Some Happy Sea CreaturesSome Happy Sea Creatures

By Margaret BarnettMary Jacobs

Hanuel Jo

Porifera Porifera (a.k.a Sponges)(a.k.a Sponges)

– No symmetry (asymmetrical)– Body is multicellular

Number of germ layers and coelom:Cells and tissues surround a water filled

space – is no true body cavity.

-2 germ layers: endoderm and ectoderm

More PoriferaMore PoriferaType of body development:-The larvae

– flagellated– swim freely for a short time

After settling down and attaching to the ground, the larvae develop into young sponges.

-All are sessile (live attached to something).

PoriferaPorifera

instead of mouths, they have tiny pores in their outer walls through which water flows.

have few tissues but no organs and a nervous system

Did you know?– Until 1765, sponges were thought to be plants because

they were so simple.– Chemicals from sponges are being used to find a cure

for cancer and other diseases

PoriferaPorifera

Reproduction: sexually or asexually

– Asexual reproduction occurs by budding or by fragmentation.

buds may remain attached to the parent or separate from it each bud develops into a new individual.

Most sponges are hermaphroditic, the same individual produces both eggs and sperm– in some species the sexes are separate.

Specialized tissues of PoriferaSpecialized tissues of Porifera Throughout the body of sponges, there are canals through

which water flows. The canals have openings to the outside, where the water enters

the sponge. – These usually small pores are called ostia – the pores are larger where the water leaves the sponge system

These pores are called oscula(singular osculum). – These canals are mostly lined with special flagellated cells called

choanocytes. Choanocytes filter small food items from the water such as individual bacteria.

skeletal elements called spicules: the cells that support the body

CnidariansCnidarians

Radial Symmetry Movement is coordinated by a decentralized

nerve net and simple receptors– If they are free swimming they have more

complex nervous systems For example eyes, a gravity sensing organ, and an

inner ear similar to the ones in vertebratesHave a sac-like body in two distinct layers

Cnidarians ContinuedCnidarians Continued

Gastro Vascular cavity- functions in both digestion and gas exchange

Two forms:– Polyp: cylindrical, sessile, the mouth is facing

upward, does asexual reproduction– Medusa: umbrella shaped, free swimming,

mouth facing downward, does sexual reproduction

Cnidarians Cnidarians

The tentacles contain cnidocytes that are cells which contain needle-like organelles called cnidae

Nematocysts are cnidae stinging capsules– Found on the end of the tentacles of cnidarians

Ctenophores Ctenophores (a.k.a.comb-jellies)(a.k.a.comb-jellies) • Ctenophore means “comb-bearer” • similar in appearance to cnidarian medusi • about 100 different species • 1-10 cm in diameter• Most are spherical or ovoid (egg shaped)• Each ctenophore has eight rows of comb-like

plates composed of fused cilia• the largest animals to use cilia for locomotion

Portuguese Man-of-War Portuguese Man-of-War ColonyColony

Not a jellyfish, it is a siphonophore Each man-of-war is composed of four types separate

polyps – One polyp makes up the gas filled structure called the

pneumatophore. When inflated, the pneumatophore resembles a Portuguese battleship floating on the surface of the water. The chamber can be deflated to allow the organism to submerge.

– The second polyp makes up the tentacles. Tentacles are an average of 30 feet long but can grow to a length of 165 feet. The tentacles contain nematocytes that sting and help capture prey.

– The third type of polyp, gastrozooids, surround the food and digests it.

Coral Reef Formation Coral Reef Formation

Coral reefs are composed of colonies of living coral organisms and limestone skeletons of dead coral

Reefs occur only in clear tropical saltwater (64 degrees) at shallow depths that allow for penetration of sunlight

Coral depends on a symbiotic relationship with the zooxanthellae, an algae that grows in coral tissue