2) and the strong radial ribs extending from suture to suture, which are widely spaced between one another (Fig. 1). Although difficult to notice at first, the ribs show slightly rounded knobs at their ventral end. BIOGEOGRAPHY: Through the analysis of the fossil morphological structures it is possible to deduce some interesting information about the organism habitat, mode of life and time period. For instance, the position of the keel, which represents the location of the siphuncle, clearly points to the placement of this cephalopod within the ammonoids clade rather then the nautiloides.
This alga attaches itself to the rocks by multicellular rhizoidal attachments, usually disc-shaped. The thalli begins its life as uniseriate filaments but this stage is eventually replaced by parenchymatous sheets of cells (1 to 2 cells thick). This is a result of intercalary cell divison or apical
WHAT ARE CORAL REEFS Coral reefs are underwater structures made from calcium carbonate secreted by corals. Corals are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps are like tiny sea anemones, to which they are closely related. But unlike sea anemones, coral polyps secrete hard carbonate exoskeletons which support and protect their bodies.
Figure 1: Coral reef trophic pyramid, showing its trophic levels. On each level, several important groups of species are shown (Diagram by Alex Rose). There are three categories of organisms in every ecosystem: producers, consumers, and decomposers. Producers, often referred to as primary producers, consist of organisms that are capable of making their own food and are consequently always photosynthetic (and in some cases chemosynthetic). Consumers are placed higher on the trophic pyramid than producers, and they can be herbivorous, omnivorous or carnivorous.
It lies dorsal to the coelom and under the brain and spinal cord. Its function is to allow the body to flex lateraly and keeps the body from collapsing when moving. This thin shaped rodlike feature is made of cells and fluid within rough fibrous tissue. A lamprey is a jawless fish and an example of a species with a notochord that serves as its backbone. Another chordate feature is the pharynx with slits.
Polyp discharges a hard skeleton that protects them from predators. The majority of corals have a symbiotic relationship with zooxanthellae, also known as algae. Algae
The Caribbean Coral Reef The world’s ocean is a very complex place, which many different organisms call home. Coral reefs occupy nearly 0.17% of the total surface of Earth (Bertness and Nybakken, 2005). They are one of the most diverse ecosystems found on Earth. Approximately 4-5% of all species are found on coral reefs (Bertness and Nybakken, 2005). A variety of fishes, invertebrate animals, and plants can be found on these underwater wonderlands.
The Osmoregulatory Abilities of Two Intertidal Worms, Nereis virens and Phascolopsis gouldii Author’s Name: ___________________________________________________ Biology Department, Hendrix College, Conway, AR 72032 Nereis virens, clam worms, are common marine annelids, which are widespread in the intertidal zone of many beaches in New England. They are particularly abundant in the upper intertidal zone (Fig. 1), where specimens may be found under rocks and in beds of mussels and algae. Phascolopsis gouldii, peanut worms, are another common worm native to the New England coast. They can often be found buried in silty or muddy areas in the lower parts of the intertidal zone (Fig.
What I find peculiar about the bull shark is its ability to live in both marine habitats and freshwater habitats. In general, being able to survive in both habitats is very uncommon for sharks. Aquatic organisms rely heavily on a process called osmoregulation that allows them to achieve homeostasis of water content within their body. Without going into too much detail on the specifics of osmosis and osmotic pressure, this process allows the organism to keep their internal fluids from getting too diluted or too concentrated. So you may be asking yourself, how does this apply to the bull shark?
Olive Ridley sea turtles, Lepidochelys olivacea are small, hard-shelled marine turtles, one of the two species of the genus Lepidochelys, and a member of the Family Cheloniidae. The adult turtle has a carapace of length 60 to 70 cm. They rarely weigh over 50 kg. It has hear-shaped carapace. Olive Ridleys get their name from the coloring of their heart-shaped shell, which starts out gray but becomes olive green once the turtles are adult.