Chapter 7 Marine Science

what are the main characteristics of sponges?

-All sponges are sessile (non-mobile and live attached) some encrust on a hard substrate -Numerous tiny pores called the Ostia, allow water to pass through the sponge -the osculum is the opening found at the top of the sponge where water exists from -water movement is required to allow sponges to filter feed (a type of suspension feeding) on plankton and dissolved organic matter in the water -water flow is also essential to carry waste away from cells and to create gametes

•Cnidarians: Stinging animals •Characteristics of Phylum:

-Cnidocytes (stinging cells) with nematocyst capsules located on tentacles. These are used for protection and for feeding -Digestive system is incomplete (sac-like with mouth only) -Nerve net throughout body coordinates movements -Some jellyfish also have sensory cells and contractile cells

. Class Anthozoa - Corals, Anemones, Sea Fans/Whips, Sea Pansy

-Colonial polyps that normally lack a medusa stage -Corals secrete calcium carbonate "shells" -Most coral species possess symbiotic algae within body tissues called zooxanthellae

•Classification of Cnidarians 1. Class Scyphozoa - True Jellyfish

-Free swimming large medusa forms with polyp only in reproductive life -All marine -They move by rhythmic contractions, but cannot fight against prevailing water currents -Many with powerful stings

what two body forms exists in cindiarians?

-Medusa- free floating form which is transported by water currents, mouth with sorrounding tentacles are positioned downward -polyp -sessile attached form with mouths and tentacles are positioned upward

•Molluscs Characteristics of Phylum

-More than 200,000 species -Name means "soft body" -Basic body plan - head, muscular foot and visceral mass in most species -Mantle- secretes shell, body wall that covers visceral mass -Many have a shell of calcium carbonate -Radula for grazing is unique to this group -Some are deposit feeders, others carnivores, some use radula for scraping algae, encrusting animals, etc. off substrates -Well developed nervous system -Open circulatory system -Complete digestive system -Trochophore larvae develops into a planktonic veliger larvae complete with shell (miniature version of adult)

Class Hydrozoa

-Mostly polyp forms with reproductive medusa -Physalia is unusual species with a colony of polyps carried by a gas-filled float -Freshwater and marine species

About ___% of animals are invertebrates.

97

The Sponges• Modes of Reproduction

Asexual budding- fragmentation of a cluster of cells from original sponge can begin growth in a new area. Sexual- sperm are released into sorrounding water, (broadcast spawning) to be picked up by a near by sponge and directed to egg Most sponges are hermaphroditic (possess male and female reproductive parts).

two tissue layers are present in cinidarians

Epidermis covers the body's surface (kinda like the skin) Gastrodermis lines the internal body cavity and is specialized for digestion what lies in between the epidermis and gastrodermis is the mesoglea

General Characteristics of Animals-

Multicellular, diploid organisms with tissues, organs, or organ systems -Heterotrophic Heterotrophic• requires oxygen for aerobic respiration • Reproduce sexually, or asexually, or both

what are the two types of cells in sponges ?

Pinacocytes- these flattened cells cover exterior of body. Porocytes- cells with a pore to allow water to pass into body

what are the different body symmetry?

Radial- round; equal parts radiate out from a central point - (like that seen in a sea star)- they have multiple planes of symmetry (cut it into different ways and make equal parts) Bilateral- organism can be divided into right and left halves that are more or less equal (ex: marine mammals)- one plane of symmetry Sponges have no symmetry and are known as asymmetrical

what is the structural support of sponges?

Spicules are the support structures made of silica or calcium carbonate These spicules have a variety of shapes from simple rods to star-shaped

Animals without a backbone are known as_____________ . Those with a backbone are called______________

invertabrates, vertebrates

All major animal groups have representatives in the _______________.• Several animal groups are ________________.

marine community, exsclusively marine

The __________ is housed within the _________ & is triggered by ____________

nematocysts, cnidocyte, cnidoai

Anatomy stinging process of jellyfish ?

there are three parts of the anatomy of stinging in jellyfish cnidocytes- The cnidocytes on jellies' tentacles discharge venom from a sac called a nematocyst cinodial- is the little hair-like part of the jelly

bivalves (molluscus phylum)

•Bivalves -Clams, Oysters, Scallops, Mussels, etc. -Two shells or "valves" -The oldest part of the shell is called the umbo -Shell grows out from the umbo in concentric rings -No head present -No radula present -Adductor muscles secure valves together -Muscular foot used for burrowing in the bottom and other locomotion -Water circulated with siphons -Gills for respiration & food gathering (filter feeding) -Some species burrow, while others attach to hard substrates via byssal threads or grow attached to each other

•Ctenophores - also known as comb jellies

•Characteristics of Phylum: -About 100 species, all marine -8 rows of thick cilia that beat continuously -No nematocysts unless they harbor some from eating cnidarians -Long sticky tentacles used to capture prey -Most species are planktonic -Can be found in warm and cold waters

give an overview of the sponges characteristics just stated

•Characteristics of Phylum: -Asymmetric body with no true tissues or organs. -Mostly marine -Varying size, shape, and color -Solitary or colonial -Regeneration capability -Filter feeders

•Reproduction in Cnidarians:

•Sexual- -Medusa is normally the sexual stage with epidermal gonads - eggs and sperm released from medusa -Fertilized egg results in a zygote -Zygotes develop into a swimming larva called a planula -Planula "settles" on a hard substrate -forms a colony -new medusa are formed and they turn into an adult medusa •Asexual -Polyps normally reproduce by budding

what are choanocytes in sponges ?

•Types of Cells: -Choanocytes (or collar cells) - • interior line canals of the body; •flagella on the choanocytes create a water current that brings more food particles into the body "Collars" on choanocytes trap food particles