Plant Adaptation to the Marine Environment Salinity in the water is the greatest challenge to which plants must adapt.

Submergent and Emergent Plants Submergent plants live entirely underwater – seagrasses for example. Must stay in the photic zone, therefore occur in shallow and sheltered water Unlike terrestrial plants, however, _______ do not possess the strong, supportive stems and trunks required to overcome the force of gravity on land. Rather, seagrass blades are supported by the natural buoyancy of water, remaining flexible when exposed to waves and currents. Hydrilla verticellata Eelgrass

Emergent plants live with their roots underwater, but with a significant portion of the plant growing above the surface – mangroves for example. Mangrove swamps are important to the environment: 1. They act as nurseries for adjacent marine ecosystems. 2. They filter runoff water protecting sensitive offshore ecosystems that would be harmed or killed by settling sediment. 3. They hold sediments in place. They slow waves and reduce erosion while retaining nutrients used by organisms living there. Other than producing food and oxygen, marine plants provide important habitats for other marine organisms.

Characteristics of Sponges Like all members of phylum Porifera, sponges aren’t very animal-like. Only have cellular level of organization Besides being multicellular heterotrophs, they have structural organization and different cell types. 1. 2. Sponges are ___________(type of suspension feeders)– the amoebocytes distribute nutrients throughout the sponge.

Porocytes = allows water to enter Choanocytes = Osculum Spicules = Spongin skeleton=

Reproduce asexually when a branch or buds break off Sexual reproduction is when collar cells in the gelatinous layer develop into gametes Gametes are released through spawning Developmental phases Early development occurs inside sponge Amphiblastula larva- planktonic larva surrounded by flagella Undergoes metamorphosis

(central)

Special Attributes of Sponges Sponge larvae are more animal-like than adult sponges because they are free-swimming organisms with flagella. The larvae swim and drift until they fix themselves in place on the reef and grow into adult sponges. Most sponges are tough and fibrous After being torn apart, Isolated pieces can regenerate into entirely new sponges.

Characteristics of Phylum Cnidaria Phylum Cnidaria includes soft and hard corals, sea anemones, hydroids, sea fans, jelly fish, and siphonophores. A.k.a. Coelenterata Significantly more complex than sponges Anatomical characteristics include: They are ____________________– symmetry around a central point. No head, front, or back They do have an oral surface (which open to a gut) and aboral surface

They have a mouth that opens into Specialized tissue allows them to swim, respond to the external stimuli, and engulf prey They have a cup or bag-like body made of two layers of cells, with tentacles around the rim. ____________________ The narrow middle layer usually contains no cells. This layer is ____________________. They have a mouth that opens into the gastro-vascular cavity (a space in the middle of their body used for digestion/reproduction). They are structurally uncomplicated, with simple nerves, muscle nets, and light receptors.

Individuals are free-floating and are called medusae. Colonial organisms are called polyps. ____________________. Individuals are free-floating and are called medusae. Some Cnidarians have both stages others have one Similar body plan: centrally located mouth surrounded by tentacles All share the ability to defend themselves with These stinging structures are composed of special cells called cnidocytes. Also used to capture and handle food

Almost all Cnidarians ____________________. The nematocysts are sticky and in some cases contain toxins Initial digestion is ____________________. ____________________.

They have no true brain but they do have nerve cells They are interconnected to form a nerve net They have primitive eyes Can tell if they are of the same group Statocysts are calcareous bodies in fluid filled chambers surrounded by sensitive hairs Used for balance

Special Attributes of Coral and Anemones The largest class in phylum Cnidaria is class Anthozoa, the coral and anemones. Members of this class are polyps that attach to the reef or other substrate. Coral and soft coral are colonial, anemones are individual organisms. Hard coral are the most ecologically significant thanks to the massive calcium carbonate reefs they build. They are sensitive to runoffs, fertilizers, etc. that can cause damage. When coral are stressed they become colorless. This is called coral bleaching – a sign of a diseased and dying colony. Soft coral and sea fans grow into tree-like structures built on protein skeletons. They are not reef builders.

Anemones have a mutualistic relationship with various species of anemonefish. The fish receive protection by living in the anemone and the anemone receives food from the fish.

Special Attributes of Fire Coral and Siphonophores Both fire coral and siphonophores belong in the class ____________________. Fire coral is one of the cnidarians that can sting humans. It gets its name from the mild burn you get from touching them.

____________________ exist as planktonic colonies, yet within the colonies are special organisms adapted to feeding, reproduction, movement and other functions. The Portuguese man-of-war is an example of this. Siphonophores can exceed 40 meters (131 feet) in length.

Special Attributes of Jellyfish The Portuguese man-of-war is in class ____________________. It is not a jellyfish. Jellyfish are members of class ____________________. Box jellyfish are members of class ____________________.

Comb jellyfish appear to be jellyfish, but are members of phylum Ctenophora. Comb jellies lack the bag-like cnidarian body shape. Unlike jellies they have cilia on their surfaces to help them move. They lack stinging cnidocytes.