites, thus producing both sperm and egg cells. • Asexually: budding • Commercially sold sponges cut the buds off the sponge, thus leaving more in the stead of the adult one they killed.
Ecological Role of Sponges • Compete for space with other bottom dwelling organisms. • Need good material to attach to- if a fertilized baby sponge doesn’t get it, it dies. • Produce chemicals to kill other species around them to make room.
Ecological Role of Sponges • Few animals eat sponges- eating the spicules is like eating needles. • Chemicals to kill off other species from settling next to them, also kill deter grazing. • Only Sea Turtles and a couple other animals are brave enough to eat them. • Sea Turtle Poop is composed of 95% of spicules. • Has a toughly lined digestive tract.
Sponges and Symbiotic Relationships • Sponge houses bacteria, that provide food for sponge while the bacteria gains nutrients and a house. • Cyanobacteria is a photosynthesizer, which produces its own food and shares with the sponge. • Sponges and crabs: the sponge grows on the crab becoming motile. The crab gets camouflage.
Introduction to Cnidarians: Stinging Celled Animals Sea Anemone Jellyfish
Cnidarians • Cnid: nettle • Includes Corals, Sea Anemones and Jellyfish • Corals: located near tropical islands • Sea Anemones: Cold artic waters to the equator • Hydra: microscopic cnidarians in freshwater • Jellyfish: float near surface of ocean • Can also exist in streams
Common Characteristics • Jelly-like materials • Carnivorous • Capture small drifting animals w/ tentacles • Some brightly colored • Graceful movement w/ tides
Body Structure • Outer layer: ectoderm has cells that capture food and secrete mucus • Jelly-like material between two layers: MESOLGLEA • Surround central cavity: gastrovasular cavity which extend to tentacles
