Post on 19-Jan-2018
description
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