Simple Marine Animals

Zooplankton in the Sea Plankton- organisms that float or drift on the ocean surface Include unicellular protists and multicellular jelly fish Plantlike plankton are phytoplankton Animal-like plankton are zooplankton

Zooplankton Diversity Divided into two groups: 1. Temporary zooplankton 2. Permanent zooplankton

Temporary zooplankton The embryos or larvae of fish, crabs, sponges, lobsters, clams and others Spend early part of their life cycle floating and drifting near the ocean’s surface When they mature, they settle to the bottom where they develop into adults (no longer plankton at this point)

Crab, sea star, barnacle & sea urchin larvae

Permanent Zooplankton Species that remain in the plankton population throughout their entire life cycle Ex. Foraminiferans Unicellular Encased in a shell or test Made of calcium carbonate (CaCO3) Shell falls to the seafloor when they die

Ex. Radiolarian Transparent because its cell wall is made of silica Have long spines that help with buoyancy & protection

Ex. Copepod Most numerous of all permanent zooplankton Shrimplike Feeds on phytoplankton like diatoms Important link in marine food chain

Protozoans Single celled Protists Divided into: Ciliophora Zoomastigina Sarcodina

Ex.Ciliophora Ex. Zoomastigina Ex. Sarcodina Largest group of protozoa All have cilia Ex. Zoomastigina Animal-like Move with flagella Euglena & dinoflagellates Ex. Sarcodina Move by cytoplasmic extensions called pseudopods Includes forams, radiolarians, and amoebas

Sponges Classified in Phylum Porifera Benthic (bottom dwelling) Multicellular animal with three layers: 1. Endoderm- inner layer of undifferentiated cells 2. Ectoderm- outer layer of cells 3. Mesenchyme-jellylike material between the endoderm and ectoderm

How does a sponge feed? Water enters the sponge through tiny pores called Ostia Water and wastes exit through the large hole, called the osculum, located at the top of the sponge Collar cells inside the sponge have flagella and produce the currents that move the water Collar cells also trap and digest food

Benefits of sponges: 1. Very efficient filters of the marine environment (100 liters of seawater/hour) 2. Recycle minerals back into the water

Rotifers Multicellular Phylum Rotifera Live in moist sand along the shore Draws in water through it’s mouth by cilia, eats the floating food, passes through the digestive tract and out the anus

Rotifer Reproduction External fertilization & development Sexual- male sperm and female egg meets up to form a zygote Asexual- (parthenogenesis) female produces one egg with two sets of DNA which can develop into a female rotifer

Bryozoans Benthic organism mistaken for a sponge Name means “moss animal” Microscopic multicellular animal that lives in a box shaped compartment Branching colonies of these “boxes” of bryozoans live together on rocks, seaweeds, and shells